My latest (well ... first) RIAA preamp
Folks
this is my first RIAA preamp, now fully working and assembled after one year or more of work. Pretty much satisfied with the results and the sound. I will be posting pics and other info slooooowly.
It sports a 10x step up, a triode strapped D3a, a high impedance LCR network (Dave Slagle's irons) and a ECC88 output stage into a tapped autoformer. Tubes are choke loaded and biased by a LED. Gain is 38.5dB at 1kHz (without 10x input transformer, attenuated at the output by the autoformer) and RIAA accuracy is within 0.2dB.
Power supply is 6X5GT into a LCRC filter + a Salas Shunt regulator.
Parts: D3a are siemens and E88CC err... I don't remember, caps are WIMA film+foil for the RIAA and solen/mundorf interstage, all irons are from Dave Slagles (nickel cores), cheap red LED, motor run caps in the power supply ... well, nothing really fancy except the inductors. The schematics itself is nothing new either but it works really good.
Attached: schematics (NB: inverse RIAA network at the input and no step up) and RIAA measured for both channel
Folks
this is my first RIAA preamp, now fully working and assembled after one year or more of work. Pretty much satisfied with the results and the sound. I will be posting pics and other info slooooowly.
It sports a 10x step up, a triode strapped D3a, a high impedance LCR network (Dave Slagle's irons) and a ECC88 output stage into a tapped autoformer. Tubes are choke loaded and biased by a LED. Gain is 38.5dB at 1kHz (without 10x input transformer, attenuated at the output by the autoformer) and RIAA accuracy is within 0.2dB.
Power supply is 6X5GT into a LCRC filter + a Salas Shunt regulator.
Parts: D3a are siemens and E88CC err... I don't remember, caps are WIMA film+foil for the RIAA and solen/mundorf interstage, all irons are from Dave Slagles (nickel cores), cheap red LED, motor run caps in the power supply ... well, nothing really fancy except the inductors. The schematics itself is nothing new either but it works really good.
Attached: schematics (NB: inverse RIAA network at the input and no step up) and RIAA measured for both channel
Attachments
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