Which preamps use 6922/6DJ8 tubes?

Roger Modjeski of Music Reference liked the 6DJ8/6922 very much, as did EAR-Yoshino's Tim de Paravicini, who uses the 7DJ8 (a higher voltage variant of the 6DJ8) in his pre-amps. I hear no evidence of microphony in my EAR 868 (isolated by Townshend Audio Seismic Pods).

Of all the preamps I’ve had, the ones with 6DJ8 have actually not been prone to microphonics issues. But I’ve had a 6SN7 preamp and another 6H30 pre that were extremely sensitive to it. The biggest trigger I’ve noticed is having too much gain. Once you get over 15dB gain, whatever the tube, you’re asking for trouble here.

Exactly @mulveling, excessive gain is to be avoided. Does Art Ferris still make his Audible Illusions Modulus pre-amp (which uses the 6DJ8 tube) with 30dB of gain (!) in the line stage?

Exactly @mulveling, excessive gain is to be avoided. Does Art Ferris still make his Audible Illusions Modulus pre-amp (which uses the 6DJ8 tube) with 30dB of gain (!) in the line stage?

@bdp24  30dB gain is "holy cow" territory lol. No wonder folks would complain about 6DJ8 being a microphonic tube if they had that unit!

It seems like there was a time (in the 90s?) when it was common to see full function preamps with an MM phono stage and a whopping 20+dB line gain. I’ve seen units from ARC and CJ spec’d like that. I guess the idea was you "could" run a Medium or even Low-output MC cartridge by filling in with line stage gain? Doesn’t work well, IME. Besides having way too much gain AFTER the attenuator (which causes noise issues for sensitive amps & speakers), I’ve not had good results feeding too small a signal into an RIAA stage and then trying to add the extra gain afterwards - dull, flat, lifeless sound.

One benefit that came out of the CD was the elimination of the need for enough gain to boost the phono input to the level required by the input sensitivity of many power amps. With separate phono and line stages each can be optimized for their function.

In the 50’s and 60’s some hard core audiophiles would take the tape out signal from their pre-amp and send it directly to their power amp (or insert an attenuator in line between the two), by-passing the line stage altogether.

When doing live music recording on my Revox A77 in the 1970’s, I hooked up it’s output directly to my Dynaco Stereo 70. The A77 has an output level control, and plenty enough gain for the ST70. Most power amps need only 2 volts to reach full output, which the Revox produced. Of course your source must also have an output impedance low enough to not cause frequency response problems. The rule of thumb is the source output impedance must be no more than 1/10 the value of the power amp’s input impedance.

The EAR-Yoshino 868 can drive a 600 ohm load! Tim de Paravicini of course did a lot of work in recording studios (including Pink Floyd’s), where 600 ohms is the standard. It’s gain is 14dB, s/n ratio 90dB, it’s weight 22 lbs. and it’s output 5 volts into 600 ohms, both balanced and single ended, two pair of outputs on XLR and RCA jacks.