I was told the one I picked up was upgraded with an auto bias for the 300B tube but I've not seen any info on it. I've emailed Cary a few times but no response.
The amp's fantastic and sounds great so this is just a curiosity thing.
Well, if your 805b amps do not have a chassis cut out hole for the bias pot or the meter jack, I would hazard a guess that your amps are a prototype of some sort. If they were upgraded/modified, they would still have the chassis cut out holes.
The Cary 805 series was never designed with auto bias. If in doubt, go to the Cary website and look at all the various 805 manuals and they all have a section on how to bias the tube. To check yours, plug in the bias meter and turn the bias pot and see if the bias changes.
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