In Reply to: Too much sibilance in my newly built amp. posted by DAK on July 24, 2016 at 01:54:01:
The grid stoppers MUST be carbon comp. I can't stress that too strongly. You may also need to cut open a sample to be sure the ones you buy are really carbon comp. Manufacturers have been cheating for at least the last 20 years; many "CC" resistors are actually spiral-wound carbon film. That entirely defeats their purpose for this use.
An effect sounding like excessive sibilance can also be caused by intermodulation distortion. Pentodes generate a lot of that, although it's not usually a problem in UL mode. Just be sure the external NFB loop is working as intended.
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Follow Ups
- Grid Stoppers MUST be Carbon Comp - Triode_Kingdom 11:18:29 07/24/16 (3)
- RE: Grid Stoppers MUST be Carbon Comp - DAK 11:42:33 07/24/16 (0)
- Vishay RNC90Y - Triode_Kingdom 11:29:29 07/24/16 (1)
- Also... - FenderLover 17:58:36 07/24/16 (0)