[avahifi]

Tubes used in AVA equipment:

Ultimate 70:  5AR4 rectifier, 4 x 6CA7/EL34 output tubes, 2 x 6GH8A small signal tubes.  Reset bias when changing output tubes.

Transcendence preamps and DAC:  2 x 12AT7/ECC81 line, 2 x 12AX7/ECC83S phono.  No adjustments needed when changing tubes.  Older series Fet Valve preamps, DAC, and Super Pas preamps use 12AX7 tubes in line section also.

Fet Valve amplifiers: 2 x 12AT7/ECC81.  Re-bias if making changes to tubes with significantly different gain characteristics (call us for details).  Older series Fet Valve amplifiers (Fet Valve 500/300 and older) use 12AX7 tubes.

Tube types cannot be substituted without circuit revisions.

Most tubes in production units at this time are JJ Electronics (Tesla) brand.

Frank Van Alstine

[Brad]

Frank,

You might want to post this as a 'sticky' for easy future reference

[sfox7076]

I was searching the archive so I could do some tube rolling in a U70 and found this helpful.  Should it be updated for the new Ultravalve? 

Shawn

[Listens2tubes]

Frank's post is from 2005. It should be updated for the current tubes used in the current models. This pre-dates the T8 and 17" chassis.

BTW More than half Frank's post would be stickys in any other forum where the facilitator is not able to respond to such questions. We are lucky and privileged to have the maker with us on our quest for audio nirvana.

[oneinthepipe]

The U70 and UltraValve can also use 6U8A signal tubes, and the Ultra and T8 preamps and DACs can also use 6CG7 tubes, provided that the cover is not re-installed on the chassis without modification, since the 6CG7 tubes are taller than the previous 6N1P and other short tubes.

[sfox7076]

And provided they are not in the small chassis.