Quick question for Eli Duttman (or others!)

Klimon · 5th June 2007, 11:27 PM

Hi,

I'm preparing an amp with the el cheapo phase-splitter and after searching the web found a recommendation from Eli for getting enough voltage out of a 6v heater winding for the B- supply. He recommended a half-wave parallel voltage multiplier with about 7 diodes. (Newby question following) What would be an appropriate value for the multiplier (not filter) caps in that circuit?

Thanks!

Simon

Eli Duttman · 5th June 2007, 11:44 PM

Simon,

The multiplier caps. are filter caps. It's the nature of the beast.

A stereo amp using the 'T7 splitter/driver needs 12-14 mA. of B-. Schottky diodes eliminate SS rectifier switching noise. Therefore, using Schottkys is obvious. If the multiplier caps. are large enough, the ripple fundamental (50 Hz. in the EU) will be well squashed, but the overtone "hash" will be significant. My seat of the pants guess is to use 100 muF. 'lytics in the multiplier, follow with a 10 mH. RF choke to kill "hash", and finish up with 220 muF. 'lytic.

Klimon · 6th June 2007, 07:03 AM

Got it, thanks alot!

Simon

5th June 2007, 11:27 PM	#1
Klimon diyAudio Member Join Date: Apr 2005 Location: Leuven	Quick question for Eli Duttman (or others!) Hi, I'm preparing an amp with the el cheapo phase-splitter and after searching the web found a recommendation from Eli for getting enough voltage out of a 6v heater winding for the B- supply. He recommended a half-wave parallel voltage multiplier with about 7 diodes. (Newby question following) What would be an appropriate value for the multiplier (not filter) caps in that circuit? Thanks! Simon

5th June 2007, 11:44 PM	#2
Eli Duttman diyAudio Member Join Date: Apr 2004 Location: Plainsboro, NJ	Simon, The multiplier caps. are filter caps. It's the nature of the beast. A stereo amp using the 'T7 splitter/driver needs 12-14 mA. of B-. Schottky diodes eliminate SS rectifier switching noise. Therefore, using Schottkys is obvious. If the multiplier caps. are large enough, the ripple fundamental (50 Hz. in the EU) will be well squashed, but the overtone "hash" will be significant. My seat of the pants guess is to use 100 muF. 'lytics in the multiplier, follow with a 10 mH. RF choke to kill "hash", and finish up with 220 muF. 'lytic. __________________ Eli D.

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6th June 2007, 07:03 AM	#3
Klimon diyAudio Member Join Date: Apr 2005 Location: Leuven	Got it, thanks alot! Simon

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