Master Volume Mods for Marshall and Fender Style Tube Amps

[@jond63]

Holy Crap, Brad! My amp sounds fabulous...without peeling the paint off of the walls! Good job, sir! I’m very impressed. I need to come over, pay my bill, and pick that bad baby up! Awesomeness!

[@TheGuitologist]

That'll work. Anytime after 5:00. Shoot me a text.

[@billedwards2657]

Lots of good info on a topic that’s frequently asked on the online forums. Love it. Thanks for making this

[@xinsertusername]

+points for Stinkfist. That Tone is unreal.

[@PapaWheelie1]

I was not expecting that - had to watch it twice! So good

[@jahjah67]

That thing sounds great. Any rock player would be happy to have that amp in their arsenal. Great job

[@vintagetubeamplifiers]

I have learned more from Gerald Weber's books and videos in the last 18 days then I've learned in the last 18 months. In my opinion he is the best amp teacher.

[@nuckinfuts5481]

I want to thank you for creating and posting this video. I successfully installed this type of into a couple of my amps as well as a couple of amps owned by friends! Cheers!

[@TheGuitologist]

Awesome! Congrats!

[@allboutthemojo]

@@TheGuitologist thank you for the fantastic video. I'm not technical at all but I've been trying to understand master volumes on Marshall amps before purchasing one and this definitely helped. 👍 . I do have a question for you, hopefully you can shed some light on it. I like the dsl 100 hr model and I'm looking to use it primarily at home. Do you know if the master volume on these amps is the " type 3" that you explained in the video? Asking because I want the master to keep as much of the tone as possible while being able to play at quiet levels at home. Visited a lot of forums and message boards and nobody is really able to say what type of master volume setup is stock in the dsl 100hr model. A lot of people are saying that because of the master in the dsl 100hr, I don't need a reactive load attenuator to play at home because it does the same thing. Appreciate your input since you are an expert on this. Thanks!

[@CR3W1SH03S]

There is an upgraded version of the Type 2 called the Lar Mar PPIMV. Solves the loss of bias if the pot fails.

[@crifox16]

dream tone right there! seriously one of the best ones i've ever heard. also crazy that it's an amp from 71 and it has all this gain without any boost or overdrive

[@50gary]

I remember speaking with Ken Fisher on the phone back in the day. Tried to get him to build an amp for me but he had Chronic Fatigue at that point and just couldn't do it. Super knowledgable guy and easy to talk to.

[@johnhuyton7966]

Did the mod on my 800 2203 and tried in rehearsel last night! Sounds awesome. Cant beleive how simple it was! Cheers brad! First time ive modded something myself. Thanx for the inspiration!

[@GTguitarworks]

did you just keep the stock Master volume on 10 to bypass it? or did you use them in conjunction with each other? Thanks..

[@TheGuitologist]

A Desktop Reference of Hip Vintage Guitars Book: amzn.to/2JXr5Cq Download Trainwreck Pages in PDF: robrobinette.com/The_Trainwreck_Pages.htm For those asking...amp demo settings: Presence: 8 Bass: 2 Mid: 7 Treble: 7 Volume 1: 7 Volume 2: 6 Master Volume: 1.5 (ish)

[@KTWap]

Hi Brad! what is the name of the song you play at 22:33?

[@joelspaulding5964]

Maybe my favorite of the 20+ vids watched so far. Tool didn't hurt. Who is this that is so gifted in the ways of science (and music)? Proper playing and amazing amp/electrical knowledge.

[@TheGuitologist]

Welcome to the channel. Pull up a chair!

[@djosephp67]

Great video series Brad.. Really enjoyed seeing the vintage Marshall content.

[@mikewallace1270]

Tone is KILLER. Wow impressed with outcome.

[@murphyhowey3109]

Same amp, same mod here, but I put the pot in front, replacing one of the 2nd chan 1/4" jack. I use an external jumper from the 1st chan to the second as well. Having that knob avail is necessary on stage.

[@ralphballinger2159]

It sounds fantastic through my phone. I cannot imagine how awesome it must of sounded in the room! I’m trying to learn/teach myself how to build/modify pedals/amps these days. I really admire amp builders/hot rodders like Ken and Howard Dumble to name a few.

