My guestimate was (near) 2k (no simulation involved )
See post 10973
Just tried Q&D (quick and dirty) removed the input BJT's substituted 2 JFets (more or less randomly selected) and guess what, it works, the gain is down to 60dB (from 80) and the sim seems to work just fine, I'm sure you can take it from here
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I suspect there are some very good MM cartridges out there.
There are. As well as a disturbing number of pretty bad MCs. Hard to generalise.
I like that Fet version for MM. Much easier to bias, no big elcaps required for decoupling and very high input impedance. 47kOhm is easy to get. No input DC nulling pot required.
I also heard that Soundsmith MI cartridges sound very good.
The decoupling caps (at sources here) are still required
and can be seen in schematic of post 10988.
I just came across this thread, not knowing the history.What i need to know is your imput regarding the amplifying current mirror. Is it stable?
But there are a few things that I noticed:
1) The 5 Ohm resistors are connected to the Drains of J3&J5, but to the Sources of J4&J6. They should all be connected to the source.
2) Of course the current mirrors are stable, but I don't get why the emitters of Q10&Q25 and Q15&Q25 are connected, leave this connection.
3) I see no reason why the current mirrors around Q1-8, Q19-22 are so extremely complex.
This could be done with far less components only playing a role for DC.
Hans