Two Six Pac's On The Bench
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- Опубликовано: 20 сен 2024
- Here are the AES Six Pac Audio Amplifiers. Both amplifiers are here for repairs and modifications. In this video, I will reverse engineer these amplifiers and provide a schematic for us to look at. Power, frequency response, and distortion specs for these Six Pac amplifiers will also be provided. We will locate a design issue, then I will show you the solution, and how to fix it. Learn about crossover distortion and vacuum tube bias. Lots of tips and tricks to amplifier design revealed in this video. See the "Carlson Super Probe" in action, and much more! To learn things about electronics that you won't learn anywhere else, go to my Patreon page. Click this link: / mrcarlsonslab
To learn things about electronics that you won't learn anywhere else, go to my Patreon page. Click this link: www.patreon.com/MrCarlsonsLab
Great video as usual, if you have any interest in speaking with the person who designed these his name is Dennis Had, who is also a ham radio enthusiast, call sign W4USR. He is still making a line of amps called “inspire”, that can be found on eBay. Blueglow Electronics also did an interview with him on RUclips. The “made in Apex, NC”on the back is what gave it away. He was responsible for starting Cary Audio, I believe these came sometime after that, but not 100% sure.
You're correct on the chronology. Dennis also founded a company called Dentron in the late '70s or early '80s. Made several impressive products. When that company folded, he founded Amp Supply, which also suffered a financing fate. His call in OH at the time was K8KXK. He the moved to NC, started Cary Audio, and changed call signs as noted above.
Hi Igor. Take what your saying to an extreme. The extreme would be one bad triode and one good triode within one bulb. The answer is quite simple.... Yes they need to be matched, and matched closely at that. There is a reason for 2 very accurate plate resistors rated at 1% 50ppm.
Mr Carlson's Lab Another great video, Paul. I couldn’t put it down. Thanks a lot!
73, de N9WHH.
Mr Carlson's Lab Thank you for the reply. I miss labeled the output tubes as EL 84s instead of EL34s. That's funny they named the smaller output tubes a higher number. Go figure. The small mod you did to more or less double the output wattage was great. I have a feeling I can learn a lot from your videos! Thankz
I think this is why the internet was invented. Thank you so much, sir. You are such an inspirational and beautiful, beautiful person. So much knowledge and experience, no insecurities, humble, not judgemental, specific to every detail without being condescending and most importantly always honest and sincere.
There's no other channel on youtube I enjoy more.
Thank you for you very kind comment!
Amen, amen and AMEN!
I've always told myself (imagined?) that I've worked on, designed and built so may amplifiers, tube and SS, but especially tube, that I can visualize pulsating magnetic fields and their couplings in a working amp, so naturally I was seriously enthralled watching your noise probe in action! Just WOW! what a great tool... what a wonderful invention. Kudos! and congratulations, and of course, thank you.
Cool vid. I appreciate how you didn't trash tubes or the manufacturer. You actually made sure you were as complimentary as possible.
I agree with you, eh. It shows maturity... as an electrical engineer.
I know that this will be way too long, but I feel compelled to say it. I find myself in amazement at Paul’s knowledge and physical skills. I have had a lot of experience along these lines. I am 82 years old, a military veteran (go 82nd Airborne) and for 35 years ran an electronics repair shop. Over that period, I worked with countless electronic techs and field engineers from various electronic companies like RCA, Magnavox, and Zenith. I was also a full-time hands-on tech doing service calls and bench repair on all makes and models of entertainment equipment including color TVs, stereos, security equipment, radios and electronic organs and keyboards. And, of course, I felt obligated to work on stuff for friends and family such as guitars and amps, dog fencing, and kitchen appliances. If it plugged in, we worked on it.
I had to hire many dozens of craftsmen and oversee their skills and knowledge. Paul knows more and can do more than anyone that I have seen. Plus, he can explain it in a unique manner. Do you realize how many college graduate EE’s cannot look at a piece of equipment and then draw a schematic and explain what each component did? Maybe one in a thousand has his depth of knowledge and skills. I don't know where he accumulated this knowledge, but it is amazing to me.
