PHONO PREAMP

Hagerman Trumpet Reference-bested the Zesto Andros by a significant margin. Uses 12ax7 and 12au7 tubes.About 7000 retail. Owner for 4 years- never had a ny issue.
NSP

Stay away from those phono  stage using 12au7s. High end tube gain stage should not use those cheap tubes w/ high output impudence and non-linear gain. High mu tubes may not Sound smooth as directly heated tubes, but at least be able to drive equalizer network w/o too much variance. Also, the real cost no concern phono stage should use inductors in equalizer.

Stay away from those phono  stage using 12au7s. High end tube gain stage should not use those cheap tubes w/ high output impudence and non-linear gain. High mu tubes may not Sound smooth as directly heated tubes, but at least be able to drive equalizer network w/o too much variance. Also, the real cost no concern phono stage should use inductors in equalizer.

I can't agree with this.

First, the 12AU7 is based on the 6SN7 and has similar linearity. Their main problem (which is not an issue with 6SN7s) is microphonics. They are not particularly 'high output impedance'; in fact are often used to drive power tubes.

Inductors say nothing about phono EQ one way or the other. One issue with using inductors in a phono stage is ringing; this calls for careful design to make them work.

@rhodes Have you considered using a balanced phono setup? All cartridges are a balanced source and it sounds like you have an amplifier that has a balanced input. An advantage of balanced operation is the effect of the interconnect cables in the system sound is reduced. 

Thanks for the tube info.

Btw,atmaphere amp sucks: its output impedance is so high that only speaker has reasonable punch driven by those type of otl amps is eletrostatic speaker. Furthermore ,even after extentive mod, atmaphere amps longtail differential driver stage is too weak (guess which tube number is the dtiver tube :)).