Marshall 1959HW - Stealth José Mod. TONES & DIY GUIDE!!

An amazing hand wired 100w Marshall Plexi has come in for some treatment. The owner wants to convert the amp into something more modern, tighter bass, more gain and a useable master volume to allow cranked style gains at any volume. We agreed on a José style mod, but keeping the amp completely stock looking.
0:00 Play in - José mod, no clipping engaged
0:41 Amp Intro
1:08 First thoughts
2:49 First tones (stock)
3:35 Modded tones
5:43 Knaggs LP - no clipping
7:27 Knaggs LP - clipping engaged
11:10 Les Paul - clipping engaged
13:17 At The Bench
37:02 Picture guide
44:40 Wrap up
headfirstamplification.com

[@warrenparker7312]

Great stuff as always Jason, you are the man!

[@lechstryzewski9350]

Awesome stuff Jason !!! Thanks for sharing.

[@mookytc]

Sounds great Jason! Fine playing and love the guitar that opens the video.

[@leosun8469]

Great video- thanks for taking the time to make this and explain your hard earned knowledge. That amp kicks ass!🤘🏻

[@mikefalcon85]

That guitar sounds epic on all your amp build 🤘awesome vid jase👍

[@jasonstone1046]

Sweet Knaggs mate, lovin the tonez :D

[@tubehead4345]

This Jose mod is killer!!! Another awesome video!!! Thanks! 👍

[@HeadfirstAmps]

Glad you like it!

[@PurposefulPorpoise]

every second of this video is glorious

[@ericandrews1661]

I appreciate all the knowledge and insight that you give not many people would do that thank you your talent also shows in your playing and your work it's always a pleasure

[@HeadfirstAmps]

I appreciate that, thank you!

[@SeQFreQ369]

Every one of your vidz I come out with a better understanding, and this one is worth watching even if you're not (yet... muahaha) interested in Jose mods, there are so many really useful tips and hints here. It's like a 1 on 1 workshop, I really felt like I was learning something. Muchly appreciated. Cheers Jason ;)

[@HeadfirstAmps]

Wow, thank you!

[@Joey.Darkwoods-Studio]

Sick, sick tone!!

[@RDamps]

What a beast!!!! beautiful

[@Skman22]

Yup...just a great amp. I have a feeling you could plug any guitar into this amp and it would respond favourably. It's uncanny how some amps are just that way. Really a beautiful build. I love how these HW builds on turret boards are ultimately easy to work on and service too. lots of space and a real lack of confusion in the layout, I'm learning this is and should be the way IMO. I plan on implementing the zeners in my current build, yet to decide on the best way to go about it but this is a nice option. Cheers, once again Jas a great vid and a pleasure to get a look into this amp.

[@LP_Freak]

Sounds killer!

[@roberteffler3382]

These vids are priceless

[@eds4754]

THIS IS THE TONE. killer work

[@HeadfirstAmps]

I trust your ears Ed, so this is high praise. Thank you man. 🙏

[@eds4754]

Very kind Jason. I totally overlooked these 1959HW’s but from what I’ve read, it really sounds like they put the R&D work in and picked the right components and circuit. IIRC the PCB 1959’s (slp etc) and 1987’s are based on different years to the HW

[@BigW72]

I finally converted one of my SL to this spec. I put the first to stages with push pull to engage the bright caps. I’ve decided I do t line bright cal on stage 1 and for stage 2, I like the 2200pF Having the switchable normal channel works way better than I thought. Not my favorite spec but I do like it and I thank for the knowledge you’ve shared…..made it much easier.

[@joshk5686]

I really dig those Saturday Night Special pickups. I have them in my Jazzmaster and they are really dynamic and organic pickups.

[@HeadfirstAmps]

Thay are a great hot PAF!

[@KB_Joys]

Man that thing rips!

[@batpigguitar]

Sounds killer man

[@HeadfirstAmps]

Thanks man. The 2204 is next!

[@bryanwilliams3665]

Awesome Mods Jason.. Love the Black Sabbath "Into the Void" at 11:10....That wasn't in our repoitoire at 'Rose & Crown' in the 1990s nor yours from memory lol! Cheers mate.

[@HeadfirstAmps]

Haha, nope! Soundgarden did a killer cover of into the void. That ‘Kick’ gig made me brush up on my fuck chops…did a lot of good for me!

[@terrydaniels9399]

A little Richie Kotzen on your Strat. Great video as well.

[@Billywagner22]

The tone is glorious!

