Announcement
Collapse
No announcement yet.

Jca50H / 100h/ 22h mod thread and owners club

Collapse



X
  • Time
  • Show
Clear All
new posts







  • Quote Originally Posted by kaoslord
    View Post

    I would like to reduce gain and compression on my JCA100 - which mod do you suggest ?

    has anybody tried to play with the cathode bypass caps on V1-V2-V3 ?




    Honestly, turning the gain knob down does exactly that. Is there a certain style/tone you're after?
    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)

    Comment








    • Quote Originally Posted by sahlomonic
      View Post

      Honestly, turning the gain knob down does exactly that. Is there a certain style/tone you're after?




      With my band I now use a 7... but I like different things, from texas blues to death metal

      Actually I am happy of the sound I get from this beast but was just wondering if one could do an easy mod to reduce gain & compression, adding some edge and a more "nervous" feeling to the amp...

      Comment


      • I've got a 22h coming next Thurs. Are there any pics/ diagrams of these mods? I'm not very good at read schematics, but do ok when I actually see a mod
        Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery.-Winston Churchill

        Comment


        • Regarding pictures/diagrams, check out posts 93 and 109. They cover the Depth Mod.



          I think the post #109 picture is the jca50. Keep in mind that the jca22 has an output board instead of wiring to each output jack. For the jca22, I'm pretty certain that the depth mod (1 meg audio taper pot and a .0047uf 400v orange drop cap) goes inbetween the FB (blue wire) that connects the two boards.



          I would also like to see some jca22 pictures of the other mods.
          Guitars: Fender Stratocaster (Deluxe Lone Star), Ibanez S420, PRS SE245, PRS Custom 24. Various Duncan & Dimarzio Pickups.
          Amps: Marshall TSL100 (Various Tubes, no mods)
          Cabinets: Egnater Tourmaster 4x12 w/ Celestion Vintage 30s
          Effects: Digitech RP1000, TC Electronic Nova Drive
          Favorite Guitar Player on YouTube: Satsuma3042

          Comment


          • Hey, Edge11 .... two rockin' thumbs up for all your contributions and enthusiasm!



            I'm a new jca22h owner and placing orders for tubes, bias tools, and parts for the depth mod. In the depth mod picture on post#109, it has a aditional 1uF cap. What is the purpose for that and do you recomend it for the jca22h? If you recomend it, I'm assuming that it should be 400v to match the orange drop cap?



            Thanks again and Merry Christmas!
            Guitars: Fender Stratocaster (Deluxe Lone Star), Ibanez S420, PRS SE245, PRS Custom 24. Various Duncan & Dimarzio Pickups.
            Amps: Marshall TSL100 (Various Tubes, no mods)
            Cabinets: Egnater Tourmaster 4x12 w/ Celestion Vintage 30s
            Effects: Digitech RP1000, TC Electronic Nova Drive
            Favorite Guitar Player on YouTube: Satsuma3042

            Comment








            • Quote Originally Posted by Borderline11
              View Post

              Hey, Edge11 .... two rockin' thumbs up for all your contributions and enthusiasm!



              I'm a new jca22h owner and placing orders for tubes, bias tools, and parts for the depth mod. In the depth mod picture on post#109, it has a aditional 1uF cap. What is the purpose for that and do you recomend it for the jca22h? If you recomend it, I'm assuming that it should be 400v to match the orange drop cap?



              Thanks again and Merry Christmas!




              If i recall correctly It's so turning the pot won't make a "scratching" sound, get back to you on that when i get up in the afternoon, it's 5 am.
              Jca 50h/ 100h/ 22h Mod thread and Owners Club
              Jca20H Mod thread and owners club
              Like me on facebook
              Follow me on twitter

              Comment








              • Quote Originally Posted by Edge11
                View Post

                If i recall correctly It's so turning the pot won't make a "scratching" sound, get back to you on that when i get up in the afternoon, it's 5 am.




                Late night studying or are you finally getting to enjoy some extercurricular activities? ;-) Hopefully, the latter!



                BTW, how do the 1st 3 pre-amp tubes affect the JCA22h? Are they just gain stages that sequentially add gain or do they get used for the different channels? Correct me if I'm wrong, I believe V4 is the effects loop and V5 is the phase inverter. I figure V1 and V2 are gain stages, but I'm not sure about V3.



                I ask, because when I am swapping tubes, I want to know what to listen for after swapping v3.



                My long term answer should probably be to learn how to read schematics. Ha! The answers are in the schematics.. aren't they? If so, what's a good (short) refernce book that would be helpful for new modders?



