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SPP 6CW5 EL86 bias resistor value?

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Pooch

Member
2010-11-01 3:24 am
I've been using 270 ohm, 5 watt, bypassed with 100uF, 50V as indicated in the assembly manual. I blew one of the 270 ohm resistors. Is there a better value for these tubes? I just got replacements in the mail and after I install them I'll post pin readings. Maybe just a bad tube?
 

Pooch

Member
2010-11-01 3:24 am
I checked Pin 2 for DCV and got .02 VDC on 3 of the tubes and .05 VDC on the suspect one that had the blown resistor. Earlier after I replaced the resistor and first plugged in the amp, I got red plate on the suspect tube. I switched the tubes on that channel and no red plate, but the new resistor started smoking. Then I switched around the 12AT7s and the amp ran, no smoke, no red plate. The above measurements were taken after that.
 
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