[@ioncewas]

I love being schooled like this. Every vid I pick up something new. Killer. Just killer, Jason. These are the tones that'll put some hair on your ass!

[@aquilarossa5191]

Marshall should hire you and open a hot rod division, plus as an amp design consultant. Milton Keynes is a bit grey though. I liked it a lot when i was a kid, but it sure ain't sunny Melbourne. NZ is good, but getting parts to mod is not simple. Everything needs importing. I want to mod my Plexi replica, but I think I will just get a 20 watt Silver Jube. My Two Notes load can not handle that monster Plexi, even though it's just a 1987. It will cope with a baby Jube though. Once the warranty is out, mod the crap out of it. I dunno. I end up just using Amplitube 5 instead. It's too easy.

[@HeadfirstAmps]

Thank you for your words of encouragement, much appreciated. I love the old circuits, but I do enjoy creating new tones from these vintage designs!

[@alexcatlow]

Facebook is down, may aswell catch up on all your videos 😂

[@tyisdead8234]

Ohhhh yeah.... Chunk for days mate.

[@FourT6and22]

Instead of a fixed resistor for one of the gains, you can use an internal trim pot so it's at least tunable if the end user wants to mess with it.

[@HeadfirstAmps]

Cool idea

[@dixonrooster5954]

Great video mate. Love what you dom especially the wizard and Jose stuff. Have you heard much about the old Friedman naked amp? Thing sounds really cool. Kinda like if mesa mark series was made in UK. I believe it's a Naylor preamp into a late 70s power section with some NFB stuff going on. Keep up the good work!

[@HeadfirstAmps]

Yes I’m familiar with it. Unique and great sounding.

[@PerfectCircle91]

​@@HeadfirstAmpsHey Jason long time fan and huge supporter of what you do and the fact you share your vast expert knowledge and time with us. As related to the OP I too am VERY interested in the Naked circuit. Can I direct message you about it further?

[@PhuketMyMac]

The "Louis Rossmann" of guitar amplifier repair/modding.

[@HeadfirstAmps]

Haha, wow. Thanks. I know who you’re referring to, and in your industry an absolute giant!

[@KrstovicNikola]

Amazing as always... Im sure u have been asked and answered already but what IR do you use for these videos?

[@rdavid3848]

My fav sound is a woolly bottom when bass on 10, but I can back away if I like.

[@clintn6677]

Into the void was a good choice

[@univalve1]

three days in to owning one it blew a filter cap. ill see if its a persistent issue. reamp plates were 220 volts through a 50/50 500 volt cap so it should have held up. sounded great until then. was running it hard through an attenuator.

[@heythere6983]

I wish I could play some of these in person because I’d be willing to buy if I enjoyed them over my jvmhjs . I can hear a bit of a difference online but I wonder how pronounced it is in real life . Ideally I want an amp that lets in enough of the round cleaner one and has enough distortion and compression to get near the level of distortion here, with maybe an overdrive circuit with a bit more on top. I guess my concern is if it’s too smooth how well it would cut in a band mix . And too much distortion just sounds washy and unfocused in some scenarios My jvm is nice but maybe a tad too sizzly and clickity/clackity . Also there really isn’t much bottom end punch. I feel like these older styles amps don’t ever sound too sizzly . But I wish I could compare and see if it’s even worth it . I find I like a clearer tone but still gainy and distorted with punch . Idk know if my jvmhjs is easy to mod. I thought about the plexi studio but for that price I might as well get an original plexi for an extra grand

[@SuperSeanXXX]

I've had my 1959 wired as a 2203 stock before then decided to try it back to 1959 stock with a ppimv..and 68 filtering....it has a tube buffered effects loop (Lee Jackson style).….but my tone is kind of getting lost in this high fizzy buzz when in high gain mode...it does it no matter what I do....(no ppimv, with ppimv) 2203 or 1959....I'm thinking the shielded cable I'm using on the inputs to grids of v1 are causing it but I'm not sure...it's driving me bananas....I'm curious to know if this pre tone stack master can do bedroom volumes good through a 4x12 cabinet with v30s and g12h30s mixed?.....I like the evh tone but I don't wanna have to use a Variac to get it....I'm wanting to get it with a more modern mod like what your showing here.....I like your channel....it's cool.

[@cap217cap217]

What are the differences in a .1, .22, .33 after the 10k feeding the pre tone stack master?