Paul, I think it would be interesting for you to make a video to explain where you got that experience and vast knowledge. How many years have you been working at it? Is it a hobby? Was it ever a full-time job? You seem to have a lot of experience with military and broadcast gear. Were you in military communications or have an FCC operators ticket? I see that you are a ham operator. What license level do you hold? I'm sure that a lot of your followers will find that information very interesting.
Congratulations once again on your amazing dedication, knowledge, skills, and techniques.
Thank you for your very kind comment Walter!
This is what my Electronics class is missing. Hands-on demonstration with the explanation and reason behind it. Not just a bunch of complicated formulas thrown at random.
👏
Mr Carlson you are an absolute jewel. There is virtually no other place from which to get a more advanced level of instruction. Almost everything out there is nothing but beginner level conversation. Also, you have all of the hallmarks of a fine electronics technician, especially your meticulous attention to detail and logically concice navigation through the diagnostic process. When I watch you do your work i almost feel like I am smart for a brief period of time. So invaluable are your instructions I promise to donate soon in some fashion to your cause as I hope others will as well. You deserve prosperity in return for your generosity to us. Thank you sir.
P.S. Please more guitar amplifier repair and modification videos.
I cannot say that I fully understand the vid.At the age of 74,I am struggling.But I love your vids Paul.Love to “Try” and understand your vids.But there is no one, on you tube or Patrion, who can explain electronics like you.Awsome.
Amazing stuff,I just learned more in 40 min than I have in 15 years of reading books.You really have a way of making things make sense.I keep meaning to sign up for Patreon and believe me I'm usually not a fan of doing so.But in your case its a absolute bargain.Thanks for all you do too.I cant wait to get time to finish watching the rest of it.
Fantastic troubleshooting. It's amazing how people designing things forget about inductance and magnetic fields. Just a little moving around of the filter made a large difference.
ESPECIALLY with the high impedance circuits that comes along with vacuum tubes.
The problem is we are swatting a fly with a sledgehammer. Khorns are the definition of a first watt speaker.
I drive mine with a 3/4 watt 45 set. Sweet with properly designed crossovers.
If you can drive 104db speakers with sixty watt push pull amps an make it sound good you are truly a god.
Btw, I really enjoy your channel and you are providing a great service to electric enthusiasts.tyvm.
Wow, Paul. This was better than a classic spy movie.
1959Berre they should make him Q on Bond that might be pumping his ego too much!
Paul started pointing to components, then caught himself, and grabbed an insulated pointer. I thought it was going to be a Pink Panther spy movie. Or, an ElectroBoom movie.
The man is phenomenal, not ID directed at all and very well socialized during middle childhood.
@@psient psient: hilarious assessment.
I remember as a six year old kid being given an old Heathkit W-5M Mono Tube Amplifier, I remember being told it was obsolete junk, My brother and I played smashy smashy. I regret that now after watching your channel.
When I went to school, it was in '99. Needless to say, I pretty much did digital electronics only. It ended me up at an engineering job dealing mostly with PLCs and writing software; not as exciting. Knowing nothing about tubes, you make very nice videos for an analog layman. I appreciate your videos, and hope you will continue to make them for the foreseeable future.
To draw a schematic as intrinsic as the one we see here, and find a place in it for all the parts involved with all separate sub-functions is just such an art! It could easily take anyone 50 attempts sketching and one might still not get it right.
I am always amazed at your knowledge, but even more impressed with how well you explain it.
I started in electronics when I was just 15 years old.My father was a TV Tech,and after only 3 jobs in my life I am now 62 years old.Great video Mr,Carlson,Steve.
Many years ago I worked with an amplifier manufacture, on final test, the toroidal mains transformer was rotated to obtain a hum null, (50hZ of course) much like you did with that choke.
To see minimum cross over distortion we used a 10khz tone and looked at the extracted distortion. One could very clearly see the glitch within the distortion which could be completely removed as the bias was increased. With total THD as low as 0.01% the cross ever glitch was almost the only visible distortion apart from low level noise. Needless to say this was a transistor amplifier!! Great video as always, thank you.
