overdrive pedal just mutes guitar

[cyberk007]

So I recently put together a stompbox based around a 12UA7 tube and its not working. I built it off of this schematic http://img155.imageshack.us/my.php?...asterv05qs5.jpg from this here forum http://www.diystompboxes.com/smfforum/index.php?topic=63479.280
and when i hit the 9 pic button that would disable the bypass it just mutes, the bypass works fine but not the effect. The LED turns on to show its engaged, but no sound. What do you think the problem might be, or would a pic be helpful, or any ideas, cuz ive racked my brain over it and i cant find anything. I did a continuity test and Im rather sure all my parts are in the right place. Any ideas as to where the problem might be?

[MikeH]

Before anyone here can really help you, you'll have to gather some information first  (I've had to do this a billion times).  Fill out the checklist in the "DEBUGGING:  What to do when it doesn't work" sticky thread and post your results, and someone should be able to help you out.

Oh, and welcome to the forum!

[cyberk007]

A full set of information about what you built
1.Valvecaster from this forum
2.see first post
3.I followed it exactly with no known changes
4.I had access to all the exact value parts
5.Whether or not it's a positive ground circuit like a PNP fuzz or a Rangemaster that has been hacked to work with negative ground. This is a special case, but a common one. "Positive ground" means that the positive/red lead of the battery clip is connected to signal ground. "Negative ground" means that the negative/black lead of the battery clip is connected to signal ground when the effect is operating. -this confuses me but i built it to exact specs so you tell me lol. I dont think it is though.
6.When It is on bypass mode it bypasses fine sounds just like it wasnt there. Then when i hit the 9pin switch to turn on the effect the LED turns on and the sound just mutes. Nothing, even if i turn amp up all the way there is only a minor buzz, not related to how i strum. No ideas.

I am using a non-dead battery not a wall plug and  i have a electronics meter. I ran a continuity check and I couldnt find any problems there. Not sure where the problem is but i checked my parts and they seemed to all be right. Any other info that would be helpful let me know, thanks for whatver help you can give.
(oh and thanks for welcome)

[MikeH]

I don't know anything about this circuit (I didn't even realize it was a point to point build) but the fact that you effect works in bypass, really doesn't say much, except that you circuit is not assembled properly.  In fact, I never even wire up a switch until I know the effect itself is working.  And the fact that the LED works, just says that you actually have power there, it doesn't actually tell us anything about the circuit. 

The imageshack link you have seems to be dead.  Do you have a link to the actual schematic?  And it would help out if you posted the voltages on each pin of your tube socket.

[cyberk007]

here you go
and how do i measure the voltages?

[cyberk007]

oh and other people in the forum have built it and i even got a sound clip from it so i know the schematic works, its just mine doesnt 

[MikeH]

Take your volt meter (set to 20 scale) and put the black end on something grounded, like the ring of the input jack.  If it's already in and enclosure you can stick the probe into and empty screw-hole.  Now probe each pin of the socket with the red lead and record what the voltage is.

[cyberk007]

ok heres voltages
pin#
1. 6v
2. -0.02v
3. 0v
4. 0v
5. 1.11v-7v, fluctuates
6. 6.5v
7. -0.09v
8. 0v
9. 3.5v

[MikeH]

Double check your connections; somethings amiss.

pin#
1. 6v - This seems plausible
2. -0.02v - seems ok
3. 0v - if your gain is turned all of the way down, this is correct
4. 0v - good
5. 1.11v-7v, fluctuates - this is wrong.  Check the connection and check your power supply.  This should be a full 9V or 9.6... whatever your power supply is.
6. 6.5v - Seems ok
7. -0.09v - I honestly don't know what this should be
8. 0v - correct
9. 3.5v - don't know about this one, it looks like it should be disconnected.

[MikeH]

Also make sure your gain pot is wired up right- it might be backwards in the layout, and if you think you have it turned all of the way up, it might actually be all of the way down

[cyberk007]

ya, no wires are touching 9 but its still hot. My power battery is only giving off like 7.8 volts and pin 5 gets up to that but it moves around though im not sure why

[cyberk007]

it seems that no matter what i do with the gain pot that voltage doesnt change

[MikeH]

ya, no wires are touching 9 but its still hot. My power battery is only giving off like 7.8 volts and pin 5 gets up to that but it moves around though im not sure why

Get a fresh battery, 7.8 volts isn't enough for a good debugging.

it seems that no matter what i do with the gain pot that voltage doesnt change

This is actually adjusting the bias of the tube IINM, which makes the signal louder or more quiet.  So make sure that the pot is good and you have it wire up right.  It seems like the voltage on pin 3 should change as you rotate the pot.

[cyberk007]

ok played with some things and  now it works BUT when i turn it on it doesnt seem to make any audible difference to when its off. When its on the volume pot controls volume but i dont here the tone or gain pots doing much, then when its off none of the pots do anything. Other then the volume control tho i dont hear any difference to when its off as to when its on.

[cyberk007]

hmm still no voltage on pin 3, when i turn the pot the resistance changes, and i did a continuity check and the wires are good and its wired up right, but ya. hmm.

[MikeH]

The layout you use has the tone pot wired wrong.  It shows lug 1 of the tone directly wired to lug 3 of the volume pot, which is incorrect according to the schematic.  I think the wiring of the gain pot in that layout is suspect also.

[cyberk007]

so what changes might you suggest me making? I unfortunately do not know alot of the theory going on behind the scenes here so Im not a lot of help there.

[MikeH]

Seems to me it should go like this.  Pin 6 connects to c3 which connects to lug 3 of the volume pot.  Then c4 should go from lug 3 of the volume pot to lug 3 of the tone pot, with lugs 2 and 1 connected to ground.]

For the gain, I'd say pin 3 of the tube socket should connect to lug 3 (or possibly 1) and lug 2 and 1 (or possibly 3) should connect to ground.

[cyberk007]

like this?

[MikeH]

Yeah, but don't run wires from both lugs to ground; connect the 2 lugs and wire lug 2 to ground.  See if that does anything to fix the situation.

Edit: Disclaimer- they might be backwards; I'm terrible at telling which lugs are which by looking at a schematic.  If they work, but work backwards, just swap the connections on lugs 1 and 3.