Pretty self explanetory, my ruby amp starts motorboating when I turn up the volume. The setup is crammed inside a small speaker cabinet, and the pc board is fully soldered but the rest of the connections (volume pot...) are all with alligator clips since I can't drill through the box yet.
(motorboating is where it's like a continuous ocatve effect, right? cause that's what it's doing)
Don't turn it up so loud.
No, seriously, which pot are you turning up? Sounds like you might have a feedback loop where there should not be one, OR the input level coming in to the ruby amp is way too hot.
Disclaimer: I've never debugged a ruby amp, specifically, but based on some other similar amps I've worked on those are the first few things I would try.
i don't know the ruby amp, but have built several valve amps...
but motorboating is not an octave type effect. it's a low frequency oscillation - like putt-putt-putt.
the octave type effect you mention, i have heard of on modded tube screamers etc. caused by changes to the feedback/clipping circuit.
have you swapped out your IC? not all chips are created equal, and for a buck a piece, it's good to have a few kicking around to try.
also maybe check your voltages right at the IC pins, just to make sure the chip is getting the power it needs to work properly, just a thought.
I deleted my reply. But it seems you can only edit. So please ignore this post.
I just spent a little bit of time debugging it and I figured out what was wrong.
My crappy soldering job created shorts when I crammed it in the cabinet. I fixed it up and I can get it to work well but whenever I move the components it starts oscillating (not motorboating) like crazy. I haven't been able to test it really well (which component movement creates the oscillations) since I don't wanna bust the LM386 because it's soldered in place (no socket, facepalm). It doesn't seem like anything would be microphonic, but I've heard bad vacuum tubes can become microphonic, but this is solid state. Keep in mind when I had it on a breadboard I stuffed it in a box to test different speakers and it worked perfectly.