[@MrGruenrock]

That Amp sounds Awesome. I like the non-clipping better. It fits more my taste. I do own a JMP2203 from 79. That Amp is stock, beside a fx loop. Curios, hi does the mod compare to a jcm 800? Does it have more or less gain? Is the mod more „friedman-like“? I like it and a friend of mine could do the work Greets from Germany

[@donlynch8285]

Hi! Would it be possible to know what cab/mic youre using and if you have an IR for that

[@irishRocker1]

I built an amp with a 1959 preamp and a 5W 6V6 power amp. It sounds good, but nothing like this amp. It sounds more like a classic crunchy plexi and needs to be turned right up to fatten it up. I think I did the high gain mod, cascaded the first gain stages instead of parallel. What other changes are recommended to get this kinda sound? Maybe it's my power amp tube choice? I think I left out the phase inverter cos it is only driving one power tube. So 2x 12ax7s and a 6V6. My memory should be close, i built it like 14 years ago but want to take it out and get it going again.

[@Fluffetftw]

Great stuff! Do you draw your own schematics? And if so, which program?

[@HeadfirstAmps]

Yes I do. I do all my PCB design work using Altium.

[@DiegoCastro-kn9tl]

Thanks Jason for another great video. what's does that cap across bypass switch?

[@HeadfirstAmps]

Across the Standby switch? That's there to prevent a audible pop when switching the standby.

[@DiegoCastro-kn9tl]

@@HeadfirstAmps yes, i meant standby. Do you know the value of that cap?

[@HeadfirstAmps]

I didn't check it in the amp, but it's common to see 4n7 there

[@anondusery1271]

Hi, what was the NFB value and tap after modding?

[@wethriveIn425]

The only part I’m hazy on is the 1meg to ground simulated pot. The resistor connects to the 2n2, then to the v1 cathode resistor grounds?

[@HeadfirstAmps]

Not sure what you mean. You can post the question in our Evolve DIY group on FB if you like.

[@submarineofdoctors]

Wow, that is the tone! Would you recommend bright cap values for the treble channel if i want to keep the two channels separated? I am also considering lowering the bypass cap in the normal channel for tightening the bottom end. What values do you suggest?

[@HeadfirstAmps]

Sure, bright caps are essential IMO to retain that Marshall roar. Re the normal channel, you could try say 10nF first coupling there, or even down to 2n2.

[@submarineofdoctors]

@@HeadfirstAmps Thanks a lot mate

[@russellesimonetta3835]

Question,, are those yellow caps vishay ??? Also ,, in your pcb builds what kind of caps do you like?? Have you tried the mallory 150's? The mojo dijons?? The vishay??

[@HeadfirstAmps]

I use Mallory 150's a lot

[@Hakujap1]

Jason, how do you monitor that sound? Are you using a cab or going through your monitors via load box or something? Sounds killer!

[@HeadfirstAmps]

In that room Bryan, it's the Suhr Reactive Load, Axe FX and monitors.

[@SuperSeanXXX]

Hey Jason you said to experiment with the 68k/68k voltage divider....I noticed you used 68k/100k .... But your using a cab simulator or impulse response right?....I'm just wondering what you would suggest for that voltage divider with a 4x12 cab with v30s and g12h30s loaded in it?

[@HeadfirstAmps]

The 100k there will deliver more gain and bass. Tune it to your own tastes

[@usernameihavechosen289]

Hi, how much more complicated would it be to add a 12AX7 tube into the 4th (0th) unused hole of the chassis and retain the 4-input style of the amp? Will it give two additional gain stages or only one due to the parallel two-channel layout?

[@HeadfirstAmps]

Yes, absolutely possible and that’s how José would often do it.

[@SuperSeanXXX]

Hey man I tried that cascade and the 68k/100k voltage divider on a marshall clone I built...but with a regular master volume and the two gains...... and no diodes yet....and it sounds killer...it's got that Dr. Feel-good tone pretty good....I can't believe that it sounds that good cascading it like that....makes you wonder why didn't Jose just cascade the stages instead of putting in another tube....

[@SuperSeanXXX]

I am so glad I get to keep my tube buffered effects loop....lol

[@SuperSeanXXX]

Oh yeah if I decided to use the two gain pot setup with a gain for each stage would I need another 1000pf cap on it as well?

[@HeadfirstAmps]

I'd put it on a switch is possible. Or just tune by ear. It can get too bright.

[@heythere6983]

Btw do you use variants to voltage regulate these old amps since they Are meant to run on 110 volts?

[@HeadfirstAmps]

I do have a variac for testing, but normally I run at wall voltage.

