Is this ever going to work? Fuzzface problems revisited

[bwanasonic]

Guess I'm not the only one who had problems posting...

Very weird.

[petemoore]

I had a big long post there but lost it when I didn't hit preview in time.
 Great research and writing Saxtim...You've done homework !!!
 Sorry I didn't look at the schematic earlier, I assumed it was a 'FF'...I've not seen this one beofre...I can't make out how it could work...I'm sure it does, but I don't understand it...
  Possibly form a specific question under a new topic, relating to the PS, this ckt, and how that works...[so someone who understands the ckt could recognize and enlighten} I would resolve this first.
 Once again decide.
 If it we're mine I would pick a 'standard' pos ground schematic, and check the battery and the 22uf's polarity [if you're using films for the other caps they can stay in the same way] put some 'grab bag PNP si's' if ya got em in it...
 I always try to remem to check between battery clip +and - [on beep mode to make sure there's no beep/short], chack that all grounds are made, that the 'other side of the battery is going to the top of the ckt where it should [I also like checkin that it doesn't go where it should'nt go by poking around here and there and there etc]...before powerups.
 I don't understand why this schematic 'is' [?] I'm sure theres a logical reason for it...'standard' FF's work just great though too...

[petemoore]

TEST TEST
 I just spent an hour typing to find the 'stupid' page..what a drag...the second time I hit preview a buncha times
 Great write Saxtim...you've done homework and research...well put together post !!!
 I would build a 'standard' Pos Ground FF...but you decide
 Rephrase the question so someone who actually understands how this ckt could work [ I dont] might recognise 'why theis ckt 'is'.

[petemoore]

I didnt' look at the schematic [I've never seen this one] earlier I guess I assumed it was a 'FF'...like I draw from memory.
 I would resolve the schematic [how it could work I dont get] issue or go for a 'standard' FF build...they work great though too.
 Possibly form a question relating to the ckt's function [how/why] under a new topic...I'm sure someone understands it.
 However it shouldn't be too hard to reverse polarity on a few' parts to make it easier for us 'standard FF guys to help you get it going.

[petemoore]

I'm interested to see you get a FF going Soon!!!

[amz-fx]

I'm building a PNP Negative Ground version

My original article might also be of use: http://www.muzique.com/lab/fuzzface.htm

Good grounding is important in this high gain circuit.

-Jack

[saxtim]

i've just looked over my PCB and I've realised it wont actually be difficult to convert this to positive ground - the only connections I have to change is the ground connection from the volume pot, which is offboard wired anyway and I'll have to disconnect the 470ohm resistor from what was ground and then wire it to the negative lead of a battery.  The rest is just a matter of putting positive power to my old ground and swapping a couple of polarised capacitors.

I'll give this ago over the next day or so and see if the positive ground version works any better.

thanks

tim

[saxtim]

I had a chance to come back to this today and I converted it to positive ground... And it worked perfectly straight away!   I don't understand why the negative ground version didn't work though  :? Has anyone else had major problems building a negative ground version?

Oh well, at least it's working now and I can move on to other things!

tim

[Kleber AG]

Has anyone else had major problems building a negative ground version?

Yeah, I just build my first Fuzz pedal it's the easy face and I made it PNP "negative ground" it works NICE I just loved the tones, but it's weird, sometimes produces noises with low guitar volume knobs settings, looks like the circuit is just too instable, sensitive? Sometimes misbiased?

I'm thinking about converting to positive ground...

Anyway I really loved the fuzz sounds...
Regards
Kleber AG

[petemoore]

There must be a reason for it.
 Ahh First FF Functioning...Kool !!!

[Kleber AG]

buuuuummmmppp  
Is there an explanation for the difference betwen "PNP" positive X negative ground?

Just ocurred to me that the fuzzes circuits usually don't have a power filter cap from V+ to ground...
so, at a negative ground the circuit will have roughly the "collectors" at the box chassis (what is suposed to be a shield protection)...
but, the point at the circuit that actualy should receive what you would want to have filtered is the point where the emissors connect...

Ahhhggg (I'm bad on english and horible on electronics, but this is what have come to my mind)

Am I totally lost on it?
If not, does a filter cap from V+ to GND just solve this situation I've described or not?

Best regards
Kleber AG