Get 7% OFF your DistroKid membership: distrokid.com/vip/csguitars Running a valve amplifier without a speaker cabinet attached is a TERRIBLE idea! Find out the importance of loads and impedance matching with this helpful video .
I already know about this kind of stuff but I will always watch your video for a bit of a different description and see what you have to say (after all you have a masters in physics) that's exactly what I got keep it loud Colin!
CSGuitars Do you know why the term used is impedance and not resistance? Because from what I can tell they are the same but different name. Measured in ohms, uses omega, has the same formulas with current and voltage. Is it just a disparage between electrical terms and acoustics/speaker terms?
Impedance and resistance are very much different. Impedance can be expressed in two parts: a magnitude and a phase component. The magnitude is what we call resistance, that gives us the value in ohms. The phase is an irrational component mathematically speaking, which is a combination of capacitance and inductance. Both influential factors which cannot be ignored in the grand picture, although were only clutter when I was referring to the relationship to Voltage and Current. They were omitted for simplicity and not to cause undue confusion. Impedance is relevant for AC signals, the phase element being prominent in an alternating signal. When dealing with DC, the phase element reduces to zero leaving only the resistance magnitude. This is important to not because simply putting a resistor over the speaker output would not function as a dummy load on its own. Load boxes are carefully designed to not only match the resistance, but also the capacitance and inductance so that it represents an impedance accurate to that of a speaker.
hey Colin, how dyou hook up 2 cabs to 1 amp head? Ive seen some orange amps that have multiple 8 ohm outputs but have no idea how it would work for a stereo setup.
I'm an electronics technician, as well as an enthusiast for tube amps, and I can confirm this video is completely accurate. I couldn't have explained it better myself, good job!
Nah...Don't opt out that early. The simple concepts are not hard. There are very simplified videos out there. Stay with me... See electricity as a flowing river or a pipeline and you're sitting in a tiny boat in that river (You're an electron). That current can flow very fast or slow depending on the applied pressure. The bigger the pressure (voltage) difference between your starting point and your destination, the easier it is to get there. So the Volts decide how much water (current measured in Ampere) will flow. Now you know how fast and how much water will flow. If there is too much fast water flow (current), the river has to be able to take it. If you read on a power supply that it will work with 1.6 Amps, that's what your gizmo can handle. Give it more and you have a flood on your hands. If that happens really quick (lots of pressured water with no flood gates) you call it a short. With your water current you can power a water wheel. The more pressure you got or the more water you have, the wheel can do more work (Watts). W = V * I possible Work(Watts) = Water pressure (Voltage V measured in Volts) * amount of water (current I in Amps) Watt = Volt * Ampere So you read on your vacuum label something about 1600W. That is the maximum possible work that COULD be done with all the pressured water it pulls out when you plug it in. It says nothing about efficiency, but about the appetite for power that you see on your electricity bill. I doesn't say anything about for how long and how hard the suction will be. Back to the water wheel and the river flowing towards it: If there are lots of big rocks(ohms) in the river, the water current is slowed down and the pressure will change. That isn't a problem when the whole river has the same amount of stones in it and the pressure stays the same. If you lead a fast stream that had almost no stones in it's way into a river bed with lots of stones, it will be slowed down and a lot of possible work the water current could do at the water wheel got wasted on the rocks (ohms) along the way. If it's the other way around, the current will speed up and that could be too much to handle. The water stream doesn't like all that Resistance of the rocks. So if the river splits and there is one leg that has a lot less rocks, most of the current will flow in that direction. The least resistance would be a waterfall (ground) with nothing in the way. All the pressured water is pushing towards it. So if something is grounded, no current wants to flow through your body since the installed waterfall is the easier path. The ground protects you. So, was that so hard?
I think that it should be noted that some early solid-state amps do have output transformers (I own one), and are therefore also susceptible to this problem. The problem here is that these early amps often use transistors that are very obsolete and hard to find, making repair/replacement of burned out components even harder than for old tube amps. My opinion is that it's just never a good idea to use an amp without a load attached.
Buying a cheaper valve amp on my first go-round turned out to be a good choice. Over the course of 3 videos I've learned 3 very important things i didn't know at all about tube amps. Infinite thanks to you!
I don't have a clue what you're saying. I can understand your words, because I'm Scottish myself, but I am too dumb to understand the science lol. I get the point I need a cab attached to my amp though, which I never knew before, being a newbie to amp heads! Thanks man.
as a beginner this video is really helpful for me trying to understand a little more about how amps, amp heads and cabs work. thanks for the uploading this video!
Some guitar amps allow you to do this though. The EVH 5150 III being one of them. The designer himself said the amp doesn't suffer if you don't plug a load in while the amp is on. (Just don't plug a cable in without a cab, because then the switchcraft jacks don't short out the power amp as intended.)
Seems like it would be relatively easy to have some kind of safety feature which checked for the presence of a physical cable jack, and if one wasn't detected, it would prevent the tubes/valves from running any voltage through themselves.
Distrokid should hire you to make ads for them, that was by far the best ad I've seen so far 👍 Great and very important video, and thanks for teaching me how not to screw my amp!
when i was at school i played bass on school concerts for my music teacher (who buys and cares for the stuff) and when i set the backline for the upcoming concert i simply put my cheapest super thin instrument cable in the amp to connect the speaker. i had no idea. I turned the amp on, nice sound was coming out, i was like hell yeah that works. the amp (peavey 400w + 4x10) worked quite well actually, until my teacher came organizing stuff on stage, he saw the cable and completely freaked out. "Who put that puny ass cable in the amp???" and i was like whats the matter i did this and he was so speechless he couldnt even yell at me. long story short: the amp worked fine and was not damaged, i did not know what i did wrong and my teacher did not educate me properly afterwards. 10 years after that i finally knew what i did wrong when i first bought a head and cabinet seperately instead of a combo :D
well in reality...most amps will work for years if you use cheap instrument cables...it is allways the "CAN break" thing...but do not get me wrong..USE Speaker cables!
@@acekkkkkk if you don't go over the maximum current rating the cable will be fine. An instrument cable should still have quite low impedance although not wanting to open circuit a tube amp is understandable if the cable breaks. Or if the insulation melts and shorts the cable
@@acekkkkkk I am hearing "Another Brick in the wall" - it's funny what we didn't know we learnt at school - bit years later we realise we were told it ... Perhaps it didn't have time to sink in. In electronics I always had to bend the cables to a right angle. Blasted cables kept unbending ... Could never make a circuit in time. Years later - topological equivalence ... Doh! I only recently got a valve combo. Just been converting my solid state combos with Cliff jacks (all my speakers are 8 ohm and that the nominal load required by my valve amp). For the solid state tests I used a guitar cable ... Then I thought expensive tube amp ... Let's Google ...and who knew - better to be safe than sorry. £15 cable from trusted source in clashing colour on its way. Thanks to you bass teacher for the implicit lesson.
