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In the Forum: Melquiades Amplifier
In the Thread: Single-stage Melquiades vs. DHT amps
Post Subject: How the YO186 was used.Posted by Romy the Cat on: 5/22/2012
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 Romy the Cat wrote: |
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I received a link with description how the YO186 tube that drives my MF was used by Russians. In 30s and 40s it was used in portable film projectors PU-12 and PU-13. Below is the schematic of the PU-13 low frequency power amplifier.
As you can see it is absolutely nothing special and made to be super economic. A pair of YO186 in PP configuration sits at 270V, with 43V bias and 3.6V filament. That is interesting as they did not use 4V for whatever reason. The current is 2x55mA and they get around 4W of full power, claiming 4.5% distortion between 80Hz and 6000Hz. The amps has the upper frequency boost to deal with compensation of photo-element and as many of the amps of the period it use voltage drop across the speaker field-coil to bias the output stage. I am sure that admirers of “vintage sound” would jump out of skin to get this amp but I am with all confidence insist that it will sound like crap and I have no interests to hear it. Still, for historical perspective for the people who use YO186 it might be fan to see how it was used. Rerurn to Romy the Cat's Site