[@rangerdoc1029]

That's the shit right there! Do you have schematics in the customer folder? Is this identical to the Cali now?

[@HeadfirstAmps]

very similar

[@marvelharris9540]

Jason, did you ever do a walk through tutorial on how to do the BE mod to a 2203? I have a handwired 2203 I would like to mod to those specs

[@HeadfirstAmps]

Not a BE (yet). Mostly hot rodded 2203/2204 circuits. It would be easy enough to do, it would mean losing the low input I think.

[@DamianMurdoch1]

Would love to see this!

[@DamianMurdoch1]

Would love to see this!

[@SuperSeanXXX]

Hey Jason if you use a 1 meg to ground in place of the gain pot, do you have to come off one side of the 1meg to go to the next stage if so which side.....

[@HeadfirstAmps]

The non-grounded side. But if you try say a slightly lower value you can control the gain and bass, if you find it’s too much. Or setup a voltage divider that simulates a 1m pot dialled back a bit.

[@SuperSeanXXX]

@@HeadfirstAmps hey man thanks for showing me this stuff....the only thing left that I have a question about is the 470k/470pf that goes between the jack and volume on a standard 2203....if I use the two volume method do I just use a straight wire there or just take it out....is it only for use with the low input?

[@seanriley9045]

Great tones! Are you using an IR loader and load box or a cab? Thank you

[@HeadfirstAmps]

Suhr RL and Ownhammer IR in this clip

[@nobirdsnomasters]

@@HeadfirstAmps which own hammer IR?

[@HeadfirstAmps]

GNR pack, 57 and 121 blended.

[@cap217cap217]

You changed the cap on V1a from .022 to .0022 and that lowers the bass going in, right? What if you left V1a at .022 and changed V1b cap to something else? Does it have the same effect? And why would someone use a Xicon Polypropylene in V1b vs a mustard or sozo style cap? I ask because I have a modded super lead that has this. I dont know the value because its on the other side.

[@HeadfirstAmps]

Yep, 0.0022 reduces the bass no matter what position it was in. Maybe the mustard was dead and the Xicon was all the amp tech had laying around!

[@cap217cap217]

@@HeadfirstAmps But Ive even seen Jose amps where he changed this cap to a poly. It seems that this cap in this value in this position had some sort of sauce that modders liked.

[@icepick859]

Im going to make a 68 plexi with evh specs (47k off 4 ohm tap, 50k mid pot, 820 resistor on v one b etc) it has a ppimv and I'm going to add the jose master to circuit. Whats your thought? Will it sound good? It sounds amazing right now with just plexi plus evh specs. But I want just a tad more gnarlyness

[@HeadfirstAmps]

The Jose master will not be that useful if you have a ppimv. Do one of the other is my advice.

[@icepick859]

@@HeadfirstAmps what do you think about a ppimv and then adding in the sat switch with diodes on it in the same place the Jose master would be? so I have the diodes on a switch instead of master

[@SuperSeanXXX]

I have a 1959 circuit that I want to do this mod to.....where can I purchase the zener diodes you use?

[@HeadfirstAmps]

Mouser. 1N4747 20v 1w Zener.

[@DistrictSoundLab]

Very cool video! Although I wonder - Why not just sell the amp and get a Friedman or something else that will get you that tone to begin with? It's turning a glorious, classic and expensive thing into something else that already exists

[@HeadfirstAmps]

I think it's because people want something unique, something that you can't buy at Sweetwater.

[@DistrictSoundLab]

@@HeadfirstAmps true!

[@MrGilbert41]

@@HeadfirstAmps Plus it says Marshall on it and not Friedman, that's cool too..... no offence Dave...

[@SuperSeanXXX]

I think I get it....the low input will just go straight into the second half of v1 through the 68k making it traditional 1959.....I hope I'm right....lol

[@SuperSeanXXX]

What kind of caps are those .68 bypass caps.....the synergy royal mustards are so huge...

[@HeadfirstAmps]

Those are MKT1813 off the top of my head.

[@icepick859]

Is this basically the same instructions for my 1968 plexi clone?

[@HeadfirstAmps]

Yeah sure, absolutely.

[@SuperSeanXXX]

The push pull master is a meg pot right?

[@HeadfirstAmps]

yes

[@SuperSeanXXX]

I thought Jose used a .22 cap on the master

[@cap217cap217]

Have you tried using 1uf/1.8k in V1a?

[@HeadfirstAmps]

Yes, I find it a little too fuzzy and bloated

[@cap217cap217]

@@HeadfirstAmps I just tried it. I agree. I went with a .68/3k3.

