STOLEN From Marshall® : Add an “EXTRA Channel” To Your TUBE Amp

[@WaylonMcPhersonGuitar]

I ❤ this MOD, you guys got any interesting ones? ** Challenge: There is a typo in this video, can you find it! 😜

[@hamishlaing1542]

My one and only mod is to my DSL20. I rerouted the output of the Green channel from RL2 to utilise an extra gain stage. It now uses V1A, and then to V2A, then V2B.. It used to go straight to V2B. Much more gainy 😊

[@romanhausner456]

It says pin 7 to pin pin 2 instead of 6 to 7. probably not the greatest idea:) great mod though, will definitely try it on one of my builds. And I haven’t seen this one before on robrob. Thanks!

[@Kanthon]

Pin 2 is connected to pin 6, not pin 7.

[@darrellparsons246]

If this is an 12AX7 preamp tube (it appears to be the cathode follower that drives the tone stack) then pins 2 and 7 are the grids (grid 2 and grid 1) of this dual triode preamp tube. So I was really confused since the mod should be between 6 and 7 (plate 1 to grid 1). But on this amp, this cathode follower tube for the tone stack has drives itself between pins 6 and 2 (plate 1 to grid 2). So when he soldered the mod between pins 2 and 7, pin 2 (grid 2) is already connected to pin 6 (plate 1) so he is essentially connecting the mod to pins 6 and 7 because on the PCB pin 2 goes to pin 6. The only typo says that the factory connects pin 2 to 7, but it's pin 2 to 6. So his mod worked fine and to me sounds great. I was really confused at first.

[@darrellparsons246]

@@romanhausner456 Pin 2 and 6 are connected from the factory, so connecting his mod to pin 2 also connects to pin 6. That is why the mod worked fine. He did not make a mistake when he connected mod to pins 2 and 7.

[@zvirb]

The bridge between the positive and negative clipping circuits doesn`t affect the sound. But it is needed to protect the LEDs from overvoltage in the non-conducting direction. Because that overvoltage is dangerous for LEDs.

[@dlflash56]

I used to be a Marshall guy (I still own a 1968 SLP, a JCM2000, and a SV20H). I stopped using Marshall amps, when I discovered Ceriatone Amplification. My first Ceriatone was a 50-watt Chupacabra, hand wired goodness from the Gods. Basically, it is a Hot-Rodded Marshall Plexi with all of the Jose Arredondo mods and a few new ones. Quality and build are impeccable. That led me to purchase the Ceriatone Plexi51 All Access, a 50-watt Plexi, with every iteration of the Plexi is built into the unit. Flip some switches and you have a Plexi Bass 50, a 1967, '68, ''70 or '72 Marshall Plexi circuit. That leads me to my latest Ceriatone purchase, a Hand Wired 100/50-watt, 2555 Siver Jubilee, with added mods. The added mods include, a resonance control, PPIMV, 3-way Bright switch a buffered FX loop, and TAD Mustard caps. This thing is a BEAST! It is everything a Marshall Silver Jubilee wishes it was... and so much more.

[@GeorgeSharp-rv6ez]

This mod sounds fantastic (through my stereo). I would think that this mod could even help an inexpensive amp. Your explanation(?) and illustration made this very easy to understand, especially for those of us who have '"no" experience. Thank you!

[@hearpalhere]

Love your videos Waylon! The mod is cool, definitely gave a bit of special sauce to the basic sound. I also want to say that your rendition of Amazing Grace was really great! My wife and I make guitar picks by hand from coconut shell and would be really happy to send you some. Let me know if you are interested.

[@davidcaro8217]

Good post! I believe Blackstar uses solid state clipping circuits in their tube amps also.

[@earthstrong-43.72]

yes, they do. I have a MK1 Club 50 head. It used clipping diodes to simulate a front end gain boost.

[@jerryhatrick5860]

Many have it was pioneered by Lee Jackson and that other dude in Cali damn I forget his name.. A Mexican dude. Very famous for nodding I think first name was Jose'?

[@davidcaro8217]

@@jerryhatrick5860 José Arredondo ?

[@davidcaro8217]

@jerryhatrick5860 thats true. Hey, speaking of Lee Jackson, I had him build a tube buffered effect loop into my marshall JMP 2203. Now I can get all the high input crunch but with stellar clean delays, reverbs and modulation! Amazing mod!

[@earthstrong-43.72]

@@jerryhatrick5860 Jose Arredondo

[@hamishlaing1542]

Super cool! I was just looking through the schematic of my JCM600, and see instantly what you're talking about. Food for thought for another day .... sounds like the perfect way to get a nicer sound on that diode clipped channel. BTW, I really enjoy seeing you noodle 😃

[@JohanSegeborn]

Sounds amazing ! Great video

[@TheJstewart2010]

Nice sounding mod. Your rendition of Amazing Grace sounded very Bonamassa-ish. And that's always a good thing!

