Finally! I really appreciate that you used a looper for the shootout. It removes the player's playing style from the equation, which is the only fair way to do a shootout. Players are influenced by the sound they hear coming out of the speakers, and play differently no matter how hard they try to play exactly the same way every time. Well done!.
V1 and V2 determine gain on clean and OD channels. V3 is the cathode follower (OD channel tone stack). V4 is the phase inverter. To tame the OD channel and retain the clean, put a 12DW7 in V2. A 12DW7 is a 12AX7 on the Clean channel side and a 12AY7 on the OD channel side. 12AT7 in V4 helps tame the OD channel as well. After a lot of research and experimenting, I run my DSL like this V1=Genelex Gold Lion 12AX7, V2=NOS RCA 12DW7, V3=TungSol 12AX7, V4 = NOS RCA 12AT7. Clean channel keeps it’s depth and character and still breaks up nicely around 6. The OD channels are tamed and lose the fuzzies. V3 has the least amount of impact on the gain but does impact the effectiveness of the tone controls on the OD channel quite a bit. Keep this one as a 12AX7 for sure. Anything weaker than a 12AX7 in V1 ruins the clean channel IMO.
5751 has the same plate resistance as a 12AX7 and is DESIGNED to replace it with less gain. 12AXU and T and Y all have different plate resistance, which your amp is likely not designed for. :)
Timely video! I just rolled tubes through all slots of my DSL100. I have a handful of ANOS tubes to play, but I ended up with: v1 - early 60's GE 12ax7 long plate, v2 - JJ ECC803s (long plate version), v3 - 60's GE 12ax7 grey short plate, v4 - 60's GE 5751. I run KT-77's in the power section. The combo of the JJ and the 5751 in the PI really smoothed out the gain and made it a really sweet sounding amp.
I love the 12au7! After much research, I put one in a my orange micro dark and it gave me almost exactly what I wanted. More head room but I was still able to rock out when I wanted to.
When I used real amps I always liked 5751 in v1. Mostly to smooth out the The gain sweep The 12au7 in v2 was really good in this. Thank you for taking the time to do this.
I go with NOS Jan Phillips 5751's in all but the phase inverter, that I use a balanced 12ax7. It gives me a little JCM 800 vibe and cleans up nicely while still having more than enough gain available.
Thanks for the video, on my MT15 I am thinking of swapping a 12ax7 for some other tube like 12at7, 12au7 or 5751 to have more control over the gain and you showed me that it works like a charm.
What about a 12ax7a vs a 12ad7? With a tube swap? 12ax7a, then 12ad7, and then a mixture of both? There's nothing on the 12ad7 vacuumtube on RUclips. Thanks if you do it.
Edit: TL;DR These High Gain DSLH/ HR amps are absolutely incredible. The problem is a lot of people dont ever get to hear how good they sound cause all the magic is crammed between the gain on 4 or lower. Especially since most of us use high gain pickups. But if you keep the gain low, then use the preamp volume to add character (higher volume= fuller bassier tone, lower volume= thinner brighter tone) then use the master to bring the over all volume up or down to match the environment and get the amp right at the sweet spot where it starts pushing those power tubes then i guarantee youll fall in love with what this amp has to offer. It can do absolutely any tone you want it to but since the gain has to be kept so low dialing it in can be unconventional at times. Which i truly believe is what causes less skilled players to miss what a great amp this is. If you know how to dial in tone, like really know how to do it by ear not by memorizing settings then this amp is just as good tonally as any other Marshall on the market. But if you dont understand how your amp works and what causes it to sound the way you want it then youll likely have trouble dialing in this or any other amp. Shit my TL;DR was longer than my original post lol. I feel exactly how you did about my DSL100HR. It sounds great but the gain is so high its not as variable as id like. The Crunch channel and OD2 Channel are effected by this the most. Throw in the fact i use a Fishman Fluence set in my 7 string and Seymour Duncan Jb / 59's in my six and youve got high output pickups just exacerbating the problem further. Its a great amp and i absolutely love it but ive noticed when im rolling the preamp tubes i have i always prefer the lowest gain jj in v1 and then my second lowest gain mullard cv4004 in v2 and so on. If i use the higher gain Mullard in v1 its just way way to full and lends itself to providing more evidence that what i need is a lower gain preamp tube, or a few lower gain preamp tubes. I think what ill try first is a 12at7/5751 in v1 with the low gain jj ecc83 then the mullard cv4004 in v3. Im not as concerned with the phase inverter. It sounds really nice an full with a higher gain tube but more manageable with a lower gain tube so either way im happy.
I am a huge fan of the 5751 having done this experiment myself last year. However, something I noticed right away was the tone stack. Because tone stacks are tube-driven, putting in a lower-gain tube will give the tone stack less dynamic range, so while your volume and gain knobs become more flexible, the EQ knobs become less flexible. Did you experience this with the DSL50? I never got around to putting 5751s in my DSL50 when I owned it, but when I was doing recording with the Ultra Gain channel my solution to "tame the gain" (if you will) was to simply roll back all the EQ knobs to 0, and then I put a Boss GE-7 in the FX loop to do the precision tweaking. Give it a go and let me know your results!! I'm curious.
Wow what a massive difference.. i never would have imagined I would like the au7 over the ax7.. but i do.. crazy.. thx for that comparison.. i gave a jvm 410.. im considering swapping out
Awesome tube rolling demo, the best I've seen on RUclips so far! Can you please, if you have time, do a similar video using a Dual (or Triple) rectifier amp? Some said that a 5751 would make the bass knob more usable, when used in the PI position. Thanks and keep up the awesome work!
