Jca20H Mod thread and owners club.

[BSS]

Originally Posted by Never say Nevar

You will notice it but I love 12AT7's in V2 of amps!

Do you run the gain wide open?

Try a 5751 instead it has little less gain than a 12ax7.

On my Jet City, I run the gain wide open.

[undermost]

Great playing

[chevys&gibsons]

Hi guys, noob here with a 20H. Think it's awesome how you are all coming together to help each other and every other owner out there.

I'm very interested in some mods. But also would like to ask what kind of re-tube yall would recommend for my playing style. I play every kind of music but my usual things are alot of high octane blues, I also play alot of clean chicken picking style stuff too so I want as much headroom as I can get while still being able to push out my lead tones. I'm like everyone else looking for my own sound, and also see alot of potential in this head being versatile enough for me to dump my fender's and vox's with this supporting my clean tone for my country stuff.

I want to add another channel for sure, and a choke. Also is there anyway to make an out for headphone and studio use?

I cannot stand the cheap chinese tubes that is in the head now, they have got to go. What do you guys think would suit my needs for my punchy cleans?

In the end I want to be able to carry this head, my matched 212 cab, my pedalboard, my les paul, and a tele. And that be it, instead of lugging around my pro reverb with me to shows too.

Thanks in advance!

[Edge11]

Originally Posted by chevys&gibsons

Hi guys, noob here with a 20H. Think it's awesome how you are all coming together to help each other and every other owner out there.

I'm very interested in some mods. But also would like to ask what kind of re-tube yall would recommend for my playing style. I play every kind of music but my usual things are alot of high octane blues, I also play alot of clean chicken picking style stuff too so I want as much headroom as I can get while still being able to push out my lead tones. I'm like everyone else looking for my own sound, and also see alot of potential in this head being versatile enough for me to dump my fender's and vox's with this supporting my clean tone for my country stuff.

I want to add another channel for sure, and a choke. Also is there anyway to make an out for headphone and studio use?

I cannot stand the cheap chinese tubes that is in the head now, they have got to go. What do you guys think would suit my needs for my punchy cleans?

In the end I want to be able to carry this head, my matched 212 cab, my pedalboard, my les paul, and a tele. And that be it, instead of lugging around my pro reverb with me to shows too.

Thanks in advance!

Definitely do the clean channel mod (If you want to go a bit further I think and depth mod.
For a cleaner sound I would go with 5751's in either v1 or both v1 and v2.
The depth mod makes this amp seem much louder, so that should give you a bit more headroom.
If you want cleaner than that you can do the scoop mod *hint*(look at how the decatone clean channel is).

[chevys&gibsons]

Originally Posted by mblooper45

Definitely do the clean channel mod (If you want to go a bit further I think and depth mod.
For a cleaner sound I would go with 5751's in either v1 or both v1 and v2.
The depth mod makes this amp seem much louder, so that should give you a bit more headroom.
If you want cleaner than that you can do the scoop mod *hint*(look at how the decatone clean channel is).

Thanks so much for the reply, what would need to go in V3, just a regular 12AX7 of what brand tubes do you recommend and where would be the best place to purchase them? Eurotubes maybe? What kind of power tubes would you go with? You obviously know alot more about this than me. But I will catch on to all of it quick I promise, I'm one of those guys that doesn't leave anything stock. lol

I will start in on the mods pronto...ALSO I wanted to let everyone know. That my indicator light also went out on my head. I got with Dan and the boys,they sent me one out, their always really great to deal with. Put it in the other night, and all is well so far. But I think we might have to come up with an alternative later on if they keep giving trouble. Love the LED, good brightness, good idea. Just that paticular assembly is not made very well IMHO.

[MatchFive]

Where can I find more info on the clean channel mod? Is it something that can be done by someone who is handy with a soldering iron and has good instructions? I have (or will have) the JCA2112RC which is the same amp except w/ reverb..

[MatchFive]

This is the only DIY "kit" I can see that can be ordered..

http://www.bitmomodkits.com/servlet/...ET-CITY/Detail

[Bleedback]

Is it true that the "Bitmo Sufra" mod is the same as Dave Friedmans browneye mod? Read it here on the forum the other day--but just hoping somebody could clarify before I jump in too deep.

[RebelShredmojo]

Got a JC2112RC on ebay! Should have it next week.

Only mod I'd be interested in is a lead boost, anyone doing that yet?