Thanks for taking the time to write Michael! Now the big question... how much feedback did that transistor amp have :^)
Well done Sir. I miss working with tubes. “Dip the plate and peak the grid” is burned in my memory. Please keep the art alive as long as you can. I regret that I will have to live vicariously through your above and beyond, excellent instruction.
Glad to have you here Rick!
This is by far one of the best electronic channels on YT, Your teaching skills are off the charts!
Thanks for your kind comment Mike!
I used to live a few blocks from where those amps were built and sold. They were always way out of my price range. Now I am in my 50s and finally, have them. Without attempting to open a huge rabbit hole... maybe it is all in my head but I still enjoy tubes over solid state.
i wish so badly i were younger....your teaching is the best there is!
Thank you for your kind comment!
Back when I got started in amateur radio all we had was the ARRL Handbook and whomever's advice you chose to believe. If a time machine is possible, I wouldn't be surprised if Mr (Dr.) Carlson could invent it! Funny that I didn't see your username before I started this comment!
I know nothing about electronics or valve tubes. I stumbled upon this video after looking up the numbers of some valves i have in a piece of art work someone made into a lamp to see if any of them could be suitable to make a guitar amp. Basically a desiccating jar filled with old valves and a light bulb in amongst them Cool effect. Anyway point is this is the most informative thing I've watched in i can't remember. Outstanding. Thank you for sharing. Im stuck here in New Zealand home Isolation because of the Covid 19 Virus. Will certainly be subscribing and watching more.
Paul, Sir Carlson of British Columbia, I hereby bestow upon you a knighthood for your services to electronic education. God bless you Sir Carlson. 😀
In my 66 yrs of electronics, I have NEVER seen information delivered like Mr Carlson can do it. He is a truly "NONE better". Not to mention he is a genius "extraordinaire". May Jesus bless him and his always.
And get this: I have taught electronics for 45 yrs; and much of what he teaches I have never heard, nor known, and that goes for my co workers. It is a pleasure to learn things in such awesome detail and understandable in such simplicity. Wow!
If I had had the test equipment that he uses and knows it from beginning to end, the untold agonizing hours I spent trying to find the "root cause" of the problem, would never have happened. He is innately gifted from Heaven as assuredly as the sun comes in the "marnin".
"After all you did purchase an amplifier not a signal generator" - tremendous :)
Always very good. Ya I learned my electronics the hands on blowing everything up first, then ask questions later method. Very cool to watch someone who's go it!
oh, wonderful
tube audio engineering with Paul
and unlike other RUclipsrs, without being condescending about "tube sound"
Thanks Max! I try to stick to the Facts. (ok... so that rhymed :^)
You're a consummate professional. It shows. Superb teacher too. Not that many like you.
@@MrCarlsonsLab "Jest the facts mam!"
Another awesome MCL vid. This was the coolest one yet IMO, I love when you get into the testing of audio gear! Whipping out the audio probe and everything! Hope everyone survived the ice storm with minimal damage, that had to be pretty stressful.
I know zero about electronics. I can find the circuit breaker box in my home and I know how to plug electrical cords into receptacles...and I can operate a power switch. But, I love to watch Paul's video because they are often like a good 'who-done-it' movie. You get to travel with Paul as he collects the evidence to find the miscreant part(s). And, he always gets the culprit.
just think about a hyper-fast fluid with magical, invisible fields that it stirs up as it moves, can kick you like a horse, stop your heart, cause brain damage and muscular damage, cause you to bite your tongue off, and burn you - then imagine that you can master and direct it to make your guitar sound awesome by making little, specific mechanisms with it, made out of chemicals that react by/with it well, that all work together to make what's called a "circuit," a "device," or a "machine."
also, imagine you can pattern or shape the flow to send messages between points... oh and the magic fields interact with each other (electric and magnetic fields [the electromagnetic force]).
I think that's pretty much it
I know just a tad bit more than you [about electronics] but a WHOLE lot less than Mr. Carlson or my dad [electrical engineer for Western Electric] or even my good friend Don Becker, for years an E.E. that I worked alongside of. I love how they all make it look so easy. [I was always a decent TECHNICIAN, but that's all.] I think this level of great insight into circuitry is at least a good part intuitive, and I mean that in a most respectful way. I always WANTED to be an engineer or electronics "genius" but never even came close. Carlson makes it VERY appealing -- downright FUN to watch. Maybe I can make the grade in the next lifetime....