[@pwnEdge1]

Great sounding ,sustain ,clarity, and dirt . As I alway say, clean distortion😀

[@jamesmccabe8736]

I'm definitely interested in this video. Very glad you made it to help me understand the ppimv mod a little better. I've god a Peavey Roadmaster that could definitely use a mod like this. Thanks again Brad nice playing too!

[@garyr081]

Playing a little Tool through that amp made my day. Thanks Brad.

[@philipdonovan5127]

Thanks Brad, well done video. I lost my mind and sprung for a PEC dual-ganged pot - $37.00. Its for a Type 2 MV in a 6V6 plexi that I"m almost finished building. The schematic calls out for grid leak resistors of 100K although Fender seemed historically happy with 220K in just about all their 6V6 amps. The PEC comes with the hope that the ganges with be better matched, more quiet and less prone to "wiper lift". For 37 bucks it ought to be! I hope my PPIMV type 2 works as well as your type 4 did! Great vids Brad, Thanks again. - Phil

[@rtopia]

that mod was a good call! (drive sounds a lot tighter ) That Weber book is a must have. I did one of his (Gerald Weber) two day “camps” where we brought in our own amps and overhauled them while he supervised.

[@PoppysGuitar]

Where does he do a camp???

[@Bsquared1972]

Very cool. Gerald Weber is the MAN when it comes to tube amps...went to one of his seminars, and he wound me a 1959 spec output transformer for my '57 Bassman!

[@alexwoolridge94aw]

Very cool series and thanks for talking in depth about the master volumes

[@sski]

I'm in lust! That amp sounds fantastic. Nice job, Brad.

[@scottjamable]

Excellent Video Brad!! I know this is an old video but I just acquired a nice 99% original 1970 SB I have converted to SL. It came with a type 4 MV Mod off the treble pot and it seems more like a MV for cleaner loud headroom. It still works better than not having one but I can't wait to try the type 3 to get the crunch at lower volumes!! Thanks man

[@jjsant3250]

Many say that type of MV can sound bad but I wish I had at least tried that one in the past based on the sound you got here. So much easier than a dual pot with 6 wires (and safety resistors to guarantee bias.) I added the Type 2 to my SFDR and there is no "whoosh" and it sounds great. I often go without pedals for jams. Even with the DC (bias voltage) on the pot there is no path for DC current to flow thru the wiper and no DC current is flowing thru the pot. So no mandatory "whoosh."

[@chuckelator]

I have a 1973 50w that might benefit from this treatment! I think people don't realize how much you can actually get out of these NMV Marshalls in terms of grunt and grit! There's a reason that I play metal through a vintage Marshall. You double it up and it sounds MONSTEROUS!

[@TheGuitologist]

Marshall style tone stacks don't get lost in the mix. All this newer metal crap is way too dark, and it all sounds EXACTLY the same. You can't hear any dynamics from the player either, so all character gets lost.

[@fiddlix]

Great job Brad and my favorite style of master volume for old Marshalls for all the reasons you listed.

[@MrGTO-ze7vb]

Great circuit review Brad..!! Fisher's book must be in any tube amp lovers library

[@TononiaWorld]

This is one awesome mod, it makes the amp more versatile and to boot doesn't kill tone or "mojo"

[@DBoonful]

Your Channel is fantastic, I've been modding from those classic Tube books for over 30 years. One thing, you're a very experienced tech -so I'm a little surprised that you are wearing 2 rings when you're inside an amp, but I would mention to other noodlers watching your show, that no matter how confident you are that you've dissipated an amp properly, and no matter how much other precaution you take, probably best to remove them before noodling around. I've seen things you people wouldn't believe -horrible things ***inserts Bladerunner meme*** . anyways, keep the good stuff coming.

[@johnhuyton7966]

So glad you've done this ive been reading up a lot on ppimv for my jcm800 2203. Ive ordered a 1meg pot and will be doing the exact same mod when it arrives. Thanx brad

[@hearpalhere]

Awesome video Brad! I love these instructional types of videos that you make, it's a great opportunity to learn a lot. Thanks for doing this and the thing sounded great too!

