DIY Simple Active Preamp

[Bodgeangles]

Completed the SSP on a perfboard today but have had some issues since.

Firstly, I had to replace the original transformer which turned out to be a dud. After that the power supply worked nicely, but I'm only getting sound from one channel at the moment. I've spent a little time poking around with a DMM and haven't found the cause yet.

Here's the project anyway. The board is divided in half, one side holding the power supply and the other end for signal, with the op amp situated in the middle.

 

[egellings]

You might want to add a coupling cap right after the wiper to keep any DC in the input signal out of the op amp. If the amp has any input bias current, the cap will stop a scratchy sound when the control is rotated as well. Something around a uF or a bit less would do.

 

[nj pheonix]

If you get s pinout of that op amp you should see identical voltages on each channel.
Double ( triple check circuit paths and solder joints)
Looks like a nice clean build

 

[Bodgeangles]

Thanks for your comments guys.

I think I've figured out the problem. I'm using RCA sockets like the one below.

It has three mounting pins - one in the centre for ground and one on each side that both have continuity with the input pin. That is, until you place an RCA plug into it, and then one of those pins no longer has that continuity. All the sockets exhibit the same behaviour.

As you can see, I've wired opposing pins of the connectors for each channel, so with RCAs inserted one channel essentially becomes open circuit.

Hopefully it'll just be a matter of resoldering to the correct pins.