[Edge11]

Originally Posted by chevys&gibsons

Thanks so much for the reply, what would need to go in V3, just a regular 12AX7 of what brand tubes do you recommend and where would be the best place to purchase them? Eurotubes maybe? What kind of power tubes would you go with? You obviously know alot more about this than me. But I will catch on to all of it quick I promise, I'm one of those guys that doesn't leave anything stock. lol

I will start in on the mods pronto...ALSO I wanted to let everyone know. That my indicator light also went out on my head. I got with Dan and the boys,they sent me one out, their always really great to deal with. Put it in the other night, and all is well so far. But I think we might have to come up with an alternative later on if they keep giving trouble. Love the LED, good brightness, good idea. Just that paticular assembly is not made very well IMHO.

I usually buy all of my tubes at antique electronic supply, but this is because they are one state over and i usually receive my parts the day after I order.
Also for power tubes I would go with a matched pair of JJs
Did you find the scheme for the clean channel?
if not I link it in this post.
also play around with v3 use which ever tube sounds best to you, I kinda like the chinese tube in v3.

Originally Posted by TheEternal

Where can I find more info on the clean channel mod? Is it something that can be done by someone who is handy with a soldering iron and has good instructions? I have (or will have) the JCA2112RC which is the same amp except w/ reverb..

It should be the same, yes some one who knows what they are doing should be able to do the mods.
here's the schem
http://acapella-legacy.harmony-centr...3&postcount=43
Be warned that you kind of need to know what you are doing with this schem as (if i recall correctly) the numbers on deus' schem don't match up with the numbers on the pcb so check it against the official schematic.

Originally Posted by TheEternal

This is the only DIY "kit" I can see that can be ordered..

http://www.bitmomodkits.com/servlet/...ET-CITY/Detail

The mods on here aren't kits they are for the most part user developed and submitted.

Originally Posted by Bleedback

Is it true that the "Bitmo Sufra" mod is the same as Dave Friedmans browneye mod? Read it here on the forum the other day--but just hoping somebody could clarify before I jump in too deep.

NO.
Not by a long shot, the bitmo mods bypass the tone stack and add some sort of a cathode cap (if i recall correctly). The brown eye mods change alot of components.

Originally Posted by RebelShredmojo

Got a JC2112RC on ebay! Should have it next week.

Only mod I'd be interested in is a lead boost, anyone doing that yet?

Use a tube screamer, That always works.

[Yarbicus]

 

Originally Posted by mblooper45

Use a tube screamer, That always works.

 

Seriously. +1. I don't get the idea of hard-wiring a solid state boost to an all-tube amp. If that's what you want get a Peavey. I set my JCA20 to clean right on the verge of breakup. They Hyper Pak is PERFECT for getting me authentic grit and the OCD takes me into blessed distortion. Stacking them = !

[RebelShredmojo]

Tube screamer won't boost the volume =)

I've been everywhichway on trying to boost the volume of a single channel amp with alot of gain. Without an actually 2nd volume, or effects loop..It ain't happening

[Dr.Picklebottom]

Originally Posted by Yarbicus

Seriously. +1. I don't get the idea of hard-wiring a solid state boost to an all-tube amp. If that's what you want get a Peavey. I set my JCA20 to clean right on the verge of breakup. They Hyper Pak is PERFECT for getting me authentic grit and the OCD takes me into blessed distortion. Stacking them = !

i know this is all opinion...but i love the gain tone of my JC. the thought of using a hyperpak* (i owned and hated it) or an ocd rather than the amp gain makes me cringe. whats the point? youre using the amp as a pedal platform... If that's what you want get a Peavey

*raspy static is what it sounded like to me.

[Yarbicus]

Originally Posted by Dr.Picklebottom

i know this is all opinion...but i love the gain tone of my JC. the thought of using a hyperpak (i owned and hated it) or an ocd rather than the amp gain makes me cringe. whats the point? youre using the amp as a pedal platform... If that's what you want get a Peavey

OK. I love the overdrive tone of the amp, too. That's why I use the Hyper Pak. It sounds almost exactly like the JCA overdriven.

But, hey, that's just me, and stuff.

[Edge11]

Originally Posted by RebelShredmojo

Tube screamer won't boost the volume =)

I've been everywhichway on trying to boost the volume of a single channel amp with alot of gain. Without an actually 2nd volume, or effects loop..It ain't happening

Get a clean boost then.
Of course it boosts the volume man!

