I bought a tube combo amp.

Discussion in 'The Backstage' started by kevinpaul, Nov 2, 2015.

  1. ultra80096

    ultra80096 Senior Member

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    R&R'd the PT in my main modded Silkyn today. Had been playing & heard a resonance(buzz) when playing a low Bb. Output tranny & choke hardware were loose. Had to pull the board to get to the nuts, & decided well, why not lol? Went without a hitch. Love the two modded amps. Dirty channel totally usable.
     
  2. ultra80096

    ultra80096 Senior Member

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    Got # 3 done today. Another success. Along with Jimi's instructions, be sure to check the mounting bolts of the OT & choke while you're in there. This particular amp I've used the most, 100+ hrs & the OT screws you could spin by hand. Impossible to snug up unless you have the board out. I also borrowed some clear nail polish from the wife to brush on the top when tight.

    On another note, I'll be having a couple of mine for sale. I don't need 4 Silkyns, lol. If you or know of someone who'd like one, let me know. Might try Craigslist or Reverb also.
     
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  3. Harold Purvine

    Harold Purvine Junior Member

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    I would like one.
     
  4. ultra80096

    ultra80096 Senior Member

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    PM sent.
     
  5. DavGrape

    DavGrape Senior Member

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    Have decided to let a pro do mine, couple options right around me.
    Because I know I will end up with a sloppy mess if I do it.
     
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  6. pinkjimiphoton

    pinkjimiphoton Senior Member

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    dear lord, i've totally spaced on shipping the xformer back to bud!!
    dav, ya made the right decision. if you're uncomfortable in any way, always better to let a pro do it.
     
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  7. Harold Purvine

    Harold Purvine Junior Member

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    dear lord isn't worried Jimmi and I am not either. I am just going to cut the bobbin flanges off and investigate with it fired up and arcing then insulate that point and do it again to see where else, other than the B+ might be harmed.
     
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  8. pinkjimiphoton

    pinkjimiphoton Senior Member

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    thanks for the patience bud. lotta crap on and off my bench lately.
    its in the box, i gotta just seal it up and get it outta here. lately its been crazy between jobs and gigs, i will get it out soon ;)
     
  9. DavGrape

    DavGrape Senior Member

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    I got the legendary Dean Zink lined up to do the swap for me.
    (He six minutes away. Had no idea!)
    Want to bump us back to the top page, is why I did this.
     
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  10. ultra80096

    ultra80096 Senior Member

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    Great deal Dav, should have him do the mods to it also, at least the reverb..you'd love it.

    I own one less Silkyn, the one I sold to Bud got delivered. So far I believe he's happy.
     
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  11. pinkjimiphoton

    pinkjimiphoton Senior Member

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    do the preamp B+ voltage raising mod, too, it really brings it to life
    having the proper voltages really brings this sucker to life
     
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  12. DavGrape

    DavGrape Senior Member

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    Where's that B+ mod, photon?
    The little stuff I'm confident doing, like resistors and junk.
    In the Squawkbox section of the forum?
    This thing sounds fine, now; seems "tubier" with the new PT.
    Could be illusion, haven't used it for awhile.
     
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  13. ultra80096

    ultra80096 Senior Member

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    I read back earlier & the only reference I could find to B+ was that yours had only 385 volts. That would sound bad. Mine have all measured 485V plus, & with the new PT's 495-505V.

    Dav, maybe the new capacitors he put in..?
     
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  14. pinkjimiphoton

    pinkjimiphoton Senior Member

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    there's a 10 k resistor that feeds b+ to the plates of the preamp tubes mentioned in uktra's original instructions.
    pop that m'fer out and replace with 6.8k resistor. raises the headroom and voltage about 15 volts or so, helps make it come more to life.

    make sure its at least a 3 watt resistor (specc'd) but 5watt will work and may be easier to find at a local jobber or junk drawer.

    do the reverb mod too. once ya do that and raise the preamp voltage, some of that ugly intermod goes away, and the preamps balance much more nicely.

    if you got your volume on 7 on the clean channel, and your gain and volume on the dirt channel about the same, the volume is close enough to unity for rocknroll now.

    try turning the dirt channel up to about 3 on master and drive for crunchy rhythm work and switching to the clean channel with everything about 7. mmmmm mmmmm good.

    also, remember i swapped the 25k mid pots out for 50's. or maybe it was 50's for 100's. whatever is in there, double it. will let you get a LOT more possible tone, 50% more of that crucial midrange across the same spread.. so if ya run it normally on 5, turn it down to 2.5 for the same tone. if you're like me and like a hotter mids, you can crank the piss outta it.

    easily undone if you don't like it. please be safe fuckin with it and remember to discharge the filters before monkeying in there. i like to strap the center tap of the ot right to ground while i'm working.

    remember its there to avoid a hell of a loud scary surprise before the lights go out ;)
     
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  15. ultra80096

    ultra80096 Senior Member

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    Yep, I did that with the other mods on two of the amps. One went to Harold (Bud). Have to get busy with the other two. Well worth doing for sure.:cheers2:

    BTW, have to give credit where it's due. The mods I did, Bluesaxe came up with the mods ideas that is in the mod thread. Wish he was still around. Haven't heard from him on here since March '16.

    I also appreciate the input you've given also! Thanks!
     
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  16. pinkjimiphoton

    pinkjimiphoton Senior Member

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    honored to try and help bro ;)
     
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