I just got a jcm 900 high gain dual reverb and its pretty harsh cranked up so I’m trying to see how to smooth it out without converting it to EL 34’s , its got all just pre amp and Sovtek 6L6 power
Also the 12AT7! You can get really down the rabbit hole with tubes. But, I find most amps designed around all 12ax7 preamps (IME, most guitar amps in general) to sound best with all 12ax7's. It's just how the circuits were designed - around those particular valves. But, some amps do just sound better to your personal ear with a swap in a certain spot. I really like a 12AT7 in the phase inverter of one of my amps, because the early stages do a lot of the overdrive work, but it keeps the power section more crisp and articulate in a really pleasing way. In others, a 12AT7 just neuters the sound and sucks. Here's a short guideline to these tubes' gain though if anybody is wondering: 12AX7: 100% 5751: 70% 12AT7: 60% 12AY7: 40% 12AU7: 20%
Exactly what I was looking for, thanks mate! I've recently bought a bargain fender super 60 red knob rack for 50€, and the overdrive on this amp is face melting. I want to tame it with those 12au7. For all of people interested in the difference between 12ax7 and 12au7- the 12ax7 has gain factor of 100, and 12au7 only 20. That means that it's 5 times less "gainy" than 12ax7. Lesson here- before you decide to sell the tube amp you don't like experiment a little, you might be surprised :-)
Thank you for another inspiring and thorough clip Leon! This is my conclusion about/experience with JJ ECC83S. This is a very gainy tube, more than most other ECC83 or 12AX7’s I believe. It is a fantastic tube to have in V1 position to bring some saturation and smoothness to the sound. But my experience also says that it is preferable to use or experiment with other tubes in the other preamp positions. An example, I bought a JCM 2000 DSL100 from 2008 last weekend. Still stock Marshall branded tubes in it. I changed to JJ ECC83S in V1 position and the amp became smoother, less harsch and more sensitive to playing. Then I put JJ ECC83S in other positions but that just made the amp mushy and less defined. Same thing with my Carvin Legacy VL100. JJ ECC83S in position V1 made the difference from kind of lifeless and stiff to saturated and smooth. Cheers!
It’s always good for any tune amp to get a Nos GE 5751 greyplate, and a EHX new 12ay7 to compare. Just my opinion depending on your amp breaker’s up. I have a Sky King on Humbuckers! It breaks up at 2 1/2 volume but is loud. A Tele I can go to 4 or so. With a 5751 I can push to 3 or so but the Nos 63 tube does change a bit. A new 12ay7 just sounds like a stock x7 but lower.
Having built several DIY valvecaster pedals, which run on a 12au7, I tried a Brimar 12BH7 tube (longer tube than the 12ax7, 12au7, 5751s etc,) and it has a beautiful tone. There’s plenty of them on eBay. Forgive me if it wouldn’t fit in that amp, but definitely worth a try if you can get your hands on one.
Love what the lower gain tube does for the red channel. Just what it needs. Problem is it sounds like it neuters the green channel quite a bit, and that is my main playground on this amp. But it also sounds like the red channel can get into that territory now. Does in make the early sweep of the red channel less compressed and more touch sensitive like the green channel?
I have a Crate V30 with three 12AX7 tubes in preamp. Sounds like a million bucks, but the volume knob and the gain knob are too sensitive and all the action is between 1 and 4. I will try 12AU7 to see if I can make it more adjustable for low to medium volume playing! Great video, thanks for the inspiration!
I have a DSL50 thats currently being repaired at the shop, but I also have a JCM900 SL-X 2500 and this has got me really thinking about trying that on it. It's a great amp and tons of gain, but some people have cited it as too muddy in it's gain. So doing what you've done here on that one has really got me wanting to try this on that. A fellow in a message board mentioned taking V2 and swapping it to a 5751 to give it more headroom and take some of the grit down. But using a 12au7 like you did here seems way more logical. Screw it, I'm gonna order a couple and give it a whirl!
I did the exact same thing about 10 years ago went with a 12ay7 in v2 and a NOS 5751 in v1. I also did a really simple mod that removed some of the brightness from the red channel. Good to know someone else was on the same page as me.
i have a jvm 205h and want to try 5751s....which preamp tubes are involved in the gain staging? I was surprised at the choice to just substitute 1 alternate tube (say 5751) in various positions versus trying all 5751s for the 4 preamp tubes? anybody do anything like that?
Actually if i m reading it correctly, i think the schematic for the 205h indicates the first 2 tubes (labeled V6 and V7...does this correspond to position 1 and position 2?) are the ones involved in the various green, orange, red gain switching selections.
I agree about the 12AU7 in slot 2. I ordered one as an experiment with my tube pedal last week, but it's not here yet. ....patience! So what's your guitar setup? Looks like a P90 at the neck.
Many good responses here, Just to chime in on the obvious. in the past i found a article saying that 12AU tube has about 80% less gain than the 12AX cousin. i have been using 12AU in V1 of a 18 watt amp i built. Input 1 uses half of V1 and is a bluesy channel that likes pedals, Input 2 uses the other half and cascades it into V2, that is kind of a crazy gain channel and don't like pedals. even if it shares the same preamp its to very different inputs. I like your conclusions and i applaud you for not hyping all the craziness about brands, gold pins, NOS tone mojo and whatever the tube cork sniffers are obsessed with ;)
I like the 12au7 in v1 from this video. I'm a huge fan of 5751's but I like them on a clean amp set up more than for overdrive or distortion applications. Thanks for the video!
Great! Very useful review...I heard exactly the same as you ...can't wait to change V2 for a JJ12AU7. Hopefully the red ch will sound more like my beloved JMP-1 Midi preamp (od ch-2) now. I will also try a 12AU7 in the Blackstar HT-Dual and DistX pedals...