[@brandonpicou8017]

Love your videos! Thank you for sharing these mods with the rest of the world.

[@tomasjones3755]

Great mod. Love it! To address the volume drop, I think you could tie the mod in on the other side of R44 and add a smaller value (feedback loop) resistor; ahead of the mod. Maybe 82k or less; not sure. A resistor selector box would be helpful here

[@ShawnWrona]

This^^

[@jublaim]

Do I understand you right, meaning like splitting R44 in two (100k + 82k) and tapping feedback from the middle? That would mean getting less signal fed to the diodes > less overdrive. Also changes the working point of the triode, changes the sound a bit, and will yield slightly more signal if taken directly from pin 6 (or 2).

[@tomasjones3755]

@@jublaim Hope I get this right.... The mod is on a switch. If the off position, it's out of the circuit. In the on position, part of the NFB signal is being fed thru the mod to the grid of the 1st stage. By tapping the mod BEFORE the NFB resistor, and using a slightly smaller resistance value, you would be getting a bit more signal thru the diodes. If I'm wrong, I'm sure someone with more EE educaiton can set me straight

[@benaragon6760]

I’d love to do this Mod to my Valve Junior. Just so I don’t make a mistake, between what Two points in the Valve Junior should I place the mod. Like !! Thank you, great video.

[@terryeaster1]

Great video! I have a stage right sb20 tube amp that I love, I just use the clean channel and use a very stocked pedalboard as well as a boss katana for effects. (I use the katana effects loop and split the signal to get it to my stage right. It's convoluted not sounds incredible

[@knuckleheadsaloon]

Very cool and thanks for sharing this mod 😀

[@johnculling9326]

After watching this video I studied the schematic to my orange tiny terror. I put the diode clipping in as described and now this amp is a monster! Thankyou so much, your videos are brilliant.

[@DanielAraujoNazar]

I wonder if a similar enough effect could be achieved with a pedal bearing a similar diode config in front of the preamp? I guess it wouldn't be 100% same, as it looks like the clipping happens after some of the signal is already distorted/overdriven by a valve?

[@MC-ee1ey]

Another simple mod is to have switchable values of cathode bypass capacitor on V1A which alters the gain of this stage a bit. Takes some experimentation to find values that you and the amp like. I have also done this on the power stage of a single ended amp (one output valve/tube) BUT be careful that you don’t end up with an oscillating output stage. Long time ago, but I think I found these in the book Inside Tube Amps by Dan Torres.

[@brandonpicou8017]

He's got a video about that specific mod. It's A GREAT mod.

[@MC-ee1ey]

@ Ahh - I haven’t been subscribing to Waylon’s channel for very long, clearly have some catching up to do!

[@redkurn]

I like it. Wonder if this would help add more distortion to the blackheart little giant I have. 🤔

[@puzzlefactorysoundstudios]

Cool stuff, mate. What brand are the 'helping hands' you're using here? Looks like a really nice build.

[@modscientist9793]

What size LEDs? The caps are Mallory? Thanks.

[@danielsaturnino5715]

I'd be sure to use a safety rated capacitor like those across de line caps that only fail on open mode. Great mod, thanks for the video.

[@soapboxearth2]

I'm trying to think if this would work on a single ended amp with one preamp tube?

[@WaylonMcPhersonGuitar]

It would but you would most likely loose too much volume!

[@soapboxearth2]

​@WaylonMcPhersonGuitar oh ok. I see. I may try it on one of my 5f6a based amps then, thanks. Interesting mod. I've never looked at the jubilee schematic before. I've been curious about the Jose diode mods but I may just give this a go first. Cheers

[@totallyunmemorable]

@@WaylonMcPhersonGuitar I've experimented with adding clipping diodes at various point on a 5-watter, and yes, you do lose volume. But it's still a very useful option, especially for home use. A 5-watt amp isn't going to have enough volume for most band situations anyway. I'm so busy (and lazy) lately, but I want to try your mod. I hope someone will weigh in on how well it works with Fender amp topologies, with the tone controls necessarily occurring before the mod, in other words.

[@robertdonosobuchner3129]

Great video as always! It sounds really good!

