SHO compact layout high pitched whine

[Vulture Moon]

Hey ladies and gents, i just finished making a Super hard on type of clean boost with a master volume and i wired it up and it rocks just fine, there is one problem though; There is a high pitched, cicada-like, whine behind all the sound when the master volume is all the way up. what could this be? all my solder joints are solid, it sounds like a SHO when you are rocking it, but that damn whine is there when you mute the strings or play soft. it is not affected by the crackle ok (gain) knob and it is still present when i turn down my guitar volume or even take out the input plug.it is not there in bypass mode and  it is only diminished when you roll off the master volume, but it doesn't go away. there were a few people on the tagboard effects forum with possibly the same problem but no real answers were stated. I should also state that i originally had the transistor in backwards, so i dont know if that would be a problem(would that burn up a transistor?)http://tagboardeffects.blogspot.com/2013/02/zvex-super-hard-on-compact-layout.html any help i would be so grateful for.

[Neil mcNasty]

You do not burn a transistor by putting it in the wrong way when running it at 9v (as far as I can tell/have experienced)
I think I've also heard that, in some circuits you can put a JFet/MOSFet in the wrong way around and it will still work/make sound.


I do not have the sollution to your problem, but I do have a couple of "quick fix" suggestion:

- Check all your ground wires and make sure it has a good connection (weak ground/cold solder can sometimes cause oscillation in high gain circuits)

- Put a 10-22pf cap from your output to ground, and it will roll off all high frequencies above a certain level (the smaller the value, the higher the frequency, and opposite, so experiment to find lowest value possible...)
This is a great trick/quick fix used by Guitar Techs in order to remove high freq squeeels/bleeds from bad power sources in a live situation, by inserting a small filter-box at the end of the pedal chain, before running into the amp... Normally the filter box is simply a signal running straight trough the box, with a 22-100pf cap going from signal to ground...

- You can also try to place the cap between the Gate and the Drain of the transistor, to prevent it from boosting/amplifying the highest frequencies (this might be more effective)

Hope this helps to fix it