With my DSL401 I only use the clean channel, the rest is all pedals. In clean channel (V1) the 5157 I put in made about the same impact as your 12AU7 in slot 2. Way more control and headroom. When you drive in the gain stages (yellow and red) a 5751 indeed made almost no difference. But for those who wonder about the clean channel… and preamp tubes in general 12ax7 = gain factor 100 5157 = gain factor 70 12at7 = gain factor 60 12au7 = gain factor 20
Thanks very useful. I have the same problem with an old Fender Roc Pro 1000. Way too much gain for my taste. I have just ordered the JJ5751, which I hope will drop the gain about 30%. However, if it doesn’t my mate has a 12Au which as you demo here really drops the gain. Cheers!
@@darkforest33 V1 on the Fender deluxe AB763 going from the 7025 to 12AT7 jacks the plate current from ~.9mA to 1.3mA an increase of around 45%. Now I haven't measured the flow on effects but if it were me I'd want to know a little more before plug and pray valve changing. I don't know whether Marshal are red star tractors like Fender but maybe talk to an amp repair guy first. One that's not hoping to see your amp in a few months.
I did this same exact tube swap with a Marshall JVM, and for the same exact reason. The JVM has so much gain on tap from the factory that it makes the gain knob unusable for me above 11 o'clock. (The OD Red mode is not usable at all.) The 12AU7 in V1 solved that problem for me. (I think it's rated at about 40% less gain that a 12AX7.) Definitley try this $20 experiment before you send out your amp to a tech for a "mod". Nice job Leon!
Alright then, in DSL 40c , I had dropped all 4 AX7s to AT7, which was still too much crunch in the clean channel. So swap v2 for a 12AU7 and it’s clean enough, but without boost from guitar it’s weak below 5. Next swap is v1 and v3 go back to AX7s as you suggest, and v2 will be a 12AY7,(ECC 82).
Me and my grandpa modified my Gibson tube amp we swapped the 12AX7 for a vintage 50s RCA 12AU7 it pretty much sounds like Luther Perkins Sears silvertone 1300 My style is more like Luther Perkins And we swapped the speaker out for a Jensen Howdy from North Carolina
I have a Vox AC30S1, too much gain for my purposes so I'm going to grab a new 12AX7, 12AT7 and a 12AU7 to experiment in the two positions. (Digital reverb and solid state rectifier, so only 2 tube to experiment with. Good for the "newb" here!). Really looking forward to hearing each combination/permutation of the tubes in my amp. I already replaced the EL84s with a set of matched Tung-Sol and it's much better than stock, eliminated the dreaded "frying egg" sound of the AC30S1 from the factory. I run the master on 10 and adjust the preamp gain to saturate to taste for the part I'm tracking. This helped a ton, thank you!
@@henriquemachado4912 Not yet, I'm waiting to talk to the people I bought the EL84s from. Never having done it, I'll get some input on which brand(s) to consider for my goals. I'll do my best to update you as I go. At the moment, I'm thinking Russian tubes, maybe Tung-Sol, Mullard or whatever they suggest. I'm going for as smooth an overdrive as I can (a la Brian May). I like really round, smooth distortion, as far from a fuzz distortion as I can reasonably get and still have it rock out.
@@henriquemachado4912 I settled on a Mullard 12AT7 to start with, based on a potential recommendation. It should arrive next week and then I'll try it out and see what happens. Being so funds-limited at the moment, I shouldn't have spent the money on experimentation but I have some recording to do and want some of it squared away first. I'll update as I can. Thank you!
@@WhaleBluePRS thanks! After reading about tubes i think I'll get a12at7. I read somewhere that the 12au7 can really affect the dynamics of the amp. I want to get a 5771 but i can't find any around where i live. Anyway, I've got myself a reverb pedal and the ax7 i have is pretty healthy. When i do get around to changing it I'll tell you how it sounds
Just did a similar thing with a 2007 Fender Hotrod Deluxe, swapping V1 for a 12AU7, I may put a 12AT7 or a 12AY7 in for gigging. The main difference between the valves is the gain factor, the 12AX7 has a gain factor of 100 (i.e. 1 watt goes in 100 watts comes out), 5751 has a gain factor of 70, 12AT7 has a gain factor of 60, 12AY7 has a gain factor of 40 and the 12AU7 has a gain factor of 17. The only caution is the lower gain factor valves (12AY7 & 12AU7) require a slightly higher power ratting on the plate load resisters then the others, so speak to a amp tech before making the changes, I'm about to change two 1/2 watt resisters to the equivalent value 1 watt in the HRD
Well done Brother! Some may think stock tubes don't have character. I've found by accidental necessity, changing tubes can help or hurt the original character of the amp! Thanks to Graham! Be Well Leon!
Marshall should have put an AU7 in there and a button to switch it to an AX7 instead of the button which goes from "ok" to "way too much". I liked the AU7 in position V2 the best as well.
Very interesting - Au7 sounded like an overall gain reduction even wide open - as much as we all love gain it’s clear we’ve taken saturation to its limit and then some over last 20yrs 🤣🤣🤣 (hopefully we’re finally right sizing gain)
Does this tune swap also affect how well the amp cleans up when lowering the guitars volume knob? I imagine it would. This tube swap sounds really nice and I think you made the right choice 👍
Well at least you still have your hair:) So did I until about 55yrs. lol I hate hats but I hate bald worse:). I really enjoy your videos keep on rockin young man.
12au7 has gain factor of 20 and has totally different specs compared to a 12ax7 (factor 100),so if you use it in place of a 12ax7 you may need to change resistors and re bias your section of circuit. I would rather go with a 12ay7 in first position or a 12at7 or 12av7 ,12 at7 is good in a phase too and you can swap it with no problems ,if your amp is to gainy it helps to tame a bit the ltp in a marshall for example ,i use it on my marshall 18 in the phase
i love tube swapping.. 12at7 in the PI (P4) and i hate JJs.. always sound wooly to my ears, but thats just me. .. i keep finding myself lovin the EH tubes..
