In Reply to: RE: hum is a non-issue. posted by 6AS7_6SN7 on July 25, 2012 at 02:26:19:
You just need to understand where the hum is coming from, and its a simple fact that many people working with DIY OTLs have not sorted that out!
Here are some fundamentals:You don't need DC filaments but you do need to watch out for electrostatic noise, but that is true of any amplifier Its OK to have a sawtooth waveform in the power supply, so long as it is canceled out in some way. I've built amps with no filter caps in the output section that hardly hum at all! Grounding the amplifier to the AC line *correctly* is important the most important thing is snub your rectifiers!!
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Follow Ups
- You don't need expensive power supplies - Ralph 08:17:25 07/25/12 (7)
- RE: You don't need expensive power supplies - 6AS7_6SN7 09:35:57 07/25/12 (6)
- Yes, I can see that in a totem pole, - Ralph 10:59:23 07/25/12 (5)
- RE: Yes, I can see that in a totem pole, - 6AS7_6SN7 23:41:55 07/25/12 (4)
- Did you forget about the EL509/PL509? - Ralph 09:58:04 07/26/12 (3)
- "Futterman legacy"? - Lew 10:42:26 07/27/12 (2)
- RE: "Futterman legacy"? - Ralph 14:33:07 07/27/12 (1)
- RE: "Futterman legacy"? - Lew 16:38:19 07/27/12 (0)