Building a Marshall 2204 JCM800 50W Clone

akuster777

Senior Member
Joined
Sep 8, 2016
Messages
225
Reaction score
309
Hi all. Feels like time for me to build a Marshall 50 watt. This will be my 9th amp build and highest wattage, my first with EL34s.

Lots of schematics and layouts online; I'll build the original 2204, play it for a bit, and then maybe tweak a few components later.

Chassis (enormous), PT, OT, choke, faceplates, a few small parts from Mojotone. Pots, most coupling caps, and can caps from Amplified Parts. Small electronic components from Mouser.

Decided on an assemblage of Sozo and orange drop coupling caps, CDE silver mica caps, Vishay 1w metal film resistors (which I've had success with in a 5F1 build), and Dales on the plates.

I'm still waiting on some items on order.

Undecided yet whether to use a mojo turret board or grommet my own fiberboard..

Meanwhile, here's what I have:

20191221_151234.jpg

20191221_152657.jpg


Best wishes,

Andrew
 

Deed J

Senior Member
Joined
Apr 2, 2012
Messages
175
Reaction score
78
Make sure to use 5.6K Carbon Comp resistor (non inductive) right at the PIN#5 on each output tube. This should be cut very short and soldered to pin terminal. This will keep any high frequency oscillations from occurring, and will make the high treble sound more natural and organic ;^)
 

yamariv

Senior Member
Joined
Jul 25, 2015
Messages
1,645
Reaction score
994
Nice OP, I'm thinking of doing the same JCM800 build once I finish my 18 Watt Clone. What layout are you using, any chance you could post it?
 

akuster777

Senior Member
Joined
Sep 8, 2016
Messages
225
Reaction score
309
hi @yamariv my second amp build was an 18w tremolo kit from Ceriatone (with minor component adjustments); it was a blast to build and I love the sound, definately a keeper. Good luck with your build!

If you google "marshall 2204 layout" or "marshall 2204 schematic" you'll find a few versions of the layout and schematic--most appear about the same. I taped my components onto a Ceriatone layout, but my filter caps for V1 and V2 will be a 50+50 can cap on the chassis not on the board, also I won't be adding an effects loop like them.

While you're there, check out the different Marshall layouts on the Ceriatone website to see the slight component changes over the years.

Also, you might find helpful the tube depot documentation for their JTM45+ at https://www.tubedepot.com/products/classic-british-jtm45-plus-tube-guitar-amp-kit-head

Most interesting to me has been Rob Robinette's site: https://robrobinette.com/How_the_Marshall_JCM800_Works.htm

I'm still waiting for parts to arrive: including can caps and mounting screws...

I do have these already:

20191223_205558.jpg
 

StubbyJ

Senior Member
Joined
Jan 25, 2012
Messages
1,422
Reaction score
806
hi @yamariv my second amp build was an 18w tremolo kit from Ceriatone (with minor component adjustments); it was a blast to build and I love the sound, definately a keeper. Good luck with your build!

If you google "marshall 2204 layout" or "marshall 2204 schematic" you'll find a few versions of the layout and schematic--most appear about the same. I taped my components onto a Ceriatone layout, but my filter caps for V1 and V2 will be a 50+50 can cap on the chassis not on the board, also I won't be adding an effects loop like them.

While you're there, check out the different Marshall layouts on the Ceriatone website to see the slight component changes over the years.

Also, you might find helpful the tube depot documentation for their JTM45+ at https://www.tubedepot.com/products/classic-british-jtm45-plus-tube-guitar-amp-kit-head

Most interesting to me has been Rob Robinette's site: https://robrobinette.com/How_the_Marshall_JCM800_Works.htm

I'm still waiting for parts to arrive: including can caps and mounting screws...

I do have these already:

View attachment 428277

Smart man.
 

Cjsinla

Premium Member
Joined
Jul 7, 2014
Messages
4,228
Reaction score
3,666
Nice OP, I'm thinking of doing the same JCM800 build once I finish my 18 Watt Clone. What layout are you using, any chance you could post it?
This is the metro layout that I used when I built my jcm800 Valvestorm clone. Mojotone’s link to their diagram seems to be broken.
 

Attachments

Last edited:

yamariv

Senior Member
Joined
Jul 25, 2015
Messages
1,645
Reaction score
994
hi @yamariv my second amp build was an 18w tremolo kit from Ceriatone (with minor component adjustments); it was a blast to build and I love the sound, definately a keeper. Good luck with your build!

If you google "marshall 2204 layout" or "marshall 2204 schematic" you'll find a few versions of the layout and schematic--most appear about the same. I taped my components onto a Ceriatone layout, but my filter caps for V1 and V2 will be a 50+50 can cap on the chassis not on the board, also I won't be adding an effects loop like them.

While you're there, check out the different Marshall layouts on the Ceriatone website to see the slight component changes over the years.

Also, you might find helpful the tube depot documentation for their JTM45+ at https://www.tubedepot.com/products/classic-british-jtm45-plus-tube-guitar-amp-kit-head

Most interesting to me has been Rob Robinette's site: https://robrobinette.com/How_the_Marshall_JCM800_Works.htm

I'm still waiting for parts to arrive: including can caps and mounting screws...