This level is when someone loves a subject and studies and practices to a level where they are a master. Experience comes with practice over the years. Think of the generations of humans who have found these forces of nature discovered their properties and employed them. We truly stand on the shoulders of giants. In those valves we have heated metals spraying electrons through a vacuum shielded and guided and affecting the paths of other electrons amazing. I should study it more. Excellent videography and well presented sir.
Mr Carlson the owners two six packs amplifier is cool
I've been watching your channel for several years (?) now. I've gone from a complete novice to actually understanding (and anticipating) what you say in this video. Awesome.
That's great! Keep moving forward!
Thanks, you have explained this very well. I have a pair of Six Pac’s, stock with the factory upgrades to better resisters, caps, wire, and connectors. The bias pot is a problem; it’s so sensitive that just touching it changes the bias. They put out a ton of heat, and a re-tube will cost you. One sweet sounding pair of amps.
The bias pot on alot of amps are touchy like that. I like to replace them with sealed, 10 turn pots..👌
Choices....ugly rainy day here....had to choose between vacuuming/dusting or Paul's video. Paul's video won.....vacuuming can bloody well wait! :-)
Great video, thanks! I'm a recently retired EE that has been designing solid state electronics for 42 years, but I've gotten interested in tube design. I built things with tubes as a HAM operator back in my teens, but never designed anything. Videos like this are very helpful. I'd like to build my son a tube guitar amp.
BTW - They would get much more effective ripple rejection by placing the 1uF cap that's presently on the emitter of the voltage regulator on the base instead (or do both). The base is a high impedance, the emitter is a low impedance. It would also greatly reduce the momentary stress on the NPN, since there is a surge current into the 1uF at turn-on (depending on the rise time of the 400V B+ rail). Also, interesting that they didn't place any small caps across the series '5408's in the B+ rectifier to help equalize the voltage drop across them.
The location of the B+ filter inductor certainly is a poor and curious one.
Mr Salerno, there are many companies making complete guitar amp kits now. Mojo musical supply,Trinity Amps, Tube Depot,Stewart Mac Donald. Fender 5E3 Deluxe,5F6 Bassman,Ab763 Deluxe Reverb,Marshall JTM 45,1974 18 watt are all popular and great circuits.I warn you though. Your gonna fall into the rabbit hole and keep going. I'm not an EE but i started working on crusty old guitar amps full time in about 1982 and never looked back.Good luck. P.S. Antique Electronics sells chassis and boards.Schematic Heaven is a web site with tons of schematics and BYOC and General Guitar Gadgets sell FX pedal kits, a whole nother rabbit hole.
I am glad to see there are people that still know how to really work electronics and old school tube equipment!
You are the circuit whisperer. I wish I could see what you see when you look at these devices.
As a very amateur hifi hobbiest I find a challenge in the practical matter of comparing the schematic to the unit. Watching you do it is most informative. In fact your series to date is just super. I watch uncle doug and a couple other similar tube channels .... Top notch tube stuff for us tubers.
Thanks.
Paul, another great tutorial on the amplifier. You explained the science of this unit to a tee., Well done. Enjoyed every minute of it.
Thanks Buddy!
That amp kinda reminds me of the Ampeg SVT bass amp, six 6550 power tubes and almost 700 volts on the plates. They put out about 300 watts. The joke from my first job years ago, You better wear your iron jock cup when lifting it onto the bench. I love watching your videos, reading the listener comments and your response. Thank you sir.
Finally I got time to watch this, and it was worth every second! Funny that you are talking about hi-efficiency horn speakers and hum, when I am listening with my Altec Lansing monster with 105 and 110dB/w sensitivity :D
The INVERTER is the heart of any tube amplifier...........you are awesome. Since running into your channel earlier today I have my first integrated understanding of how a high speed switching supply works and I've been repairing them for over a decade. I really appreciate you posting this. I'm looking forward to more. One of my clients owns two monoblocks from NC that are coming in for service in a couple weeks. They have been here years ago. The bias (and standby) method is pretty different. I installed allen bradley multi turn trim pot with a locking shaft to avoid problems with the bias adjustment knob. Man, some of the parts and the wiring method, 100 Ohm screen resistors on all things pentode.......these look just like the monoblocks from North Carolina that have been to my shop before.
duuuuude!!! hahahaha I used the RV6 type but Damn!