[@bhosterman]

Sounds awesome. I could watch these all day

[@Xpyburnt_ndz]

Great vid Brad! Man I wish I knew about modding back in the 70's...I had a super lead 100 that needed a master volume, BAD!!!.Just too young n dumb back then to know any better! Thanks man for the great vids you do! Cheers!😎

[@mikewallace1270]

Chris Lake Me too. Actually had a 71 Marshall like the one in the video and did hundreds of gigs with it without a master volume. Sure wish I’d had one!

[@robertbevilacqua8548]

Fantastic. Love that you used stinkfist as a demo song. Been ages since I heard that and you just rekindled my live for that song (at least I thouht it was that song lol)

[@brentstewart59]

The amp stuff was great but Stinkfist in PJs just makes you a legend here in Canada Brad. Great stuff

[@Eventual420]

Very useful. Monday is turning out great. Thanks Brad!

[@brianneill3609]

great job on that one Brad. Super cranky but balanced at the same time. sounds great!

[@TwentyFour76]

Just what i was looking for! Thanks for the info and great refrence book!

[@stevemcgee510]

Bad Brad, you are my favorite amp tech. By far bro.

[@mikeh2599]

Thanks for the trainwreck, a wealth of info.

[@marccarter1350]

It's the very reason I bought the new "ish" Vox AC15HW1X. I obtain that classic Vox creamy drive' without the need to have the volume at home. My neighbours are sure happy too :-) Great stuff as always Brad!

[@peterdavies5358]

I've just got the cream AC4 TV and I've got a Rat Hot Rod Valve Special with the Power Scale on it. No conclusions yet but when you live somewhere you just can't make a row it's essential. I've got Guitar Rig 5 and a Yamaha THR10C, I don't think there is a best.

[@marccarter1350]

@@peterdavies5358 I only own one amp at a time. So i need it to cover everything. From home, live, rehearsal. With the master volume control, plus being about to lower the output from 15 watts down to 7.5, it covers all of my needs. Your correct, there is no best, but there is best for my needs. There is also the sound you want. This amp was built for me. I love it, warts n all!

[@TheGuitologist]

There's still nothing like cranking to the sweet spot on the power tubes and having the entire cabinet resonate with the harmonic feedback like a tuning fork! ;)

[@deth800lg]

i love the content brad and i found this video surprisingly educating

[@Floodedisposition]

Man, I need to get a Marshall head like this. The Tool Stinkfist riff sounded so good going through it. I was looking at the 1987X 50w head.

[@demonaz9931]

Good choice of Tool riffs to show off the classic Marshall tone!

[@TheVanShow]

That woke the old Marshall up!!! Awesome work.

[@garyeggleton1142]

this is a video from you that I have hoped to see....thats one of the books ive used to learn about this stuff, and having someone I respect make a video on it is great. The other book that made me interested in amp mods is Dan Torres book "inside tube amps"

[@smokepeddler]

Good info. I moded my 67 Pro with a master volume. Realized it just isn't meant to push the front end. I changed it back to stock.

[@LemmyBass]

Hi Mr. Guitoogist, I installed the same mod in my lemmy style amplifiers and I simply added a 5K potentiometer in series, so fine-tuning even works up to bedroom level : )

[@robertbevilacqua8548]

You really are either up really late or up really early uploading this... Bless you haha

[@boggsty]

Oh yessssssss this is quality content

[@niekdriesschen3376]

awesome man! and killer riffs dude!

[@blkjckgtr3075]

Yep!sounds like a Marshal,good job Brad,Cheers

[@Wildman9]

What a great sounding amp bud.And the mod was simple as hell.Great book too!That owner is going to be happy as a clam with the new found sounds.Hahaha.👍🎸

[@UltraViolence74989]

I have a book by Aspen Pittman called The Tube Amp Book Volume 3 I got in like 1991. It's chock full of all the tube amp schematics from every manufacturer. It looks almost identical to the book you have except the Trainwreck pages. Going to have to get me a copy of that.

[@TheGuitologist]

UltraViolence74 I have the Pittman book too. Both are worth owning. The Weber book is more "pro tip" oriented.

[@jimbeaux4988]

Really an ingenious and simple mod!

[@circuitsmith]

Re 11:55 - the existing coupling caps block any DC current through the pots, thus they won't be noisy. If there's no output tube control grid current (and there shouldn't be) all legs of the pot will be at the same DC potential. I would use audio taper pots here as well. 12:38 - if there's no grid current, changing the grid resistors within reason won't change the DC bias. 13:30 - A possible problem with type 3 is that low master settings might lose some bass response due to the coupling caps.