That is very well explained, which is why I like solid-state amps better, because you don’t have to worry about them so much, like how you do with valve tube amps, I still love valve tube amps, but I don’t wanna like not be careless about them and Destroy the amp, which is why I have a special amp that is good for both live and practice. It’s a line 6 spider V 30, It’s affordable it’s Distorted and it’s certainly worth buying
Great video! I always appreciate the accuracy in your videos. Better than the typical "it'll burn your output transformer!!!" stuff you hear repeated over and over again with no explanation or actually theory behind the statement. I'll have to share this instead of typing a novel trying to explain load matching to people myself.
So, in all these years, amplifier makers haven't thought of doing something as easy and simple as cutting current from some key components when a speaker is not connected? Wow.
You, Sir, explained these important things in such a little time! I learnt something useful not only for taking care of amplifiers. A rare thing in the videos I dig everyday. Thanks a lot!!👏
Very glad I watched this. New to tube amps and was about to get one without a cabinet, now I'm gonna save a little more and pick up a good cabinet to go with it
Nice vid, damn always wondered about this on valve amps......in RF we work on 50Ω out and 50Ω in. mismatch it on low power and you'll have issues. mismatch even with a 1 watt amp and P00FFFF. I'm wondering tho....in my world a miss match (like not plugging anything in), causes, pritty much, all the power send out to be reflected back. that is what causes the damage. PS: just be careful not to mix Resistance Ω with Impedance Ω Keep up the great work Colin
I have my Crate Power Block CPB150 150 watt amp head connected to my stereo Akai SW-155 speakers which are 8 ohms each and I have them wired in parallel which gives me 4 ohms for the pair. I also have a 250 watt car woofer at 4 ohms connected to the other speakers in series which gives me a total of 8 ohms. This setup sounds great and my wife is always telling me to "turn it down!" I have been relegated to the deck outside so I can practice. The Crate is a stereo amp with stereo effects loops. I can't wait to get a few effects pedals.
I'll have to check out your video on speaker cables vs. instrument cables. I have a combo amp and I've been thinking about getting a large cabinet to plug into it. Definitely don't want to do any damage. Thanks!☺
funny thing is..in old Fender amp manuals they allways said "Never run your amp without a cab, but what cab in what output does not matter...just try and use what sounds best to you" ;o)
This was very valuable video, just ordered new tube amp to replace my combo, and was thinking about testing it with audio interface while waiting for cab, but maybe i wont now 😅 thanks!
Low to high might not blow your amp up, but it doesn't provide the power to drive the speaker effectively. Certainly not a 'fine' solution. Always match the impedance is a much better rule to follow.
Well Low to High isnt always good. Like Colin said, dont connect a speaker at all is like "Low to Very Very High". But yeah given the common impedances what you said is right xD
I have a Boogie 50 cal combo and wanted to send it to a Marshall 4 x 12" cab with 16 ohms , my only option on the Boogie was sending 4 ohms to the Boogie combo 1 x 12" speaker and 4 ohms to the Marshall cab, it sounded weak , so I guess this idea is not going to work for my set up correct ?
Probably said but you can use a 4-16 ohm, 100-200 watt non-inductive resistor also know as a "Dummy Load" for troubleshooting or just warming up the amp. I sometimes install amps and use a switch jack for switching between the dummy load or speaker. So when no speaker is present, the dummy load will be engaged and once you plug in a speaker, it will disengage and the amp will play as normal. 2 caveats: If you do this you need to use a "make before break" jack and wire it up so the dummy load and speaker will be in series. If you have an 8 ohm dummy load and an 8 ohm speaker, the make before break switch jack will go to 16 ohm for a few milliseconds then back down to 8 ohms. If you have 8-32 ohm speakers you can get away wiring in parallel but don't do it with 4 ohms in parallel, you don't want it going to 2 ohms. You can do this with relays as well.
Thanks Colin! Would be good to take it to the next steps (primarily because I’m unsure!): How does running lower impedance into a higher impedance cab affect wattage? (Eg, what’s the difference in wattage between an 8 ohm, 100 watt amp into an 8 ohm cab VS 8 ohms into 16 ohms?) And for extra credit, because it’s entirely controversial/subjective, what’s the effect on tone? 8 into 8. 8 into 16. 16 into 16. Etc.
As explained in the video, matching the impedance between amp and cabinets provides maximum power transfer between the two. Failure to match the impedance means that either the speakers will not see the power they require to operate effectively, or there is an excess of power at the valves. In the case of the former your speakers will not drive as loud as they should and tone will be compromised, in the case of the latter you risk damaging your valves. I see no real reason for 16 to 16 sounding any different to 8 to 8 as they should both be getting the most power the amp can provide. The only difference would be in the speakers themselves. The difference between a speaker being 8 or 16 ohm comes down to the voice coil, what thickness of copper it is wound from and how many turns it has. 16 ohm will use thinner wire with more turns to achieve the higher impedance than the 8 ohm, and while in theory this difference points to a variance in frequency response and speaker sensitivity, it is likely too small to notice, and any variation in tone can probably be attributed to any number of larger factors. Potentially any two 8 ohm speakers of the same type could sound as different as an 8 and a 16. Also, speaker manufacturers will likely spend a lot of time and money to ensure that a particular model of speaker sounds the same no matter what impedance you choose.
16ohms vs 8 ohms vs 4 ohms. The 2 most common ohms rated CABS are 16ohm and 8 ohms. Some people say it makes no tonal difference what ohms you run and some people say it does. Alot of people love the oversized mesa cabs which are 8 ohms with vintage 30 speaker. The newer peavey cabs have vintage 30s and are 16 ohm rated.
nice video right there. i’ve left the speaker cable out once or twice for about several seconds :0, and quickly going f.... and turned of the amp. the amp still sound good so think i got away with this stupid mistake. i think the speaker cable should be the 1st to think about when connecting.
Another thing you should consider is the power rating of the amp and the speaker. Always make sure the power (watts) of the speaker is higher than the amp, otherwise you could blow out your speaker.