[@aquilarossa5191]

Questions: 1. Where did you get the components in NZ? Import via Digikey or whatever? Always puts me off, because of shipping costs costing more than the parts themselves. I did import a bunch of caps and stuff, but no diodes. 2. Where would you put it in a JMP 1987 clone? I figure in the case of my amp you are saying it would tap off the anode of V2b and feed back into the grid, so the clipped sound then goes back out the anode and on to the V2b cathode follower? Yeah, or yeah, nah? 😆 BTW. I have not 2204'd it, so the second gain stage is not on V1 like with the JC20H. I really like its Angus tone wired as a JMP 1987 and with a 0.0022uF coupling cap between V1 and V2, but sometimes I need a little more drive and squish etc. The Mr Scary V2 mod is the easiest way to add more drive :P (it's not cheap to import though). P.S. I think it might be possible to use 3-way switching so this mod does this method of clipping, but also so it grounds like a regular Jose mod. More faffing around, but the regular Jose clipping like that Headfirst Jason fella does over in Aussie does sound really good, especially when he adds his tweaks (he's a Kiwi BTW).

[@totallyunmemorable]

Yeah, shipping costs. I just got back from USPS. I put a transformer on Reverb, but neglected to decide what to do about international buyers. So I only listed it at $20 for shipping. Wouldn't you know it, someone from Norway bought it. $101 shipping. (!!!) I made less than $17 on the deal.

[@vessal1]

some LED's have the flat spot on the Anode side, I'm confused what it should really be. Some show the cathode as the longer lead too.

[@HOLOCULT]

Going to do this to my epiphone SoCal 50. I think it will really wake it up!!!

[@TheRealcdawg22]

I have one of those.

[@modscientist9793]

What size LEDs?

[@kft590]

I don't know if you have heard of the AX84 projects but there is a high octane version of a 5 watt tube amp that gets to VanHalen levels of distortion.

[@Granite165]

Is this similar to the gain boost on the Peavey ValveKing's dirty channel? Sounds crazy on the JCA!

[@HOLOCULT]

Ok so... On my SoCal 50... I've located v2 and the gain control on the amp... So I can just solder this from pin 7 to pin 6 on v2 and it will work??? ***Correction!!!*** I see pin 6 to pin 2!

[@giulioluzzardi7632]

Seems to make the tone "Fatter" and more touch-sensitive. Can we do this on a Fender Deluxe style amp? Cool.

[@WaylonMcPhersonGuitar]

Yes, it works on a Deluxe, cheers!

[@modscientist9793]

Diodes at how many volts?

[@wallpapermusique]

Can I add this mod between V1a and V1b (12AX7..V1a vol and V1b tone stack) like a Dr. Z Carmen Ghia clone?? Thanks

[@Jubaluptoearly]

Amazing Grace sounded awesome

[@benligil]

use IRF530 series transistors in series as diodes you'll be happy :)

[@WolfgangSambs]

Could you please explain about those?

[@benligil]

@@WolfgangSambs I was modding my practice amp and my boss ds-1 pedal and at a point creating overdrive you have go over 2 clipping diodes. they can be LEDs, Germanium or Silicon based or transistors. they clip the signal because they have a max voltage passing value. and that creates distortion. I found out in mt experiment that transistors are more tubey than leds that are very harsh and fuzzy creating distortion.

[@uglitchymcglitchfacevideoc1640]

​@@benligil Sorry if this is a dumb question, but can you be a bit more explicit about which terminals on the transistor you are using for this, and how you connected them? Thanks, I'm very interested in trying this!

[@Johnnybananass-_]

So you’re just installing a tube screamer circuit into the amp . The Ibanez tube screamer amps had this built in as well .

[@boddumblues]

What tube screamer works with 600 volts??

[@sytharnia1717]

Damn I wish I still had my JCA 20 ... this mod would have made me keep the amp

[@martydibergi5228]

anyone know Any Pro amp repair in Toronto Canada? thanks this video is Excellent! i still own my original 1964 deluxe reverb. yes, old now❤

[@charlesdeal771]

So, you bridged pins 2 and 7 with the diodes? I would expect it to be between pins 6 and 7.

[@WaylonMcPhersonGuitar]

Correct, 2 & 6 are connected on this particular amp, cheers!

[@jublaim]

Look at 4:21; pin 6 & 2 are connected in this kind of circuit.

[@darrellparsons246]

Confused me also. Pins 2 and 6 are connected from factory on the board. so connecting to pin 2 is also connecting to the plate 1 (pin 6) so in effect, pins 6 and 7 are going through the mod. There is a typo on the video that says that pins 2 and 7 are connected on his amp, but he meant pins 2 and 6 are connected.

[@gstube1]

So this creates more asymmetric distortion?

[@larrysteinke1839]

yes, because of the different number of diodes in each direction. this results in more even harmonics than odd and less dynamic compression than symmetrical clipping of both positive and negative halves of the wave.

[@totallyunmemorable]

yes.

[@gstube1]

​@@larrysteinke1839 Would more diodes improve the amount of harmonics or is this about the limit with as far as asymmetry goes?