[@rikm2625]

I'm lost lol I am wanting to try this as it sounds killer but your sites changed and i can't find it. Any help would be very appreciated!

[@HeadfirstAmps]

DNS change over. Website is back online now.

[@rikm2625]

Thank you! @@HeadfirstAmps

[@Frankentoane]

Is the push pull pot a 1meg pot as well?

[@HeadfirstAmps]

Yes

[@johnmarshall3903]

Jason, where can these pots be purchased from? Thanks in advance.

[@HeadfirstAmps]

I think these are the ones I have, www.amplifiedparts.com/products/potentiometer-alpha-audio-solid-shaft-dpdt-7mm-bushing

[@johnmarshall3903]

@@HeadfirstAmps Thanks for you quick response! Your new Headfirst amp sounds great btw.

[@SuperSeanXXX]

Your switch for the diodes only looks to have 4 contacts instead of 6.....I guess it's just how the picture looks

[@Cpt_Adama]

Sounds Awesome. How does this mod compare to Mick Mars (Dr. Feelgood) SL amp that Pete Thorn demoed ( kzbin.info/www/bejne/qJ3Jo2euppeNsLs )? In other words is this the same? Never mind you answered this is video after I wrote this 😁 I really love that Dr. Feelgood tone.

[@SuperSeanXXX]

You forgot to show the low input....that's the only thing I'm not sure how to implement into the circuit....I know it goes before the second stage but how....lol

[@HeadfirstAmps]

Same as 2204. The low input goes into the gain pot....

[@SuperSeanXXX]

@@HeadfirstAmps so if I use two gain pots I should go into the low input from the .0022u coupler and then into volume 1? Then into the 68k divider....I was hoping there was a way to implement the 1meg resistor on the low input to make it a high sensitivity as well....but I don't think you could run the high input through it then....

[@SuperSeanXXX]

@@HeadfirstAmps actually it seems like I should go from the .0022 cap to volume 1 then into the low jack to the 68k/100k divider into second stage back through .022 into volume 2 into 470k/470k/470pf then to v2a stage

[@michaeldemento3480]

Sounds like an 800. An I wrong?

[@HeadfirstAmps]

Well, kinda but not really. I detail the circuit in the clip.

[@mrt7476]

Wonderful. But why didnt the owner just get a JCM800 or a JMP 2203? Bizarre to spend so much money on a 1959HW and then have it modded to what a cheaper JCM does….

[@HeadfirstAmps]

I think he just wanted to hang on to amp that he’s had for years

[@pk952]

For one these look better and also have four inputs to do any mods you want without drilling extra holes. That alone ought be enough 😉

[@HeadfirstAmps]

@pk952 you’re right, 💯 people buy them because of how they look.

[@sempercompellis]

i just don't understand why someone would do this to a HW plexi?? From what I understand the 50w 1987 is more 2003/4 than it is a 59/87 plexi.. Correct me if I am wrong -ive always heard 1987X was just a plexi in appearence and more a mid-late 70s MV amp. YOu could buy 2 of those for the money you would get for selling the 1959HW. You may argue that it is different because you would be trading 100w for 50w....but aren't we trying to get more gain here...wouldn't the 50w lend itself to that better. IDK??? the 100w plexi is not very different to a JTM45 (obviously barring the wattage) what are there....3 component value differences... The Super Bass pretty much is spot on a 100W JTM-45. One of the Online/KZbin amp techs repeatedly makes the joke how Marshall wasn't its own company until the mid 70s... before that they were building higher watt fender tweed clones. I think people hear the word Plexi and it conjures up something that doesn't match reality. This was a great video btw.!!

[@HeadfirstAmps]

They do it because they want more gain and tightness. Metal players. The 50w 1987 is not a 2204, it’s the same as a 1959 except for the power section.

[@sempercompellis]

you replied to a staw man- 1987X not 1987 ..big difference@@HeadfirstAmps

[@HeadfirstAmps]

No there isn’t

[@TheXxPSYCHO]

How does the diode clipping after the valves compare to if the clipping was done before V1?

[@HeadfirstAmps]

Before V1…meaning before the amp? That’s what a distortion pedal is.

[@TheXxPSYCHO]

@@HeadfirstAmps yes, distortion pedals use diode clipping. Congratulations. And having them after the last valve is just like putting a distortion pedal in your FX loop. Do you put your distortion pedal in the FX loop? Didn't think so.