DC offset on Yamaha rs202d

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Jul 22, 2023
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I decided to meter the terminals on the Yamaha after blowing a pair of mission mx3s on all four drivers.
The law of averages has me suspicious as for all four to go at the same time is abnormal although I suppose not impossible.

The usual paranoia ensued as usual and the late night OCD head scratching commenced.
I decided to measure the DC offset expecting around 20mv as usual but found a uniform 40mv across all the speaker terminals.

It's late and I've just popped the lid back on after finding it's a non adjustable amp whilst fishing the speaker terminal spring out from inside the amp that I'd pushed in with the multi meter probe 🤬

I know that up to 50mv is usually deemed acceptable and that the higher quality amps are much lower.
I tested my 30 plus yr old pioneer a400 and got only 4.2mv left channel and 2.5mv right.

That caused me to track down the service manual for the Yamaha RS202d and from what I can make out 27-136mv is normal but it's not exactly clear.

I find it on the high side which has me questioning things.

I have attached a picture of the service manual and would really appreciate your insight.
Am I reading it correctly?
It's late and it's possible I'm reading it wrong.

Is 40mv considered ok on such an amp.

As some of you know the Yamaha is within my second set up with the pioneer a400 via an amp/speaker switching box but after purchasing the new speakers (fayne audio) for my primary hifi as mentioned on another post I'm planning on moving the QA 3050i they've replaced into this system thus replacing the blown mission mx3s.

I'm now pondering even though my common sense dictates otherwise that 40mv DC offset could of contributed to early failure.

Anyway any advice would be helpful.


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Any replies please post here instead, as the threads deal with the same issue:
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