Interesting video. I might add that I heard a major difference between then 883 AND 5751 (AT7), although not as strong of a difference as the AU7... However, and I might add, one reason you *probably* like the AU7 more aside from the less gain, was the fact that it's a vintage tube! IMO JJ preamp tubes are, um and as you Brit dudes(blokes) would say: BOLLOCKS! lol... Yeah man, don't like JJ preamp tubes at all. I use all vintage preamp tubes...i.e. Raytheon, GE, Sylvania...etc...much warmer sounding 'valves' (lol).. But yeah, thanks for the video dude... gonna experiment with some AT perhaps AU7s in both my DSL 100s... plus I wanna try at AT7 in my 2204 which is really gainful and hyper. Prosit!
We have entirely different styles but I find that the 5751 makes enough difference in my largely clean, sometimes a bit crunchy style to be worthwhile. It give me the ability to make more subtle adjustments and, huge for me, I like the tone. I don't care for the sound of 12AU7's. For grins you might try a 12AY7. Even less gain but sounds better in my opinion. Obviously all of this is entirely subjective of course. New Zealand? Thanks for taking the time. Typically V1 is biggest difference in Fender and Vox stuff, then V2 if that is adl gain. Cheers
To me JAN Philips 5751, Brimar 12AT7 and Mullard 12AT7 are the best sounding tubes I ever tried. I don't like the JJ ECC83S and the 12AU7 sounds a little bit too thin to my ears.
your marshall most likely is a hybrid type amp where its not pure tube. Marshall when they came out with the silver jubilee series incorporated some solid state electronics with the tubes.....so the amps were not pure tubes as the older ones were and what made marshall its name. So solid state can be IC's and or transistors and it includes clipping diodes which might be LED's. If you have a trained ear from dealing with electronics.....you'll hear the character between LED's and silicon with clipping diodes......and also know the difference in tube ...as in pure tube and the hybrid stuff. You are getting the shift in gain due to favoring the 12au7 amplification factor which is very low compared to a 12ax7. You need to try a 12ay7 which is the next step up in amplification factor. The steps would be the 12au7, 12ay7, 12at7, 5751, 12ax7
Leon, the DSL is pretty similar to the TSL where V1's the primary gain tube, V2 is an additional gain tube, V3 is for the tone stack/cathode follower and V4 is phase inverter. Hence why you probably went with a lower gain 12au7 tube in V2. The amplification factor of the tubes are 12AX7 = 100, 5751 = 70, 12AU7 = 20 BTW There's a few places that sell a 12ax7 assortment (different manufacturer tubes) as they all sound slightly different. V1's generally the more important tube to replace (tone-wise).
I will NEVER again put another JJ tube in my Marshall jvm Joe Satriani.....EVER just total shit....I had 6 tubes yes 6 all brand new fail and take out the input chip and red plate a couple times...i switched to Mullard new stock and Tungsol not only did I not have a Failure the amp sounds awseome!!
Finally! I really appreciate that you used a looper for the shootout. It removes the player's playing style from the equation, which is the only fair way to do a shootout. Players are influenced by the sound they hear coming out of the speakers, and play differently no matter how hard they try to play exactly the same way every time. Well done!.
V1 and V2 determine gain on clean and OD channels. V3 is the cathode follower (OD channel tone stack). V4 is the phase inverter. To tame the OD channel and retain the clean, put a 12DW7 in V2. A 12DW7 is a 12AX7 on the Clean channel side and a 12AY7 on the OD channel side. 12AT7 in V4 helps tame the OD channel as well. After a lot of research and experimenting, I run my DSL like this V1=Genelex Gold Lion 12AX7, V2=NOS RCA 12DW7, V3=TungSol 12AX7, V4 = NOS RCA 12AT7. Clean channel keeps it’s depth and character and still breaks up nicely around 6. The OD channels are tamed and lose the fuzzies. V3 has the least amount of impact on the gain but does impact the effectiveness of the tone controls on the OD channel quite a bit. Keep this one as a 12AX7 for sure. Anything weaker than a 12AX7 in V1 ruins the clean channel IMO.
@rdavid3848not to revive a dead thread but I thought the same thing!
I never knew you could mix preamp tubes or even the position of them. This just opened a whole new tonal level for me!
The AU in V4 sounded pretty awesome!
5751 has the same plate resistance as a 12AX7 and is DESIGNED to replace it with less gain. 12AXU and T and Y all have different plate resistance, which your amp is likely not designed for. :)
That's good to know!
Thank you for sharing the experiment!
Timely video! I just rolled tubes through all slots of my DSL100. I have a handful of ANOS tubes to play, but I ended up with: v1 - early 60's GE 12ax7 long plate, v2 - JJ ECC803s (long plate version), v3 - 60's GE 12ax7 grey short plate, v4 - 60's GE 5751. I run KT-77's in the power section. The combo of the JJ and the 5751 in the PI really smoothed out the gain and made it a really sweet sounding amp.
That same tube swap works wonders for the DSL-20HR too!!!
Changing the settings on the amp was like changing the date. Loved them all.
I have put a 5751 in the v1 position of my Fender hot rod Deluxe, has made it much better. Haven't tried the other positions yet.
I love the 12au7!
After much research, I put one in a my orange micro dark and it gave me almost exactly what I wanted. More head room but I was still able to rock out when I wanted to.
I do the same thing with my Micro Dark. It takes my pedals better and has a lot more headroom.
Hi Leon, Excellent video, I love that Amp! Brilliant Playing!
Take care.👍👍👍
Melbourne, Australia.
Can really tell the difference with the 12AU7 in v1 vs v2/v3/v4. Gain gets more pronounced as it moves down the line. Great demo. Thank you.
Glad you enjoyed it!
When I used real amps I always liked 5751 in v1. Mostly to smooth out the The gain sweep The 12au7 in v2 was really good in this. Thank you for taking the time to do this.
Exactly what I'm planning on my Bugera 333 glad to hear it works out for folks.
