Guitar Gear Forum

I got my 2204 all set up with a 3 way stock/JEL/34 switch. Also, a v2a cathode switch for no bypass/0.68uF/22uF. I used a 4n7 bright cap because... Why not?

https://on.soundcloud.com/MJTwA

https://on.soundcloud.com/ja6n6

https://on.soundcloud.com/3WqGq

I'm at a gig right now but I'll listen to it later. The JEL mod is killer though!!

Nice!!! All three sound killer

spawnofthesith wrote:Nice!!! All three sound killer

This. Nice job, awesome tone machine!

Wow - very different gains - love it!

Any chance of some pointers once I start digging back into my 2204 kit?

Tortuga wrote:Wow - very different gains - love it!

Any chance of some pointers once I start digging back into my 2204 kit?

Sure! It's actually pretty simple with a 3 way dpdt switch (on-off-on).

Tortuga wrote:Wow - very different gains - love it!

Any chance of some pointers once I start digging back into my 2204 kit?

Like Ledveder said, it's easy stuff for the JEL mod.

SIR 34 mod is a little different sort of flavor, but just as easy to do. Definitely hit him up (or I) for some pointers if you need some.

ledvedder wrote:I got my 2204 all set up with a 3 way stock/JEL/34 switch. Also, a v2a cathode switch for no bypass/0.68uF/22uF. I used a 4n7 bright cap because... Why not?

https://on.soundcloud.com/MJTwA

https://on.soundcloud.com/ja6n6

https://on.soundcloud.com/3WqGq

I'm definitely going to put a switch on my V2a bypass cap. Originally had a 22uf, but this weekend changed to a .68 - and that made a pretty big difference in the feel of the amp. I will say, if you're doing these mods to smaller EL84 amps (like a Jet City 20H), 22uf may be a better choice there.

BTW - clips sound killer

Yeah man these clips sound great!!!

Would you guys mind posting up the changes you'd recommend for the JEL mod? Really liking the sound of that - especially if it's switchable back to stock

Tortuga wrote:Would you guys mind posting up the changes you'd recommend for the JEL mod? Really liking the sound of that - especially if it's switchable back to stock

First coupling cap change from .022 to .0022 (I always like this on a 2203/2204 regardless of what other mods I'm doing)
Change the 10k cold clipper cathode to a 2.7k, and bypass with .68uf (usually electrolytics recommended for this one)
Add a 220k across the outer lugs of the Gain pot
Bypass the 3rd gain stage 100k cathode with a 470p
Add a depth control pot, or just wire in a 220k // .0047 cap
Change NFB resistor to 47k, and move to 4 ohm tap - again another standard mod I like with these amps
(not part of the JEL mod, but might be worth looking at - change PI 'fizz cap' from 47pf to 100pf)

*You can drop a 3k3 or similar parallel on the stock 10k cold clipper to bring it down close to 2.7 if you don't want to remove that resistor
**Drop a 50k parallel on the factory 100k NFB to bring it down close to 47k if you don't want to remove it.
***Lar-Mar style PPIMV is also not a bad thing if you are playing lower volumes. I have mine set at noon almost all the time.

If you want a little more of a Jose/Friedman style thing, you can change the V1b plate from 100k to 330k and bypass with a 470p

Jason walks through all the mods in this video. https://youtu.be/kWub3TvLyeI

I put the changes on a 3 way switch similar to this. When switched to the right, it's grounding the 3k3/.68 in parallel with the 10k cold clipper, as well as grounding the 220k from the gain pot. There are a few other minor changes with the JEL mod that aren't as noticeable, like the 22uF bypass cap on the 3rd gain stage and the 470pF bypass cap on the 100k cathode follower. I have the cathode follower bypass cap permanently in.

I'm not sure why, but I no longer get email notifications for thread responses. I have the option checked off.

Awesome!!! Thanks dudes!

Will probably get back to you after I get back to building and try not to blow my shit up

Sounds good all around but really liking the JEL clip.

these sound good

Finally checked out that video - I didn't realize they were publishing their schematics

https://headfirstamplification.com/mods ... %26-repair

Tortuga wrote:Finally checked out that video - I didn't realize they were publishing their schematics

https://headfirstamplification.com/mods ... %26-repair

Yeah man! I've learned a ton from them. His Facebook DIY group is awesome too!

ledvedder wrote:Jason walks through all the mods in this video. https://youtu.be/kWub3TvLyeI

I put the changes on a 3 way switch similar to this. When switched to the right, it's grounding the 3k3/.68 in parallel with the 10k cold clipper, as well as grounding the 220k from the gain pot. There are a few other minor changes with the JEL mod that aren't as noticeable, like the 22uF bypass cap on the 3rd gain stage and the 470pF bypass cap on the 100k cathode follower. I have the cathode follower bypass cap permanently in.

