I'm fishing about for something to build with the parts i've collected and need a decent MC phono amp. After some research, i'm interested in this. Thanks to Richard Lee for the front end and an unknown Sony engineer for the back. Any comments? Improvements?
If i simulate an inverse RIAA circuit on the front, i get a mild bump around 30Hz and rolloff below and a very small rise at 20kHz, otherwise flat.
TIA, Rex
If i simulate an inverse RIAA circuit on the front, i get a mild bump around 30Hz and rolloff below and a very small rise at 20kHz, otherwise flat.
TIA, Rex
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There is about 1/2v across C2 under no signal conditions. ~1v across C4.
I sim'd a few different values in place of 180k, but that was best.
I sim'd a few different values in place of 180k, but that was best.
Why listen to a bunch of nay-sayers? I say innovate, break the barrier and go for simpler than possible 😀
The feedback is along R{309,310,311}. If i remove R311, gain becomes flatish and around ~60dB. Q301 has gain and splits phase, Feedback from the collectors of the outputs go back into the emitter of Q301. It's a bit unorthodox and could do with a whisker more gain, but it looks pretty elegant to me.