NMD: 6505+ 112 revoice

Discussion in 'Gear & Equipment' started by LiveOVErdrive, May 22, 2019.

  1. LiveOVErdrive

    LiveOVErdrive CNC hack

    Messages:
    2,543
    Likes Received:
    1,866
    Joined:
    Aug 17, 2016
    Location:
    Minneapolis, MN
    I took apart my 6505+ combo and modded the lead channel to be voiced closer to an SLO100. Previously I always felt it was too thin. I found the reversed remnants of someone else's mods inside. Looks like the previous owner played around with voicing too.

    Here's a video with bad camera audio. I'll do a proper mic-up later when I install it into a head shell and plug it into my recto cab.

     
  2. DudeManBrother

    DudeManBrother Hey...how did everybody get in my room?

    Messages:
    1,709
    Likes Received:
    1,391
    Joined:
    May 3, 2014
    Location:
    Seattle
    Sounds great. How would you describe the tonal differences vs the previous circuit?
     
  3. LiveOVErdrive

    LiveOVErdrive CNC hack

    Messages:
    2,543
    Likes Received:
    1,866
    Joined:
    Aug 17, 2016
    Location:
    Minneapolis, MN
    It's got more bass and low mids in the front end. So it's a little more liquid and ballsy.

    Basically at the front of the lead channel there's a high pass filter that cuts frequencies below about 700Hz. I removed this and then rearranged the following shelf filter to match the SLO. So you get more bass in the front end and because of the rearranged shelf filter, the preamp gain knob no longer brightens the tone as you turn it down.

    Truth be told I didn't play the lead channel before doing the mod because I was also debugging that channel being dead (its been years... Turns out it was just a bad tube), so I didn't do a before and after comparison. Should have. Oh well. However I do remember it being a lot thinner than the rhythm channel and they are now more comparable. So there is a difference!
     
    oneblackened and DudeManBrother like this.
  4. LiveOVErdrive

    LiveOVErdrive CNC hack

    Messages:
    2,543
    Likes Received:
    1,866
    Joined:
    Aug 17, 2016
    Location:
    Minneapolis, MN
    I played around with tube rolling because the gain is so goddamn high. A 12au7 in the front is... Okay? Makes the clean channel quite nice.

    The lead channel might be too bloated on its own now. But it is NASTY with a boost in front of it.

    Still, I might have to play around with tightening it back up just a little.
     
  5. KailM

    KailM SS.org Regular

    Messages:
    1,763
    Likes Received:
    1,301
    Joined:
    Oct 23, 2014
    Location:
    MT
    Nice — kinda wish I’d kept mine to try the SLO mod. I modded my lead channel to original 5150 specs and it definitely brought on a lot more low end and low mids — sounded way better than the 6505+ circuit IMO. Bought a 120 watt 6505 head later on and the two were almost indistinguishable.

    Is the effects loop modded on yours? If not, you’re missing out if you’re using the effects loop. All the mod is is a .022 uF cap to the legs of R86, just behind the “send” jack. It negates the poor buffer that comes stock (if you’re using the effects loop without the mod , the buffer sucks out most of your low end and adds fizz.).
     
    wakjob likes this.
  6. LiveOVErdrive

    LiveOVErdrive CNC hack

    Messages:
    2,543
    Likes Received:
    1,866
    Joined:
    Aug 17, 2016
    Location:
    Minneapolis, MN
    I took the chassis out to do the effects loop mod originally and found that someone had already done it.

    [​IMG]

    At least I'm pretty sure that's the case, with that red wire in there. I think they did the mod where you remove a couple resistors and bypass the buffer with a wire.

    I'll have to put a jumper in the loop and see if it sounds different.
     
  7. KailM

    KailM SS.org Regular

    Messages:
    1,763
    Likes Received:
    1,301
    Joined:
    Oct 23, 2014
    Location:
    MT
    Yeah, that’s the other way to fix the loop. And ideally, with the mod it should sound the same whether you use the loop or not, unlike the stock configuration where it sounds terrible as soon as you use the loop.
     
  8. wakjob

    wakjob SS.org Regular

    Messages:
    3,330
    Likes Received:
    374
    Joined:
    Oct 4, 2011
    Location:
    C-137
    Does sound throaty...I like it.
    Would sound great in a mix.

    I didn't hold onto mine long enough to monkey around with any alterations to the circuit.

    In fact, I don't hold on to any Peavey high gain stuff for very long. They "wow" me with shear gain & saturation at first. Then the gain texture begins to irritate me and grate on my ear after a while.

