2 effects on same board,same psu, what am I doing wrong?

[momo]

I built a Ruby, added a Heartthrob tremolo, everything was fine, they were seperate boards,shared the 12v Psu. I decided to add a booster, the tremolo was a perf job, so I decided to do the etched version, and since I was adding a booster, I decided to etch it on the same board as the tremolo side by side.

Now usually, if you put effect boxes in series, the grounding of all this is done thru the chassis/pots and cabling with individual psu. My problem is in the voltage and not sound I guess.
Now if both effects share the same 12v(Im not sure that the booster handles 12v), the ground connection is made thru the negative of the psu. In other words the main psu arrives on the tremolo, and is bridged to the ruby and the booster(positive and negative). Is this the way to connect a shared psu?, should I link the ground on each effect, or is the psu grounding enough to make the ground link?

Right now, I just about thru everything to the garbage....Its frustrating to spend time etching and having it work less than a perf job!
Now smoke was coming out of the booster, so I guess it does not take 12v, althought I did not try it isolated with the 12v so I dont know if its because the booster does not take 12v, or is it the result of something else that I cant understand.
Unplugged the booster, just plugged the ruby and tremolo toghether, this worked fine on the perf, so I can confirm that the heartthrob takes the 12v.....but then when I plugged the psu, which is going in the etched tremolo and is bridged to the ruby....well as soon as I plugged the psu, the 386chip in the ruby started to smoke!
I just dont get it....im probably doing something wrong on the psu connection,(jeese, you would think that 2 wires would be easy!)
Now I guess I would have to swap the trannys also, as those might have blown out?
Im positive there are no shorts on the board!
Ah man, I have this great setup for this build, ive been spending 2 weeks on this....I cant wait to get it done!

If anyone could maybe give me a psu signal flow(wireing diagram) to put these toghether that would be awsome!

I would want to power the ruby and tremolo with the same 12v and then add a 12 to 9 v regulator circuit for the booster, all using a C battery 12v design. Apart from the fact that the booster might not take 12v, I think my problem might be with ground loops?

[ulysses]

are you able to test each board in isolation? if not, do you have a schem of "moulded together" circuit?

cheers
ulysses

[momo]

Ok, I have worked all  day at this and have progreessed, I will exclude the booster in the debug for now, as I have a new problem.....2 weeks ago, I did a Heartthrob and Ruby on perf board, they were both powered using the same 12v. I had no problem, apart from a short burst of squeeling while plugging the 12v.
I decided to do a cleaner and smaller job on etched pnp, and this is what I was having problems with the booster, I blew some diodes on the booster, so I can confirm that it does not work on 12v.
Anyway, I tested my new etched Ruby alone, works fine, tested the tremolo alone, works fine, exept that the swell pot does not seem to be doing the propr job. Now I plugged again the tremolo and Ruby toghether, the same way as my perf build. Now, If I push the Ruby volume all the way, it starts to squeel badly with the gain at half, full gain and no notes can be heard as the squeel has become permanent and loud!

So what the hell?, the 386 seems to go into severe feedback with too much gain.
Also, if any of you could help with the swell pot problem....(MarKM!!), I thought that this tremolo would clean up to unity gain with no decernable effect heard with the swell completly down, that would give me the clean signal to the Ruby( signal flow: Guit-tremolo-Ruby).
But full on swell is fine, but full off and the sound gets real choppy and I loose lots of gain.
If the swell was not designed to "clean up", then I guess Ill have to add a switch to use the tremolo or not!
Ill do another debug thread on the booster as it works on 9v
thanks guys!
I cant wait to have my portable vintage looking Ruby working...gotta have it for my cottage vacations! in July...

[momo]

Anybody have experience on squeeling effects?, why does this happen?
thanks a bunch!

[petemoore]

Anybody have experience on squeeling effects?,
  Oscillation does that. Could be it's oscillating somewhere in there, I'm not saying miswire, which can cause that.
  In other words the main psu arrives on the tremolo, and is bridged to the ruby and the booster(positive and negative). Is this the way to connect a shared psu?, should I link the ground on each effect, or is the psu grounding enough to make the ground link?
  I don't know...but would just run the Ruby ground separately back to the power supply, perhaps the high current AC signals needed to drive the speaker are putting sewage in the ground line..the booster is on, use filter caps on the AC supply.
  Now smoke was coming out of the booster, so I guess it does not take 12v, althought I did not try it isolated with the 12v so I dont know if its because the booster does not take 12v, or is it the result of something else that I cant understand.
   pre-test for non-shorting conditions on all of the power rails to each other and ground, than apply voltage.
  Smoke brings 'shorting' to mind.
  so I guess it does not take 12v Are your components rated for <12v?

[momo]

I will try the regrounding to psu on the Ruby, thanks Pete,I was not aware that the signal driving the spkr was AC? , Im using batteries, maybe you thought I was using a transfo?, Im still learning alot so, maybe there is something special about an amp design that induces ossilation if its not properly done as far as sharing psu?
For the grounding issue, as far as I know, you cant really get ground loops on DC?, and if you can, could that be a cause of ossilation?, is oscilation only a psu issue?
Ok, Ok...Ill get on a ossilation search

[petemoore]

I was not aware that the signal driving the spkr was AC?
  I don't know if the Ruby sends alot of hash out from the speaker return gnd. or any other places.
  I do know that speakers Gnd. has AC 'signal' in it, running a booster 'up front' [where the signal is then magnified many times by the circuit] with it's ground on a ground that is carrying 'lots' of current, AC current, that ground doesn't 'hold still'...ac spikes may be present, using this as a ground reference 'may' cause troubles.
  That said I admit I ran my 5e3 speaker ground through the chassis for a long time before I figured that one out, also a first LM3886 needed grounding attention and improved when I separated ground wires, running high current grounds back past wherever the amp/preamp got their ground...they call it 'sewage', you want to dump the sewage in the ground, right where it 'goes out' to the PS, and have the booster or amp on a separate ground.
  I don't know if that's the oscillation problem though. testing the chip IME is easiest by replacement swap test w/known good chip.
  I'd test the voltages and supply voltage, read the data sheet Max V for the chip and components etc. then try it again with another chip, ground sewage would just hash up the signal, and that doesn't translate directly to 'damage' other than with signal integrity.

[momo]

Ok, I changed the grounding and grounded the ruby to the psu...that helped alot!, now I only get ossilation at the last bit of drive pot with volume all on.
So ill have to reread what you just wrote, I just wanted to ask fast if putting longer either + or - cables help the last ossilating bit?

[momo]

So ill try to develop this a bit,... Pete, when you talk of dumping the sewage back to psu-pre effect,thats what I did, but it occurred to me, or should I say, Id like to clarify....to me there are 2 ground types, signal and psu, in a non balanced system like stomp boxes, the signal and PSU ground share a common link, so when you say to seperate amp ground and effect ground...well, to me, its the same ground wether its linking thru jacks,pots,or - battery link!!!??

I think I understand the "bypass effect ground for amp ground", but they are all together, so is it distance that works here?
I hope I dont sound too confused cause...I am

[momo]

Me again,....so I read that the 100uF cap from + voltage to ground is to permit low impedance path to ground for any AC. Can putting a higher value cure the ossilation?