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I've noticed a string of threads showing the journey of development for this phono amp. Why no love for it, no builders, so few participants here ? - the design looks very interesting. Is it uncommon tubes, use of batteries - what's scaring folk away - I wish to learn as I'm wanting to choose a phono design myself.
This one was the evolution of two earlier designs and isn't bad at all. I think the problem is partly that I did not offer a PCB for this design, and it uses weird, but excellent Russian tubes.
There seems to be a strong and largely inexplicable bias against Soviet surplus tubes; the Russians continued to develop new and interesting types well beyond the end date of such work here in the West and some of them are truly excellent. No one is really listening.
I subsequently designed a strain gauge pre for the Panasonic strain gauge cartridges and offered a few left over PCBs to any takers. I was stunned by the level of interest and ultimately ran a small group buy. I ended distributing boards to about 24 other people.
The author is an obscure fellow who hasn't achieved cult status here..
There seems to be a strong and largely inexplicable bias against Soviet surplus tubes; the Russians continued to develop new and interesting types well beyond the end date of such work here in the West and some of them are truly excellent. No one is really listening.
I subsequently designed a strain gauge pre for the Panasonic strain gauge cartridges and offered a few left over PCBs to any takers. I was stunned by the level of interest and ultimately ran a small group buy. I ended distributing boards to about 24 other people.
The author is an obscure fellow who hasn't achieved cult status here..
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Joined 2009
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For MM cascode makes a lot of sense, very low miller capacitance suitable for MM cartridges that don't like very high capacitances (and you can also pad up for those that do) and no partition noise unlike with pentodes.
Cascode also makes a lot of sense where SUTs are concerned as the miller capacitance is multiplied by the impedance transformation ratio (square of the turns ratio) and starts to look like a significant capacitive load to the cartridge.
The original Mini used a 6J9P in pentode connection and was sonically disappointing. I may not be done with that concept and may try again at some point.
A conventional triode input works really well with HOMC cartridges which are not that sensitive to even relatively large amounts of input capacitance.
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