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SPICE Phono MC with split RIAA. Is it O.K.?

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karsten21

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Joined 2010
#1
Dear folks,

this is my first try of a LTSpice simulation of a MC Phono Preamp using split RIAA network which I try to develop. 😀
I want not to use NOS tubes. V1 is a selected by low noise. The RIAA divigation is only -0.25dB max which is realy great for me. The R/C and load of the transformer is an outstanding part which I must do in physical experiments.

Any comments concerning things that I can do in a better way will be great.

Thanks a lot and best Regards
Karsten
 

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#2
S/N ratio considerations are preeminent, at the μV. signal levels LOMC cartridges produce.

It is extremely difficult to obtain a satisfactory S/N ratio driving tubes directly with LOMCs. A 6C45Π (6s45p) cascode is a possibility, but the type will oscillate "at the drop of a hat".
 
#3
Dear Eli,

Well, increase S/N ratio is the reason why I use a step up 1:10 transforme. This will rise the signal out of the mud (I hope.. ). Nevertheless you are totally right: Phono preamp is allways a big challange.
The MM version I build works great. Absolute no hum or noise even if I fire up the Amp to the end of the scale.
For better handling the gain using passive RIAA I choose the split version and a three stage gain chain.

Best regards
Karsten
 
#4
6Z52P perhaps?

Just a suggestion -- for the cartridge source, instead of the resistor/cap network use an E-Source (voltage controlled voltage source) a la:
 

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