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Odd phono channel issue unless receiver is un Pure Direct mode

WaveWobbler

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Jun 5, 2020
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Hey folks,

I come to you today with a little technical oddity that has me completely stumped.

Current hardware chain: Technics SL-D202 turntable (AT-VM95E cartridge) >--[stereo RCA]--> ART Pro USB Phono Plus >--[stereo RCA]--> Pioneer VSX-1023-K (CD analog input)

Playing a record with this setup using the receiver in its default auto mode results in the left channel playing fine but the right channel level is extremely low with audio noise/crackle. Switching to 'Direct' mode produces an identical result. Switching to 'Pure Direct' immediately solves the issue and plays back exactly as expected.

Monitoring the output from the preamp via the headphone monitoring output shows the stereo signal is perfectly fine coming from the deck and out of the preamp.

This turntable used to be my father's, and he had mentioned the same channel issue when I picked it up, believing it to be the cartridge. Thinking back to how this was set up back CA. 2006 or so I remember he had recently swapped out the vintage (late-70s, early-80s or so) Yamaha Natural Sound stereo receiver for a contemporary Yamaha 5.1 HTR about the time the "problem" showed up but I guess never connected the two since the turntable wasn't used very often.

Based on this I'm inclined to believe the problem is most likely being caused by some portion of the audio processing going on in both of these HTRs, hence not showing up on the source signal and disappearing when using Pure Direct mode.

Any and all help is appreciated!
 
D

Deleted member 46664

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Using the same inputs on your Yamaha with the same settings... but with a different input source (maybe a CD player or Smartphone) do you get the same result?

If you connect the phono chain to a different amplifier and play a record, do you get the same result?
 
OP
W

WaveWobbler

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Using the same inputs on your Yamaha with the same settings... but with a different input source (maybe a CD player or Smartphone) do you get the same result?

If you connect the phono chain to a different amplifier and play a record, do you get the same result?

Excellent questions. Just went back and re-tested all 3 analog inputs using a separate source (DAP source with 3.5mm>RCA cable) and replicated the same result as the phono chain: right channel problems unless in Pure Direct. Swapping L/R input shows issue remains internal to the amp in the right channel.

Honestly at this point besides the curiousity of understanding what's actually going on here, fixing it isn't a huge deal. The HTR is entirely fed via ARC anyway, and with the digital input I haven't had any trouble at all.
 
D

Deleted member 46664

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It's good that it's just the anlog inputs ... but problems like this do tend to fester and get into other stuff over time.

From your definition it is definitely in the amplifier's right channel.

It's probably not a difficult repair, I'm guessing bad solder, so you may want to hook up with a technician and get a quote...
 

DVDdoug

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May 27, 2021
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Does the Pioneer have some kind of "reset to factory defaults"? And try unplugging it from the power, but it probably has some kind of non-volatile memory so that may not reset everything.

I don't know the difference between "direct" and "pure direct" but it might be some kind of fouled-up processing that can be reset.
 
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