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May 26, 2020, 07:50:03 PM

Author Topic: No sound in right channel [resolved]  (Read 120 times)

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Offline thekak

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No sound in right channel [resolved]
« on: April 04, 2020, 06:49:58 AM »
I'm aware of other posts with similar titles and problems. I have looked through them but am unable to resolve the issue.

My seduction is probably something like 13 years old. I can't remember exactly when I bought it, maybe around 2007?

I have used it in the last 3 years, in a speaker system. As far as I could tell, I was not having any issues. Recently, I got a crack kit. I'm really loving that. I tried to hook it up to my turntable and seduction, and immediately noticed a rushing noise in the right channel without any audio coming out. If I swap the stock tubes in that came with the seduction, that have almost no play time on them, the rushing noise goes away, but there's no audio in the right channel.

The assembly job I did on the seduction all those years ago is not great. So I thought I would touch up the solder since I had everything out from recently completing my crack. This turned out to not be a great idea as soon enough I plugged it back in and most of the LED lights were out.

I ended up buying a special solder sucker tool. Finally got some time today to touch up all the joints that I thought looked bad, and bingo, all of the lights were back. I plugged the seduction in, hooked up my crack, and still there was no audio in the right channel. What I said earlier about the tubes still applies: The stock tubes are silent, one of the Amperex tubes produces that rushing noise.

I no longer have the manual and I'm unable to check voltages and resistances. I have referenced other posts here for those values, specifically " please help with my seduction problem." The problems that that person was experiencing seemed similar to mine however I have checked the transistors on the C4S board and everything appears to be nominal there, except for those transistors are measuring 700 ohm whereas Doc suggested in that discussion that they shouldn't measure below 1,000,

The other thing that I have done is, from the center terminal of the left channel output jack, measured resistances to all of the tube pins as well as the terminal boards on either side of the tubes and compared these values to the right channel. They are all measuring the same, including the  value from the left input to the left output and the right input to the right output.

Any ideas?

« Last Edit: April 04, 2020, 12:36:31 PM by Paul Birkeland »

Offline Paul Birkeland

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Re: No sound in right channel
« Reply #1 on: April 04, 2020, 06:59:55 AM »
Here are the terminal numbers.  It's not completely necessary to measure the voltages on the tube pins themselves, as they are close together and there's some risk to shorting things out if you aren't careful. 



Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Paul Birkeland

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Re: No sound in right channel
« Reply #2 on: April 04, 2020, 07:01:42 AM »
Here's the voltage list.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline thekak

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Re: No sound in right channel
« Reply #3 on: April 04, 2020, 08:50:31 AM »
T12-125V
T27-92.5
T29-91.7
T30-91.5
T34/44-125

12, 34, 44 are probably within tolerance but I included them anyway.
« Last Edit: April 04, 2020, 08:53:38 AM by thekak »

Offline thekak

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Re: No sound in right channel
« Reply #4 on: April 04, 2020, 08:52:53 AM »
I should add that I did not measure the tube pins.

Offline thekak

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Re: No sound in right channel
« Reply #5 on: April 04, 2020, 08:57:33 AM »
This may be one of the ugliest wiring jobs you have ever seen. Posting it here in case it's helpful.

Offline Paul Birkeland

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Re: No sound in right channel
« Reply #6 on: April 04, 2020, 09:02:02 AM »
You have a lot of parts that go through the pins of the tube sockets but don't wrap, that's risking poor connections. 

Having said that, your voltage checks show that your tubes are conducting and functioning.  This is either a case of a shorted input/output RCA jack (you can check the DC resistance between the center pin and shell with your meter), or a short in the RIAA EQ that is dragging down the signal.  The short would happen because of leads touching each other that shouldn't be, and I do see some concerning areas in that build that could be causing that kind of problem.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline thekak

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Re: No sound in right channel
« Reply #7 on: April 04, 2020, 09:30:47 AM »
Okay, I will see what I can do there.

What do you mean by DC resistance?

I was aware that there could be a short on the output jack. If there was one, the resistance would read 0 between the center of the Jack and the outer ring, correct?

Thank you for helping me on the weekend.

Offline Paul Birkeland

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Re: No sound in right channel
« Reply #8 on: April 04, 2020, 09:32:22 AM »
I was aware that there could be a short on the output jack. If there was one, the resistance would read 0 between the center of the Jack and the outer ring, correct?

Yes.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline thekak

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Re: No sound in right channel
« Reply #9 on: April 04, 2020, 11:10:46 AM »
Thank you so much for the help. I confirmed there was no short. Next, I got in to that mess of wires and started (trying to) wiggle them. Quickly found that a red wire coming off of the thick stranded wire was loose. Soldered it and we're good to go!