I go with NOS Jan Phillips 5751's in all but the phase inverter, that I use a balanced 12ax7. It gives me a little JCM 800 vibe and cleans up nicely while still having more than enough gain available.
Will try the 12au7 though.
Great tubes. I use NOW Jan Phillips 5751’s in a lot of my amps and U47 mic clones
Thanks for the video, on my MT15 I am thinking of swapping a 12ax7 for some other tube like 12at7, 12au7 or 5751 to have more control over the gain and you showed me that it works like a charm.
What about a 12ax7a vs a 12ad7? With a tube swap? 12ax7a, then 12ad7, and then a mixture of both? There's nothing on the 12ad7 vacuumtube on RUclips. Thanks if you do it.
Edit: TL;DR These High Gain DSLH/ HR amps are absolutely incredible. The problem is a lot of people dont ever get to hear how good they sound cause all the magic is crammed between the gain on 4 or lower. Especially since most of us use high gain pickups. But if you keep the gain low, then use the preamp volume to add character (higher volume= fuller bassier tone, lower volume= thinner brighter tone) then use the master to bring the over all volume up or down to match the environment and get the amp right at the sweet spot where it starts pushing those power tubes then i guarantee youll fall in love with what this amp has to offer. It can do absolutely any tone you want it to but since the gain has to be kept so low dialing it in can be unconventional at times. Which i truly believe is what causes less skilled players to miss what a great amp this is. If you know how to dial in tone, like really know how to do it by ear not by memorizing settings then this amp is just as good tonally as any other Marshall on the market. But if you dont understand how your amp works and what causes it to sound the way you want it then youll likely have trouble dialing in this or any other amp. Shit my TL;DR was longer than my original post lol.
I feel exactly how you did about my DSL100HR. It sounds great but the gain is so high its not as variable as id like. The Crunch channel and OD2 Channel are effected by this the most. Throw in the fact i use a Fishman Fluence set in my 7 string and Seymour Duncan Jb / 59's in my six and youve got high output pickups just exacerbating the problem further. Its a great amp and i absolutely love it but ive noticed when im rolling the preamp tubes i have i always prefer the lowest gain jj in v1 and then my second lowest gain mullard cv4004 in v2 and so on. If i use the higher gain Mullard in v1 its just way way to full and lends itself to providing more evidence that what i need is a lower gain preamp tube, or a few lower gain preamp tubes. I think what ill try first is a 12at7/5751 in v1 with the low gain jj ecc83 then the mullard cv4004 in v3. Im not as concerned with the phase inverter. It sounds really nice an full with a higher gain tube but more manageable with a lower gain tube so either way im happy.
Thanks for sharing all this info. Years later still appreciated. And i really like how your TLDR section worked out :D
I am a huge fan of the 5751 having done this experiment myself last year. However, something I noticed right away was the tone stack. Because tone stacks are tube-driven, putting in a lower-gain tube will give the tone stack less dynamic range, so while your volume and gain knobs become more flexible, the EQ knobs become less flexible. Did you experience this with the DSL50? I never got around to putting 5751s in my DSL50 when I owned it, but when I was doing recording with the Ultra Gain channel my solution to "tame the gain" (if you will) was to simply roll back all the EQ knobs to 0, and then I put a Boss GE-7 in the FX loop to do the precision tweaking. Give it a go and let me know your results!! I'm curious.
Jeez. 3 yrs and no answer. That sucks.
I have a dsl20hr laying around. Has 3 preamp tubes. Def going to give this a shot to see how much it clears that distortion control up!
I put a Tung Sol 12AX7 in my DSL20H - weaponised it
There are no components available in Sri Lanka to build tube amplifier s
Try a NOS Raytheon from late 50's in V1...a recent EH in V2 and Sovtek LPS tubes in 3&4....
Wow what a massive difference.. i never would have imagined I would like the au7 over the ax7.. but i do.. crazy.. thx for that comparison.. i gave a jvm 410.. im considering swapping out
In the original bass man they used a 12AY7 in V1 so it's not surprising about the lower gain tubes.
I agree with your choice on this Leon. I did a similar thing to an ADA MP2 preamp I had years ago. Made it much more usable.
Great result with 12au7 at v2! I'm gonna try it to my 2204 clone. Thanks!
Awesome tube rolling demo, the best I've seen on RUclips so far! Can you please, if you have time, do a similar video using a Dual (or Triple) rectifier amp? Some said that a 5751 would make the bass knob more usable, when used in the PI position. Thanks and keep up the awesome work!
I just got a jcm 900 high gain dual reverb and its pretty harsh cranked up so I’m trying to see how to smooth it out without converting it to EL 34’s , its got all just pre amp and Sovtek 6L6 power
Did you try a pre-amp tube swap yet?
Thank you. 12au7 have less gain and less internal resistance, this is why it must sounds some brighter in v4 position (especially on clean sound)
I would love to see you do a similar vid on changing out valves on overdrive pedals
yeah, like the high voltage Blackstar pedals
Also the 12AT7!
You can get really down the rabbit hole with tubes. But, I find most amps designed around all 12ax7 preamps (IME, most guitar amps in general) to sound best with all 12ax7's. It's just how the circuits were designed - around those particular valves. But, some amps do just sound better to your personal ear with a swap in a certain spot. I really like a 12AT7 in the phase inverter of one of my amps, because the early stages do a lot of the overdrive work, but it keeps the power section more crisp and articulate in a really pleasing way. In others, a 12AT7 just neuters the sound and sucks. Here's a short guideline to these tubes' gain though if anybody is wondering:
12AX7: 100%
5751: 70%
12AT7: 60%
12AY7: 40%
12AU7: 20%
just picked up a few more tubes, looking forward to exploring this rabbit hole!
