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In the Forum: Analog Playback
In the Thread: The LCR RIAA correctors
Post Subject: Gain calculation and LCR advantagePosted by Thomas Mayer on: 11/11/2009
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Paul,

The gain of my phono stage has the RIAA loss factored in. Without the RIAA loss counted, the gain would be about 66-68 dB.


 Paul S wrote:
I have never used the 417 or 437, but I have heard plenty of whining from folks who do.  They often pay a small fortune for "special" tubes and wind up with tubes they simply cannot use for low-level input.

I never had a lot of trouble with high transconductance tubes. I use the EC8020 a lot.

 Paul S wrote:
Lastly, gain and impedance in the input or output tubes absolutely affect the sound of a tube phono stage.  As Roger Modjesky pointed out, these factors actually wind up affecting the "RIAA Curve" itself in any LCR RIAA circuit, whether "split" or "continuous".

This is true for RC RIAAs, not for LCR RIAAs. This is one of the big advantages of the LCR technique. The network has a constant 600 Ohms input impedance, if it's terminated by the proper 600 Ohm value. Variation in the driving tubes rp does only affect the loss in the network, but the loss is always the same over the frequency band. So the RIAA curve will not chabge when the tube detoriates or when tubes are changed.

Best regards

Thomas

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