Fuzz experience

[Tek465b]

Oh sorry, no solder bridge.. my fault i was confused. just remove the blue wire and if Q1 is not bad it should be good.
i was confused between the 22k yellow wire pads and the green blue wires pads sorry bout that.
But you do need to remove the blue wire.

[Xplorer]

thanks Tek yes i'll disconnect this blue wire tomorrow, going to bed now.
what bugs me is that in either position, there's no sound.
even if on one position the blue wire connects A to the 22k / 1M point, which is wrong , the other position should be ok anyway, but it's not.
We'll see later. Thanks man

[Tek465b]

thanks Tek yes i'll disconnect this blue wire tomorrow, going to bed now.
what bugs me is that in either position, there's no sound.
even if on one position the blue wire connects A to the 22k / 1M point, which is wrong , the other position should be ok anyway, but it's not.
We'll see later. Thanks man

With the blue wire connected and if the 1m pot was set to low ohm, Q1 is probably bad now and need replaced.
Will see what else can be done tomorrow
EDIT:
am sorry if i said to connect the point A together. i dont remember doing so but maby i did unintensionally.
i guess i missed those point A when i checked your edited schematic picture when i said it was correct.
Really sorry. hoping that Q1 is not bad now.

[Xplorer]

oh ! it can kill a transistor ??

it was the highest hfe of all three. i'll unsolder it and see, anyway , i have one spare.

[Tek465b]

oh ! it can kill a transistor ??

it was the highest hfe of all three. i'll unsolder it and see, anyway , i have one spare.

Say if the 1m was set to low or 0 ohm, and the switch making contact with that blue wire.
That mean alot of base current, more than the transistor can withstand

[Xplorer]

It's working ! thanks again

i may not have set all the pots right when i first tried but anyway, there were some bugs to correct.

i still need to put the 0,05 uf cap in it.

well, i should test more to see if it goes bog or not, i'm not sure. sounds nice though
and it can deliver a huge load of fuzz, it gets some feedacks easily.
Thank you Dave for the experience

i notice that the Q1c requires a different value on the pot , between the two positions ( clean / high gain ) to work. on the high gain position it has a larger value bandwith possible, but on the other one, there's only one small spot where the fuzz put out some sound, and it's a different value so if i switch it, i need to correct the pot value too.

i replaced the transistor by the spare i have, about half less hfe than the other one, which now shows 75 hfe, and before it was more like 89 hfe. i didn't test it again , i just removed it and replaced it directly.

will test more later.

[Tek465b]

woot ! its working.
And i think my Germaniums are comming in today.
Yeah its going to take a bit of time to find the sweet spot. can't wait to hear a clip.

Dont know about the switching bias change. I don't think it should be happening. Dave?? .

[Tek465b]

Pfft just received my germanium from gordelux on ebay.. out of 20 just one test above 40 hfe(most of them in the 20-30 and 3 of them in the 10's..).. really dissapointed.
Most of them are in the 20-30's hfe.
I guess they will work in a normal fuzz but i dont think am going to build the Dave fuzz for now. .
In fact i dont think am going to use them at all.. will prolly give it a try in a FF since i have them but.. really dissapointed

[Xplorer]

oooh , so sorry about this.
if you see my pictures, you'll perhaps see the 2n525 i've purshased , these are of a higher range, if you feel like trying again

it says NJS 7750 , with gold legs.

good luck, come back to it when you can

[daveweyer]

I'm not sure exactly what kind of an arrangement you have going. Maybe you could post the circuit diagram as it currently exists, there should be no difference in the output between a lot of negative feedback and very little, since the feedback is AC and doesn't affect the collector voltage of Q1. You may have a high frequency oscillator built there because of leakage, lead dress, component layout etc, in which case the output will be affected by the amount of negative feedback.
On the clean setting there should be plenty of sound, but no fuzz when the control is down.

[Tek465b]

Dave got a question.
I got my Ge transistor and they are very low gain (higest one is 48 all the rest are under 40) so its almost unusable.
It work but i get little fuzz, so am thinking of using one ge and one si to increase the gain and retain the Ge sound as much as i can.
Where do you think the Si will work best in Q1 or Q2? and what gain for the Si? i have a 120 and a 168. and maby raising the nfb resistor value if i leave 2 low hfe Ge in it.
I know i should try it and see what i like, but i want your input first .

Am thinking i should build the 3t fuzz anyway, so i could get some good gain/fuzz even with low hfe Ge?(i know its not going to sound as it should but it could be interesting)

And did you happen to name that fuzz circuit? i don't know how to call it, the 3T-ff or the DaveWeyer fuzz or something else?

[daveweyer]

We've been calling it the West Coast mod, but any name will do. There were other West Coast mods too, and we may be able to build those as well.
The first transistor needs some beta, because it only has a guitar signal for base current unless a Wah is running.
Very low beta chips won't give you much gain consequently. So you might want to try the Q1 position and see how it sounds. Q2 has plenty of base current from Q1 collector circuit, at least what a 37K will deliver from the supply.
I designed the unit to run with current gains around 100, and if Ge devices are no longer available with that kind of current gain, then either Si devices or perhaps NOS Ge devices will work. Other than that, the circuit could be redesigned for lower beta transistors.

[peter25]

Just for info. Took some ac128's (Hfe of around 170) out and put 2n525's (Hfe 75 and 95) in a fuzz I had lying around. I can totally hear the Hendrix vibe he had at woodstock coming in. That hollow sound if you know what I mean. 2n525's were made by Philips. Bought 10 of them 2 were around 100 Hfe. Next thing I will do is get some 2n526's or 2n527's. According to datasheets they have the same specs as 2n525's but with higher minimal Hfe. So more gain. My guess is that one 100 Hfe and one 160 Hfe will get more sustain out of the fuzz. this with a two transistor setup. Does this make any sense Dave? Or am I too simplistic about it?

[daveweyer]

I think you'll have a good experience with the 527. I used them myself and they are real nice for this application.
Generally, more gain equals more fuzz, but a lot depends on how the circuit is set up, where Q1 collector voltage is for a start.
The old 525s by GE apparently had more beta than what folks are getting now; 100hfe is very desirable for the circuit, and this can be raised up to a point where the circuit begins to sound too modern (super sharp fuzz which sustains and is harsher).

[shakti]

Just trying to shake some action here...how is everyone doing with their fuzz builds? Did anyone complete a functioning three-transistor fuzz? Did anyone make up some circuit boards?