My take is to keep the impedance matched where possible - but if your amp manual says you can deviate then should be ok for your amp ... There again a mate of mine had some monitor speakers that blew. The manufacturer claimed he had been driving the hard (maybe) ... He referred them to the marketing blurb and owners manual "these speakers are.made to be driven hard" ... "We don't endorse that" - small claims court agreed with my mate and he got full refund. Red Bull now gives you Wingssss
I see a lot of people are asking about running a tube amp output into a line level input. You would need to RE-adjust the impedance. like the video explained, the hiZ tube output gets converted to a LoZ output via the output transformer. so now the world sees a LoZ output meant for driving a speaker. line level is higher-Z as it is a voltage signal with very little current SO you need something to RE-convert that LoZ back to hiZ. whatever your impedance matching device is, it still would have to be able to dissipate the full wattage output of the amp you wanted to direct-record. That's the theory, I'm sorry I am not up on the gear that might do this already
A few dags ago I accidentally turned my 5150 on without the cable fully pushed in the back of the amp. Took about a minute or so before I realized why I wasn’t getting sound. Didn’t harm my amp. Looked around some forums to see if maybe I caused some sort of damage that will show in time. Seems like a lot of us accidentally do this from time to time. The consensus seemed to be if it’s a relatively short period of time it’s probably ok but it’s like flipping a coin if it blows.
I was effraid because I use a Mooer Radar cab simulator on my Peavey 6505MH since one year, so I was looking for a load box to avoid my head tu burn. And them I asked myself : wow, it's amazing that this head is still alive. The 6505mh has a cab sim (awefull), and is equiped with a dummy thing in it, nice :D
FWIW, I would suggest it's also a good idea with solid state amps to have them plugged in before powering up. With speakons it's not really a problem, but if your speaker connectors are phono jacks, there's a chance for shorting the tip and sleeve. If this happens even momentarily while your amp is powered, you will damage it. Hopefully just a fuse, but maybe a mosfet or two. This is why speaker cabs usually have plastic jacks. I have seen sparks from someone unplugging an old cab (with metal sockets) while their amp was still on.
Unless you have a power-soak built in. :) I've been running my Hughes and Kettner without a cab for months (home recording mostly) and just recently bought its matching cab.
4:34 - 4:47 Is the absolute best thing I've ever heard someone say to explain exactly WHY not having speakers connected will kill your amp, and not just that it *DOES* kill the amp. Not an electrician at all. I grossly understand the concept of resistance, and slightly more detailed but still gross concepts regarding current type, voltage, amperage, and polarity (mostly just in context of ensuring I don't blow up any of my guitar pedals and/or studio equipment). However, I have always struggled to understand how the different parts of a circuit, or a guitar amp and speaker cab would relate/interact with each other with regards to impedance. THIS made so much sense though. -No cab = nothing to regulate the 'dumb' amp power components to stay within their power limits. -Amp see's nothing on its output and basically does the equivalent of an "I can't divide by zero" moment, and interprets it as a metric shit ton of resistance instead. -Amp components react by increasing their voltage draw to overcome this metric shit ton of resistance that isn't actually there -More voltage = More heat -Components continually get hotter at a faster pace than they can dissipate the heat, and end up far beyond their power/heat spec -Components fail -ampy no worky no more and is possibly on fire
So basically. valve amplifiers have severe separation anxiety, and when they are separated from their cabinet they panic to the point where they end up killing them selves, right?
I like all this. I knew about this. My first question is this. I'm a human. Sometimes humans make mistakes. So if I ever accidentally switch on one of my valve amps (Brent Hinds Terror & Rocker 15 Terror) when the speaker cabinet is connected to another amp, how much time do I have to notice my error, before any damage occurs? My second question is: from what you say about solid state amps, is it ok to connect my one or two 16ohm cabs to my Katana Artist's 16ohm jacks and disconnect the combo's internal 8ohm speaker (in order to get output at the 16ohm jacks) without powering down?
Attempting to amplify a signal with no speaker attached will certainly damage the output tubes due to arcing between the electrodes, but the main concern is the output transformer. Voltage spikes of 1kV and upwards appear across the primary and can break down the insulation between the windings, rendering the transformer useless. Also, conductive carbon tracks can be deposited on the valve socket, disrupting the operation of a replacement valve.
Is hooking in a cabinet necessary when using the valve amp with headphones ‽ I bought the bugera T5 recently (not received yet) , but I want the tube amp sound mostly for quiet play at midnight ; so I won't be wanting a cabinet hooked in or the bulk of it in my area , Is this gonna create a problem ‽
I grew up using solid state amps for about 30 yrs. Just recently I bought a used Hughes & Kettner 20th anniversary 20 watt tube combo. I usually play at bedroom volume levels. At the risk of sounding like an idiot, does this mean I have to use a cabinet with the tube combo?
What about preamps with interchangeable outputs, though? I have an Engl e530 preamp and I'm a little confused about it because the cabinet output can also be toggled to be a headphone output, meaning it won't be running through a cabinet at all - obviously. Is that different in any way?
Good vid! If you want to run your amp without a cab you can also use a loadbox like a Two Notes Torpedo Live. I had two amps not connected to a cab for a few minutes (because a cheap speaker cable broke and one time because a idiot unplugged my amp before playing a show) my amps didn't break and I still operate them with the same set of tubes so it's not that extremly dangerous to the amp as long as you don't do it all the time!
Amps will likely survive a few minutes of being powered on with no cabinet connected, but it's when you send signal through the valves that you will definitely destroy it. Playing guitar into an amp with no speaker is when things go very wrong. I will address load boxes in another video soon.
A good indicator if you've left your amp on (with no guitar or speaker plugged in) is hearing a massive hum from the amplifier itself. This is coming from the output transformer as its oscillating at an audible frequency and sounds quite scary, so turn the amp off.
I tried playing with the amp both times and they didn't blow up....I guess a good old Made in England Laney with military grade tubes can withstand substantial abuse ;) I also played a show with one of the cabs of the backline fullstack disconnected by some idiot, got terrible noise from the amp I couldn't figure out until after the show but everything was allright.
