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Re: 211 slow warm-up??...

Mike -

My 211 is based heavily on PAE's design, with a 6C45 choke loaded and driving the 211 thru an oil cap. Output and chokes are from Magnequest.

The power supply is a bit strange design with an ACRO-550 driving 866jr --> 6CG3 --> Swinging choke ---> 15uf vintage oil ---> smoothing choke ---> 30uf vintage oil.

B+ is low for 211's at 825vdc. I tried a few operating points between 600-1000vdc and was pleased with this compromise. 211's are run at 65ma. I've used various 211's but run GE VT4C's 90% of the time.

The only electrolytics are in the lower 250vdc supply for the driver stage and bias supplies. Bias is solid state rectified, driver stage uses a very slow starting Bendix 6106 rectifier, also choke loaded.

The supply preheats the filament for 4 minutes before B+ is applied, and then the 6CG3 slow start the 866jr's in a "Slagle" configuration.

I would bet that the oil caps and choke loaded supply contribute to the lack of any significant sonic changes with warm-up, just my swag. In any case, I don't appreciate any significant improvement after the first 15-20 minutes.



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  Michael Percy Audio  


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