What amazes me is all the research into making that a great amp has been undone with bad component placement like that..........its like going 90% of the way and then slap happy for the last 10%.......crazy stuff.
Yeah the design is good but the implementation looked pretty messy.
For being unscripted... You did an excellent job! I will be reviewing more of them.
Just a friendly FYI... The word is audible, not AudiAble.
He's a clever guy and good at showing things, like to watch these vids....
Thank you Mr Carlson, you said something in your video that helped me out a ton, thank you! We all wish we knew what you have forgotten.
I'm revoicing a Sunn amp into a high gain machine (with only basic skills) you showed me that I may be mistakenly utilizing my heater power supply in AC, not half wave rectified DC, thank you again!
Great Job Paul, this amp is a real beauty and your friend is a lucky guy, having you, working on his amp! Can't believe 1,5h are gone! I'd really appreciate to hear and see the final result. Many thanks for sharing this with us!
Thanks for your kind comment Ralf!
This right here, is exactly what RUclips was created for! Educational video's like this are invaluable.. More people need to create video's like this.. Thank you so much for wonderful and informative video Sir.
I know why the amplifier was humming! It didn't know the words :D
Bom bom tsssch.
This is why I keep my amplifier underneath a Singer sewing machine. Of course, bad puns like this one probably won't have anyone in stitches. It's about as funny as bobbin for french fries. I mean, I'm hanging by a thin thread, as I destroy the social fabric. My career has gone down the tubes, since I decided to live off the grid. I no longer pay rent; I pay space charge. Admittedly, I still have a lot on my plate.
That one was old whent the Dead Sea was a little bit sick!!
@@gyrgrls Nothing wrong with living off Grid mate.I set up a RAPS (Remote Area Power System) System for my oldies 20 years ago & it's still going strong. It's a Hybrid system and even has enough power for the small workshop and start 2 hp motors easily on top of running the house. The only thing is Batteries Die occasionally.
@@gyrgrls , So bad that it's good!
The 'Noise Sniffer' was a great idea & product.
- Yet another top class 'inside the case & mind' of Mr Carlson's lab.
.
Mr Carlson. I applaud you for doing this channel. It is the most informative channel I've come across in a Long time. I learn alot from you. Seriosly. It's like going to a classroom. Very serious stuff and no hassle.
Keep on doing what you do!
Thanks for your feedback!
As a high school teacher, I noticed he changes his tone... it's technical a-plenty.... yet his voice won't make one sleepy. Nicely modulated, eh.
A brilliant mod on the bias resistor. Absolutely necessary
Hey Paul! Thank you for another great repair video! As always, top-notch content!
Regards, Phil
Very nice job! I enjoyed every minute of it. The last time I built an audio amp was in 1962 so it's been a long time. I used large chassis with all power components far away from the input. It disturbs me that the "shield" side of the input is above ground. What preamplifiers have a sheild side that is not grounded. It's more like a balanced input, which I would have two inner conductors both shielded. Broadcast equipment audio running long distances use 600 ohm balanced input. I admit I am not up to par an newer equipment.
Thanks for another great video Paul! I would think about switching from choke input to CLC filtering for B+ with a full wave bridge rectifier connected to two 300v secondaries in parallel. This would allow to a) more effectively use both electrolytic capacitors with no risk of over voltage and b) greatly reduce hum and vibration from the choke which does not seem to fit for choke input application anyway. The risk of this mod is that some B+ voltage drop might occur which would be difficult to fix.
I'm baffled by the numbers of RUclipsrs that talks in a radio voice. Very unnatural. This guy is an exception for sure - thank you.
