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  • #61
    I am running 2-JJ-EL84

    2-JJ-12AX7 Standard (V1 & V2)

    1-JJ-12AX7 Balanced (V3)

    1-JJ-12AX7 HighGain (V1)

    1-JJ-12AT7 Low Gain (V2)

    1-Tungsol 12AX7 Standard (V1 & V2)



    Try this , I did it on accident....run the JJ HG in V3 and the balanced in v1 and normal in v2



    It did not sound bad at all I played it this way for a while before I noticed it was backwards when I started to swap the tubes out..........but here is what I settled on

    2-JJ-EL84 @22mA bias

    1-JJ-12AX7 HighGain (V1)

    1-JJ-12AT7 Low Gain (V2)

    1-JJ-12AX7 Balanced (V3)



    I am in the process of adding the BitMo Surfa tonight



    BSS what did you BIAS the tubes at?????



    theDogger
    - Ibanez MTM2(EMG-18Voltz) -
    - Mesa Boogie Single Rec -
    - Egnator Vengeance -
    - TC Electronics G-Major
    - Custom 4x12 Build DIY -
    - https://www.facebook.com/bfgcabs/

    Comment


    • #62
      Well did the BitMo Surfa mod late last night. From what I could tell at the level I was at I like it. The install is smooth and easy just take your time. The only change that I am making it to the 2nd switch with by passes the M*style tone stack. with the suggested resistor the Mid and Treb are not active. Bruce supplies a different resistor that give back the mid and treb control. I just found it to be way to VOX'y if you will.



      But the I am waiting to get home so I can crank the master and enjoy the OD boost.



      theDogger
      - Ibanez MTM2(EMG-18Voltz) -
      - Mesa Boogie Single Rec -
      - Egnator Vengeance -
      - TC Electronics G-Major
      - Custom 4x12 Build DIY -
      - https://www.facebook.com/bfgcabs/

      Comment


      • #63
        This is a custom grill from Reliable Hardware Company. It's 3/4 inch bend on all four sides brings it forward and gives it a nice finished look.



        www.reliablehardware.com







        Ibanez RGA121VLF Prestige
        Agile Valkyrie
        Agile AL-3000 "Les Paul"
        Ibanez XPT700BCM
        Jet City JCA22H
        Engl Screamer 50
        Marshall DSL50
        Genz Benz G-Flex 2x12

        Comment


        • #64
          Does anyone know what the OT is rated at? Is it a single tap or multi tap? I was looking at the schematic and was wondering....Also when I called JCA and asked they told me that the input jacks on the back are misleading. That actually the 2-8ohm outs are meant for 2-16ohm cabs to take it to 8ohms...not 2-8ohm cabs to 16ohms..is that right?????





          theDogger
          - Ibanez MTM2(EMG-18Voltz) -
          - Mesa Boogie Single Rec -
          - Egnator Vengeance -
          - TC Electronics G-Major
          - Custom 4x12 Build DIY -
          - https://www.facebook.com/bfgcabs/

          Comment


          • #65






            Quote Originally Posted by Twebbz
            View Post

            This is a custom grill from Reliable Hardware Company. It's 3/4 inch bend on all four sides brings it forward and gives it a nice finished look.



            www.reliablehardware.com











            What were the measurements that you used on the site? How accuratlly did it fit with or without tweaking??



            theDogger
            - Ibanez MTM2(EMG-18Voltz) -
            - Mesa Boogie Single Rec -
            - Egnator Vengeance -
            - TC Electronics G-Major
            - Custom 4x12 Build DIY -
            - https://www.facebook.com/bfgcabs/

            Comment


            • #66
              I used 18" wide and 5 1/8" tall with a 3/4 inch bend on all four sides. You may be able to see that I added a 3/4 square strip of wood on each side of the head thinking that I'd have to have something to screw the grill on to. However the grill bends were bent a little outwards so it appeared that the grill was too wide. A little hammering of the bends inward made it a tight fit to the point that fastening with screws was unecessary.
              Ibanez RGA121VLF Prestige
              Agile Valkyrie
              Agile AL-3000 "Les Paul"
              Ibanez XPT700BCM
              Jet City JCA22H
              Engl Screamer 50
              Marshall DSL50
              Genz Benz G-Flex 2x12

              Comment


              • #67
                Can anyone answer this question?



                I am a little confused by the primary impedance on that OT. Two EL84 tubes in almost every amp we have run across would be around 8k. That sticker is showing a primary impedance of 3.6k. This seems very, very low for two EL84 tubes. Is it not??