                Thanks again!
                Guitars: Fender Stratocaster (Deluxe Lone Star), Ibanez S420, PRS SE245, PRS Custom 24. Various Duncan & Dimarzio Pickups.
                Amps: Marshall TSL100 (Various Tubes, no mods)
                Cabinets: Egnater Tourmaster 4x12 w/ Celestion Vintage 30s
                Effects: Digitech RP1000, TC Electronic Nova Drive
                Favorite Guitar Player on YouTube: Satsuma3042

                Comment


                • Borderline11
                  Borderline11 commented
                  Editing a comment

                  Borderline11 wrote:
                  BTW, how do the 1st 3 pre-amp tubes affect the JCA22h? Are they just gain stages that sequentially add gain or do they get used for the different channels? Correct me if I'm wrong, I believe V4 is the effects loop and V5 is the phase inverter. I figure V1 and V2 are gain stages, but I'm not sure about V3.


                  I've been reading "The Guitar  Amp Handbook".  The schematics are starting to make sense and I thought I would answer my own question! Ha! The preamp tubes in the JCA22h seem to follow the same signal path as the JCA50H.

                  V1 - Primary Gain stage for both Crunch/Overdrive channels

                  V2 - 2nd Gain stage for Overdrive channel  (activated by footswitch)

                  V3 - Tone Stack (signal from both channels go through v3 and arrive at shared tone controls)

                  V4 - Effects loop

                  V5 - Phase inverter (hands off the signal to the power tubes)

                   


              • What are some speaker preferences? I have a Swamp Thang and Texas Heat. I'm liking the Texas Heat better, so far. I have the stuff for the depth mod, but the amp is still new, just got it Thurs. JCA 22H, by the way
                Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery.-Winston Churchill

                Comment








                • Quote Originally Posted by kissmyace
                  View Post

                  What are some speaker preferences? I have a Swamp Thang and Texas Heat. I'm liking the Texas Heat better, so far. I have the stuff for the depth mod, but the amp is still new, just got it Thurs. JCA 22H, by the way




                  V30s are pretty much the standard for these amps. I'm liking Celestion Lynchbacks with mine, but even some WGS Retro or Veterans would work well, too.
                  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)

                  Comment








                  • Quote Originally Posted by Borderline11
                    View Post

                    Late night studying or are you finally getting to enjoy some extercurricular activities? ;-) Hopefully, the latter!



                    BTW, how do the 1st 3 pre-amp tubes affect the JCA22h? Are they just gain stages that sequentially add gain or do they get used for the different channels? Correct me if I'm wrong, I believe V4 is the effects loop and V5 is the phase inverter. I figure V1 and V2 are gain stages, but I'm not sure about V3.



                    I ask, because when I am swapping tubes, I want to know what to listen for after swapping v3.



                    My long term answer should probably be to learn how to read schematics. Ha! The answers are in the schematics.. aren't they? If so, what's a good (short) refernce book that would be helpful for new modders?



                    Thanks again!




                    Been out drinking with some friends since two days ago probably not going to be sober enough to give advice till the 2nd.
                    Jca 50h/ 100h/ 22h Mod thread and Owners Club
                    Jca20H Mod thread and owners club
                    Like me on facebook
                    Follow me on twitter

                    Comment


                    • Regarding an amplifier reference book for beginers.... I purchased "The Guitar Amp Handbook" by Dave Hunter. It seems to be exactly what I need to understand the schematics and what changes affect tone.
                      Guitars: Fender Stratocaster (Deluxe Lone Star), Ibanez S420, PRS SE245, PRS Custom 24. Various Duncan & Dimarzio Pickups.
                      Amps: Marshall TSL100 (Various Tubes, no mods)
                      Cabinets: Egnater Tourmaster 4x12 w/ Celestion Vintage 30s
                      Effects: Digitech RP1000, TC Electronic Nova Drive
                      Favorite Guitar Player on YouTube: Satsuma3042

                      Comment


                      • So, Edge - time to move this thread to another board? There's great stuff here in this thread - would hate to see it lost to this hideous mess of a forum 'upgrade'

                         

                        The Open Jam looks like a good board. What'cha think?

                        Come join us at the NEW Jet City Lounge on guitarampboard.com: http://www.guitarampboard.com/forum/...php?f=5&t=1615

                        Comment


                        • Borderline11
                          Borderline11 commented
                          Editing a comment
                          Hey Grimespace, ... I thought the conversion has already happened? The gear/guitar/amp forum still shows as a forum in the menus.

                          Also, I appreciate all your posts! It built my confidence to see you go through the mods.

