rectifier controversy [message #8388] |
Wed, 04 August 2004 02:28 |
Manualblock
Messages: 4973 Registered: May 2009
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Illuminati (13th Degree) |
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Hi Eric; Reading through some past issues of V.T.V. I see that you sometimes favor tube rectification,("Because tube rectifiers add more magic and 3d realism to the music than cheap silicon diodes"), I am still studying up on pre-amp schematics for my project to replace the AES. Any clarification. Is the tube vs. SS application contingent on design? or do we want tube rectification as a given. You even give the nod to Tube rectifiers over HEXFREDS later in the essay. So what gives?
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Re: rectifier controversy [message #8391 is a reply to message #8388] |
Wed, 04 August 2004 10:16 |
elektratig
Messages: 348 Registered: May 2009
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Grand Master |
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FWIW, Ron Welborne has a discussion of the advantages and disadvantages of tube vs. ss rectification in the context of his drd amps at http://www.welbornelabs.com/drd.htm (under the heading "The Sound", about 4/5 of the way down the page) and surprisingly comes down on the side of ss for that design. I'd also note that the Foreplay uses ss, and with a snubber added I haven't seen posts complaining that that aspect of the design limits its musicality. On the other hand, my Welborne Laurels use tube rectification and sound glorious!
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Re: rectifier controversy [message #8400 is a reply to message #8388] |
Sun, 08 August 2004 15:43 |
metasonix
Messages: 103 Registered: May 2009
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Viscount |
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Yes, it is contingent on design. The main disadvange to cheap silicon rectifiers is their slow switch-off delay, which causes a big peak current to be drawn for a very short time. This can result in added "hash" noise in the circuit, esp. if the circuit grounding and wiring arrangement isn't optimal (as in, rigid star grounding, component layout etc). FREDs and tube rectifiers don't have so much of this problem, thus are less prone to putting "hash" into the circuit. Also, tube rectifiers have the slow warmup built-in, always a good thing to use to prevent possible cathode stripping in power tubes. A well-designed amp would optimize layout and DC supply filtering to use silicon rectifiers properly, so it's often a wash as to which is "superior" to the others. Now, if you're a hobbyist building your own tube amp, and you don't have lots of time to sit and build multiple revisions of the chassis and test each one for noise floor, a tube rectifier is handy. If you want a recommendation for a DIY amp, I'd say use damper diodes-- they are extra-rugged and usually have very slow warmup.
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