Is the 3-way switch a DPDT On-Off-On?

Is it 3-way because you're switching something else on the other side (ie: the SIR mods), giving you a selector that does JEL/stock/SIR?

Is the line going between the upper and lower center lugs representing a jumper? I'm guessing it must be, otherwise the resistor wouldn't jump both lugs of the pot

Hipster Salad wrote:

Tortuga wrote:Would you guys mind posting up the changes you'd recommend for the JEL mod? Really liking the sound of that - especially if it's switchable back to stock

First coupling cap change from .022 to .0022 (I always like this on a 2203/2204 regardless of what other mods I'm doing)
Change the 10k cold clipper cathode to a 2.7k, and bypass with .68uf (usually electrolytics recommended for this one)
Add a 220k across the outer lugs of the Gain pot
Bypass the 3rd gain stage 100k cathode with a 470p
Add a depth control pot, or just wire in a 220k // .0047 cap
Change NFB resistor to 47k, and move to 4 ohm tap - again another standard mod I like with these amps
(not part of the JEL mod, but might be worth looking at - change PI 'fizz cap' from 47pf to 100pf)

*You can drop a 3k3 or similar parallel on the stock 10k cold clipper to bring it down close to 2.7 if you don't want to remove that resistor
**Drop a 50k parallel on the factory 100k NFB to bring it down close to 47k if you don't want to remove it.
***Lar-Mar style PPIMV is also not a bad thing if you are playing lower volumes. I have mine set at noon almost all the time.

If you want a little more of a Jose/Friedman style thing, you can change the V1b plate from 100k to 330k and bypass with a 470p

Really loved these explanations and your notes in conjunction with the Headfirst video... making total sense. Many thanks, as usual!!!

PS - (sorry for the temp thread hijack) I brought my JCA50H out of storage, and it's a noisy muddafugga... wondering if you might help me with some understanding of heater elevation and any other noise-reducing mod. Also may do the SLO mod that I've always been interested in - may hit you up for some more help down the line, but that's for another thread.

Jason shows DC elevated heaters at the 56 minute mark of this video, https://youtu.be/cXG5z-INT-4. Basically you tap off of the B+ supply and use a voltage divider and smoothing cap to bring it down to around 65v. Then connect the heater center tap, which is normally grounded, to the voltage divider 65v reference.

^this


Also, if you're bringing the 50H out of storage, check into modding the loop so it can be more pedal friendly. Epic/Bryce has a really good mod for it. I did it to my SLO modded 50H, and at some point might do it to my 100H.

There's also a simple "clean" mod you can do to the Normal channel - which is basically a switch that sends more signal to ground via resistor. (excuse the shitty solder joints - I did this years ago before I really paid attention to things like that)

Well... almost a year later


I'm seriously considering trying the JEL mods to my new 2204 build (thread here, if anyone interested: viewtopic.php?f=5&t=54405), but want to be able to switch between stock and the modded version. I really like what you did with yours. For the stuff you have to change that doesn't wind up on the switch (like the 22n to 2n2 cap on the gain channel input, NFB/fixed depth changes, and cathode bypassing on V2), how does that affect the stock tone and feel?

Tortuga wrote:Well... almost a year later


I'm seriously considering trying the JEL mods to my new 2204 build (thread here, if anyone interested: https://guitargearforum.com/forum/viewt ... =5&t=54405), but want to be able to switch between stock and the modded version. I really like what you did with yours. For the stuff you have to change that doesn't wind up on the switch (like the 22n to 2n2 cap on the gain channel input, NFB/fixed depth changes, and cathode bypassing on V2), how does that affect the stock tone and feel?

Changing the first coupling cap from 22n to 2n2 cuts a good amount of bass, so it makes it tighter and more crisp in the lows, then with the depth control you sort of bring it back at the end of the signal chain. Cathode bypass caps usually bring in a little more midrange and a touch more perceived gain if I remember right.

I went back and forth with the 34 and JEL mods on my 2204, and ended up just keeping the JEL style mod personally. Did a few minor tweaks on top of it, and it's a pretty good contender for early VH type tones.

I think the JEL mod is my favorite setup for a 2204. It's what the 800 should have sounded like in the 80s. It's no wonder so many players were doing similar mods back then. Or even boosting it.
The stock, unboosted tone of the 800 is not all that great IMHO.

Last year I did a big 2204 comparison and the JEL was my favorite by a large margin.

My Egnater Seminar amp has the V1 mod on the second gain stage cathode. 2.7K resistor with a .68 bypass cap same as V1A. Depth mod with a similar setup except on the 8 ohm tap. I may switch it to 4 and give that a whirl. It’s a pretty awesome little 50 watt amp.