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#1
Posted to rec.audio.tubes
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Get your Cheminium rectifiers now!!
Check this out. Ebay 130010957907
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#2
Posted to rec.audio.tubes
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Get your Cheminium rectifiers now!!
Raymond Koonce wrote: Check this out. Ebay 130010957907 Hilarious. Even more hilarious that anyone would think it makes any difference to a preamp's power supply. Graham |
#3
Posted to rec.audio.tubes
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Get your Cheminium rectifiers now!!
Raymond Koonce wrote: Check this out. Ebay 130010957907 I presume you mean selenium. Doesn't look unlike a copper oxide rectifier either but never come across a high voltage one of those. Graham |
#4
Posted to rec.audio.tubes
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Get your Cheminium rectifiers now!!
Eeyore wrote in
: Raymond Koonce wrote: Check this out. Ebay 130010957907 Hilarious. Even more hilarious that anyone would think it makes any difference to a preamp's power supply. What makes a difference is using solid state rectifiers without snubbers. Rectifier switching combined with transformer secondary leakage inductance and interwinding capacitance makes for a nice LC oscillator. Though the DC filters after the rectifiers would remove it from being conducted to the load directly, the ringing gets induced capacitively and by radio into neighboring circuits if the PSU is not shielded from the rest of the amp. It's at several hundred kHz so out of the audio band, but it's modulated by the mains frequency. On a scope, I can see the ringing easily near the extremes of peaks across the secondary, even using soft recovery fast diodes or schottkies, and an RF probe held nearby also picks it up. Tube rectifiers never have this problem. For solid state rectifiers, an RC snubber across the secondary (rather than C's across the rectifiers as one commonly sees) is the correct solution, and calculations for optimal values can be seen in http://www.hagtech.com/pdf/snubber.pdf (measurement of the transformer parasitics is difficult so I use trial and error and the scope, though it can be a bit hard to zoom in on the ringing at the AC peaks). |
#5
Posted to rec.audio.tubes
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Get your Cheminium rectifiers now!!
Raymond Koonce wrote: Check this out. Ebay 130010957907 Check his other stuff... It's no better. And the shipping charges... Peter Wieck Wyncote, PA |
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