Exactly what I was looking for, thanks mate! I've recently bought a bargain fender super 60 red knob rack for 50€, and the overdrive on this amp is face melting. I want to tame it with those 12au7. For all of people interested in the difference between 12ax7 and 12au7- the 12ax7 has gain factor of 100, and 12au7 only 20. That means that it's 5 times less "gainy" than 12ax7. Lesson here- before you decide to sell the tube amp you don't like experiment a little, you might be surprised :-)
I liked the 5751 tube in slot 2, and 12AU7 in slot three 🤙
Thank you for another inspiring and thorough clip Leon!
This is my conclusion about/experience with JJ ECC83S.
This is a very gainy tube, more than most other ECC83 or 12AX7’s I believe.
It is a fantastic tube to have in V1 position to bring some saturation and smoothness to the sound.
But my experience also says that it is preferable to use or experiment with other tubes in the other preamp positions.
An example, I bought a JCM 2000 DSL100 from 2008 last weekend. Still stock Marshall branded tubes in it.
I changed to JJ ECC83S in V1 position and the amp became smoother, less harsch and more sensitive to playing.
Then I put JJ ECC83S in other positions but that just made the amp mushy and less defined.
Same thing with my Carvin Legacy VL100. JJ ECC83S in position V1 made the difference from kind of lifeless and stiff to saturated and smooth.
Cheers!
It’s always good for any tune amp to get a Nos GE 5751 greyplate, and a EHX new 12ay7 to compare. Just my opinion depending on your amp breaker’s up.
I have a Sky King on Humbuckers! It breaks up at 2 1/2 volume but is loud. A Tele I can go to 4 or so. With a 5751 I can push to 3 or so but the Nos 63 tube does change a bit. A new 12ay7 just sounds like a stock x7 but lower.
Having built several DIY valvecaster pedals, which run on a 12au7, I tried a Brimar 12BH7 tube (longer tube than the 12ax7, 12au7, 5751s etc,) and it has a beautiful tone. There’s plenty of them on eBay. Forgive me if it wouldn’t fit in that amp, but definitely worth a try if you can get your hands on one.
Love what the lower gain tube does for the red channel. Just what it needs. Problem is it sounds like it neuters the green channel quite a bit, and that is my main playground on this amp. But it also sounds like the red channel can get into that territory now. Does in make the early sweep of the red channel less compressed and more touch sensitive like the green channel?
I have a Crate V30 with three 12AX7 tubes in preamp. Sounds like a million bucks, but the volume knob and the gain knob are too sensitive and all the action is between 1 and 4. I will try 12AU7 to see if I can make it more adjustable for low to medium volume playing!
Great video, thanks for the inspiration!
I have a DSL50 thats currently being repaired at the shop, but I also have a JCM900 SL-X 2500 and this has got me really thinking about trying that on it. It's a great amp and tons of gain, but some people have cited it as too muddy in it's gain. So doing what you've done here on that one has really got me wanting to try this on that. A fellow in a message board mentioned taking V2 and swapping it to a 5751 to give it more headroom and take some of the grit down. But using a 12au7 like you did here seems way more logical.
Screw it, I'm gonna order a couple and give it a whirl!
I did the exact same thing about 10 years ago went with a 12ay7 in v2 and a NOS 5751 in v1. I also did a really simple mod that removed some of the brightness from the red channel. Good to know someone else was on the same page as me.
This is my top 1 youtube channel for 2019
i have a jvm 205h and want to try 5751s....which preamp tubes are involved in the gain staging? I was surprised at the choice to just substitute 1 alternate tube (say 5751) in various positions versus trying all 5751s for the 4 preamp tubes? anybody do anything like that?
Actually if i m reading it correctly, i think the schematic for the 205h indicates the first 2 tubes (labeled V6 and V7...does this correspond to position 1 and position 2?) are the ones involved in the various green, orange, red gain switching selections.
12wd7?
Whats a 12WA?
I agree about the 12AU7 in slot 2. I ordered one as an experiment with my tube pedal last week, but it's not here yet. ....patience! So what's your guitar setup? Looks like a P90 at the neck.
Many good responses here, Just to chime in on the obvious. in the past i found a article saying that 12AU tube has about 80% less gain than the 12AX cousin. i have been using 12AU in V1 of a 18 watt amp i built. Input 1 uses half of V1 and is a bluesy channel that likes pedals, Input 2 uses the other half and cascades it into V2, that is kind of a crazy gain channel and don't like pedals. even if it shares the same preamp its to very different inputs. I like your conclusions and i applaud you for not hyping all the craziness about brands, gold pins, NOS tone mojo and whatever the tube cork sniffers are obsessed with ;)
Big difference with that 12au7 that classic gain sounds great too wonder what a ts9 or a 808 would do to that
Thanks for posting this!
12AX7 have that tasty midrange sound!
5751 in v3 and v4 position gives a 3D character to the amp sound. Why not use it there too?
I like the 12au7 in v1 from this video. I'm a huge fan of 5751's but I like them on a clean amp set up more than for overdrive or distortion applications. Thanks for the video!
Very cool experiment man. Hmmm... Considering how much gain is on tap on a Dual Rec, I wonder if a tube swap like this would help that amp out too?
Works a treat, ordering more so I can pop them in mine
Great! Very useful review...I heard exactly the same as you ...can't wait to change V2 for a JJ12AU7.
Hopefully the red ch will sound more like my beloved JMP-1 Midi preamp (od ch-2) now.
I will also try a 12AU7 in the Blackstar HT-Dual and DistX pedals...
Love the JMP-1!
With my DSL401 I only use the clean channel, the rest is all pedals. In clean channel (V1) the 5157 I put in made about the same impact as your 12AU7 in slot 2. Way more control and headroom.
When you drive in the gain stages (yellow and red) a 5751 indeed made almost no difference. But for those who wonder about the clean channel… and preamp tubes in general
12ax7 = gain factor 100
5157 = gain factor 70
12at7 = gain factor 60
12au7 = gain factor 20
Thanks very useful. I have the same problem with an old Fender Roc Pro 1000. Way too much gain for my taste. I have just ordered the JJ5751, which I hope will drop the gain about 30%. However, if it doesn’t my mate has a 12Au which as you demo here really drops the gain. Cheers!
