diy Project - two Screamer in one Enclosure ...

[Oliver]

Hi,

i soldered a circuit with two Tubescreamers to build a 2 Channel
OverdriveUnit, having some problems with the Sound now, but dont know,
the source of the Probs....  
The Switching works fine.. (first Stomp to Bypass the Circuit/ second one to switch between TS-1 and TS-2)

The circuit is build as followed:

Input Stage is Stock TS. The First Channel is hooked up directly at Pin
3 of the first OP and ends with the Output of the Level Pot.
The Output Buffer is left away and the circuit ends after the 0,1uF Cap after the Level Pot.

Both Circuits work (i got the Feeling, that the 9V Bat. is a bit small to
power two circuits - i had to take a fresh one to get a sound out of it)

I earn only the Bypass Signal Level, when Levelpot and Drive is cranked up.

Does anybody know, if the two circuits affect each other, or why the OutputLevel is so low?
Perhaps i have to use two separat Bias Networks, one for each TS Circuit, or something like that?

can anybody help?

thank You !!

Oliver

[aron]

It's too hard to tell what's going on. There should be no problem running 2 of the TS circuits in one box.

It must be some sort of wiring problem.

[Oliver]

hmmmmm - i'll go to test a little bit..

is it possible, that the missing OutputBuffer can cause the lower OutputLevel??

I build a TS Circuit without any Buffers - that works OK

thanx..

Oliver

[Oliver]

Hi,

i made a fast illustration of my Circuit Design from fragments of an existing TS Schematic (i hope thats OK)

The two Switches are DPDT Footswitches.

Can You see any reasonable mistakes ??

bye
Oliver

[petemoore]

Ok to my eye anyway...
 Don't see why the plan won't work.
 Just regular old debuggin should cause something to pop up at you.

[MarkB]

Unless I'm reading your diagram wrong - you have this set up as a 2-channel (either A OR B) and not cascading them (A AND B).. so you may need the output buffer on the end of the circuit.

I haven't experimented with TS'es much, but if that buffer has anything to do with make-up gain...
"-)

[spongebob]

The output volume pot should be referenced to ground IMHO, right now you might have 4.5V DC offset at the output... Also C10 is not necessary I think... :?:

[Samuel]

spongebob: isn't C10 cleaning off that 4.5VDC bias?

[spongebob]

I'm not sure, but wouldn't that require some 0V DC reference on the other side of the cap? At least in most schematics you see a blocking cap followed by a resistor or pot to ground, or whatever voltage level is needed.

[Samuel]

It seems (to my admittedly limited knowledge) that his schem would work, but if it were me, I'd redesign as you suggested, with an output cap on each circuit, followed by the volume pot with one end tied to 0V ground, and then off to the DPDT.

[TheBigMan]

I'd agree with the previous post, looks like the output pot should be tied to ground to me as well.  The lack of an output buffer shouldn't make a difference, most of the DIY layouts (E.g. JD Sleep's) only have an input buffer.

If both circuits are suffering from the same lack of volume then I'd look at the pot wiring.

[Oliver]

Hi,

im ashamed.....

all things working now fine

i made a beginners Mistake (accidentally) i changed the Level Pot
Pins Vr and middle  :oops:

I tried for two hours with different caps at the end and other places,
to wire the Level Pot to ground instead to Vr... and randomly i shorted (accidentaly) the Pins with a Screwdriver and for a Second the Level grown up very loudly
I would be soldering still now, if i hadnd this help from (who the hell was it?)



Thanx for all your support!!!!!!!!!

ciao
Oliver