mwhouston wrote:
single triode phono stage?
Hi.
Disclaimer: I don't think know posting too much on tube amp will be deemed O.T. in this SS forum.
Very briefly, it is a 1/2 ECC83 with B+=440V & super simple RIAA passive EQ &
battery cathode biased.. It is still in on a breadboard for half a year now sitting on the metal cage of my Dyanco ST-70 power amp. I don't want to rebuild it properly as I don't want to miss its sound for one day!
This is supposed to be fed into a linestage to get 'adeqate' gain to drive any power amp. But being a "less electronics deliver more musc" die-hard, I have it hooked up to drive my super-upgraded Dynaco ST-70 power amp direct.
With volume control (500KR) set to max for low level classical reocordings & 4/5 full volume for pop/light music, I'm amazed by the extreme transparency, details,
precise soundstaging & imaging (my first priority consideration in sizing up any audio system) &
vocal interpretation (e.g. the forceful voice of Pavarotti, the Hi-C king) delivered by this breadboard !!!.
How can a one-stage phonostage breadboard can deliver such superb sound despite being a bit too low gain to drive a power amp direct?? Sonically, it beats any SS & tube phonostages, DIY, brandnames I have auditioned.
All textbooks on this planet preach us a phonostage 'MUST' get 40dB gain, blah blah blah...Now I have proven this is not neccessariy all true
IF if one gets a pair of ears that go for music quality rather than music quantities.
The logic I can gather is the music goes thru minimum active electronics with minimum 'condamination' & therefore sounds superb. It's that simple.
While I am still working on 440V regulated PS (which is imperial, IMO, for such a simple phonostage), & so far not much luck with the LR8 chip. Once I completed the regulated PS, I think it should sound even better.
Other option is a chip CCS to replace the 100K Rp so that regulated PS is not that crtical.
Anyway, once I finsihed the whole thing to my own design satisfaction (though it already sounds very good), I''ll post it.
c-J