Bottlehead Kits > Crack-a-two-a
Right channel output dropping [resolved]
larcenasb:
Hello all,
I've been enjoying my Crackatwoa greatly for just about two years now. Everything was working perfectly from the start. However, just lately the volume in the right channel droops very low while listening. I noticed if I turn the volume knob up, the right channel makes a little click and comes back to the same level as the left. But then, over time, the volume droops low again.
Anyone experience this or have an idea what might be causing it? I'll try troubleshooting any suggestions later in the week. Thanks for any help. Cheers
- Lowell
My system: Chord Mojo 1 -> DIY Mogami IC -> Bottlehead Crackatwoa -> AKG K240 Sextett
Doc B.:
Pretty much the same as we always recommend - run the amp upside down and poke at various connections with something non-conductive to see if you can create the dropout or create the situation where the level comes back up when it is dropped out. Check all your voltages and report any that are out of spec. Try different tubes.
larcenasb:
Thanks Doc, will try these steps later in the week and will report back. Cheers
larcenasb:
Alright, first troubleshooting was all the easy stuff, one at a time: switched input tube, switched output tube, switched headphones, switched input, switched DAC ...all to no avail.
I then flipped over the top plate to take a look at the circuit and solder joints. Nothing jumped out as a bad/cold joint. When I completed the build two years ago, the joints were shiny and all resistance and voltage checks were good.
So, as Doc suggested, I turned the amp on while the top plate was inverted. And after downing a Monster for extra alertness, I carefully started probing the amp with a plastic chopstick, gently tapping on solder joints. First the RCA jacks, then the input selector, the balance pot, volume pot, tube sockets, terminal strips, output caps -- and there! The channel comes and goes when I tap one of the right output cap solder joints. The joint looked a bit dull upon close inspection. I turned off and unplugged the amp then reflowed the joint, added a little more solder, and kept the heat on the joint for a few more seconds before pulling the iron tip away. Nice and shiny!
All's good again! I've been listening for the past three hours and the output is strong, even, and without any drops.
Thanks for the checkup, Doc!
Paul Birkeland:
Bravo!
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