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!

[Doc B.]

Cool! This is why we suggest simply going thru a Crack and reflowing all the joints if you have this kind of issue. Works fairly often and takes maybe 15 minutes.

[larcenasb]

Thanks PB! Thanks Doc!

Like I said after building this, so happy with it and am keeping for life.

[Thermioniclife]

Love the Spinal Tap "IT GOES TO ELEVEN, THATS ONE MORE RIGHT" Looks great hope you enjoy it. I use a C2A and Mainline depending on what flavor I need that day.

[larcenasb]

Thanks, Lee! Yeah, I'm just so happy with the Crackatwoa. And aw man, I've always been curious about a Mainline too. Awesome duo you have to choose from! Cheers and enjoy!

[Thermioniclife]

The Mainline is my go to amp, having said that I was on the fence for a while but it proved itself as a very articulate amp but the C2A is no slouch either. I plan on building a stand to hold both instead of lugging one amp off and lugging the other out.  I use them with an ANK 2.1 DAC. I plan on building a rack to hold them both similar to my Monamour stand

[larcenasb]

Purpose-built perfection. Sah-weeeeeet!