A friend of mine has that turnover record changer! It's a mechanical wonderment to say the least!
Quote:
Originally Posted by old_coot88
That's a weird one. They coulda did it like this. Works great, albeit with slightly reduced gain due to no cathode bypass cap.
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Definitely! Spending some time looking at it in detail. It's sort of a quasi paraphase phase inverter? One of the 6V6 grids driven right after the audio amp/tone stack, the other being driven from the inverted signal of the 2nd 6AV6. What makes it a little bit more interesting is that capehart introduces some negative feedback around the 2nd 'phase inverter' 6AV6. I guess that makes the circuit a little more immune to gain variations in 6AV6's in order to keep the push-pull grid drives fairly balanced. A Cathodyne phase inverter would have used the same tube line-up, but been easier, better matched and fewer parts - maybe that one hadn't yet made it's way into hifi!
05-24-2019, 10:04 AM
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