Tone Bender Mkii with bias mod, oscillation?

[Megatron]

im confused... 

No need for that, Chromesphere. Kesh obviously has a little homework to do and it should have been done before adding his comments.

[Kesh]

don't be silly megatron, we're talking about 2 different resistors. read lucifer's post again

[Megatron]

Also wondering what is the purpose of the 100 ohm resistor on the emitter of Q3 that is on the posted schematic, but not on the schemtaic at fuzz central.

The 100R resistor serves a limiting function and tames the amonut of fuzz available. With that in place you can only access 90% of the pedal's fuzz. My comment above about "losing gain" should have read along the lines of a loss of fuzz.

...which I would assume is why Lucifer recomended adding that to chromesphere's build. The 100R resistor mught cure the oscilation.

[chromesphere]

Ive probably got homework to do too, but, i thought, 100 was 10% of 1000...is attack at 100% when the resistance from emitter to ground is 0 or 1000 ohms?  Cause if its at 100% fuzz when its at 0 ohms, then putting that 100 ohm resistor in there, would prevent it from ever getting to 100% attack (it would stop at 90%)....100 of 1000 = 10%...?  Not being a smart a$$ here, serious question.  I'm an experienced builder, but unfortunately not that good with theory...but you know, im trying

Edit: 2 different resistors! now im really confused
Edit2: ok im on the right track with megatron! cheers!
Paul

[Kesh]

I was talking about the other of lucifer's resistors, to kill wall wart hum. And thought megatron was.

[Megatron]

You have it, Chrome.

Kesh shot out a post without any reference behind it. That why it is confusing to everyone. It would have been clear if he quoted the part of Lucifer's post and explained what was trying to be said.

Still, Lucifer's advice would work.

[Kesh]

and if you'd referenced which 100R resistor you were talking about, we'd all have been happy.

[chromesphere]

Well, before this turns into a punch on, i'd like to say thanks to everyone, cause i think i actually learnt something from this

Paul

[Megatron]

and if you'd referenced which 100R resistor you were talking about, we'd all have been happy.

I answered the question in the rpeceeding post. I did not throw out a random comment several posts later.

[Kesh]

well aren't you miss perfect

and that post referenced a previous post with two 100Rs in it

[Megatron]

He specifically asked about the Q3 resistor. Try readin the thread again.

[Megatron]

Well, before this turns into a punch on, i'd like to say thanks to everyone, cause i think i actually learnt something from this

Paul

I try to do the same every day!

[Kesh]

no u

[Megatron]

Thanks for you insight, it was a great addition to the thread.

[chromesphere]

I gotta agree with you both on this, lucifer said 'powerrail 100r'.  I looked at the schematic didnt see the emitter resistor first time i looked at it, and thought he just meant, wack in a 100r on the powerrail to reduce voltage into the circuit.  Then Megatron pointed out the emitter resistor and i went "ooooohhhh!!!" and it clicked.  Thats what reduces the fuzz.  I can see how it works.
So your both right
Paul

[Kesh]

Thanks for you insight, it was a great addition to the thread.

you're a patronising wanker aren't you.

[Kesh]

I gotta agree with you both on this, lucifer said 'powerrail 100r'.  I looked at the schematic didnt see the emitter resistor first time i looked at it, and thought he just meant, wack in a 100r on the powerrail to reduce voltage into the circuit.  Then Megatron pointed out the emitter resistor and i went "ooooohhhh!!!" and it clicked.  Thats what reduces the fuzz.  I can see how it works.
So your both right
Paul

and you're a peacemaker

[chromesphere]

I gotta agree with you both on this, lucifer said 'powerrail 100r'.  I looked at the schematic didnt see the emitter resistor first time i looked at it, and thought he just meant, wack in a 100r on the powerrail to reduce voltage into the circuit.  Then Megatron pointed out the emitter resistor and i went "ooooohhhh!!!" and it clicked.  Thats what reduces the fuzz.  I can see how it works.
So your both right
Paul

and you're a peacemaker

Thank you!  I try

Edit: honestly though, thats exactly what happened...peace maker or not...
Paul

[Megatron]

Thanks for you insight, it was a great addition to the thread.

you're a patronising wanker aren't you.

Perhaps, but at least I have reading comprehension skills and the courtesy to use them before offereing eroneous comments on other's posts.

Have a nice day Kesh!

[fuzzy645]

All interesting stuff to learn here!

So I breadboarded my first one and it  appears to work fine, but it sounds, well.......not too good yet.

I'm guessing this is because my tranny's are WAY above the recommended HFE (which is why I asked).  I've got a Q1 at 110-ish,  and Q2 & Q3 over 200.  I will now try swapping them out for some lower gain trannys and see how if I fare any better.

I have also seen variations on 3 other parts of the circuit where I have questions:

1). the first resistor before the base of Q1, I have seen as 100K and 10K.  I have my breadboard using the 10K.  I will try to swap that for a 100K before I change the tranny's.

2). I have seen it mentioned to change the 470 ohm resistor to a 1K to boost output.  Not sure why this would boost output. I would assume increasing resistance would decrease voltage.  Just curious.

3).  I have seen the resistor on the collector of Q2 as either 100K or 47K.  I have my breadboard using the 47K, but I will try swapping that out too. 

Any thoughts?

Thanks!!