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Re: Looking for a GOOD 211 / VT4-C Schematic

Acutally my power supply is very different than the one on PAE's site. I use individual AC transformers for each 211 filament, the 866jr and the 6C45 filament. The large Acro TP-550 provides 825-290-0-100-290-825 as well as additional 5 and 6.3v filament taps.

At turn-on the individual filament transformers for the 211, 6C45 and 866jr's are started. There is a 2 minute delay to allow the 866jr's to come to full temperature before the TP-550 is started. This is done with a digital delay board.

When the TP-550 comes on it feeds the 825-0-825 to a pair of 866jr's, which go thru a damper diode for slow turn-on. This is choke loaded with a swinging choke --> 15uf/1000v oil ---> smoothing choke ---> 30uf/1000v oil with a small bleeder resistor for the B+

The power supply for the 6C45 is a 6106 (bendix indirect 5Y3GT with a very slow turn-on) into 12H, then 100uf for the driver stage.

The 100V tap provides bias voltage thru a 1N4007 and simple filter/divider network.

All said, it's pretty simple. First pre-heat 866jr's and filaments on 6C45/211's and bring up the bias. 2 minutes later start B+ which has a slow turn on because of the damper diode. Lastly the B+ for the driver stage comes up.

Even with AC on the 211's I get very reasonable hum levels. The power supply actually has a bridge rectifier and cap to filter the 10V supplies installed, but I never wired them up. AC was plenty quiet - even on Altec speakers.



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  • Re: Looking for a GOOD 211 / VT4-C Schematic - Gary Kaufman 07/19/0305:29:08 07/19/03 (0)


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