No sound in left channel.

[crappyjones123]

I recently mailed my perfectly working crack to a gentleman who is mentioning that he is not getting any sound out of the left channel when he pushes the headphone jack all the way in. However if he pulls it back a bit, he get sound in both channels but it is very poor quality. Any thoughts on what the issue might be or what troubleshooting steps I can suggest to him? He has tried different tubes and different headphones already.

[Doc B.]

The amp is only playing through one channel. It plays through both because both channels of the headphone plug make contact with the right channel of the jack when it is partially inserted. The issue could be at the headphone jack or somewhere ahead of the headphone jack in the circuit. It is probably either some connection that came loose in shipment or perhaps one of the contacts in the headphone jack is not making complete contact. Since you assembled it and are familiar with the process you probably have a better chance of sorting it out than the buyer.  I also feel the most responsible approach would be to take it back and fix it, unless you sold it "as-is, no guarantees".

Short of that, I would suggest that the buyer come on here and ask for some help. It would probably be easier to work thru the issue if we can communicate diectly with the person who has eyes and hands on the repair work.

[crappyjones123]

I was going to ask the gentleman to Mail it back to me so I could take a look at it but only wanted to do that if there wasn't an easy fix. I'll report back once I have it. Once I do have it though, any thoughts on where to start troubleshooting?

[Doc B.]

Look for a loose connection.

[bernieclub]

I thought I'd comment about the partially inserted plug.    The 1/4 inch adapter on my Senns is sized slightly out of spec., and when it's fully inserted, one channel does not play.    If I back it out the thickness of a thin metal washer, it works fine, in stereo.

Bernie