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hugeshows hugeshows is offline
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Default Restoring a Sherwood S-5000

Good god, those voltages are HIGH! Quick question - did you per chance take those measurements with the power tubes removed? That would explain why they are so high. If so, please take the measurements again with the power tubes installed. If not, what is your AC line voltage? Can you measure the AC HV coming off the transformer?


Thanks,

-forkinthesocket

On Saturday, January 18, 2014 9:53:18 PM UTC-5, wrote:
OK, here are the stats. The main filter cap has been replaced with another can. Others have been replaced underneath.

Link to pics: https://www.dropbox.com/sh/zoqcrtzbmn1saha/JxXYbkaIIc



C1/a 472VDC

C1/b 470VDC

C1/c 388VDC

C2/a 301VDC

C2/b 217VDC

A lot higher than what you had, and what specs show! No wonder the 6BQ5's I originally tried for power amps were arcing.



There is an additional cap (see it in the C1 photo, to the right of the can) that has 46VDC on it.



Bias caps; These have been replaced, so my measurements are left to right as viewed in the pic:

-26.6vdc, -34.5vdc, -26.1vdc



As for the DC filiment voltages, the only one I found was 13.3VDC on the first two 12AX7's where is the 24V supposed to be?



Selineium rectumfryers have been replaced with diodes, see pic.



Tubes are as follows from the top, Left to right nearest the front: three Telefunken 12ax7, two Tesla ecc803s. Adjacent the filter cap are two RCA 7199.



I will note that the phono hum seemed to be less on my workbench than in the workshop that I am using the amp, not sure if that is because of smaller speakers, or lack of 8-ft flourescent lights above, or just power situations. But, it is still there. The amp is quite silent on FM input (used for my iPod)



--JRC