Hey Colin, I just turned on my Engl fireball 25 and no sound was coming out. I checked the ins/outs and FX loop; then, I realized that the speaker cable wasn't plugged in all the way in the head. This whole operation lasted about 45 seconds - 1 minute. The amp seems to be ok, but how much damage are we talking about? Thank you! 🙏
Ok. I have a chinese made johnson( the ones sold I believe at Costco with the wooden cabinet or looks like wood. The power switch is broken. I can repair it when I get the want to do so. My point is there are speaker jacks on back and two honey symphonic 12 in speakers in the cab. They are creamy when they get used for a few minutes. Can I just plug into the speaker jack on the chinese amp without turning it on like a cabinet. I haven't pulled the back off to see the wiring. This is not a Johnson millennium solid state a modeling amp. I will still ask but I think it is how the wires come from the speakers to the jack. Hey You are a good teacher for such a young man. Thanks for fun and informative videos. Stay on the high road. James.
Two things: 1. Why do modern amps not have some sort of savety mechanism for that? 2. How long does it usally take till damage occurs? Is it enough to just have the amp accidentally turned on for a second or two?
Once I was messing around with my valve head on, and I ended unplugging the speaker cable for about two seconds and nothing happened, my amp still works perfectly.
The safety mechanism is the fuse in the power tube path. Tube shorts, fuse blows, limited damage. Tubes are not that expensive (as long as you don't go for the NOS hype). The amp can usually take it for a while. It should red-plate for a while before the tubes go. Buddy of mine had a problem with a speaker jack during a gig. The thing just popped out. Took us a few minutes to figure out. Amp still works, but it will reduce the lifetime. You amp is not suddenly going to blow up.
1) Some amps use a switching socket to switch in a dummy load when no cable is installed in the amp. This does not overcome fuckwittery entirely if the cable is inserted in the amp, but not the cab....It's also possible to have the cable partially inserted and thus negate the dummy load while not seeing the cab load either. Make something idiot proof and a more highly skilled f'tard will come along. 2) How long is a piece of string. If the volume is set low and there's no signal going through, it may last a long time. The output transformer can act like an ignition coil in a car. Very high voltage spikes can occur. These can pagga the valves, or cause burn through in a winding, among other nasties. It can occur in an instant, it can take a while. If there is a spike, ie, a change in level, that's when things go bad quickly.
If the amp has a dummy load, as with the Laney IRT studio or the Marshall Origin 50 Head, you can use it without speaker connection, but carrefully read the manual first, to be sure or prepare yourself to go full RockNRolla !
Great video but have a question new amp day and switched on twice for a half minute not realizing the speaker cab wire was in the effects loop intead of the cab 16ohm socket will that damage it immediately in that short time
I'm pretty sure I have made that exact same shrieking noise Homer Simpson makes after realizing my amp is not connected and turning it on while waiting for it to warm up.
Here's a question for your next tata's vid - what would happen if you plugged a pedal into a speaker cab WITHOUT any amp? (such as a Moor preamp into a 1x12)
What about “safe mismatches” as stated in my Mesa mkII manual, these heads only offer 4 and 8 ohm options for mono In the manual it shows a 8 ohm output from the head will run a 16 ohm 4x12 or equal load and actually run cooler utilizing less of the power tubes as a “safe mismatch” They also mention to try moving from a 8 ohm out to a 4 ohm out from the head into a 8 ohm cab for a brighter punchier feel, I assume if it’s in the Mesa boogie manual it would be legit I’m more of a Marshall player and every 4x12 I still have is operating at 16ohms as the Marshall heads I own all allow for 4,8 and 16 ohm options, I also considered the Weber ohm matcher, any thoughts on that box?
Hey man I just got the EVH 5150 iconic 80 watt head and 4X12 cab. Is there any recommended speaker cable I should get? Sorry for the random question it’s just been awhile since I’ve had a real setup
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Running a valve amplifier without a speaker cabinet attached is a TERRIBLE idea! Find out the importance of loads and impedance matching with this helpful video
.
I already know about this kind of stuff but I will always watch your video for a bit of a different description and see what you have to say (after all you have a masters in physics) that's exactly what I got keep it loud Colin!
CSGuitars Do you know why the term used is impedance and not resistance? Because from what I can tell they are the same but different name. Measured in ohms, uses omega, has the same formulas with current and voltage. Is it just a disparage between electrical terms and acoustics/speaker terms?
Impedance and resistance are very much different.
Impedance can be expressed in two parts: a magnitude and a phase component.
The magnitude is what we call resistance, that gives us the value in ohms. The phase is an irrational component mathematically speaking, which is a combination of capacitance and inductance. Both influential factors which cannot be ignored in the grand picture, although were only clutter when I was referring to the relationship to Voltage and Current. They were omitted for simplicity and not to cause undue confusion.
Impedance is relevant for AC signals, the phase element being prominent in an alternating signal.
When dealing with DC, the phase element reduces to zero leaving only the resistance magnitude.
This is important to not because simply putting a resistor over the speaker output would not function as a dummy load on its own. Load boxes are carefully designed to not only match the resistance, but also the capacitance and inductance so that it represents an impedance accurate to that of a speaker.
Mada faka. Talk tpo much and not show anything
hey Colin, how dyou hook up 2 cabs to 1 amp head? Ive seen some orange amps that have multiple 8 ohm outputs but have no idea how it would work for a stereo setup.
Well explained Colin... For the sake of my amp repair business I just hope that none of it sinks in...
Best comment!
I'll try not to educate too hard.
Marcel van der Linden sneak
I actually love this comment ahaha👌🏻👌🏻👌🏻
Hahaha brilliant
Colin your accent made it harder to understand it
I'm an electronics technician, as well as an enthusiast for tube amps, and I can confirm this video is completely accurate.
I couldn't have explained it better myself, good job!
Nah...Don't opt out that early. The simple concepts are not hard. There are very simplified videos out there.
Stay with me...
See electricity as a flowing river or a pipeline and you're sitting in a tiny boat in that river (You're an electron). That current can flow very fast or slow depending on the applied pressure. The bigger the pressure (voltage) difference between your starting point and your destination, the easier it is to get there. So the Volts decide how much water (current measured in Ampere) will flow.
Now you know how fast and how much water will flow. If there is too much fast water flow (current), the river has to be able to take it. If you read on a power supply that it will work with 1.6 Amps, that's what your gizmo can handle. Give it more and you have a flood on your hands. If that happens really quick (lots of pressured water with no flood gates) you call it a short. With your water current you can power a water wheel. The more pressure you got or the more water you have, the wheel can do more work (Watts).
W = V * I
possible Work(Watts) = Water pressure (Voltage V measured in Volts) * amount of water (current I in Amps)
Watt = Volt * Ampere
So you read on your vacuum label something about 1600W. That is the maximum possible work that COULD be done with all the pressured water it pulls out when you plug it in. It says nothing about efficiency, but about the appetite for power that you see on your electricity bill. I doesn't say anything about for how long and how hard the suction will be.