[@Mark-iq6hi]

Couldn't believe you busted out Tool ! Awesome brother.

[@wolfey4138]

Les Paul through a Marshall... especially in Dropped D, nothing better.

[@outthereassociates7155]

Best one yet Brad.

[@destaagengperwira]

I've been googling for weeks and skip this video at first until i was stuck... And what do i need is only this. Gonna build my first amp which is 2061x, and impossible to use it in my neighborhood so i need this mod. Thanks in advance. Cool vid and playing....

[@KozmykJ]

Sounds sweet, good choice of mod. I recall my lead guitarist back in 1974 having a Master mod done on his 100W Marshall. It worked fine but he had to get used to it's harsher tone. Maybe it was the style of mod that interacted with the Presence like you mentioned . Nice Les Paul you have there. You just showed me a new playing technique. Holding the barre at the nut position, I'll have to try that. I don't have my guitars at home, I'm being kicked out after 30 years of renting this place. 😡 Dirty tricks I can't fight... Life will go on... somewhere or other.

[@oimate4201]

Great explanations and presentation. Thank you!

[@karlkonigshofer2629]

Wowowow, that amps sounds great! 😮😮😮

[@dnspsk79]

Thanks for crawling out of bed to make this video.

[@RockHardRiffs]

Enjoyed the video!

[@AuntAlnico4]

This is ACTUALLY pretty interesting ! This feels like it's about 2 years ago when we just looked at amps 😉

[@normanmozley3659]

I set a 200w stack on fire about 1974 playing a club (2500) capacity, luckily I had a spare, happened at Springfield Illinois. Your friend in tone, Norman Mozley

[@robertcalkjr.8325]

Thanks Brad! It sounds great!

[@Thatdavemarsh]

Great video. I’ve got a ‘74 Traynor that needs this “fix”. Love it’s sound, can’t turn it up past 1.5 in the house...

[@99gwest]

Hell Yeah Brad! Great job, great sound!

[@timidater4803]

just built a twe-1 trainwreck emulator pedal!! love it!!

[@martincockburn6821]

thanks for this video... i just put a volume on my 59hw. works a treat. bit bassy and boomy way down low on the volume but thats no big deal. good job mate :-)

[@SteveHacker]

Love your channel and always love your videos! One of my favorites! One of the best in the world! I must say, though, that the background music while you are talking and explaining is quite distracting...

[@TheGuitologist]

Experiment. Thanks for the feedback.

[@drmaawenz]

Hi Brett. I'm really enjoying your videos, keep them coming. In terms of post PI master volumes, I only had success with those amps running "open loop" output stages, since the "closed loop" output stages will overdrive the PI, since it will try to compensate for the signal that is attenuated by the MV. I consider it a major design flaw (even practiced by professionals), and i need "to do it right" on my Orange OTR since it sounds like sh** unless the master volume is dialed up pretty high.

[@jerrymorganjr]

I've never understood how the mod with the knob in the back of my super lead. Thanks Brad!

[@DBCisco]

I just change the 10 to an 11 on the face plate. lol

[@grhinson]

But this one says 11...

[@MrWilly2204]

That sounded pretty wicked.

[@BigTrouble324]

Gonna go for the "type 3" on my selmer amps. (Now it has the "type 1".) Very simple, less coloring and less signal loss. Why didn't i think of this?? Thanks!!

[@Nazzz65]

You've got a Selmer amp?? Which amp?

[@BigTrouble324]

I've got two T&B 50 MKll with rectifier tubes. Sounds like a mix between a Marshall plexi and Vox AC-30. Great amps!

[@EarlofBaltimore]

Interesting. Mr. Fischer used the stylized version of harDCore which was native to Washington DC. It makes sense. He was located in New Jersey, only a couple hours away. Also, the punk bands of DC in that era were using Marshalls in a lot of cases. Makes me wonder if he modded amps for any of those players.

[@TheGuitologist]

Interesting observation.

[@LTJR.]

@@TheGuitologist no need...in punk, volume knob is knocked off with a rusty chisel set to ten.....yes, both the knob, and chisel set to ten!...... and in Russia.........

