Denon AVR X3700H - degraded sound quality from specific outputs

[hotwingsandbeer]

Hello all,

Hope the day is treating you well so far. I purchased a refurb Denon AVR-X3700H back in Nov 2021 from Amazon (mistake), along with a Klipsch Reference Premiere set. I noticed degraded sound quality in the last few months from 2 of the speakers, and confirmed this issue is from the receiver. The affected Atmos speaker has to be at +6db to maintain volume w/ the other, and isn’t as clear. The affected main speaker’s tweeter has light static when I put my ear to it and ~20% degraded highs/mids during playback.

I confirmed this by replacing wire with banana plugs, and switched wire around to confirm speakers and wiring aren’t the issue. Denon provided replacement tweeters and the issue persists.

I spoke to Denon again and was told it seems like the terminals are bad/degraded. Before I take into a repair shop Monday, I am curious if there is anything else that may cause degraded quality from the receiver (bad caps/fuses, whatever else). I am flirting with the idea of performing my own replacement, but want to ensure I check out everything I should.

I appreciate your comments! I am a frugal DIYer and am flirting with the idea of doing my own repair. Currently looking for my multimeter to test watts output from the connections.

 

[AnalogSteph]

Looks like you've got several ohms worth of output impedance on the affected outputs.

Does the speaker exhibit more hiss on one of the good outputs?
If so, it's probably just a bad solder joint at the terminal (maybe an actually broken terminal if you're unlucky), or a bad protection relay. Neither is anything that a repair shop shouldn't be able to fix with some ingenuity, it shouldn't even take any special tools beyond a multimeter. The most expensive part is going to be the time for taking the whole thing apart and putting it back together.
If not, the repair would get more involved as there is likely to be something wrong with the actual power amplifiers.

 

[hotwingsandbeer]

Looks like you've got several ohms worth of output impedance on the affected outputs.

Does the speaker exhibit more hiss on one of the good outputs?
If so, it's probably just a bad solder joint at the terminal (maybe an actually broken terminal if you're unlucky), or a bad protection relay. Neither is anything that a repair shop shouldn't be able to fix with some ingenuity, it shouldn't even take any special tools beyond a multimeter. The most expensive part is going to be the time for taking the whole thing apart and putting it back together.
If not, the repair would get more involved as there is likely to be something wrong with the actual power amplifiers.

The R speaker (exhibiting the hissing) has no hiss/issues when I switch the wires to the L terminal. The hissing switches to the L speaker.

This response is exactly what I came for. I very much appreciate your time and feedback! I’ve identified a good shop locally in case I am unable/uncomfortable performing the repair.