Phono Transfer System Construction Information

Construction information for DIY projects, including the MS Mid Side Matrix, Elliptic Equalizer, Mastering Console, Phono Transfer System, Insert Switcher and the Dual Class-A Amplifier. You can post your baby pictures here.
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mediatechnology
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Re: Phono Transfer System Construction Information

Post by mediatechnology »

4.7µF, the max available in PP, should be large enough since it moves the cutoff frequency down to about 2.4 Hz.
It varies a little bit as the gain jumper is moved from 10K to 14K3 to 20K for -3, 0, and +3 dB gain.

The RIAA path through the first input has two coupling caps - one at the input the second at the output - so the cutoff is about 1.6X higher IIRC.
With a FET op amp in the RIAA section you might be able to eliminate the one on the RIAA output.
Gold
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Joined: Sat Dec 01, 2007 5:20 pm

Re: Phono Transfer System Construction Information

Post by Gold »

mediatechnology wrote: Thu Mar 28, 2024 9:52 am The RIAA path through the first input has two coupling caps - one at the input the second at the output - so the cutoff is about 1.6X higher IIRC.
With a FET op amp in the RIAA section you might be able to eliminate the one on the RIAA output.
I always wondered whether it was better to drive the RIAA EQ with the opamp from the first input or directly from the 1200 in the second input, since the 1200 doesn’t have as much drive capability.
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