                        • Edge11
                          Edge11 commented
                          Editing a comment

                          I'm going to take my time deciding what forum I want to go to.
                          I'll keep supporting this thread regardless.
                          Also if you sent me a pm question before the new harmony central, it got deleated, sorry, feel free to pm me again.


                      • I made an amp holder to use during mods. This way, I don't have to worry about the tubes or it being unbalanced while I'm working on it.

                        Built out of 2x8, with pieces of 3/4 plywood nailed to the sides. The gray carpet is a 4x4 sample piece from Home Deopt. I cut it with scissors and glued it to the plywood. The 2x8 is longer than the JCA22 because I may own full size heads at some point. If I'm working on a larger amp, I can just unscrew and reposition the right side. Total cost 6$ (I already had the ply scraps and wood glue).

                        Amp holder JCA22H

                        Amp holder 2

                         

                        The metal tray is a magnetic tray. It's great for keeping screws from getting lost!

                        Attached Files
                        Guitars: Fender Stratocaster (Deluxe Lone Star), Ibanez S420, PRS SE245, PRS Custom 24. Various Duncan & Dimarzio Pickups.
                        Amps: Marshall TSL100 (Various Tubes, no mods)
                        Cabinets: Egnater Tourmaster 4x12 w/ Celestion Vintage 30s
                        Effects: Digitech RP1000, TC Electronic Nova Drive
                        Favorite Guitar Player on YouTube: Satsuma3042

                        Comment


                        • Edge11
                          Edge11 commented
                          Editing a comment

                          Borderline11 wrote:

                          I made an amp holder to use during mods. This way, I don't have to worry about the tubes or it being unbalanced while I'm working on it.

                          Built out of 2x8, with pieces of 3/4 plywood nailed to the sides. The gray carpet is a 4x4 sample piece from Home Deopt. I cut it with scissors and glued it to the plywood. The 2x8 is longer than the JCA22 because I may own full size heads at some point. If I'm working on a larger amp, I can just unscrew and reposition the right side. Total cost 6$ (I already had the ply scraps and wood glue).

                          Amp holder JCA22H

                          Amp holder 2

                           

                          The metal tray is a magnetic tray. It's great for keeping screws from getting lost!


                          Thats a pretty sweet set up!

                          Attached Files

                      • What cap# did you come up with as the bright cap on the OD channel for the jca22?

                        C6?

                        Comment


                        • Or the jca50/100 for that matter?

                          I did the predator mod on my 22 today and the OD channel seemed a bit bright after.
                          So I lifted a leg of c6 and it seemed to do the trick.
                          Also, when figuring out reference #s from the 50 and 22 schematics, the resistor and cap for "the sucker punch" seem obvious when comparing the schematics something seems weird.
                          C23 and R34 on the 50 seem to be C7 and R10 on the 22 but the stock values aren't 120pf and 2.2m in the 22?!

                          The only cap and resistor combo with those values on the 22 is nowhere close to the same spot as the 50.

                          Also there is no cap on the 22 that works for C28 on the 50.

                          Comment


                          • Borderline11
                            Borderline11 commented
                            Editing a comment

                            Motocooney wrote:
                            Or the jca50/100 for that matter?

                            I did the predator mod on my 22 today and the OD channel seemed a bit bright after.
                            So I lifted a leg of c6 and it seemed to do the trick.
                            Also, when figuring out reference #s from the 50 and 22 schematics, the resistor and cap for "the sucker punch" seem obvious when comparing the schematics something seems weird.
                            C23 and R34 on the 50 seem to be C7 and R10 on the 22 but the stock values aren't 120pf and 2.2m in the 22?!

                            The only cap and resistor combo with those values on the 22 is nowhere close to the same spot as the 50.

                            Also there is no cap on the 22 that works for C28 on the 50.

                            Edge would be the expert on this..... Edge, what advice do you have for the JCA22 owners trying to apply the same mods as the JCA50?

                            You are correct about "C23 and R34 on the 50 seem to be C7 and R10 on the 22". It's the same design, but the JCA22 uses different values. This may be something we 22 owners have to play with. I think the principle of R10 is to allow more voltage to V1, thus running the tube hotter (more gain). The C7 probably shapes the tone.

                            I also noticed the missing "c28" cap on the JCA22. My assumption would be to not use one. I'm assuming that a cap there shapes tone and the JCA22 doesn't need a tone modifer for R5 (r42 on the JCA50). Adjustments to R5 allows more or less gain from V1.

                            How did you like the preditor mod? Could you describe the sound difference?













                        Working...
                        X