High voltage bakelite blocks?? - Printable Version

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+--- Thread: High voltage bakelite blocks?? (/showthread.php?tid=7452)

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High voltage bakelite blocks?? - hunter2115 - 09-12-2013

Looking at the specs on the Repair Bench site for bakelite blocks, I see many that have working voltages listed as 1000 and 1200 volts. Do these require replacement caps that are rated this high?? Ot are the typical 630v caps sufficient?
Im especially concerned with the micas. I typically use 500V silver micas for these, but 1000v replacements are available (at a higher cost of course).
Thoughts?

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RE: High voltage bakelite blocks?? - Mondial - 09-12-2013

It really depends on where in the circuit the cap is being used. Normally, a 500V silver mica or 630V mylar cap will be fine, the exceptions being in the plate circuit of the audio output tube(s), where a 1000V cap should be used, and across the AC line or from AC to chassis ground where a X or Y rated safety cap should be used.

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RE: High voltage bakelite blocks?? - hunter2115 - 09-12-2013

Then, on the 118, should the .01uF cap in bakelite block 3903P (part#56 on schematic) be a 1000v cap?
http://www.nostalgiaair.org/PagesByModel/125/M0013125.pdf

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RE: High voltage bakelite blocks?? - jerryhawthorne - 09-12-2013

Yes, note Mondial's comment about the plate circuit of the output tubes.
Jerry

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