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Audio and Video Talk
Valves / Vacuum Tubes
Amp Dog & Family Dog, this ones for you...
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<blockquote data-quote="ludo" data-source="post: 34816" data-attributes="member: 691"><p>No arguments.</p><p></p><p>I was thinking something like this, with ex-ATX supplies like Gert suggested. You can salvage some of the bits you need. The bridge rectifier, the caps (2 per dead supply) and maybe the 100nF X2 type cap as well. There might be one in the EMI mains-filter bits in the supply (if fitted, yikes!)</p><p></p><p>Don't leave out the 220k resistors, they help to keep the balance of Voltage close to 50/50 on the caps.</p><p></p><p>I don't know if you'll need the bits in the dotty box at all, but maybe you do. They help to tame the switching noise from the diode bridge which tends to ring against the stray inductance in the transformer secondary. Proper values are another thing, but those should be a start. It's hard to measure and depends on the diodes used. X2 caps are rated for use directly on the mains, which is basically what you'll have there. Rather don't use other caps for this. </p><p></p><p>If the thing buzzes like all hell in spite of your RC filters, you might try adding the bits in the dotty box. Carefully, you know.</p><p></p><p>If the learned gentlemen conclude that this is nonsense, trust them, not me. I know very little about valves.</p><p></p><p>Edit: too late to fix the pic now. The (+) poles of the 220u caps all go towards the top of the pic, (-) poles to the bottom.</p></blockquote><p></p>
[QUOTE="ludo, post: 34816, member: 691"] No arguments. I was thinking something like this, with ex-ATX supplies like Gert suggested. You can salvage some of the bits you need. The bridge rectifier, the caps (2 per dead supply) and maybe the 100nF X2 type cap as well. There might be one in the EMI mains-filter bits in the supply (if fitted, yikes!) Don't leave out the 220k resistors, they help to keep the balance of Voltage close to 50/50 on the caps. I don't know if you'll need the bits in the dotty box at all, but maybe you do. They help to tame the switching noise from the diode bridge which tends to ring against the stray inductance in the transformer secondary. Proper values are another thing, but those should be a start. It's hard to measure and depends on the diodes used. X2 caps are rated for use directly on the mains, which is basically what you'll have there. Rather don't use other caps for this. If the thing buzzes like all hell in spite of your RC filters, you might try adding the bits in the dotty box. Carefully, you know. If the learned gentlemen conclude that this is nonsense, trust them, not me. I know very little about valves. Edit: too late to fix the pic now. The (+) poles of the 220u caps all go towards the top of the pic, (-) poles to the bottom. [/QUOTE]
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Audio and Video Talk
Valves / Vacuum Tubes
Amp Dog & Family Dog, this ones for you...
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