Starting a 2204 Build

[Pete Farrington]

possible to make it footswitchable?

Sure, just need a relay, power supply for it, somewhere to mount them, and socket for the footswitch lead.

But really, what’s the actual benefit? ie will it really be feasible to switch between 2 significantly different amp architectures without also needing to tweak any controls?

 

[ledvedder]

Sure, just need a relay, power supply for it, somewhere to mount them, and socket for the footswitch lead.

But really, what’s the actual benefit? ie will it really be feasible to switch between 2 significantly different amp architectures without also needing to tweak any controls?

Yeah, you make a good point. It's probably not worth it.

 

[Chris-in-LA]

Looking great so far! I am contemplating building one of these if I can make it out alive from my upcoming Hiwatt build.

Does anyone know if you can do a 2204 inside of a 24" wide Marshall head cabinet? Wasn't sure if they'd fit in those smaller box head cabinets, or if they require the 29" wide ones?

The chassis from Valvestorm is only about 18” wide, easily fits in a regular 1987 style Plexi head case.

 

[BenTobith]

The chassis from Valvestorm is only about 18” wide, easily fits in a regular 1987 style Plexi head case.

View attachment 114740

Thanks for the reply!

I was planning to use a Valvestorm chassis for a stand-up style PT. Do you know if that would fit in the small box 50 watt head shell? (9" tall by 26" wide)

 

[Chris-in-LA]

Thanks for the reply!

I was planning to use a Valvestorm chassis for a stand-up style PT. Do you know if that would fit in the small box 50 watt head shell? (9" tall by 26" wide)

Yes. Absolutely. There is a small lip inside the top of the Sourmash cabinet. You still have 5 inches of clearance.

 

[Chris-in-LA]

The standup PT in my Marshall, 1987X stands four and a half inches tall. Sourmash Plexi cab is on the left, contains my Valvestorm 2204.

 

[AndyD]

The chassis from Valvestorm is only about 18” wide, easily fits in a regular 1987 style Plexi head case.

View attachment 114740

Looks very smart! Is that a Modulus Plexi faceplate?

 

[Chris-in-LA]

Looks very smart! Is that a Modulus Plexi faceplate?

No, that came from Valvestorm.

 

[AndyD]

No, that came from Valvestorm.

Looks good!

 

[Rotorcraft230]

Looking nice, I like small box amps.

 

[Smokie 54]

I'm laying out the parts to start what I think will be a 2204 build. A lot of this came from a Modulus plexi kit, but I already have my Ceriatone Plexi. After a lot of back and forth, my thought is to build a straight up 2204, then add any additional mods or tweaks from there. I'll obviously have some extra holes, since thus is a 4 hole chassis. Maybe Jose clipping, FET boost, effects loop, etc. I'm definitely open to suggestions. I'm not exactly certain if this turret board will accommodate a 2204 circuit, but I think back in the day the 1987 and 2204 used the same board? The smaller board on the right came from a Trinity 20 watt jcm800 kit. I used the rest of that kit to build a different amp. View attachment 112977

Hi! Great idea to build your own 2204. While I haven't built one I know my way around them and spent many hours and soldering sessions on exactly that amp, having owned one and used one extensively since 1989. It should be an easy build as they're so easy to work on. My best advice is to be really sharp with the "lead dress" to help keep the noise floor as low as possible. I could provide many other minor tweaks in pursuit of that goal and good clear tone but that's for another post. A small pot for adjusting the bias is a good idea. I made mine capable of using either EL34 or 6L6 types. There are 3 basic modifications I would highly recommend for the 2204 to improve its sound:

First of all DO NOT carry out the Tone Lounge Lizard's mod of replacing the treble peaking with a 68K resistor. It's fun for about five minutes but sounds crappy and muddy and renders the tone stack useless for all practical purposes. I love the guy and have enjoyed reading his site countless times but it's a lousy mod. Instead there are a few (3) key resistors to change the values slightly and you're to perfection.

1) Replace that 470K resistor with something lower (I settled on 330K after several trials) but from 270K to 360K is a good range. Then replace that 470pF cap that's on top of it with something smaller, between 150pF-270pF. This reduces the icepick just enough without losing the crispness, provides a tiny bit more gain, and retains the tone stack's usefulness.

2) Replace the Bright Cap that bypasses the gain pot with a smaller value (anywhere from 150pF to 330pF) but DO NOT REMOVE it. So many tell you to snip it out and throw it away but then you can't dial the input gain down without losing all the high end. No wonder they can't lower the gain pot without losing the brights. By clipping on different values to try, one can find a sweet spot.

3) The 10K cathode resistor on the gain stage can be lowered to achieve more distortion. It's best not to go lower than 3.9K but somewhere between that and 6.8K warms up that stage nicely without turning into a buzzsaw. If you go "apeshit" (lol) like 1.5K it will sound like crap.

These three are the only ones the 2204 needs (imho).

A mod I'd consider for a new build would be to make the Low and High inputs switchable so you could go between the two without pulling the cable out. I've never had a need for parallel inputs on this amp and a single input jack would be great. A pot could be installed to help balance the levels. Just something I always wished for my 2204 but not enough to butcher the stock configuration.