Something about those long plate tubes that’s just magic.
Hi Leon were you able to find out if the 12AY7s were gainier than 12AX7s or not?
yeah, 12AT, AU or AY in either socket 1 or 2 will increase clean headroom in any tube amp.
LOL
Not with out changing the circuit they wont. There's nearly 50% difference in the plate current for a start.
Peter Walker weird, always works for me.
@@darkforest33
V1 on the Fender deluxe AB763 going from the 7025 to 12AT7 jacks the plate current from ~.9mA to 1.3mA an increase of around 45%. Now I haven't measured the flow on effects but if it were me I'd want to know a little more before plug and pray valve changing. I don't know whether Marshal are red star tractors like Fender but maybe talk to an amp repair guy first. One that's not hoping to see your amp in a few months.
Peter Walker i'll ask me tech, thanks
I did this same exact tube swap with a Marshall JVM, and for the same exact reason. The JVM has so much gain on tap from the factory that it makes the gain knob unusable for me above 11 o'clock. (The OD Red mode is not usable at all.) The 12AU7 in V1 solved that problem for me. (I think it's rated at about 40% less gain that a 12AX7.) Definitley try this $20 experiment before you send out your amp to a tech for a "mod". Nice job Leon!
Maybe try a 12AU7 in both V1 and V2 at the same time?
A 5751 is a must have for me especially in Orange amps specifically the single channel OR50
Interestingly, I like the lower gain tubes in V2 over V1 in your clips.
Great vid. For me, I didn't like what the au7 did in the green channel, just my taste. It always seems to be a compromise here or there...
Tho I know how this should work it's nice to see you to put it to actual use. Nice video.
I liked the 5751 in V1,....thats the best spot for all big sound tubes. V2 V3 V4 u want matched front back side powers as best can be.
Every once in awhile I put a u7 into some of my amps. But I always return to the X7.
Alright then, in DSL 40c , I had dropped all 4 AX7s to AT7, which was still too much crunch in the clean channel. So swap v2 for a 12AU7 and it’s clean enough, but without boost from guitar it’s weak below 5. Next swap is v1 and v3 go back to AX7s as you suggest, and v2 will be a 12AY7,(ECC 82).
Hi Todd!
How are you?
Im waiting for your reviews on Boss GT-1000 Core and Line6 Pod Go? Is it possible?
Cheers from Portugal 🍺🤘
Working on it, hopefully soon!
I know this is a pretty old post, but did you try the 5751 in v4 with the AU7 in V2?
Me and my grandpa modified my Gibson tube amp we swapped the 12AX7 for a vintage 50s RCA 12AU7 it pretty much sounds like Luther Perkins Sears silvertone 1300
My style is more like
Luther Perkins
And we swapped the speaker out for a Jensen
Howdy from North Carolina
Great demo of the difference..... also sneaked in a little Judas Priest🤟🤟🤟
I have a Vox AC30S1, too much gain for my purposes so I'm going to grab a new 12AX7, 12AT7 and a 12AU7 to experiment in the two positions. (Digital reverb and solid state rectifier, so only 2 tube to experiment with. Good for the "newb" here!). Really looking forward to hearing each combination/permutation of the tubes in my amp.
I already replaced the EL84s with a set of matched Tung-Sol and it's much better than stock, eliminated the dreaded "frying egg" sound of the AC30S1 from the factory. I run the master on 10 and adjust the preamp gain to saturate to taste for the part I'm tracking.
This helped a ton, thank you!
Have you got them already? How does the au7 compare against the ax7?
@@henriquemachado4912 Not yet, I'm waiting to talk to the people I bought the EL84s from. Never having done it, I'll get some input on which brand(s) to consider for my goals. I'll do my best to update you as I go. At the moment, I'm thinking Russian tubes, maybe Tung-Sol, Mullard or whatever they suggest. I'm going for as smooth an overdrive as I can (a la Brian May). I like really round, smooth distortion, as far from a fuzz distortion as I can reasonably get and still have it rock out.
@@WhaleBluePRS yeah, I just got a Epiphone Valve junior and it's way to hot, gonna try a 12au7 to get less breakup
@@henriquemachado4912 I settled on a Mullard 12AT7 to start with, based on a potential recommendation. It should arrive next week and then I'll try it out and see what happens. Being so funds-limited at the moment, I shouldn't have spent the money on experimentation but I have some recording to do and want some of it squared away first. I'll update as I can. Thank you!
@@WhaleBluePRS thanks! After reading about tubes i think I'll get a12at7. I read somewhere that the 12au7 can really affect the dynamics of the amp. I want to get a 5771 but i can't find any around where i live. Anyway, I've got myself a reverb pedal and the ax7 i have is pretty healthy. When i do get around to changing it I'll tell you how it sounds
Just did a similar thing with a 2007 Fender Hotrod Deluxe, swapping V1 for a 12AU7, I may put a 12AT7 or a 12AY7 in for gigging. The main difference between the valves is the gain factor, the 12AX7 has a gain factor of 100 (i.e. 1 watt goes in 100 watts comes out), 5751 has a gain factor of 70, 12AT7 has a gain factor of 60, 12AY7 has a gain factor of 40 and the 12AU7 has a gain factor of 17. The only caution is the lower gain factor valves (12AY7 & 12AU7) require a slightly higher power ratting on the plate load resisters then the others, so speak to a amp tech before making the changes, I'm about to change two 1/2 watt resisters to the equivalent value 1 watt in the HRD
I went back and forth, and I'm hearing a definite increase in brightness with the 5751's.
noticed the low-gain 12au7 had the biggest effect on V1 (cleaner/brighter, higher range).