I do have these already:

View attachment 428277
Nice, I'm going to be starting on my 18 Watt build tomorrow hopefully! I've never played a Marshall 18 watt with EL84's..How would you describe the sound difference that makes that amp so unique?
 

akuster777

Senior Member
Joined
Sep 8, 2016
Messages
225
Reaction score
309
Nice, I'm going to be starting on my 18 Watt build tomorrow hopefully! I've never played a Marshall 18 watt with EL84's..How would you describe the sound difference that makes that amp so unique?
Cool! I'd love to follow your build if you start a thread (or post some pics after you're done). My 18w sounds very sweet and woody for cleans and has a glassy overdrive tone. Quite touch responsive. Not alot of lows, but even mids and highs. The tremolo channel is fuller sounding than the normal channel on mine. According to the specimen that the guys at 18watt.com reverse engineered, the normal inputs only use one or the other half of V1--and the breakup that results is a lovely blend of preamp and power tube distortion. However, I wired the normal channel high input to use both sides of V1 for more breakup. When I play, usually I choose one chanel, set it on max vol and tone at about 3:00, set the other channel vol to 0 (jumpering channels doesn't work with these circuits because how the PI is wired), and then I play with my guitar vol and tone controls to get a variety of sounds.

I like what this guy says about his 18w clone, and nice playing as well:

I'm hoping for some time tomorrow to build a bit of the big brother...
 

yamariv

Senior Member
Joined
Jul 25, 2015
Messages
1,645
Reaction score
994
Cool! I'd love to follow your build if you start a thread (or post some pics after you're done). My 18w sounds very sweet and woody for cleans and has a glassy overdrive tone. Quite touch responsive. Not alot of lows, but even mids and highs. The tremolo channel is fuller sounding than the normal channel on mine. According to the specimen that the guys at 18watt.com reverse engineered, the normal inputs only use one or the other half of V1--and the breakup that results is a lovely blend of preamp and power tube distortion. However, I wired the normal channel high input to use both sides of V1 for more breakup. When I play, usually I choose one chanel, set it on max vol and tone at about 3:00, set the other channel vol to 0 (jumpering channels doesn't work with these circuits because how the PI is wired), and then I play with my guitar vol and tone controls to get a variety of sounds.

I like what this guy says about his 18w clone, and nice playing as well:

I'm hoping for some time tomorrow to build a bit of the big brother...
That guy is a heck of a player, great tone out of his 18 Watt, hope mine sounds like that! I've been working on my 18 Watt build for several days and just finished it up and tested the voltages, which the 6.3v heater line is a little high at 6.88vac. I've got some large resistors on order to bring that down a bit. I complicated the build a bit by using old transformers out of a Hammond A0-50 but it looks like it should work out in the end but I have yet to plug in a guitar..I have the Combo cab on order from Sourmash and a new Greenback on the way as well!

Also added a few mods/options, - Master Vol, Tone Cut, Tube rec/Solid State switch and Hi/Low Speed Tremolo switch

20200109_233313_resized.jpg
 
Last edited:

akuster777

Senior Member
Joined
Sep 8, 2016
Messages
225
Reaction score
309
@yamariv that build really looks terrific! I'm looking forward to a sound report, and your opinion about that ss rectifier mod, which I haven't heard in an 18w. Like you, I also got a sourmash cab for mine and it's excellent. I built the amp from a ceriatone kit w sozo coupling caps, and as you can see the chassis has tubes on the bottom:

rsz_20190824_155205.jpg


Meanwhile, these past weeks my job and my son have kept me away from progress on my 2204 jcm800 amp build. I only had time to mount the hardware; my next step is to wire the transformers and heaters.

rsz_20200111_192854.jpg

rsz_20200111_192756.jpg


Sorry so slow. I'm taveling next week, but afterwards I'll have more time for this build...
 
Last edited:

yamariv

Senior Member
Joined
Jul 25, 2015
Messages
1,645
Reaction score
994
@yamariv that build really looks terrific! I'm looking forward to a sound report, and your opinion about that ss rectifier mod, which I haven't heard in an 18w. Like you, I also got a sourmash cab for mine and it's excellent. I built the amp from a ceriatone kit w sozo coupling caps, and as you can see the chassis has tubes on the bottom:

View attachment 432348

Meanwhile, these past weeks my job and my son have kept me away from progress on my 2204 jcm800 amp build. I only had time to mount the hardware; my next step is to wire the transformers and heaters.

View attachment 432350
View attachment 432351

Sorry so slow. I'm taveling next week, but afterwards I'll have more time for this build...
Thanks, I'm happy with how it turned out and will let you know how she sounds once I get the cab in and do some quick resistor mods to the B+, looking forward to updates on your 2204 Build!

Next for me is a 5E3 Tweed Head then I'll move onto a Randi Rhodes tribute 2204 all in white and gold! :dude: :naughty: I have all three of the cabs on order at Sourmash, I've heard great things about them!
 

Cjsinla

Premium Member
Joined
Jul 7, 2014
Messages
4,228
Reaction score
3,666
@Cjsinla yes the chassis and transformers are from Mojotone, most of the rest will be from Amplified Parts and Mouser.

I saw your recent metr jcm800 small box build thread https://www.mylespaul.com/threads/metro-jcm800-small-box-build.422418/

Do you still have two 2204s and a 2203? Any guru advice for my build?
I still have all 4, two are clones. The small box one used Valvestorm parts and Classictone iron. But I’m not the guru, there are others here who know far more than me and are very helpful. All you have to do is ask specific questions.
 

rock09

Junior Member
Joined
Jan 16, 2012
Messages
7
Reaction score
2
I don't have much to add, but any advice to cut unpleasant highs is gold with this one. I have a clone and tone cut, like in Vox, was a must as much as I was resisting to it. Love it, though...lol
 

Cjsinla

Premium Member
Joined
Jul 7, 2014
Messages
4,228
Reaction score
3,666
Turn the treble and mids to 0 and the gain and bass to 10. That amp will sound so dark you won’t believe it. Your ideal settings will probably be somewhere in the middle. Go easy on the treble and mids.
 




Top