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Tetra Phono Preamp as a DAC analog stage
Tetra Phono Preamp as a DAC analog stage
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Old 6th December 2009, 08:11 AM   #1
regal is offline regal  United States
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Default Tetra Phono Preamp as a DAC analog stage

My problem with tube DAC's is there is always a big compromise, either its just a cathode follower after an opamp or its a gain stage after a too large I/V resistor which causes non-linearities with the DAC chip.

Has anyone ever tried a phono preamp (minus the RIAA eq) as an analog stage for a current output DAC like the PCM1704? It has been shown elsewhere that the PCM1704 performs best with an I/V resistor smaller than 10ohms which requires a lot of gain. The first phonostage would basically be working like a step-up transformer in the old audionote patent. My concern is if the phono stage would be quiet enough to handle a mV p-p signal ?
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Old 6th December 2009, 08:48 AM   #2
Allen Wright is offline Allen Wright  Switzerland
Join Date: Dec 2001
Location: Schaffhausen Switzerland
A MC phono stage has to handle sub millivolt signals, and a good one is down near the theoretical absolute as far as noise goes. No idea what a Tetra Phono pre is - but a good phono pre (without the RIAAS eq of course) is pretty much perfect for what you are suggesting.

Regards, Allen
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Old 6th December 2009, 09:10 AM   #3
Franz Gysi is offline Franz Gysi  Switzerland
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Hi Allen

The Tetra Phono Pre is from John Broskie Tetra Phono All-in-One & Broskie Impedance Multiplier

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Old 6th December 2009, 03:41 PM   #4
Eli Duttman is offline Eli Duttman  United States
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Location: Monroe Township, NJ
The subject of current O/P DAC chips in a phono preamp like regime was discussed some time ago. Look here. AW may appreciate the mention of a 6922 cascode.
Eli D.
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