Back to the water wheel and the river flowing towards it: If there are lots of big rocks(ohms) in the river, the water current is slowed down and the pressure will change. That isn't a problem when the whole river has the same amount of stones in it and the pressure stays the same. If you lead a fast stream that had almost no stones in it's way into a river bed with lots of stones, it will be slowed down and a lot of possible work the water current could do at the water wheel got wasted on the rocks (ohms) along the way. If it's the other way around, the current will speed up and that could be too much to handle.
The water stream doesn't like all that Resistance of the rocks. So if the river splits and there is one leg that has a lot less rocks, most of the current will flow in that direction. The least resistance would be a waterfall (ground) with nothing in the way. All the pressured water is pushing towards it. So if something is grounded, no current wants to flow through your body since the installed waterfall is the easier path. The ground protects you.
So, was that so hard?
blackcorvo does this apply to combo amps
It applies to all amplifiers with a valve power amplifier.
M W but do combo amps not contain an amp and cabinet
Impedance is actualy calculated is Henry, but ya you can convert it to SI units pretty ez
To get sound
Solved
Stop
Love you baby 😘
Ok
@Rudy Ayoub
Nice boy Colin changes shirt during ad so you can tell where it ends when you fast forward
Don't skip, watch his ad, -it's the most entertaining ad you'll ever watch.
Kenton Park nah
Kendall Lingard That’s the first thing I thought! lol
Legend
That’s what I thought, but also so he doesn’t have to re-record the ad if he uses it in another video.
I think that it should be noted that some early solid-state amps do have output transformers (I own one), and are therefore also susceptible to this problem. The problem here is that these early amps often use transistors that are very obsolete and hard to find, making repair/replacement of burned out components even harder than for old tube amps. My opinion is that it's just never a good idea to use an amp without a load attached.
Buying a cheaper valve amp on my first go-round turned out to be a good choice. Over the course of 3 videos I've learned 3 very important things i didn't know at all about tube amps. Infinite thanks to you!
I don't even sing/write music/play instruments. I just like the videos. And his accent.
"This vedio is brought to you by Destrokid!"
Sorry Colin, couldn't help it. I love your accent! XD
Admit it. You just wanted to be haired.
I like his accent also.
Destrowkedd*
Greeet Scot!!
Hey Colin, You should do a video about changing tubes yourself.
Coming soon
Yes please !!!
I don't have a clue what you're saying. I can understand your words, because I'm Scottish myself, but I am too dumb to understand the science lol. I get the point I need a cab attached to my amp though, which I never knew before, being a newbie to amp heads! Thanks man.
as a beginner this video is really helpful for me trying to understand a little more about how amps, amp heads and cabs work. thanks for the uploading this video!
Some guitar amps allow you to do this though. The EVH 5150 III being one of them. The designer himself said the amp doesn't suffer if you don't plug a load in while the amp is on. (Just don't plug a cable in without a cab, because then the switchcraft jacks don't short out the power amp as intended.)
Seems like it would be relatively easy to have some kind of safety feature which checked for the presence of a physical cable jack, and if one wasn't detected, it would prevent the tubes/valves from running any voltage through themselves.
Distrokid should hire you to make ads for them, that was by far the best ad I've seen so far 👍
Great and very important video, and thanks for teaching me how not to screw my amp!
And then some idiot still plugs a instrument cable to the back of a cab, saying "Its all good bruh" 😧
when i was at school i played bass on school concerts for my music teacher (who buys and cares for the stuff) and when i set the backline for the upcoming concert i simply put my cheapest super thin instrument cable in the amp to connect the speaker. i had no idea. I turned the amp on, nice sound was coming out, i was like hell yeah that works. the amp (peavey 400w + 4x10) worked quite well actually, until my teacher came organizing stuff on stage, he saw the cable and completely freaked out. "Who put that puny ass cable in the amp???" and i was like whats the matter i did this and he was so speechless he couldnt even yell at me. long story short: the amp worked fine and was not damaged, i did not know what i did wrong and my teacher did not educate me properly afterwards. 10 years after that i finally knew what i did wrong when i first bought a head and cabinet seperately instead of a combo :D
acekkkkkk call your teacher, say sorry. ;)
well in reality...most amps will work for years if you use cheap instrument cables...it is allways the "CAN break" thing...but do not get me wrong..USE Speaker cables!
@@acekkkkkk if you don't go over the maximum current rating the cable will be fine. An instrument cable should still have quite low impedance although not wanting to open circuit a tube amp is understandable if the cable breaks. Or if the insulation melts and shorts the cable
@@acekkkkkk I am hearing "Another Brick in the wall" - it's funny what we didn't know we learnt at school - bit years later we realise we were told it ... Perhaps it didn't have time to sink in. In electronics I always had to bend the cables to a right angle. Blasted cables kept unbending ... Could never make a circuit in time. Years later - topological equivalence ... Doh!
I only recently got a valve combo. Just been converting my solid state combos with Cliff jacks (all my speakers are 8 ohm and that the nominal load required by my valve amp). For the solid state tests I used a guitar cable ... Then I thought expensive tube amp ... Let's Google ...and who knew - better to be safe than sorry. £15 cable from trusted source in clashing colour on its way. Thanks to you bass teacher for the implicit lesson.
That is very well explained, which is why I like solid-state amps better, because you don’t have to worry about them so much, like how you do with valve tube amps, I still love valve tube amps, but I don’t wanna like not be careless about them and Destroy the amp, which is why I have a special amp that is good for both live and practice. It’s a line 6 spider V 30, It’s affordable it’s Distorted and it’s certainly worth buying
A perfect explanation. I feel like I owe you $, Colin. Thanks for all you do. You continue to fill in all the holes.
Well done my friend. I now fully understand something that had been wrinkling my brain.
Great video! I always appreciate the accuracy in your videos. Better than the typical "it'll burn your output transformer!!!" stuff you hear repeated over and over again with no explanation or actually theory behind the statement. I'll have to share this instead of typing a novel trying to explain load matching to people myself.
Great job with the ad transition.
It was also a great ad lol
Tons of love from Canada.
xoxo
So, in all these years, amplifier makers haven't thought of doing something as easy and simple as cutting current from some key components when a speaker is not connected? Wow.
FANTASTIC explanation. Always was curious as to HOW this is dangerous more than WHY you don't wanna do it, and you cleared that RIGHT up.Thanks!
