SE to Balanced tube preamp idea

[analog_sa]

Originally posted by hollow_man
Would you believe that the thing measured f3dB 300KHz but sounded more like 5KHz?

Once you start listening you notice such "discrepancies" all the time. Still, i'm curious why you blame the CCS. I use a similar circuit with a single fet ccs and a Jung reg for the negative voltage and it sounds quite ok. Maybe your high voltage reg carries some of the blame. Or the passive parts.

[hollow_man]

Still, i'm curious why you blame the CCS

I didn't think it was possible too, but hooking up two windings erroneously, so that -ve bias was much reduced, more high frequency content was restored. The reduced voltage meant that the JFETs operated in their resistive region, i.e. bye-bye to the cascode.
Then I changed into a different CCS topology, as used by Nelson, and all the high frequencies reappeared. But the sound still was unconvincing so if the ccs had such a dominant effect next was its power supply. Out with the LM337 and replaced it with a discrete, no feedback regulator and there was marked improvement. Initially I thought I cracked it, but further listening left me unimpressed. The low frequencies may be excellent and the soundstage very precise, but realism in mid to high frequencies is just not up to expectations. Transistor sound.
With regards to passive components, resistors are all Dale RN-65 and capacitors low-inductance metalized polypropylene. There are no electrolytics anywhere but the filament voltage regulators. Maybe the 6H6Ps are just cr@p, so a pair of 6H30Ps is on its way. BAT and Conrad Johnson must know something about that!
In the meantime, its back with the old nice and simple SE passive preamp.

[analog_sa]

Originally posted by hollow_man

Transistor sound.

Thanks for the explicit reply. My build also has some of the "transistor sound" although the bass is very nice indeed.

[hollow_man]

B@gger, it's back to SE!