[@kevinshumaker3664]

Super cool! Any idea what would happen installed in an Ampeg SVT 3 Pro bass amp? Love your videos, cheers! 🤘

[@WaylonMcPhersonGuitar]

oooo! That's a interesting idea! That could sound really cool!

[@MadScientistGuitarLab]

Does this mod necessarily have to go on a cathode follower?

[@WaylonMcPhersonGuitar]

No, It has to go on a Gain Stage, cheers!

[@tasteapiana]

I wonder how this would be done in an EHX/Sovtek Mig-50. Anyone have thoughts on that?

[@No-fw4qj]

Add more tubes to a dsl1 head

[@HeadCannon1776]

so it's just a built in tube screamer?

[@williambock1821]

Thanx man! Keeping this in my pocket. Nice to find an Amp tech channel without religious overtones and conspiracy theories bubbling up in the background. 🤘

[@theduppykillah]

I always say, “ it’s not who you know, it’s who knows you!”

[@dorzsboss]

Sounds like the AC/DC. You have EL34 tubes in your amp don't you?

[@WaylonMcPhersonGuitar]

EL84's in this one :)

[@AuntAlnico4]

I don't have to build this mod since it comes stock in my JCM600 .

[@jackthompson9241]

Quality content as always. Thank you!

[@HOLOCULT]

Doesn't this make positive feedback going from pin 6 to pin 2???

[@JohnParker-of2cy]

So more like tubescreamer clipping than distortion + clipping.

[@flecht]

Now I wonder how my slightly modded AC30cc2x (TB channel) would sound with this mod.

[@flecht]

Little update: the volume drop is massive, but it sounds really interesting.

[@johnlerro997]

Actually on a Silver Jubilee engaging Rhythm Clip on the clean channel also engages diodes (1N4007's). The Rhythm clipping is synchronous and Lead clipping is asynchronous. Both sound incredible.

[@kft590]

Layout is extremely important when adding Tubes because the will easily oscillate due to wire placement. Adding the diodes to cut off the top of the signal is the easiest way to do that, I have heard that Zener diodes are a little more musical. Heavy Metal rock foot pedals use the diode cut off circuit.

[@steeldaemon5445]

Yet another "forgotten" idea to put diode clipper into tube amp. This is the reason why so many people hate JCM900ish sound.

[@7171jay]

@steeld. Not just the 900, many JCM800 amps has clipping diodes as well as lots of other amps.

[@AuntAlnico4]

Silver jubilee and JCM600 as well.

[@skidmark316]

The JMP-1 had diode clipping.

[@7171jay]

​@@AuntAlnico4 I believe Blackstar Amps uses clipping diodes as well. It's certainly not a "forgotten" practice at all.

[@steeldaemon5445]

@@skidmark316 Yes, this preamp is often called poor man JCM900.

[@Theansilgregoryshow]

Nice

[@MikeGervasi]

Let me finish building the amp first THEN I'll add the mod.

[@terencekaye9948]

Sounds buzzy

[@johnnyennis9864]

Anyone tried this on a Blues Junior?

[@7171jay]

This isn't at all "adding an extra channel". Properly stated this would be modifying a channel for more distortion with clipping diodes.

[@jerryhatrick5860]

There is already a product on the market one can buy that. Simply plugs in.

[@7171jay]

@jerryhatrick5860 Yeah, plenty of overdrive pedals use clipping diodes to make guitar distortion, none will sound exactly like building this mod into your amp but the pedal route is obviously much less intrusive and you have options of tons of pedals that all do this somewhat differently that you could try. Honestly I can't see building this mod into an amp unless it included a way to be able to switch it out.

[@JONNIE_ROCKER]

Very interesting 👍👍🍺

[@joegood4155]

It’s a channel because there’s a switch to engage it and disengage it. It’s the same reason the ire is “three” channels with the boost.

[@DerpRulesAll]

I did 'add an extra channel.' It's an Overdrive, complete with advanced EQ, which my amplifier doesn't even have. Even a Boost with a similar EQ would've qualified as an 'extra channel.'

[@profedneyrossi]

Hi, I'm a friend from Brazil, I also built your Jubilee Mod on a single ended tube amp. See how it turned out: kzbin.info/www/bejne/eWbOmKiJpbemf6ssi=3JxCqS8xm0gUnfms

[@tinfoilcat5446]

Has nothing to do with adding an extra channel. It's modding an existing channel

[@nasticanasta]

Do yourself a favor and do what major bands Like Judas Priest, Richie Blackmore, Steve Morse, Marty Friedman.... ditch the Marshall and get ENGL

[@DANTHETUBEMAN]

Judas Priest defenders of the faith is jcm 800 at its best