Great video! You check frequency response with the DSA without negative feedback against a dummy load. I think it would have been more interesting using a real speaker for that test because it would have introduced non-linearities (which maybe NFB would have corrected). Also at which output power was the plot performed?
Wow really illustrates why having the power supply in a separate chassis is a great idea,especially on a preamp. Not a cheap solution but you have all the room you need for a no compromise power supply. Great video.
I'm a bit late here. My first reaction at the beginning of the lecture was 'holly ... so much lab equipment, this guy must be very serious, maybe slightly nuts, why does he need so many scopes'. Definitely I would be in heaven with just a few of the lab pieces. This might be one of the best vacuum tube dissection video I have have seen. Strange, the designer(s) should be a bit more aware of magnetic coupling and other issues that you mentioned. But, many people this days usually own rather inefficient loudspeakers, my self included - maybe when they manufactured the amp it wasn't tested on 95dB+ 'real' speakers. A lot of people get a bit hyped up at prospect of purchasing tube gear. Not that I'm against tubes, but like you mentioned one should know what is he getting into, especially NOS tubes and tube rolling. I remember to use tube tester, because the Pro Audio place fixed a lot of tube gear, definitely a must for someone does for living. The probe is a really cool testing tool. Also some of Hi-end equipment back in the 80s, 90s had copper shielding or plating to fight RFI issues.
Those Scandinavians, always up to something in audio. I will watch more of your videos, well worth the time and very informative. Thanks.
"Why does he need so many scopes?" It's his equipment collection - like a personal museum.
"Strange, the designer(s) should be a bit more aware of magnetic coupling and other issues that you mentioned."
Why pray tell? What with the horridly and obnoxious, loud noise called music now, WHO in the pluperfect hallelujah cares? Huh?
Not to mention that the hum and the audio is so ensconced into noise and distortion from hell; that nothing could bring it out, but Jesus. Sad indeed.
With very sensitive spkrs, hum and other issues are noticeable between songs, or very low signal levels, say if someone listens to classical music. Not everyone cares about latest POP music. Plus it's a good design practice to make equipment as quiet as possible.
And, I absolutely admire the number of test equipment the man has in his lab. He knows his stuff and he's not afraid to correct the design of this particular product 👍. Sorry if I offended anyone.
This is why I always like your channel.
You always seem to know how to be careful enough to do the right thing.
This case is now the exception, and thanks you for this also.
No.1 ..... no words! Respect, Mr. Carlson!
Dr. Carlson is a walking encyclopedia of all electronics knowledge. Imagine reverse engineering an amp like this. Thanks for posting this Dr. Carlson
I watched for over over an hour and i thought i was only 20 mins in. Love Love Love your vids.
I can listen to this guy all day....Clearly and easily explains electronics. Good review / reminder / discovering electronic theory
Two six packs in 90 minutes! You Canadians! ;-p Very nice and informative. Thanks! :-)
I can already see that it's going to take me a week to get through this video - taking copious notes for the near future work planned on rebuilding my pair of Bogen Challenger AC220 amps - little 8W jobs: (4) ECL82, (3) 12AX7, and a GZ34 power tube. Hoping to make a very retro quadraphonic system out of them. Thank you for the thorough detail, Paul.
You're welcome Jeff, good luck with your rebuild!
A newbie to the channel and I enjoyed every minute, now in catch up mode :)
A "period of time" vs a period of sugar or period of flower. Glad you keep clearing that up!
The real question is: Is it important for you to know the exact period? Is that period important to other viewers, and would mentioning that period be important to them. Read the comments and see if you can find anyone else leaving a comment like yours.
Would be interesting to see the effect of copper shielding around the transformer coil for both hum and induction value.
maybe not copper but nickel-iron
I've added a copper shorting strap around power transformers. It reduced the external magnetic field and didn't change its operation at all that I could tell.
Thanks for making such great videos! I love how much detail you provide. You fill in every detail of the way you test things and then why and then what to look for. I typically have your videos on while I'm tinkering in the garage and I always learn something new.
You're very welcome!
Just brilliant, fantastic and accurate in every way! I shall see you on patreon !
See you there!
You just showed all of us a simple and safe way to check capacitors for residule charge. Thank You.
