In Reply to: Question about recapping a Dynaco ST70 posted by Alpha Al on July 10, 2014 at 13:13:47:
There's some good advice here.
I ended up using the stock value cap. As Paul mentioned, perhaps Dynaco did recognize a need to have 30uF as the first capacitor. And, as others have suggested, that is not too capacitance much for a 5AR4.
One of my concerns was preserving the original Mullard made rectifier. This amp is pristine, all tubes are original. I added diodes in series with the plates as Chip and Eli suggested. I have read other places that this helps prevent arc-overs.
I also added an additional 47uF in parallel with the 20uF for the reservoir after the choke. This gave me 30uF for the first cap, and 67uF for the reservoir, which is close to what Michael suggested.
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Follow Ups
- Thanks to all who responded - Alpha Al 12:55:29 07/11/14 (2)
- RE: Thanks to all who responded - Eli Duttman 18:07:14 07/11/14 (1)
- RE: Thanks to all who responded - airtime 09:33:56 07/13/14 (0)