You, Sir, explained these important things in such a little time! I learnt something useful not only for taking care of amplifiers. A rare thing in the videos I dig everyday. Thanks a lot!!👏
Colin continues to be one of the smartest and most helpful guys on RUclips!!
Very glad I watched this. New to tube amps and was about to get one without a cabinet, now I'm gonna save a little more and pick up a good cabinet to go with it
I swear, Colin, you're one heck of an educator.
Thank you.
Information on the point, no YT chitchat---- THX for this video , wish You all the best for Your music ;))))
This channel is really, really, really good
Nice vid, damn always wondered about this on valve amps......in RF we work on 50Ω out and 50Ω in. mismatch it on low power and you'll have issues. mismatch even with a 1 watt amp and P00FFFF.
I'm wondering tho....in my world a miss match (like not plugging anything in), causes, pritty much, all the power send out to be reflected back. that is what causes the damage.
PS: just be careful not to mix Resistance Ω with Impedance Ω
Keep up the great work Colin
I have my Crate Power Block CPB150 150 watt amp head connected to my stereo Akai SW-155 speakers which are 8 ohms each and I have them wired in parallel which gives me 4 ohms for the pair. I also have a 250 watt car woofer at 4 ohms connected to the other speakers in series which gives me a total of 8 ohms. This setup sounds great and my wife is always telling me to "turn it down!" I have been relegated to the deck outside so I can practice. The Crate is a stereo amp with stereo effects loops. I can't wait to get a few effects pedals.
Viagra fixed my impedance, now my loads are infinite.
volvoplz reading that comment with your thumbnail. Lol why i love the internet and youtube comments
Lol i farted ... pls don't get overloaded.
Pinoy keyboard warrior TMI
I'll have to check out your video on speaker cables vs. instrument cables. I have a combo amp and I've been thinking about getting a large cabinet to plug into it. Definitely don't want to do any damage. Thanks!☺
funny thing is..in old Fender amp manuals they allways said "Never run your amp without a cab, but what cab in what output does not matter...just try and use what sounds best to you" ;o)
This was very valuable video, just ordered new tube amp to replace my combo, and was thinking about testing it with audio interface while waiting for cab, but maybe i wont now 😅 thanks!
Another excellent clip, I stumbled across one last night now I'm jumping from one to the next.
Remember: Amp to Cab - Low to High will fly, High to Low will blow
so say, a 4ohm amp output to 16ohm cab- fine.
16ohm amp output to 4ohm- amp death.
is that right?
Low to high might not blow your amp up, but it doesn't provide the power to drive the speaker effectively. Certainly not a 'fine' solution.
Always match the impedance is a much better rule to follow.
Well Low to High isnt always good. Like Colin said, dont connect a speaker at all is like "Low to Very Very High". But yeah given the common impedances what you said is right xD
Most modern tube amps can actually handle a 2:1 mismatch up or down.
I have a Boogie 50 cal combo and wanted to send it to a Marshall 4 x 12" cab with 16 ohms , my only option on the Boogie was sending 4 ohms to the Boogie combo 1 x 12" speaker and 4 ohms to the Marshall cab, it sounded weak , so I guess this idea is not going to work for my set up correct ?
Thank you big time,That helped me out a lot.Im changing my tubes in my marshall and I’ve learned a lot about bias setting.
Hi Colin! Next, you could do a video on running multiple cabs and when 2 x 8 = 4
;)
Sidenote: you were right about DistroKid!!! Best way to finally upload my music!!
DestroKid
Highly appreciate you making this video. Most answers out there seem to be, "just because".
as an electric technician, i must say you killed it.
"PLEASE BUY MA MYUZIK!" 😂
Great vid, Colin. 👍🏻
I just wanna say that i love your ACCENT
Is it Scottish?
Probably said but you can use a 4-16 ohm, 100-200 watt non-inductive resistor also know as a "Dummy Load" for troubleshooting or just warming up the amp. I sometimes install amps and use a switch jack for switching between the dummy load or speaker. So when no speaker is present, the dummy load will be engaged and once you plug in a speaker, it will disengage and the amp will play as normal. 2 caveats: If you do this you need to use a "make before break" jack and wire it up so the dummy load and speaker will be in series. If you have an 8 ohm dummy load and an 8 ohm speaker, the make before break switch jack will go to 16 ohm for a few milliseconds then back down to 8 ohms. If you have 8-32 ohm speakers you can get away wiring in parallel but don't do it with 4 ohms in parallel, you don't want it going to 2 ohms. You can do this with relays as well.
Hi Colin, you've touched on solid state amps, but what about the hybrids with a valve pre-amp and a Class-D power amp? Keep up the good work, Cheers
The only thing that matters here are power amps, so hybrids with a ss power amp are fine without a speaker
Thank you for posting this vid. It is a treasure trove of information!
Thanks Colin! Would be good to take it to the next steps (primarily because I’m unsure!):
How does running lower impedance into a higher impedance cab affect wattage? (Eg, what’s the difference in wattage between an 8 ohm, 100 watt amp into an 8 ohm cab VS 8 ohms into 16 ohms?)
And for extra credit, because it’s entirely controversial/subjective, what’s the effect on tone? 8 into 8. 8 into 16. 16 into 16. Etc.
As explained in the video, matching the impedance between amp and cabinets provides maximum power transfer between the two.
Failure to match the impedance means that either the speakers will not see the power they require to operate effectively, or there is an excess of power at the valves.
In the case of the former your speakers will not drive as loud as they should and tone will be compromised, in the case of the latter you risk damaging your valves.
I see no real reason for 16 to 16 sounding any different to 8 to 8 as they should both be getting the most power the amp can provide. The only difference would be in the speakers themselves.
The difference between a speaker being 8 or 16 ohm comes down to the voice coil, what thickness of copper it is wound from and how many turns it has.
16 ohm will use thinner wire with more turns to achieve the higher impedance than the 8 ohm, and while in theory this difference points to a variance in frequency response and speaker sensitivity, it is likely too small to notice, and any variation in tone can probably be attributed to any number of larger factors.
Potentially any two 8 ohm speakers of the same type could sound as different as an 8 and a 16.
Also, speaker manufacturers will likely spend a lot of time and money to ensure that a particular model of speaker sounds the same no matter what impedance you choose.
CSGuitars Thanks Colin! Very much appreciated. Rock on! 🤘🏼
16ohms vs 8 ohms vs 4 ohms.
