[cgrums]

Hey all,

I'm taking a break from my Alien DAC building to put together a PIMETA in an H659V case for a X-mas present. The parts list is completely stock with OPA2132PA/132PA and single BUF634s running off a single 9V. I've got everything wired and soldered but am only hearing a very, very faint output. I measured the following:

+ - input at board: 9.23V
V+ to V- at 2132PA (L/R): 9.2V
V+ to V- across right/left buffer: 9.2V
V+ to V- at 132PA (G): 9.0V

The led lights and nothing gets overly warm at all.

I've noticed that when I apply pressure to the casing of the pot (Alps RK097) I can get the volume to increase. I didn't see any solder joint isssues but then I'm not 100% sure I'd know one if I saw one.

This evening I'm planning on troubleshooting more, starting with swapping the pot (I have a spare RK097). What else should I be looking for? I've read through many PIMETA troubleshooting threads and none of the issues seem to match what I'm dealing with.

As always, thanks for the help!

 

[FallenAngel]

Your voltages are fine.

What's the DC offset on the output, always like to check since for me whenever an amp is acting up, I always had it.

Volume changes with pressue on pot : make sure you soldered the pot correctly and you don't have any cold joints.

 

[n_maher]

Sounds like a weak/cold/crappy joint to me. I'd resolder most of the joints on the board paying special attention to the pot long before I swapped out the pot. The pressure volume change could be caused by any nearby joint as you flex the board..

 

[pddjsteve]

Also make sure you have the inputs wired to the pads near the caps, not the pads near the opamps. I had that problem with mine.

 

[cgrums]

I was thinking solder joint as I did things in a slight hurry last night. I'll go back over and check everything again tonight...if I ever get to leave work

stupid projects

 

[cgrums]

So I redid most of the solder joints on the board and moved the input wires to the left of the pot...works beautifully! It works so well, in fact, that I started throwing together a second CMOY for the x-mas present and plan to use this little guy for my portable rig.

 

[aestuo]

Is your Hammond case metal? If so the volume pot could be shorting your circuit's virtual ground to the case's ground. Remember that (almost) everything connecting to the case has to be isolated from each other - see tangentsoft for details on this.

edit- oh it works, nevermind.