coupling caps for phono prepre

This may well develop into one of the many "phono input bias current"
discussions (at least a few minutes ago).

I built a large number of phono stages, some of them using Jan's regulators,
a few even using boards that he designed (these two amp examples not of
my design) and do not use input coupling caps. Be it base or emitter input I
never had any problems with input offset or current flow. This is a more than
25 years experience now.

Any electrolytic coupling cap is in big disadvantage here, because these do
not want to work without dc applied and this is also a big long term quality
problem in a particular historic amp series with only 0.5 V on the caps (emitter
voltage).
 
yeah right....the audiophile world hates tantalum in capacitors, but loves it in resistors...it's just the 2 million euro CT scan equipment that ignore audiophile world opinion and use them by millions in ultra low noise circuits because you can't hear the analogue to digital processing giving you a clear picture with your brain tumors...
 
Nichicon UES series inexpensive, great quality and sound.
You do want that cap it protects the cartridge if it does nothing else.
I would think you don’t want any DC on a cartridge in that it may offset the stylus but I may be wrong.

Nice looking pre.
 
[HA-55 is very close, both use parallel tantalums too

anyone measure a panasonic poscap for noise?
 

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Concerning the Sony circuit I do not think that a differential amp is a good idea for a pre-pre.
It has 6dB more noise then a parallel symmetric design. They may have used it for other good reasons like low distortion and good DC precision. They use a massive 40mA idle though and in that time they had the great Toshiba, ROHM and Hitachi devices, long gone now, that combined super low Rbb with high and linear Hfe, plus high early voltage and low Miller capacitance. That where the days folks ! And I was just a child working with NE5534 and BC550,560.
 
There is another issue. Elcaps in older equipment may have aged due to heat. That makes the electrolyte dry out. No reforming can change that. So it makes good sense to replace them.
Yes, that gives a better sound but that does not explain that the new cap TYPE sounds better then the old one. That should require to use an NOS version to replace the old one and then comparing to other types.
 
i wonder if this type of caps are the perfect cap for this application.these are the ones used as battery for memory dumps.220 000uf/5.5vdc although i have a feeling that the writing on themmight be wrong and the actual value is 22 000uf.still very high.I can't measure it anyway.
 

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Lots of new phono preamps have demag circuits built-in for just this: someone's been brave to pass DC current through their favourite MC 😛

Interestingly, people who probably understand the underlying physics like Mr VDH think it's much better to not magnetize the former in the first place.