AC15C1 Mods thread - Pics

Discussion in 'Amps and Cabs' started by diaz, Jul 24, 2010.

  1. diaz

    diaz Member

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    Thought I'd share this thread here:

    ***Official thread here: http://acapella.harmony-central.com/showthread.php?p=40404857#post40404857 - It will be updated more often at that link, and will eventually have video clips***



    ** Disclaimer: Do this at your own risk. Do not attempt it if you do not know what a filter capacitor is, looks like, and how to drain them. If you absolutely need these mods and cannot perform them, a competent tech should be able to execute this quite easily. **

    To get into the amp, unscrew all these:


    [​IMG]

    Inside:

    [​IMG]

    [​IMG]


    Mod 1 - Bright cap mod:

    This mod will allow you to use a much larger spectrum of pedals in front of your amp.


    [​IMG]


    1. Remove C67 - 10pf ground (Reads 100)

    It is located near the Top Boost volume knob. It is used to kill high end harshness. It is there to counteract the harshness which is brought on by the 120p cap, but is no longer needed when removing the 120p. This 10p capacitor was not part of the original AC15/30 schematic either.

    2. Remove C8 - 120p high pass (Bright cap - Reads 121)

    It is right next to C67. It is the capacitor that adds tons of sparkle when the top boost volume is low, and the master is high. It is a nice touch, but also kills any chance of most pedals sounding good in front of the top boost.


    [​IMG]


    Mod 2 - AC30 tonestack mod: (Original vintage tonestack setup for AC15/30)

    This one is a little tricky, since there are no spaces on the board to solder a jumper wire off the bass tone pot. I improvised something that works well. The sound difference is night and day. It provides a much bigger spectrum of tones. The treble and bass become much more "extreme". You will notice a boost of low end in your sound as well. I keep my bass around 3-4. The biggest difference for the bass control is from 0 to 4 - then there is not much difference between 5 and 10. The biggest difference for the treble control is between 5 and 10. From 0 to 4 only changes the mid range response slightly.

    1. Remove capacitor C67 10p. You will be using the lug where there is no trace leading anywhere, which is ground. To verify, use multimeter on "beep" mode and verify ground once capacitor is removed.

    2. Cut about 8" of 22awg hookup wire - do not use bare wire. Start by bending one end (crimped) and stick it in the tiny hole under the bass tone pot. If standing behind all the pots, its the first lug on the left - it is the lug that DOESNT have a trace going to the treble pot. You will notice a tiny hole where the wire will fit. Its a bit crowded, but its possible to solder there.

    3. Cut the wire so it has a bit of slack to reach the C67 ground lug - I suggest more slack if you plan on adding a switch. Crimp it, and bend it so it doesnt flick out of the grounded hole. If uncertain, verify its the proper hole by checking ground with the big green ground wire/nut.

    *OPTIONAL - Not shown in picture*

    *4. Add an SPST switch near the tone controls. Once the AC30 tonestack mod is completed, as long as you have plenty of slack left, you can cut the wire in the middle and attach each end to an SPST switch to toggle between standard and custom.

    [​IMG]
     
  2. Blues Jr

    Blues Jr Member

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    Cool thx for posting Diaz, those are some interesting mods.

    I'd like to know what the proper Accutronics reverb tank replacement is for the C1. I'm not a big fan of the stock reverb sound.
     
  3. Scott57

    Scott57 Member

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  4. Blues Jr

    Blues Jr Member

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    Hey thanks Scott! That was fast!
     
  5. diaz

    diaz Member

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    Thanks! Yeah I'm looking at doing some more mods.. stay tuned :D
     
  6. Ryguy

    Ryguy Supporting Member

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    Any news on a reverb mod other than swapping the tank? Reverb sounds muddy, with a long, dark decay. I tried the accutronics tank from my Swart AST in the Vox, but it didn't help too much.
     
    Last edited: Dec 1, 2010
  7. sherm

    sherm Member

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    To remove the C67 and C8 is there anything special that needs to be done before snipping them? are these the ones that hold enough juice to zap you real good? I'd like to do mine but know nothing about this stuff.
     
  8. Rod

    Rod Tone is Paramount Gold Supporting Member

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    So diaz, when removing both bright caps, is the amp warmer sounding?? [I've always thought that most guitar amps have to much treble designed into them]
     
  9. moredirt

    moredirt Supporting Member

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    Anybody else try the bright cap mods? Particularly interested in how/whether that helps with OD or fuzz pedals?
     
  10. thealmightycapo

    thealmightycapo Member

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    Thanks Diaz, these mods look great... I'm really interested though... how exactly does the bright cap mod on the Top Boost channel change the clean tone of the amp? I want my overdrive to sound its best, I think there is room for improvement... but I do NOT want to lose the sparkling clean tones that the amp naturally has. By taking the bright caps out of the top boost channel, am I going to lose the Vox sound and reduce this thing to a dull, boring clean sound (albeit one that reacts great to overdrives)?
     
  11. XmasTree

    XmasTree Member

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    good job dude

    i wish it was this easy to remove 2 caps from my AC30cc2x
     
  12. Rod

    Rod Tone is Paramount Gold Supporting Member

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    I just did it to my other guitarists' new AC15C1.....Before the mod my Hardwire OD and Distortion sounded pretty awful...Now they sound huge, smooth ect 1000% better
     
  13. moredirt

    moredirt Supporting Member

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    Thanks Rod, appreciate the feedback. On a related note, has anyone tried a VVR kit in the AC15C1? I'm wondering if I can just replace the existing master with the VVR, or whether I need to keep the master in the circuit and add the VVR.
     
  14. Rod

    Rod Tone is Paramount Gold Supporting Member

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    You're welcome...What's a VVR Kit??
     
  15. ry-guy

    ry-guy Supporting Member

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    I have one of these....did the bright cap mod....takes pedals much better. You have a small amount of 'cleans' when playing with single coils....humbuckers, probably not much. I find the amp is nowhere near as harsh and bright as it was before....couldnt dial out the brightness at all, not to mention I was playing a bright Tele through it. ;)

    For me, I always have the master cranked, This amp works good for many smaller gig situations.....played it through an ASW Elegante and the cleans are NICE. :D Thinking about trying the AC30....
     
  16. moredirt

    moredirt Supporting Member

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    Last edited: Feb 5, 2011
  17. ry-guy

    ry-guy Supporting Member

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    Well, I find I can always bring in more highs with the cut or one of my pedals......but I only clipped the two on the top boost as that's the only channel I'm using at the moment. FWIW, I naturally have a brighter sound with my tele and the tone from my fingers :), so YMMV.
     
  18. moredirt

    moredirt Supporting Member

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    Sounds good, thanks for the input! I usually run my cut pretty high and treble fairly low on TB, so I've got a lot of high end to give as well.
     
  19. Rod

    Rod Tone is Paramount Gold Supporting Member

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    The bright cap mod didn't really affect the highs to much strait in...
     
  20. moredirt

    moredirt Supporting Member

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    Great, I'm going to try to get to it this weekend. If I do I'll post my results.
     

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