In Reply to: RE: Cap change or bypass? posted by Crazy Dave on August 27, 2007 at 10:14:28:
Dave, hi. The amp currently is a single 6SN7 unit (the other unit idled with grid to ground and a little B+ and the cathode seeing a load) RC coupled to another 6SN7 SRPP RC coupled to 300B grids. I interstage coupled another amp and have been thinking about doing the same to the parallel 300B. I am thinking Tango NC-18 as the interstage. The only thing in the way is this: Mike Samra had me try some RU K-40Y - both 0.22 and 0.10. Let me explain. I should say Mikey badgered me 'til I tried 'em.
The first cap is point 1. The second is point 22. I have a Rel-Cap TFT Teflon and tin foil for 0.10 cap and had a Aeon polypropylene and tin in second position. I have also had Jensen copper foil and oil for the 0.22 which sounded excellent. The K-40Y for 0.22 is just out of this world good. I am still letting them settle in as the cap has way less than 200 hours on it. I did install the K-40Y 0.10 for a little while this past week. My feeling on it at this point is it may be too much of a good thing. It is always troublesome to use the same type of cap twice in the same circuit. Right now the Rel-Cap TFT 0.10 and the RU K-40Y 0.22 combination is breath takingly good. I am rethinking the whole RC thing with these parallel 300B amps. As far as single 300B goes I have one with paralleled units 6SN7 RC coupled to SRPP 6SN7 RC coupled to 300B grids (thinking about changing all this) and one with 6900/7119 one unit direct coupled to the other and switchable driver with plate choke RC or interstage coupled (Tango NC-14) into 300B grid. Not sure if this is clear. I can switch from either RC or transformer coupling. Currently I think the interstate coupling tops RC with plate choke in this amp.
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Follow Ups
- RE: Cap change or bypass? - elektron 08/27/0711:28:09 08/27/07 (3)
- RE: Cap change or bypass? - Crazy Dave 12:22:19 08/27/07 (2)
- RE: Cap change or bypass? - elektron 14:37:39 08/27/07 (1)
- RE: Cap change or bypass? - Crazy Dave 09:37:13 08/29/07 (0)