[R-390] R390 RF Cap Confessions

[Larry H]

Dennis,  Good luck changing the caps.

In ref to changing the C553 filter coupling cap, try to use a low noise and low distortion type.  Some caps are ok for bypassing, but not so good as a coupler.  Charles Steinmetz suggests using an SBE series 225P, 418P, or 715P orange drop (film and foil), and not a 'metalized film' type (reliability, noise, and distortion issues).  I agree with him on this.  See the thread on 8/6/14.

As far as voltage goes, if your using tube recs, your R390-A will not see above 260V.  So, a 400V cap is good, and for this particular one a little higher is better (safer).

Regards, Larry