I have now build the circuit. It worked right away without problems. I measured input offset in both channels to be under 0,5mV with a 5 Ohm cartridge. Fanatics may wish to trim that away and this is certainly possible.
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"Anyway, the impedance of the feedback network can be reduced".
Yes, as per the hint above in 11183.
On the other hand, the diode/resistor network establishes bias and
feedback at the same time. I consider this as a practical problem.
You are using a two transistor input stage - long tailed pair without
a tail - is this not the same noise penalty as using a diff amp input ?
Compare to Zetex app note https://www.diyaudio.com/forums/ana...ra-low-noise-mc-head-amp-160.html#post5939775
where the coupling caps can be left away.
Yes, as per the hint above in 11183.
On the other hand, the diode/resistor network establishes bias and
feedback at the same time. I consider this as a practical problem.
You are using a two transistor input stage - long tailed pair without
a tail - is this not the same noise penalty as using a diff amp input ?
Compare to Zetex app note https://www.diyaudio.com/forums/ana...ra-low-noise-mc-head-amp-160.html#post5939775
where the coupling caps can be left away.
Thats right But the Zetex Transistors i use have less then 2 Ohm Rbb. So the total Noise from that chain inclusive the 1Ohm is under 5 Ohm. My LYRA Atlas has 5 Ohm impedance. So Not considering the influence the Feedback resistors have it worcence the Noise of the cartridge by only 3 dB. I do Not know what will Happen to the Gain when i substitude the 60 Ohm resistor with a Diode.
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Reminds me of Broskie's Bastode circuit...
http://www.tubecad.com/2019/11/20/MC Pre-Preamp 20dB 2N4401 2N4403 Bastode 12Vdc Power Supply.png
http://www.tubecad.com/2019/11/20/MC Pre-Preamp 20dB 2N4401 2N4403 Bastode 12Vdc Power Supply.png