12au7 has gain=20, 12ax7=100
It has 60 gain, not 20
Mate. This is the vid I've been searching for. Absolutely superb. Made my mind up. Cheers.
That's awesome to hear!
Well done Brother! Some may think stock tubes don't have character. I've found by accidental necessity, changing tubes can help or hurt the original character of the amp! Thanks to Graham!
Be Well Leon!
Marshall should have put an AU7 in there and a button to switch it to an AX7 instead of the button which goes from "ok" to "way too much". I liked the AU7 in position V2 the best as well.
Very interesting - Au7 sounded like an overall gain reduction even wide open - as much as we all love gain it’s clear we’ve taken saturation to its limit and then some over last 20yrs 🤣🤣🤣 (hopefully we’re finally right sizing gain)
Does this tune swap also affect how well the amp cleans up when lowering the guitars volume knob? I imagine it would. This tube swap sounds really nice and I think you made the right choice 👍
Well at least you still have your hair:) So did I until about 55yrs. lol I hate hats but I hate bald worse:). I really enjoy your videos keep on rockin young man.
my favorites are sovteks
12au7 has gain factor of 20 and has totally different specs compared to a 12ax7 (factor 100),so if you use it in place of a 12ax7 you may need to change resistors and re bias your section of circuit. I would rather go with a 12ay7 in first position or a 12at7 or 12av7 ,12 at7 is good in a phase too and you can swap it with no problems ,if your amp is to gainy it helps to tame a bit the ltp in a marshall for example ,i use it on my marshall 18 in the phase
Those 18w Marshalls are incredible little beasts!
@@LeonTodd i agree Leon ! I built mine as a hybrid between a superlite and a fender bj ,very powerful🤟
i love tube swapping.. 12at7 in the PI (P4) and i hate JJs.. always sound wooly to my ears, but thats just me. .. i keep finding myself lovin the EH tubes..
Dare I ask what you are using in the MP-1?
going to try a 12AX7/12AU7 real soon i think. Will post results!
@@LeonTodd Sounds awesome!
Interesting video. I might add that I heard a major difference between then 883 AND 5751 (AT7), although not as strong of a difference as the AU7... However, and I might add, one reason you *probably* like the AU7 more aside from the less gain, was the fact that it's a vintage tube! IMO JJ preamp tubes are, um and as you Brit dudes(blokes) would say: BOLLOCKS! lol... Yeah man, don't like JJ preamp tubes at all. I use all vintage preamp tubes...i.e. Raytheon, GE, Sylvania...etc...much warmer sounding 'valves' (lol).. But yeah, thanks for the video dude... gonna experiment with some AT perhaps AU7s in both my DSL 100s... plus I wanna try at AT7 in my 2204 which is really gainful and hyper. Prosit!
What tubes do you run in your Recto?
I keep hearing you say sluts instead of slots. Valve Sluts is definitely what I am and would be a great band name 1:37
We have entirely different styles but I find that the 5751 makes enough difference in my largely clean, sometimes a bit crunchy style to be worthwhile. It give me the ability to make more subtle adjustments and, huge for me, I like the tone. I don't care for the sound of 12AU7's. For grins you might try a 12AY7. Even less gain but sounds better in my opinion. Obviously all of this is entirely subjective of course. New Zealand? Thanks for taking the time. Typically V1 is biggest difference in Fender and Vox stuff, then V2 if that is adl gain. Cheers
I liked the 12au7 in first slot personally. Not bad in second though.
Don't know why this gave me flashbacks of dime playing this tune on the vulgar videos
Had a 50w 5150iii Head for a while , put a 12au7 in v1.
Made channel 2 much more organic and playable , ch3 was still insane 😂
Those things have SO much gain man.
To me JAN Philips 5751, Brimar 12AT7 and Mullard 12AT7 are the best sounding tubes I ever tried. I don't like the JJ ECC83S and the 12AU7 sounds a little bit too thin to my ears.
Are you Ralph Fiennes brother?
your marshall most likely is a hybrid type amp where its not pure tube. Marshall when they came out with the silver jubilee series incorporated some solid state electronics with the tubes.....so the amps were not pure tubes as the older ones were and what made marshall its name. So solid state can be IC's and or transistors and it includes clipping diodes which might be LED's. If you have a trained ear from dealing with electronics.....you'll hear the character between LED's and silicon with clipping diodes......and also know the difference in tube ...as in pure tube and the hybrid stuff. You are getting the shift in gain due to favoring the 12au7 amplification factor which is very low compared to a 12ax7. You need to try a 12ay7 which is the next step up in amplification factor. The steps would be the 12au7, 12ay7, 12at7, 5751, 12ax7
AFAIK the DSL doesn't use any diode clipping, unlike the split channel 800, Jubilee and 900's. Very keen to try a 12ay7 as you suggested!
The 12au7 has less gain
I'm getting a 5751. If you can't hear the difference.. Man.
Leon, the DSL is pretty similar to the TSL where V1's the primary gain tube, V2 is an additional gain tube, V3 is for the tone stack/cathode follower and V4 is phase inverter. Hence why you probably went with a lower gain 12au7 tube in V2.
The amplification factor of the tubes are 12AX7 = 100, 5751 = 70, 12AU7 = 20
BTW There's a few places that sell a 12ax7 assortment (different manufacturer tubes) as they all sound slightly different. V1's generally the more important tube to replace (tone-wise).
The x7's are bigger. The u's are cleaner..u's success on gain check..
Turned the video off the second you said you wanted less gain
Wise
I will NEVER again put another JJ tube in my Marshall jvm Joe Satriani.....EVER just total shit....I had 6 tubes yes 6 all brand new fail and take out the input chip and red plate a couple times...i switched to Mullard new stock and Tungsol not only did I not have a Failure the amp sounds awseome!!
5751 is much closer to a 12ax7 than a 12t7