The 2 most common ohms rated CABS are 16ohm and 8 ohms.
Some people say it makes no tonal difference what ohms you run and some people say it does.
Alot of people love the oversized mesa cabs which are 8 ohms with vintage 30 speaker.
The newer peavey cabs have vintage 30s and are 16 ohm rated.
Already have all three of your songs Colin!!!
nice video right there. i’ve left the speaker cable out once or twice for about several seconds :0, and quickly going f.... and turned of the amp. the amp still sound good so think i got away with this stupid mistake. i think the speaker cable should be the 1st to think about when connecting.
Cheers Colin - always nice to know why my amp has exploded if I do manage to forget to attach my cab.
Another thing you should consider is the power rating of the amp and the speaker. Always make sure the power (watts) of the speaker is higher than the amp, otherwise you could blow out your speaker.
I read on Mesa Boogies website that if you hook up an 8ohm out to a 16ohm cab it’s a safe mismatch
Hughes & Kettner also. Worst case scenario is usually just more mids.
My take is to keep the impedance matched where possible - but if your amp manual says you can deviate then should be ok for your amp ...
There again a mate of mine had some monitor speakers that blew. The manufacturer claimed he had been driving the hard (maybe) ... He referred them to the marketing blurb and owners manual "these speakers are.made to be driven hard" ...
"We don't endorse that" - small claims court agreed with my mate and he got full refund. Red Bull now gives you Wingssss
Yeah. Always read the manual.
Fantastic video. Thank you again for the time you took to make it.
Colin's ad for Distrokid is the best!
I see a lot of people are asking about running a tube amp output into a line level input. You would need to RE-adjust the impedance. like the video explained, the hiZ tube output gets converted to a LoZ output via the output transformer. so now the world sees a LoZ output meant for driving a speaker. line level is higher-Z as it is a voltage signal with very little current SO you need something to RE-convert that LoZ back to hiZ. whatever your impedance matching device is, it still would have to be able to dissipate the full wattage output of the amp you wanted to direct-record. That's the theory, I'm sorry I am not up on the gear that might do this already
been wondering about this for a long time, thank you!
In regard to solid state amps - "This is much of the reason why the amps are so much cheaper." ...and lighter.
Great Video... good thing there is a option for playback speed :-)
That was informative, thank you very much!
A few dags ago I accidentally turned my 5150 on without the cable fully pushed in the back of the amp. Took about a minute or so before I realized why I wasn’t getting sound. Didn’t harm my amp. Looked around some forums to see if maybe I caused some sort of damage that will show in time. Seems like a lot of us accidentally do this from time to time. The consensus seemed to be if it’s a relatively short period of time it’s probably ok but it’s like flipping a coin if it blows.
How's the amp doing?
I was effraid because I use a Mooer Radar cab simulator on my Peavey 6505MH since one year, so I was looking for a load box to avoid my head tu burn. And them I asked myself : wow, it's amazing that this head is still alive.
The 6505mh has a cab sim (awefull), and is equiped with a dummy thing in it, nice :D
You've successfully made the mid ad watchable!
FWIW, I would suggest it's also a good idea with solid state amps to have them plugged in before powering up. With speakons it's not really a problem, but if your speaker connectors are phono jacks, there's a chance for shorting the tip and sleeve. If this happens even momentarily while your amp is powered, you will damage it. Hopefully just a fuse, but maybe a mosfet or two. This is why speaker cabs usually have plastic jacks. I have seen sparks from someone unplugging an old cab (with metal sockets) while their amp was still on.
recently bought my first tube amp and an oversize 4x12 and did not know that, thanks!
and its a DIY home workshop build, so has metal phono jacks
Thank you! Always answering the questions I feel too stupid to ask myself.
Unless you have a power-soak built in. :) I've been running my Hughes and Kettner without a cab for months (home recording mostly) and just recently bought its matching cab.
4:34 - 4:47 Is the absolute best thing I've ever heard someone say to explain exactly WHY not having speakers connected will kill your amp, and not just that it *DOES* kill the amp.
Not an electrician at all. I grossly understand the concept of resistance, and slightly more detailed but still gross concepts regarding current type, voltage, amperage, and polarity (mostly just in context of ensuring I don't blow up any of my guitar pedals and/or studio equipment). However, I have always struggled to understand how the different parts of a circuit, or a guitar amp and speaker cab would relate/interact with each other with regards to impedance.
THIS made so much sense though.
-No cab = nothing to regulate the 'dumb' amp power components to stay within their power limits.
-Amp see's nothing on its output and basically does the equivalent of an "I can't divide by zero" moment, and interprets it as a metric shit ton of resistance instead.
-Amp components react by increasing their voltage draw to overcome this metric shit ton of resistance that isn't actually there
-More voltage = More heat
-Components continually get hotter at a faster pace than they can dissipate the heat, and end up far beyond their power/heat spec
-Components fail
-ampy no worky no more and is possibly on fire
So, how fast would the amp be damaged if you didn't connect an cabinet to it? asking for a friend xd
5:16 modern ones, but certain older transistor amps did require output transformers, especially amplifiers that used germanium transistors.
Great and useful video, thanks Colin
Great video, loads of info, one question, can I use just one channel on a pa amp to power only one speaker, will I blow the amp?
So basically. valve amplifiers have severe separation anxiety, and when they are separated from their cabinet they panic to the point where they end up killing them selves, right?
Thanks, you saved my Fender Studio Bass. I didn't know that.
I like all this. I knew about this. My first question is this. I'm a human. Sometimes humans make mistakes. So if I ever accidentally switch on one of my valve amps (Brent Hinds Terror & Rocker 15 Terror) when the speaker cabinet is connected to another amp, how much time do I have to notice my error, before any damage occurs? My second question is: from what you say about solid state amps, is it ok to connect my one or two 16ohm cabs to my Katana Artist's 16ohm jacks and disconnect the combo's internal 8ohm speaker (in order to get output at the 16ohm jacks) without powering down?
Thanks - very clear and important!!!
Ironically I found out about this on my own on accident about 6 months ago, wish I'd seen this sooner XD
Attempting to amplify a signal with no speaker attached will certainly damage the output tubes due to arcing between the electrodes, but the main concern is the output transformer. Voltage spikes of 1kV and upwards appear across the primary and can break down the insulation between the windings, rendering the transformer useless. Also, conductive carbon tracks can be deposited on the valve socket, disrupting the operation of a replacement valve.