    I liked the Peavey tube Vypyr 120 on the 6505/green channel w/boost the most, followed my the 6534 next.

    Speakers are EVERYTHING with 5150 circuit imo.
     
    LiveOVErdrive likes this.
  9. LiveOVErdrive

    LiveOVErdrive CNC hack

    Messages:
    2,543
    Likes Received:
    1,866
    Joined:
    Aug 17, 2016
    Location:
    Minneapolis, MN
    Yeah I can't wait to hear it through my recto cab. Sounded great through it before the mod. Probably better now. The above video is through my 112 with an Eminence g12 in it. So it does that hot rod Marshall pretty well.
     
  10. LiveOVErdrive

    LiveOVErdrive CNC hack

    Messages:
    2,543
    Likes Received:
    1,866
    Joined:
    Aug 17, 2016
    Location:
    Minneapolis, MN
    I guess I may as well give it an adjustable bias while I've got it on the bench. This time I'll do a proper before and after video. I'm really curious to compare.
     
  11. LiveOVErdrive

    LiveOVErdrive CNC hack

    Messages:
    2,543
    Likes Received:
    1,866
    Joined:
    Aug 17, 2016
    Location:
    Minneapolis, MN
    Measured the current bias. It's cold (30mA). but not as cold as some people have reported (19mA... Probably at the plate tho). Once I get the adjustment pot in there I'm gonna shoot for about 40mA.

    IMG_20190525_172233.jpg
     
  12. LiveOVErdrive

    LiveOVErdrive CNC hack

    Messages:
    2,543
    Likes Received:
    1,866
    Joined:
    Aug 17, 2016
    Location:
    Minneapolis, MN
    Turns out the 6l6s that came in this thing were not matched. At all. They even have dramatically different readings printed on the stickers. The current in one was 40, the other was 60. Not good.

    So I threw in some Mesa tubes I've had lying around. Ohhh it sounds good now.

    Unfortunately even with my adjustable bias installed, my LOWEST setting is actually about as high as I'd want to go. And I've got a higher resistance in there than it came with stock. So I'm not sure what is going on there. But it's sitting at a nice 40-ish MA now. Sounds great. 6 across the board on the tone controls and it sounds like a beautiful chainsaw. OCD clone in front and it tightens right up and sounds modern. Love it.

    Time to put it into a head cabinet (no more combo) so I can try it on my Mesa cab.
     
    XPT707FX, DudeManBrother and mnemonic like this.
  13. LiveOVErdrive

    LiveOVErdrive CNC hack

    Messages:
    2,543
    Likes Received:
    1,866
    Joined:
    Aug 17, 2016
    Location:
    Minneapolis, MN
    Forgot to post a pic of the mod.

    IMG_20190527_133119.jpg

    Dunno what it is but I love this type of look. Clean install with sharpie label or whatever - something that is clearly hand done.

    I might swap the front panel knobs for these ones. I don't love the default chicken head ones.
     
  14. LiveOVErdrive

    LiveOVErdrive CNC hack

    Messages:
    2,543
    Likes Received:
    1,866
    Joined:
    Aug 17, 2016
    Location:
    Minneapolis, MN
    Feast your eyes on this mother

    IMG_20190619_194307.jpg

    Rocking that retro clean amp look.
     
  15. NickS

    NickS Rocket Surgeon

    Messages:
    1,382
    Likes Received:
    562
    Joined:
    Apr 19, 2012
    Location:
    Seattle, WA
    How's it sound through the Mesa cab?
     
  16. LiveOVErdrive

    LiveOVErdrive CNC hack

    Messages:
    2,543
    Likes Received:
    1,866
    Joined:
    Aug 17, 2016
    Location:
    Minneapolis, MN
    Monstrous. I'll mic it up and post a demo video when I have more time.

    Takes an OCD boost like a champ too.
     
  17. LiveOVErdrive

    LiveOVErdrive CNC hack

    Messages:
    2,543
    Likes Received:
    1,866
    Joined:
    Aug 17, 2016
    Location:
    Minneapolis, MN
    I got an ABY pedal yesterday so I could run my Mark and this 6505+ at the same time. I've got them each running into one half of the same recto cab.

    Holy. Fucking. Shit. You guys.

    I've heard some of you say that running two amps at once is awesome. But I never expected this. I'm running the Peavey pretty dark and the mark pretty bright. They layer up and form this 3d stereo imaged wall of absolute mayhem. It sounds like studio double tracking. Except it's just me playing live. Dear God. I am in love.
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.