Brownface Overdrive

Discussion in 'Amps and Cabs' started by PlumBob, Feb 19, 2008.

  1. PlumBob

    PlumBob Member

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    Hi,
    I have a '62 Princeton that I'm trying to figure out. The amp sounds beautiful clean, but the breakup (which starts around 4 even with a Tele) sounds buzzy/transistor-ish to me. A little like a cheap fuzz pedal. I have read through the threads here that talk about the sound of this amp and everyone seems to like the overdriven sound. So I figure that mine's not working right. But before I haul it off to a tech, I wanted to get an idea of whether maybe what I'm hearing is just the normal sound of an overdriven brown Princeton. So if anyone can give me a description of the overdrive sound of their Brownface Princeton or other Brownface Fender, I'd be much obliged. Oh, and I should mention that mine has had a recent cap job and basic servicing and is nice and quiet and all that.
    Okay, thanks for any descriptions/opinions....
     
  2. thintele

    thintele Member

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    You might try experimenting with different brands and versions of preamp tubes in V1. 12ax7, 7025 and 5751
    Call Mike at KCA and see what he suggests
     
  3. PlumBob

    PlumBob Member

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    Thanks. Yeah, someone on another thread suggested the same thing. I have a few lying around I'll try.
     
  4. erksin

    erksin Member

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    Does yours have the stock Oxford in it? That's a huge culprit - that speaker does NOT handle volume well at all...
     
  5. PlumBob

    PlumBob Member

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    No, I put a Weber Silver 10 in it, which really improved the clean tone but didn't change the distortion characteristics as much as I had hoped. It really sounds like it overdrives in the wrong part of the circuit or something. A little like overdriving a 60s Ampeg. But listening to clips that someone posted on the other Fender brown thread that's going, I think that might be the nature of the beast.
     
  6. erksin

    erksin Member

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    Has the speaker had enough of a break in period?

    You could try different 6V6s in it too...
     
  7. Rumblefish

    Rumblefish Silver Supporting Member

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    Well if you're turning up over 5 or six,you'll only get that trash sound.6 seems to be the sweet spot.Be sure to stand at about a 45 degree angle from the front of the amp when playing so you don't hear just the dust cap of the speaker.
     
  8. PlumBob

    PlumBob Member

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    I tried a 5751 in V1, and it definitely smoothes things out a bit. Oddly, it also makes the amp noisier (60 cycle hum noise). Maybe just more detail in that frequency.

    As to 6V6's, I've tried a few but would try more if I had em.

    The speaker is approaching broken in but will probably keep getting better.

    Thanks for the ideas....
     
  9. redtoploader

    redtoploader Member

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    So it sounds like clips in the brownface thread?

    Sounds like you either have an overbiased amp(harsh grainy distortion) or a bad coupling cap(makes a blown spaeker type sound, splatty, farty). These are NOT the same as electrolytic caps...not sure what you had changed.

    Or you just dont like the amp. Hard to tell without hearing it myself.
     
  10. PlumBob

    PlumBob Member

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    I'd say it sounds like the clips in the other thread but with a bit of a splatty sound mixed in. I think only the electrolytic caps were replaced, so sounds like I need to have someone check the coupling caps, huh? Could the clean sound be this good if there's a bad coupling cap?
     
  11. redtoploader

    redtoploader Member

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    Yeah, the clean sound can be fine...you really hear it when you overdrive the tubes. Depends on how bad the cap is leaking. I'm going to listen to those clips quick.

    I had a brown prince for awhile and it was anything but splatty, pretty smooth overdrive...and it should be even more so with a silver bell. The circuit is almost exactly the same as a tweed vibrolux.
     
  12. redtoploader

    redtoploader Member

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    Where are the clips for those brown amps?
     
  13. PlumBob

    PlumBob Member

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  14. redtoploader

    redtoploader Member

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    Ahh I see. The live clips are pretty clean. The allen amp is real close...sounds like he's getting a bit of digital distortion there though.

    If you got some 'splatt' going on, you may just want to get it checked out. The circuit is always going to have a bit of 'grittiness' to it though.
     
  15. PlumBob

    PlumBob Member

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    Bringing this back. I took my Princeton to a well known, well regarded tech and had him look it over and see if he could improve the distortion characteristics. He checked out how the amp was running and decided that a 5u4 rectifier tube would improve the sound, mainly by reducing "crossover distortion." He was right, the distortion is a lot smoother and throatier now, rather than raspy and crackly. And he says the transformers and caps can handle the 5u4. Just thought I'd report.
     

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