Debugging a woolly mammoth

[kin0]

Name of the project: Woolly Mammoth (with some mastotron mods)

I used this layout (here is the link to the site: http://tagboardeffects.blogspot.co.il/2011/02/zvex-woolly-mammoth-vero.html)


As it stated in that site you can add a relax/pull pot and a sub switch from this Mastotron layout:


Here is the final layout I drew and used (the values written down are the values that should be when the circuit works properly - found them on the web):


It makes some sound but it is clean and the volume always bounces (it jumps from regular volume to nothing to very quiet). I still haven't wired up it all the jacks and the 3pdt switch (I bread boarded all things beside the circuit itself and the potentiometers).

Q1
C = 1.91V
B = 0.01V
E = 0V

Q2
C= 1.3V
B= 1.91V
E= 1.28V

I checked the web and these are the values that should be:
Q1
C = 1.37V
B = 0.61V
E = 0V

Q2
C = 1.71V
B = 1.37V
E = 0.74V

[Kipper4]

I dont know about that vero version.
Did you check it against the schematic.
I built this one and it works a treat. I had to debigg a few faults but that was the usual operator error.

it kinda sounds like the transistors are not properly biased from the sound description.
Did you check your pinout?

[kin0]

The pinout is right and yes, I checked it against the schematic.

[craigmillard]

Hey Kin0

Your Q1 base is off and it would suggest it is tied to ground somehow.. I would check for solder bridges between the tracks, maybe run a knife between them to make sure there are no joins..
Concentrate on Q1 and the 10nf area..

[kin0]

After tweaking the pots and rechecking the values here is what I've got:

Q1
C = 1.15V
B = 0.47V
E =0V

Q2
C = 0.5V
B = 1.15V
E =  0.5V

I think I've probably just checked the Q1 base wrong. Now it seems that the most problematic value is the Q2 collector. I didn't find any soldering bridges. Any ideas what can cause this?

[giappui]

under the 100uf cap there is a cut!!

in your layout the 100k res is connected with 100uf cap...wrong

[kin0]

Totally missed this  . I'll fix this later today and see what happens

[kin0]

Everything works great now! Thank you very much guys! 

[giappui]

now try this with a V eq

is fu****ng insane!! 

[kin0]

what is a V eq?

[giappui]

mid cut

bass and treble boost

[kin0]

oh, ok. First I have to wire up the box with the switch, the led and the jacks