Right channel output dropping [resolved]

larcenasb · 8001

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Offline larcenasb

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on: September 02, 2024, 08:16:13 PM
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
« Last Edit: September 08, 2024, 04:45:46 AM by Paul Birkeland »

Lowell B.


Offline Doc B.

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Reply #1 on: September 03, 2024, 05:04:30 AM
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.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline larcenasb

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Reply #2 on: September 03, 2024, 06:25:44 AM
Thanks Doc, will try these steps later in the week and will report back. Cheers

Lowell B.


Offline larcenasb

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Reply #3 on: September 07, 2024, 10:37:49 PM
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!


Lowell B.


Offline Paul Birkeland

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Reply #4 on: September 08, 2024, 04:45:37 AM
Bravo!

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Doc B.

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Reply #5 on: September 08, 2024, 04:53:26 AM
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.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline larcenasb

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Reply #6 on: September 08, 2024, 09:08:35 AM
Thanks PB! Thanks Doc!

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

Lowell B.


Offline Thermioniclife

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Reply #7 on: September 08, 2024, 10:17:17 AM
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.

Lee R.


Offline larcenasb

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Reply #8 on: September 08, 2024, 11:05:19 AM
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! :)

Lowell B.


Offline Thermioniclife

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Reply #9 on: September 08, 2024, 02:24:19 PM
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

Lee R.


Offline larcenasb

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Reply #10 on: September 08, 2024, 02:31:38 PM
Purpose-built perfection. Sah-weeeeeet! :)

Lowell B.


Offline larcenasb

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Reply #11 on: September 12, 2024, 08:22:33 PM
Oh noooo! While listening tonight, something strange happened. The channel slowly faded out again ...but not the right channel. This time it was the left channel. What could cause drops in either the right or left channel? Could it be a power supply thing?

This weekend, I'll examine the solder joints again, do the chopstick test, and do voltage/resistance checks. Any insight beforehand, or tips on what to focus on, is much appreciated. I'm actually excited to demystify this and refine my problem-solving skills. Thanks for any help as I work on this.

Lowell B.


Offline Karl5150

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Reply #12 on: September 13, 2024, 02:14:46 AM
Sorry to hear you have another gremlin, I'm sure you'll get it sorted. As mentioned, that is a great looking build. Touches like the black acorns and the vol/bal panel make it look very professional.
Karl

Karl
Downstairs: Planar3>PH-16>Stereomour II>OB Betsy+
Upstairs: RP1>Eros/CD5004>Seductor (2x Monoblocks)>FH3
Office: Modi Uber 2/Sirius>SEX2.1.1>µFonken FF85WK + DC160 subs
BR: FiiO M6>SEX3.0.1>ScanSpeak 10F + TangBand W6 (Mono)/DT770Pro
Garage: X12 streamer>Quicksand>Minimus 77


Offline Paul Birkeland

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Reply #13 on: September 13, 2024, 04:48:40 AM
What could cause drops in either the right or left channel? Could it be a power supply thing?
A bad solder joint (or two).

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline larcenasb

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Reply #14 on: September 13, 2024, 06:16:48 AM
Thanks Karl, yes, I’m so happy with this build. And oddly happy with this speed bump as it’ll be a good learning experience.

Alright PB, I’ll examine tonight. However, I’m starting to think perhaps it’s my detachable output cap mod… Remember I used detachable spade connector things to be able to switch output caps easily? Which of course I’ve never done because I love the sound as is! But when I did the chopstick test, perhaps it wasn’t the joint but the connector next to it causing the intermittent output. I’ll take a close look at that as well and perhaps will remove it.

Hope all’s well and hope everyone reading has a great Friday! :)

Lowell B.