Another excellent video, Paul. Beautiful amplifiers and your narration is excellent and informative as always. 👍🏻
Top notch PhD coverage of an audio amp design from circuit to impact of layout.
For audiable - see audible.
LOL
You are the best educator I ever met. Thank's a lot for your interesting lessons here.
My pleasure!
One of the most well made and informative videos i’ve ever seen on youtube, and I’ve seen a lot of videos…
Best quality picture on RUclips
Great Video. The most informative I have seen on RUclips. The AES six packs were made by Cary Audio. Designed by Dennis Had. I own a Cary SA-280 more commonly Known as a V-12R. It is basically 2 of the 6 packs in a stereo format. The original input tube is a 12BZ7 with a 12AX7 as the first substitute. The other difference is no feedback switch, but it does offer a triode/ultralinier switch. 50W in triode, 100 in ultralinier mode.
I would like to see if you would be interested in doing a once over tune up on it.
I haven't seen where anyone figured out the 100W mod. Those EL34 can take up to 800V, so my guess is that you added a cap on the input side of the choke to boost the B+ voltage.
**We Have A Winner!** Good call Russell... about 22uF /900V (2 caps).... B+= 600V
Nice Russell, Paul even gave a clue (I see now) about adding that and the effect on the output.
I am sure that cap also would have reduced the hum from the choke. Why didn't you install it permanently?
Probably just a matter of using the 4 ohm out instead of the 8 ohm out. Fairly standard to see amp power out jump nearly 2x when going from 8 ohm to 4 ohm. This was one of the many specsmanship tricks from manufacturers to get their amp power ratings way up.
Not in tube amps
AES was the kit division of Cary Audio, and their products were all designed by Dennis Had. Over the years I had their phono amp, pre-amp, SE811 SET amps and then the Six Pacs. Never cared for the Six Pacs, but the SE811s were great.
Wow I love your your videos. I am an audio fan from way back. Tubes rule!
I was having such a bad day...following a bad weekend.
And then I saw this video was up...so much better now!
Glad to make your day better Gregory!
Wow... if you can’t find a Sam’s or a good schematic for your project just draw one of your own lol
Geeesh!!! that schematic is so good it looks almost original... I would not know where to begin to draw one of those for a large complete circuit such as this... maybe a small one but not in that detail as you have Carlson.
Finalmente ho trovato un canale che mi piace,sono cresciuto con le valvole. Bravissimo!!!
I instructed Mil Std 2000 Category "C" soldering, wiring, and electronic assembly, as part of my job - for 17 long years. When I blinked, and you changed views to the underside of the chassis, I couldn't believe the rat's nest. Proper lead dress, and component placement were in no way primary considerations during the design phase of these unit's implementation. Shielding and ventilation were never taken into account. I could see taking short cuts with lower end "get it out the door" type merchandise, but not with anything sold with the intent of satisfying fussy audiophiles.
Soapbox dismounted before going on a "pride of workmanship" rant. (sorry, I'm becoming an "habitual bitcher" - as I age like 'milk'.)
It looks like they focused on component placement on top of the chassis and did the wiring as a bit of an afterthought. You are right in that very fussy audiophiles would probably develop an eye tumor after seeing the lack of regard to the separation of AC, B+ and C- from input and output audio.
+Tisha Hayes, many thanks for the reply, as I'm normally not one who tries to be critical about the work of others. With that said, I've had Mcintosh equipment apart, and initially figured that the two brands are "somewhat on par" stylistically. What I believe to be the case, is that AES developed a stellar design for the "Six Pac", and failed to follow the quality of design - through implementation and production.
AMStationEngineer the whole design seems a little ridiculous to me... Using an entire el84 and multiple chokes to regulate things, but then letting it out the door with significant coupled hum. Plus, going through all that work, having all that weight of iron, and that much moneys worth of glass, and all that heater amperage baking your room, all to push only 50 watts out of all that gear.
I guess that kind of clean linearity over such a (very excessively) wide bandwidth is nice to have though. But seeing how ugly it is inside and the clear design fail on that choke is troubling.
