In Reply to: Agree but not an issue because... posted by Triode_Kingdom on April 6, 2007 at 07:28:47:
GM70 was mostly used with AC heating in PP amps where filament hum cancels out.DC filaments sound wrong not because of principle, but because of implementation. Diode bridge plus capacitor, or voltage regulator are not the right way to do it. The right way is dedicated filament transformer, choke input filter, and CM choke to block line contamination by audio signal. It could be 40 pounds of iron per one GM70 filament, but it sounds good.
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- It depends. - sser2 12:31:23 04/06/07 (4)
- tx-rectifiers-lclc-cmc-hum pot-filaments - nc 12:48:53 04/06/07 (3)
- Right. - sser2 13:23:15 04/06/07 (2)
- More research & an article by Lynn Olson - nc 14:14:00 04/07/07 (1)
- Sure it won't hurt to have more. - sser2 16:46:26 04/07/07 (0)