Recently developed problem

[clauswitz]

I've been using this amp for awhile now but just recently it's stopped working for the left channel, odd thing is that if I turn it off and let it sit for awhile when I turn it back on both channels work for awhile, in addition both channels work for a moment when I turn it off. Any advice on what I can do to figure out what went wrong and how to fix it would be greatly appreciated.

[Paul Birkeland]

Start with voltages and resistances (but mostly voltages).

-PB

[clauswitz]

Worth check voltages as soon as turn it on and then later once the left channel stops working?

[Paul Birkeland]

Yes, when the left channel dies, there may be a funny voltage accompanying it.

[clauswitz]

Wow I really should have looked at what I was typing in the previous post.
Anyways all the voltages are ok except A1 which is fine when the left channel is working but is 0 when it wasn't. I didn't actually try to figure out what it was in the moment that it cuts out as that would be PITA to do but if its really necessary I can do that.

[Paul Birkeland]

0V at A1 is an unusual value, some likely causes are:

A bad solder joint on the wire from A1 to terminal 5.

A bad solder joint on the 22K resistor from terminal 4 to terminal 5.

A bad solder joint on the wire from terminal 4 to terminal 5.

Let us know what you find in this area.  Frankly, I would just reheat all of these joints for good measure. 

-PB

[clauswitz]

I did as suggested and I everything seems fixed (left it on for an hour and the voltage on a1 still checked out). Thank you for your help, without it I'd have been pretty lost.

[Paul Birkeland]

Awesome!

[clauswitz]

DAMNIT, and apparently I didn't leave it on long enough. I can trying doing the same thing once again or I have no idea actually. Is it possible the tube is starting to go bad? As this tube has alot of hours on it.

[Paul Birkeland]

Eh, a tube that dies tends to get weak and distorted before it poops out, but it would be worth giving it a shot. 

[clauswitz]

Ok redid all the points again, and left it on overnight at which point I was still getting voltage on point A1. Started using it and the left channel still cuts out, though apparently if i turn the volume up it will come back. I have not yet switched out tubes as I'd need to order those most likely. At this point is it worth ordering tubes? If so should I replace both or just one of them?
It does sound as if the left channel is distorted when it is there but I'm unsure if I'm hearing it because I think it should be there or if it's actually there.

[Paul Birkeland]

Reheat the solder joints on the volume control.

-PB

[clauswitz]

Did that though I realized that I didn't explain how it worked correctly, if I turn the volume up the left channel comes back and stays even when I reduce the volume back to the previous level, other then that sound level does track the volume control and the left channel isn't any quieter then the right.

At this point I think it might actually be the headphones which I have to admit I didn't really even consider at the beginning as the odds of something made professionally breaking versus the odds of me having screwed up the first thing I've soldered together ever seemed rather in favor of my amp being the cause. I managed to borrow a pair of headphones from a friend and so far everything seems to work with those.
If this is the case I have no clue how I screwed up the voltage reading on A1 though (besides apparently incompetence).
There should be nothing that would cause this to happen on one set of headphones and not another correct? (borrowed headphones have much lower impedence and massively higher sensetivity).

Thank you for your help in this, though I am sorry that I appear to have wasted your time.

[BNAL]

I have been there as well. When troubleshooting a problem, I would think it was because of one thing only to to find out hour or days later it was something else.

[grufti]

There is another recent thread under the Crack heading Subject: "Music only playing through one ear". That one has been quiet since I asked: "Have you plugged your headphones into another amp recently to make sure that your headphone cable and/or your headphones are OK?"

I have ultimately found so many problems, where I had never thought to look initially, that questioning cables, connectors, power supplies, whatever has become a bad habit of mine. Finding the problem is all that matters, who cares how.