Kay Fuzz schematic fix

[mrsage]

Okay...I'll check around and see if I can find a substitute for the 20A90.

I have a few different diodes laying around...Can I just throw them in there, or will that mess things up?

I'm new enough to this that I don't know how diodes are supposed to work...for instance, I've got some 1N914s I could try. What would happen if it was the wrong kind of diode?

[Dan N]

mrsage, they are 2ea. OA90's. Any germaniun diode should be fine. Your 1N914's are silicon and will make the fuzz louder and harsher. I noticed in another thread you wanted 2SC6445's. Those are 2SC644 S. Good luck!

[mrsage]

Ah...That makes total sense! Thanks!

Actually, louder and harsher might not be so bad. I'll definitely use sockets and see what gets me the sound I'm hoping for!

[brian wenz]

Hello Hello Guys--
      hhhmmmmm......I'm pretty sure I used silicon diodes in mine.....maybe "louder and harsher" is working for me......I use a class-A EL84 amp and a little less "mush" on the front end may be good.
Brian.

[mrsage]

Yeah, this is either going into an AC-15 or an AC-30 brilliant channel...

[brian wenz]

Hello Hello-
     That's going to sound pretty good!
Have you done any "fine tuning" on the bias for that second stage??
Brian.

[mrsage]

I haven't actually built it yet. I've got a PCB on the way and then I'll take a shot at it.

How can you tell what transistors you can use in the circuit? Just by trying different ones out? I have some 2n5089s and bs170s laying around...

Could I try those? Or would it be better to try for bc184/182 like you did?

[brian wenz]

Hello Hello-
    Somewhere I have the gains for the original trannys  [400 and 200] so I just found some BC's in my stash that matched up.
They seem to work pretty good.
Brian.

[mrsage]

Hey--

I definitely think the bias needs adjusting...

I'm just not sure how to do it for this circuit.

The fuzz just fades out too fast. It sounds good with a slight boost in front of it, but doesn't quite pull its weight on its own.

What should I be looking at?

Do you have sample voltages? Mine seem a bit weird...

[brian wenz]

Hello Hello Mrsage--
      Try lowering the 100K on the collectors of the second pair of trannys and see if that helps.   Sometimes I just take a 100 - 250K pot and clip it into the circuit at different points  [such as between collector and  +9 v] and turn the pot until there is a change in sound.
Brian.

[mrsage]

Okay, I'll give that a try.

What should my voltages be (approximately) for the second set of transistors?

[brian wenz]

Hello Mrsage--
    Crap.....my Kay clone is all boxed up with epoxy all over the circuit board....can't take any voltage readings on anything!  Sorry I can't help on that one.   With these "unknown" circuits I usually just try  inserting the pot into every collector and emitter junction of the transistors until I get a reaction.  Quite often it boils down to the collector of the last tranny in the circuit.  What trannys did you end up using??
Brian.

[mrsage]

2N3904s (first stage) and BC549s (second stage).

[brian wenz]

Hello Hello--
    The trannys with the highest gain  [around 400] are supposed to go in the first stage and the trannys with the lower gain [200] go in the second stage.  What's the gain of the BC 549??
Brian.

[mrsage]

Wow...that worked really well.

I actually lowered it all the way down to 10k and it sounds great with these transistors.

Thanks!

[brian wenz]

Hello Hello-
     Great!  Did you keep the BC-549s  in the second stage or move them to the front of the circuit??
 One thing I noticed when I was "biasing" mine was that if I lowered the value of the resistor too much the circuit got REAL hissy.  I just kept raising the value until the hiss went away.
Brian.

[brian wenz]

Hello Hello--
     bump  bump
Brian.

[mrsage]

I kept them in the second stage.

I don't notice that much hiss with mine. I adjusted the trimpot (in place of that 100k resistor) until I got a good combination of low noise and low gating.

Here are two samples:

www.voxblues.com/projects/kayfuzz1.mp3
www.voxblues.com/projects/kayfuzz2.mp3

First is les paul -> kay fuzz -> AC-15
Second is strat -> kay fuzz -> direct to computer sound card

[brian wenz]

Hello Mrsage--
    Great!
Thanks for the clips.
Brian.

[RCZ53]

Hey people I have one of the original orange ones. It has a cool octave effect, however when using the pedal (tone or fuzz control) it gets real noisy...sort of like ground noise. Anyone else have this in their circuits?