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  • Quote Originally Posted by FuelGTRX
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    Anyone know how to mod a JCA100H to reverse the switching of the overdrive and normal channel? As in, when no footswitch is plugged in, it by default the amp goes to the normal channel. If not that, the addition a of channel switch on the chassis would be a cool mod to know.



    Anyone know how to perform these mods?




    My JCA100H defaults to the Normal channel when the footswitch isn't plugged in FWIW, but yes, a chassis mounted channel switch would be excellent. The SLO can have that feature easily, so it should be fairly easy to duplicate that to the JCA.
    Jet City EarhartJet City JCA100H -> Avatar 2x12 -> Celestion LynchbacksPRS SE 245Sterling AX40FOR SALEBuy/sell/trade referencesMy primary band page (Seventh Day)My secondary band page (Adam Evolving)Proud member of the Jet Setters (Jet City Lounge)

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    • Quote Originally Posted by FuelGTRX
      View Post

      Anyone know how to mod a JCA100H to reverse the switching of the overdrive and normal channel? As in, when no footswitch is plugged in, it by default the amp goes to the normal channel. If not that, the addition a of channel switch on the chassis would be a cool mod to know.



      Anyone know how to perform these mods?




      It's very possible. The footswitch is basically just a switch that instead of a toggle uses a stompswitch to change positions. A very easy way to do it is to figure out how the footswitch is wired then wire a toggle switch with the same poles and throws as the foot switch inside the amp. One position will be the od channel and the other will be the normal/ position you put it in when the footswitch is plugged in. It's incredibly easy to do and any tech worth his salt should be able to do it.
      Jca 50h/ 100h/ 22h Mod thread and Owners Club
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      • My 50 defaults to the lead.

        I biased my buddies 50 yesterday and it was biased pretty cold.

        16ma one tube and 8 the other
        Jca 50h/ 100h/ 22h Mod thread and Owners Club
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        • Someone know a brown mod to convert the jet city jca50 into a marshall sounding amp?

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          • I took my slightly modded JCA22H out for it's first gig last night and it sounded even better than it does at home. It cut through nicely. So far, all I've done is cut the bright cap for the OD preamp (which is essentially a permanent Warren Haynes mod if I understand it correctly) and swapped the tubes (Fender/GT v1, Sovtek 5751 v2, Tung-Sol v3, JJ v5 and JJ power tubes). I left the stock 12ax7 for v4 since I didn't know if it'd make that much of a difference with it being the fx loop buffer tube. I might do the SLO and maybe the clean/crunch switch eventually. I got the schematic from Jet City. I'm assuming they'd be OK with me sharing it, but I don't know how to post it here. Some of the values are different from the ones listed on the first page for the JCA50 (which I guess makes sense since it's different power tubes, etc.) but for the most part the layout is the same but with different reference numbers. One thing that's odd is the cap that is going to the normal preamp pot on the 50 (C28) isn't on the 22. Anyway, if anyone needs the schematic or the numbers for the 22h to compare it to the schematics listed on the first page, lemme know.

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            • Post it up, in what format is it?
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              • pdf. It's the whole service manual. I don't know if I'd be able to post pages separately or not. If someone can tell me how, I'd be happy to post it up here. Either that or I can just email the whole pdf to someone who can do it if that's easier.

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                • I'll do it

                  send it to

                  underthebridge11@hotmail.com
                  Jca 50h/ 100h/ 22h Mod thread and Owners Club
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                  • Anyone have the schematics from the JCA 2212C?

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                    • I gotta say after trying all sorts of tubes... nos, chinese, russian, my favorite combo is JJ ECC83 in v1-v3, EH 12ax7 in v4 and a sovtek 12ax7lps in v5. It has great punch and clarity and way smoother than the stock pres. I actually like the stock shuguang el84s too. Theyre not much different than the JJs imo.
                      Proud Member of the Jet Setters (Jet City Lounge)

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                      • Quote Originally Posted by Giobo91
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                        Someone know a brown mod to convert the jet city jca50 into a marshall sounding amp?




                        Brown, as in...

                        brown can mean alot of things.
                        Jca 50h/ 100h/ 22h Mod thread and Owners Club
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                        • brown i mean less gain on lead channel, and more clarity when i do chords, like

                          When i do chords, using the lead channel, the high notes of the chords were confused and "ear-bleeding", on my marshall the chords are perfect on all strings and well defined, what can i do to resolve this problem? I have jca50 and i have replaced all caps with malloy caps of the same value and done the depht mod, can it be a bias problem?

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                          • Can someone send me the jca22h schematic kokoh is offering up.it would save me lot of time. Thanks

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                            • ok got the schematic for the jca22h thanks kokohi5.

                              1)on the jca50 r19 for the slo mod changes to 220k. but on the 22h its a little different it has two resisters..im assuming make the total resistance 220k and keeping r32 that feeds the p.i.?

                              2)on the depth mod.is it as simple as inserting the pot in between the fb wire it self?like cutting it in half and soldering the pot in?

                              thanks

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                              • Quote Originally Posted by tpruitt1
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                                ok got the schematic for the jca22h thanks kokohi5.

                                1)on the jca50 r19 for the slo mod changes to 220k. but on the 22h its a little different it has two resisters..im assuming make the total resistance 220k and keeping r32 that feeds the p.i.?

                                2)on the depth mod.is it as simple as inserting the pot in between the fb wire it self?like cutting it in half and soldering the pot in?

                                thanks




                                2 is correct, sorry I haven't had time to post up the 22h schemes, haven't even looked at them yet.
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