Howling Muff

[Loud and Low]

Asking humbly for your knowledge.

I have my buddies NYC reissue muff. When you turn up the sustain and/or volume it just howls like hell between notes. Is there a way to fix this without losing it's muffiness?

[petemoore]

I have my buddies NYC reissue muff. When you turn up the sustain and/or volume it just howls like hell between notes. Is there a way to fix this without losing it's muffiness?
   Either there's something wrong with it or it is a fairly common 'feature' of a high gain distortion pedal.
   It's hard to tell from the description if it is 'natural' or if maybe there's a ground lifted somewhere in it.
   If the circuit is 'correct' but unruly, some measures can be taken to 'tame' it...whether it gets tamed and doesn't lose 'muffiness''..another matter.
   Also the type of guitar pickups/amp settings etc. can make a high gain distorter behave uncontrollably.
   Some players use that sound by playing it and just hit that bypass before all the uncontrollable squealing starts the instant playing stops...others turn it down a little.
  still others may adjust the gain of 1 or more transistors, or alter the frequency gain of 1 or more stages.

[Loud and Low]

Either there's something wrong with it or it is a fairly common 'feature' of a high gain distortion pedal.
As I have little experience with the NYC muff, I cant be 100% sure. My opinion is that the pedal is "correct".

   Also the type of guitar pickups/amp settings etc. can make a high gain distorter behave uncontrollably.
I have tried numerous combinations of amps/amp gain/ guitars with different output pickups.. to no great difference in the "howl"

If the circuit is 'correct' but unruly, some measures can be taken to 'tame' it...whether it gets tamed and doesn't lose 'muffiness''..another matter.
  still others may adjust the gain of 1 or more transistors, or alter the frequency gain of 1 or more stages.

I did some mods on a russian muff, and it turned out quite nice, less gainy, but a more agreeable character. Retains it "muffiness".
I tried a mod on his nyc muff which was called a noise gate mod, it definitely would control the instant feedback howling, but also cut the gain considerably...Too much for his tastes.. So, maybe the lower gain transistors is the way to go..

Any suggestions on what transistors to change to what transistors??

Thanks in advance for any help.

[Loud and Low]

Any Ideas ..Anyone... I am placing an order tonight for other components, and I'd like to get some parts to try out in the NYC muff... It would be nice to get some steering, instead of trial and error...

[petemoore]

  Audio probe to see if you can tell where the howl originates.
  Sounds a bit like you have oscillation going on [howl].
  Perhaps you can squelch some of it with 'well placed' HF rolloff cap, and compensate with tone knob adjustment if a little treble content is lost.