                If so what would be a good after market upgrade to the OEM OT



                theDogger
                - Ibanez MTM2(EMG-18Voltz) -
                - Mesa Boogie Single Rec -
                - Egnator Vengeance -
                - TC Electronics G-Major
                - Custom 4x12 Build DIY -
                - https://www.facebook.com/bfgcabs/

                Comment


                • #68






                  Quote Originally Posted by theDogger
                  View Post

                  I am running 2-JJ-EL84

                  2-JJ-12AX7 Standard (V1 & V2)

                  1-JJ-12AX7 Balanced (V3)

                  1-JJ-12AX7 HighGain (V1)

                  1-JJ-12AT7 Low Gain (V2)

                  1-Tungsol 12AX7 Standard (V1 & V2)



                  Try this , I did it on accident....run the JJ HG in V3 and the balanced in v1 and normal in v2



                  It did not sound bad at all I played it this way for a while before I noticed it was backwards when I started to swap the tubes out..........but here is what I settled on

                  2-JJ-EL84 @22mA bias

                  1-JJ-12AX7 HighGain (V1)

                  1-JJ-12AT7 Low Gain (V2)

                  1-JJ-12AX7 Balanced (V3)



                  I am in the process of adding the BitMo Surfa tonight



                  BSS what did you BIAS the tubes at?????



                  theDogger




                  Have not biased yet. Need to get back under the hood andcheck it out when I get time.
                  SPAM:
                  Blackheart Little Giant Head
                  BG Dark Bucker Pickups - Brand new

                  Comment


                  • #69
                    I assume that these mods will work on the JCA2112RC as well since it is basically the same amp but with reverb in combo form...

                    Comment


                    • #70






                      Quote Originally Posted by theDogger
                      View Post

                      I am running 2-JJ-EL84

                      2-JJ-12AX7 Standard (V1 & V2)

                      1-JJ-12AX7 Balanced (V3)

                      1-JJ-12AX7 HighGain (V1)

                      1-JJ-12AT7 Low Gain (V2)

                      1-Tungsol 12AX7 Standard (V1 & V2)



                      Try this , I did it on accident....run the JJ HG in V3 and the balanced in v1 and normal in v2



                      It did not sound bad at all I played it this way for a while before I noticed it was backwards when I started to swap the tubes out..........but here is what I settled on

                      2-JJ-EL84 @22mA bias

                      1-JJ-12AX7 HighGain (V1)

                      1-JJ-12AT7 Low Gain (V2)

                      1-JJ-12AX7 Balanced (V3)



                      I am in the process of adding the BitMo Surfa tonight



                      BSS what did you BIAS the tubes at?????



                      theDogger




                      Bias your tubes depending on your situation, the equation for it is on deus' how to bias video.

                      I updated the page to include the jet packs.

                      if any one has any more clips put them up.







                      Quote Originally Posted by TheEternal
                      View Post

                      I assume that these mods will work on the JCA2112RC as well since it is basically the same amp but with reverb in combo form...




                      Probably assuming that the parts are numbered the same.
                      Jca 50h/ 100h/ 22h Mod thread and Owners Club
                      Jca20H Mod thread and owners club
                      Like me on facebook
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                      Comment


                      • #71
                        What will biasing do for the tone? I'd like to pull the chassis tonight and try it.
                        SPAM:
                        Blackheart Little Giant Head
                        BG Dark Bucker Pickups - Brand new

                        Comment


                        • #72






                          Quote Originally Posted by BSS
                          View Post

                          What will biasing do for the tone? I'd like to pull the chassis tonight and try it.




                          It will do a lot per say....if it is cold then it will be fizzy and harsh.....biasing it @ 65%-70% is perfect....really smooth things out and makes it sing!





                          theDogger
                          - Ibanez MTM2(EMG-18Voltz) -
                          - Mesa Boogie Single Rec -
                          - Egnator Vengeance -
                          - TC Electronics G-Major
                          - Custom 4x12 Build DIY -
                          - https://www.facebook.com/bfgcabs/

                          Comment


                          • #73






                            Quote Originally Posted by theDogger
                            View Post

                            It will do a lot per say....if it is cold then it will be fizzy and harsh.....biasing it @ 65%-70% is perfect....really smooth things out and makes it sing!





                            theDogger




                            Got it biased after work today. Biased up to ~19.09 mA.



                            My voltage read 368



                            @ 12 watt, 60% = 19.56mA

                            @ 11.5 watt, 60% = 18.75mA



                            I was a bit nervous at first, but thanks to Deus' tutorial, it was a breeze. Thanks Deus!!!



                            Also, mblooper (and all who've contributed), thanks for this thread; it's a great resource for us Jet City owners.



                            It sounds really awesome now, especially at >5 on the volume. Even improved the low volume sound a bit.
                            SPAM:
                            Blackheart Little Giant Head
                            BG Dark Bucker Pickups - Brand new

                            Comment


                            • #74
                              Id take it up to 70% around 21-22mA will sound so much better I still think that 19Ma is on the warm end of cold. Try it it won't hurt it...



                              theDogger
                              - Ibanez MTM2(EMG-18Voltz) -
                              - Mesa Boogie Single Rec -
                              - Egnator Vengeance -
                              - TC Electronics G-Major
                              - Custom 4x12 Build DIY -
                              - https://www.facebook.com/bfgcabs/

                              Comment


                              • #75






                                Quote Originally Posted by theDogger
                                View Post

                                Id take it up to 70% around 21-22mA will sound so much better I still think that 19Ma is on the arm end of cold. Try it it won't hurt it...



                                theDogger




                                I was thinking of doing this, so I took some readings again. It appears that my wall voltage sucks (I'm getting upwards of 135 V in my wall outlet). I am getting up to ~380+ V on my B+ at times, then when my A/C kicks on, washer and dryer, etc., it runs back down to as low as 362-364.



                                What voltage should I bias at? It seems that if I bias at one voltage, it's off at another one.
                                SPAM:
                                Blackheart Little Giant Head
                                BG Dark Bucker Pickups - Brand new

                                Comment













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