In Reply to: I've racked my brain... posted by lipmanl on March 5, 2007 at 14:08:12:
1/ The rough solution: Eli talks about it above and VTL did this with their "Ultimate" preamp - a BIG cap coupling the cartridge into the cathode. The disadvantage is obvious - passing the ultra fine detail signal off a good MC through a big elko cap just makes me cringe!Plus there could be enough leakage in such a cap to "bias" the cartridge, or at least slowly magnetise it.
2/ The elegant solution: place the cartridge between the cathodes of a (double) current sourced diff pair of MATCHED input tubes. The match has to be perfect of course, so there is no current through the carridge - but that would work perfectly! I have often wanted to try this, and my RTP3 input stage would be the ideal test bed, but a slight disadvantage is that if any little thing goes wrong - let alone a tube failure - the megabuck cartridge is toast...
Regards, Allen
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Follow Ups
- There are two ways I know of - both with a few disadvantages... - Allen Wright 06:04:30 03/06/07 (2)
- Re: There are two ways I know of - both with a few disadvantages... - lipmanl 07:52:14 03/06/07 (1)
- Re: There are two ways I know of - both with a few disadvantages... - Allen Wright 06:26:41 03/07/07 (0)