You certainly aren't the only one that said "what a ratsnest!" as soon as he took off that bottom cover. I was building better laid out ultralinears when I was 12 (admittedly at my father's direction) than the underside of that thing. But what really bothered me about the design was that loose knob to set the bias, without a locking ferrule or screwdriver adjustment.
+I Wilton, My high school electronics teacher would've talked three other teachers (of unrelated subjects) into failing me for the year, had I wired something like this. They "pretty'ed up" the top side, and didn't give a damn about the bottom. I am admittedly not an audiophile anymore. Age, and years of working concerts, and around jet aircraft took care of that a few years back, however, my component rack was "harnessed", anything capable of noise emission was shielded (and ferrite beaded). When I sold that equipment, I recouped most of what I had in it. It may be that we are living in too different a time, and are inordinately 'fussy'¿?
Love the way you explained the circuit. I learned a lot from this about tubes and what the different elements in them do.
Glad you enjoyed it!
Absolutely glued to this video for the whole time, really informative and interesting and a great explanation of how it works .what is the drive voltage for the audio input for this type of amplifier, I would guess around 3-500 mV?
Since there's no input pot or tone/gain control circuitry and a real pre-amp stage I assume that it has the gain set for a line output device to drive it. A line input level electrical signal typically has a voltage ranging from 0,3 to 2 Volts
I watched it as a thriller! Perfect! Clear and visible explanation! Thanks! Good luck!
To me it looks like the power supply filtering was never quite optimized in the design phase of this otherwise high performance amplifier. Clearly the ripple current trough the reactor is too high and the reactor is not correctly physically oriented related to the output transformer.
I have an idea that redesigning to a lower ripple and re-orient the reactor, still located same place, would do almost the same as you moving it away from the input section out to the side.
Moving the capacitor connection directly to the diodes through a low ohm current limit resistor, and then connecting 2 smaller capacitors in series on the output side of the reactor, would possibly get you close to the same result.
But it would save you a major physical rebuild.
There is a tremendous amount of knowledge in this video! Just what the doctor ordered! Great job Paul thank you!
Glad you enjoyed it!
Would have like to see the final arrangement inside the chassis after you were done?
Seconded!
+1
Here: ruclips.net/video/JPm5eQdJm38/видео.html
Thank you, this amp configuration is similar to my old Ampeg SVT bass amp, which uses (6) 6550 output tubes. These amps running Klipsch corner horns would be like standing in front of the main speakers at Woodstock.
Whew! I thought you were going to electroboom yourself for a minute there. This video is Awesome!
Thanks for your tutorial on vacuum tubes amplifier ..it is definitely the simplest way to understand troubleshooting and also how to use basic instruments in a lab.
Where did the time go? Once again you have done an excellent job on this video. Perhaps as a follow up (sequel?) you could show us how and where you got that choke reinstalled. Secondly I wonder if you could include the description of the operation of the phase inverter tube circuit. Finally I wonder if a metal shield could be constructed around the choke as well as rotating it's mounted position. Again, very well done!
Excellent video on what is likely a common problem with many of the lower priced tube amplifiers and amplifier kits.
Hmmm. Did you simply throw that switch on the back of the amp to the 4 ohms position to get 100W out of it? Great video as always, Paul! A joy to watch.
NO... But good try!
My guess is you shorted out the 22k resistor in the feedback loop. Or just dialed the bias way too hot. There is no harm in a little redplating for a good show-off =P
I don't know much about electronics, but I recognize an expert when I see one! Very interesting indeed.
Love it!
Brilliant work young man, a few things you can do to this amp:
Build a small 555 and thyristor circuit and introduce an automatic standby this will limit current at switch on, a hum balance in the output bottle filaments is also good, i cannot see if the filament wires are twisted also a good measure. I would suggest when biasing try and apply a 1k sine wave into the front end run the output into a dummy load and crank up the gain then reset your bias limiting your crossover this is rarely done but essential. You’ll need one of your good sig gens with a high output voltage or drive the input with a preamplifier.
On another note I have over 80k of circuits a lot of the gear you look at I have original schematics just a quick email and I’ll slip you what you need! A very informative channel keep up the good work your sure to be inspiring the next generation of tech heads.