question about increasing volume of Pedalpcb Mantle Fuzz

[Vivek]

Dear Snow,

Do you have :
Oscilloscope
DMM
Audio probe ?

[snow123]

Dear Snow,

Do you have :
Oscilloscope
DMM
Audio probe ?

Oscilloscope - I have a mini DSOshell Oscilloscope.
DMM - yes
Audio probe - yes

[Vivek]

Could you please post scope output on collector of Q2 and Q3 when 400mvp sinewave of 1khz injected at input.

[snow123]

Could you please post scope output on collector of Q2 and Q3 when 400mvp sinewave of 1khz injected at input.

wait i dont think the DSOshell is working at the moment since it uses center positive power, and ive tried using center negative power with it. several times...

[bluebunny]

it uses center positive power, and ive tried using center negative power with it. several times...

Seriously? 

[snow123]

it uses center positive power, and ive tried using center negative power with it. several times...

Seriously? 

yea..... I didn't realize it used center positive until yesterday.... *facepalm*

[antonis]

I presume 25 replies deserve more than one facepalm..

[snow123]

I presume 25 replies deserve more than one facepalm..

in my defense, i don't think it said so in the manual that was included, so being used to pedals taking center negative, i didnt even take the polarity into account and just assumed it used center negative instead of center positive.

[bluebunny]

Guitar pedals are the exception.  The rest of humanity does centre-positive.   

There's a schematic here.  The DC pin is clearly positive.  Luckily, there's a 1N4007 protecting against reverse polarity, so yours may not be toast.  The manual also says it's centre-positive.

[mdcmdcmdc]

can anyone help me with the issue tho?

Have you been able to compare it against an actual MXR unit? They don't have a lot of output, so this may just be a case of disliking a circuit rather than a malfunction/build error.
If everything's fine and you just wish it had more output, just build a LPB-1 with a trim pot on vero, tuck it in the enclosure, and never think about it again.

[snow123]

can anyone help me with the issue tho?

Have you been able to compare it against an actual MXR unit?

nope

[Phend]

Have you tried turning the controls in your amp UP.

[snow123]

can anyone help me with the issue tho?

They don't have a lot of output, so this may just be a case of disliking a circuit rather than a malfunction/build error.
If everything's fine and you just wish it had more output, just build a LPB-1 with a trim pot on vero, tuck it in the enclosure, and never think about it again.

another one of the issues is that there just isnt much gain on the fuzz, so i cant really get a good fuzz tone with it, so when the blend control is below 12 o clock, the fuzz is just dark and weak, but with it above 12 o clock, its mostly just a big sub octave with not much fuzz.

[duck_arse]

it uses center positive power, and ive tried using center negative power with it. several times...

Seriously? 

you've got to be certain, don't want to go off half cocked.



is there any reason you haven't posted photos of your build yet?

[snow123]

it uses center positive power, and ive tried using center negative power with it. several times...

Seriously? 

you've got to be certain, don't want to go off half cocked.



is there any reason you haven't posted photos of your build yet?

Oh, sry about that.
Here:

[duck_arse]

there is a resistor next to pin 1 of the IC, probably R4, please measure the resistance of same. also, what are the markings on that yellow blob cap, probably C3, next to that resistor?

[snow123]

also, what are the markings on that yellow blob cap, probably C3, next to that resistor?

301.
its a 300pf cap.

[snow123]

there is a resistor next to pin 1 of the IC, probably R4, please measure the resistance of same.

without any power it measures at around 460k, and with power, it fluctuates in between 600k and 820k.

[duck_arse]

well, both those parts seem ok for value. why are you attempting to measure resistance with power on? you never ever ever measure resistance under power, as the meter feeds a known current to the resistor under test. power on will just give nonsense, useless, meaningless reading.

[antonis]

you never ever ever measure resistance under power, as the meter feeds a known current to the resistor under test. power on will just give nonsense, useless, meaningless reading.

I might be wrong but I've the impression of the above said (and repeated) in every OP's thread..