Is hooking in a cabinet necessary when using the valve amp with headphones ‽
I bought the bugera T5 recently (not received yet) , but I want the tube amp sound mostly for quiet play at midnight ; so I won't be wanting a cabinet hooked in or the bulk of it in my area , Is this gonna create a problem ‽
I grew up using solid state amps for about 30 yrs. Just recently I bought a used Hughes & Kettner 20th anniversary 20 watt tube combo. I usually play at bedroom volume levels. At the risk of sounding like an idiot, does this mean I have to use a cabinet with the tube combo?
Very helpful explanation.
Love this guys voice. I’m Scottish but was born in Philly. Not a great accent “Yo Adrian..”
Lively explanations. Subscribing.
What about preamps with interchangeable outputs, though?
I have an Engl e530 preamp and I'm a little confused about it because the cabinet output can also be toggled to be a headphone output, meaning it won't be running through a cabinet at all - obviously.
Is that different in any way?
Don't own a tube amp. Watched the whole thing including the add.
Nice work
Good vid!
If you want to run your amp without a cab you can also use a loadbox like a Two Notes Torpedo Live.
I had two amps not connected to a cab for a few minutes (because a cheap speaker cable broke and one time because a idiot unplugged my amp before playing a show) my amps didn't break and I still operate them with the same set of tubes so it's not that extremly dangerous to the amp as long as you don't do it all the time!
Amps will likely survive a few minutes of being powered on with no cabinet connected, but it's when you send signal through the valves that you will definitely destroy it.
Playing guitar into an amp with no speaker is when things go very wrong.
I will address load boxes in another video soon.
A good indicator if you've left your amp on (with no guitar or speaker plugged in) is hearing a massive hum from the amplifier itself. This is coming from the output transformer as its oscillating at an audible frequency and sounds quite scary, so turn the amp off.
I tried playing with the amp both times and they didn't blow up....I guess a good old Made in England Laney with military grade tubes can withstand substantial abuse ;)
I also played a show with one of the cabs of the backline fullstack disconnected by some idiot, got terrible noise from the amp I couldn't figure out until after the show but everything was allright.
Hey Colin, I just turned on my Engl fireball 25 and no sound was coming out.
I checked the ins/outs and FX loop; then, I realized that the speaker cable wasn't plugged in all the way in the head.
This whole operation lasted about 45 seconds - 1 minute.
The amp seems to be ok, but how much damage are we talking about?
Thank you! 🙏
You can alway plug in a resistor or potentiometer pad of appropriate value.
Ok. I have a chinese made johnson( the ones sold I believe at Costco with the wooden cabinet or looks like wood. The power switch is broken. I can repair it when I get the want to do so. My point is there are speaker jacks on back and two honey symphonic 12 in speakers in the cab. They are creamy when they get used for a few minutes. Can I just plug into the speaker jack on the chinese amp without turning it on like a cabinet. I haven't pulled the back off to see the wiring. This is not a Johnson millennium solid state a modeling amp. I will still ask but I think it is how the wires come from the speakers to the jack. Hey You are a good teacher for such a young man. Thanks for fun and informative videos. Stay on the high road. James.
I have a question about turning valve output to something suitable for line out (directly into pc)
Two things:
1. Why do modern amps not have some sort of savety mechanism for that?
2. How long does it usally take till damage occurs? Is it enough to just have the amp accidentally turned on for a second or two?
I'm aware that "mechanism" is not exactly the most accurate Term
Once I was messing around with my valve head on, and I ended unplugging the speaker cable for about two seconds and nothing happened, my amp still works perfectly.
The safety mechanism is the fuse in the power tube path. Tube shorts, fuse blows, limited damage. Tubes are not that expensive (as long as you don't go for the NOS hype). The amp can usually take it for a while. It should red-plate for a while before the tubes go. Buddy of mine had a problem with a speaker jack during a gig. The thing just popped out. Took us a few minutes to figure out. Amp still works, but it will reduce the lifetime. You amp is not suddenly going to blow up.
My amp saw momentary operation with no speaker cable hooked up. Still rips just fine.
1) Some amps use a switching socket to switch in a dummy load when no cable is installed in the amp. This does not overcome fuckwittery entirely if the cable is inserted in the amp, but not the cab....It's also possible to have the cable partially inserted and thus negate the dummy load while not seeing the cab load either. Make something idiot proof and a more highly skilled f'tard will come along.
2) How long is a piece of string. If the volume is set low and there's no signal going through, it may last a long time. The output transformer can act like an ignition coil in a car. Very high voltage spikes can occur. These can pagga the valves, or cause burn through in a winding, among other nasties. It can occur in an instant, it can take a while. If there is a spike, ie, a change in level, that's when things go bad quickly.
Phew, luckily for me, I'm in the 21st century where we learned, a long time ago, to use a modelling device, straight into the PA. 👍😁
If the amp has a dummy load, as with the Laney IRT studio or the Marshall Origin 50 Head, you can use it without speaker connection, but carrefully read the manual first, to be sure or prepare yourself to go full RockNRolla !
Well done Colin!
Great video but have a question new amp day and switched on twice for a half minute not realizing the speaker cab wire was in the effects loop intead of the cab 16ohm socket will that damage it immediately in that short time
Does this apply to a combo amp? Or just heads and cabs?
what about the amps i get for 100 dollars, do they need a cab or are they good to go cos they only support 10w
I'm pretty sure I have made that exact same shrieking noise Homer Simpson makes after realizing my amp is not connected and turning it on while waiting for it to warm up.
Me today, so Im here again
Here's a question for your next tata's vid - what would happen if you plugged a pedal into a speaker cab WITHOUT any amp? (such as a Moor preamp into a 1x12)
What about “safe mismatches” as stated in my Mesa mkII manual, these heads only offer 4 and 8 ohm options for mono
In the manual it shows a 8 ohm output from the head will run a 16 ohm 4x12 or equal load and actually run cooler utilizing less of the power tubes
as a “safe mismatch”
They also mention to try moving from a 8 ohm out to a 4 ohm out from the head into a 8 ohm cab for a brighter punchier feel,
I assume if it’s in the Mesa boogie manual it would be legit
I’m more of a Marshall player and every 4x12 I still have is operating at 16ohms as the Marshall heads I own all allow for 4,8 and 16 ohm options, I also considered the Weber ohm matcher, any thoughts on that box?
Hey man I just got the EVH 5150 iconic 80 watt head and 4X12 cab. Is there any recommended speaker cable I should get? Sorry for the random question it’s just been awhile since I’ve had a real setup