[@chokkan7]

Good ol' Brad, rockin ' out in his PJs in the basement to the adoration of his legions of fans, and all the while paying the rent...hat's off to ya, dude...keep living the dream in the US of A...

[@kosmicwizard]

very good video, thanks! i was able to follow your example and install the #3 on my amp! :D only thing i question is your explanation on #1, "cranked to 10" in my mind means maxed volume knob inducing distortion on Marshalls, not over biased power tubes, or whatever it was that you were trying to explain it as. cheers

[@sidneysnottley6414]

Rocking it out using a pick!! .. Great vid.. Even a greenhorn like me got a handle on what went down, mod wise.

[@donaldheitger6731]

I hate getting bad pot,although that doesn't happen to much anymore

[@adksherm]

@@donaldheitger6731 got my card this year, god bless America haha

[@CR3W1SH03S]

LoL!!! I suggested this mod on the repair video when you mentioned how loud the amp was.

[@markhoskins]

I'm a huge plexi Marshall fanboy and I've always wondered about these mods. Do they hurt the amp? Which one is the best for purpose? What happens if they go bad? This video is friggin' gold!!! Cheers Brad! :) :) :) Any chance of doing a video on the cascading gain mods available???

[@PoJoWo]

The first cascading Marshall was the 2204, and the 2203 which became the first jcm800. A common mod is the 'one wire' that is similar to the fender one in that both channels are run in series rather than parallel. Supposedly thats what marshall did for Randy Rhoads and others like Blackmore and Martin Barre but who knows!

[@TheGuitologist]

If you go to my channel page and watch the Amp Conversions playlist, you'll see me adding a lot of cascading gain stages. There's also a good couple examples in my Bassman mod videos.

[@donaldmoser212]

When you were looking at page 32 in your book (8:32 in the video), there is underlined text that indicates each type will sound distinctly different. While it seems Type-3 was the likely best choice, could you try to explain what the tonality differences would be with each type? Also, which type would be closest to a JMP?

[@TheGuitologist]

The "JMP" designation spans a lot of models. Even some 1959 had JMP on them, but I assume you mean the JMP 2203 and 2204 Master Volumes... those are Type 4.

[@donaldmoser212]

The Guitologist - Correct.

[@fishpotpete]

Question about wiring the potentiometer - I saw you soldered the shield to ground on the chassis circuit board end, but I could not tell if you soldered the other end to the pot cover?

[@johnb4024]

He did not shield on the pot. One side is enough

[@alguitarchristie]

It sounds great man! Great video thanks :)

[@jammer70s]

Oy! Now that's a chewy beast, to be sure. It is amazing that it has that much crunch with an essentially unmodified preamp stage- that is, no cascaded stages.

[@PhilipCockram]

Nice Marshall Tones . That LP Classic is sweet too.

[@danletter9357]

Coolest vid yet.

[@hrsey71]

which one is the LAR/MAR PPIMV? I have a MV on my Marshall with a dual pot, but I have no idea which type it is

[@GrrumpDaddo56]

nice job , cool idea on the little earth tag on board securing bolt. Just a small point but it would be nice if you had done a single coil guitar and demonstrated clean up [ if any ] on the guitar volume

[@frustreradpunk]

Is that Nirvana Spank Thru riff at 21:10?

[@SanFranciscoFatboy]

good vid....... i have had this PPMVM (#3 i think) to my 1973 twin reverb............. wow, a whole new rip roars Super Lead Killer !!!!!!!! a super lead w/ a hint o california tone

[@robvoyles]

hi, is 24 guage wire big enough and do you not also solder the shield to the back of the pot? thank you. gonna mod my 73 marshall 50 watt.

[@mfowler8808]

On most Marshalls I use the 1MA pot off the treble wiper for Master Volume. On many other types of amps Including Trainwreck I use the LAR-MAR Larry & Mark PPIMV it is very transparent no change in tone. I use a 250k linear dual pot, 2m2 safety resistors and coax.

[@stevenwilliamdewitt]

Great video and explanation!

[@7125Mhz]

Quality video. Top notch!

[@katman11]

What did you have the pre amps vols channel 1 & 2 set to? Looks like you have the channels jumpered as well