MPP

The problem with transimpedance RIAA is that you have to consider the output impedance of the stage before the frequency shaping network and also the input impedance of the following buffer. Both impedances appear in parallel to the frequency shaping networks.
Best is to publish your design and then one of my team puts that in the simulator.
I still use pencil and paper hard mathematics plus trimming but i know that i am a dinosaur.
 
Anselm Kiefer
 

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I hope this means first batch ?

Yes, these are rev1 boards. I tried all the tricks I am aware of to get rid of the oscillations, but these are pretty stubborn (stuff for me to learn, I guess ;-)


The rev2 boards do not have that oscillation issue, I think. I did put transistors with HFE=510 in mine and it works beautifully. Don't know what Le'Flu used exactly , but he also has rather high values for HFE. His boards also worked at first turn-on ;-)