Originally Posted by Dr.Picklebottom

i know this is all opinion...but i love the gain tone of my JC. the thought of using a hyperpak* (i owned and hated it) or an ocd rather than the amp gain makes me cringe. whats the point? youre using the amp as a pedal platform... If that's what you want get a Peavey

*raspy static is what it sounded like to me.

Us your pedal as a boost, set the distortion low or to zero and put the level/volume high.

[theDogger]

Ok I am waiting fora MetroAmp Zero-Loss Loop kit. Here's the link http://metroamp.com/store/index.php?...roducts_id=499

Pretty straight forward to install. Steve has been great in providing info and help. I'll post some more info. later today when I get a chance.

Here is a pic of the connections (rough draft I'll post the final with instruction when I get the loop.


Hopefully now once the loop is in I will be complete.

theDogger

[jet city amps]

Originally Posted by theDogger

Ok I am waiting fora MetroAmp Zero-Loss Loop kit. Here's the link http://metroamp.com/store/index.php?...roducts_id=499

Pretty straight forward to install. Steve has been great in providing info and help. I'll post some more info. later today when I get a chance.

Here is a pic of the connections (rough draft I'll post the final with instruction when I get the loop.


Hopefully now once the loop is in I will be complete.

theDogger

Glad you found a solution on your loop quest, Dogger - and I'm eager to learn about how this is for you to install. Good luck!

[MatchFive]

Originally Posted by theDogger

Ok I am waiting fora MetroAmp Zero-Loss Loop kit. Here's the link http://metroamp.com/store/index.php?...roducts_id=499

Pretty straight forward to install. Steve has been great in providing info and help. I'll post some more info. later today when I get a chance.

Here is a pic of the connections (rough draft I'll post the final with instruction when I get the loop.


Hopefully now once the loop is in I will be complete.

theDogger

It that red thing on the bottom right a level switch?

[spawnofthesith]

Hey Dogger, how idiot proof is installing that loop? I am a noob when it comes to the inside of amps, but I've heard that Metro's directions pretty much make it easy for even beginners to figure stuff out

[Duesentrieb]

I wouldn't ground the loop directly at the chassis - you can try it of course and you may be lucky, but if you're not ground it where the master vol. is grounded.

[theDogger]

Originally Posted by VH4

I wouldn't ground the loop directly at the chassis - you can try it of course and you may be lucky, but if you're not ground it where the master vol. is grounded.

The board gets grounded directly to the chassis and the signal wires are grounded to the back of the Treb and MV pots.

Should work out fine

theDogger

[theDogger]

Originally Posted by TheEternal

It that red thing on the bottom right a level switch?

no that is a by-pass switch.



How easy to install...I'll let you know I'll put a complete DIY write up with a lot of pics...

B+ Power
Red wire with 2w 33k (47k resistor w/ Choke installed) to R3 ( or you can tap into to R5 or R7 the side that does NOT directly connect to a pin 9 of an EL-84) for B+ power

Signal
So 1 shielded wire connects R14 closest to VR3.(Treble) Other end connects to the middle right lug on the switch.
The other shielded wire connects to the end of the lifted 470Kr (Master Volume) Other end connects to the middle left lug

In & Out
White Out to left top lug on switch
Brown In to right top lug on switch

Grounds
Loop board to the chassis ground bolt and Ground the shielded wires to the back of the Treb and MV pots



theDogger

[chevys&gibsons]

looking forward to this!

Originally Posted by theDogger

no that is a by-pass switch.



How easy to install...I'll let you know I'll put a complete DIY write up with a lot of pics...

B+ Power
Red wire with 2w 33k (47k resistor w/ Choke installed) to R3 ( or you can tap into to R5 or R7 the side that does NOT directly connect to a pin 9 of an EL-84) for B+ power

Signal
So 1 shielded wire connects R14 closest to VR3.(Treble) Other end connects to the middle right lug on the switch.
The other shielded wire connects to the end of the lifted 470Kr (Master Volume) Other end connects to the middle left lug

In & Out
White Out to left top lug on switch
Brown In to right top lug on switch

Grounds
Loop board to the chassis ground bolt and Ground the shielded wires to the back of the Treb and MV pots



theDogger

[spawnofthesith]

Ok, maybe this is a noob question, but how in the hell do you get that back plate off??? I took out all the screws and it seems like its glued in there or something...


EDIT: nevermind got it

[spawnofthesith]

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