I think a lot of modern day tube preamps are hard on tubes. I have several that vary, CJ premier 14, et5, and Audio Research ph5 all eat tubes. Allnic h3000 and dehavilland ultra verve 3 tubes have lasted thousands of hours.

The old adage that signal tubes last 1,000 to 1,500 hours is complete bull for some preamps.

Hey guys is the ET7 S2 clearly better than the ET5?

Think they may be trying to do too much with too few tubes. When they get down to less than 2-tubes per channel invariably they have started adding solid-state devices in the signal path, which we all know is an audio-abomination creating an aura of bad juju :no: in the listening space, upsetting the audio gods. My preamp has eight (8) tubes. Seems about right to me. :thumbsup: Nice aura. :music:

There are no hard and fast rules about how to achieve functionality.

Over the years, CJ has moved from more tubes in their linestages to fewer. This is consistent with their design intent of keeping circuits as simple as possible. This design paradigm has been adopted by a number of other manufaturers as well, including First Sound. These design principles are also consistent with Altschuler's TRIZ Principle of Ideality.

My CT-5 has one tube per channel, compared to my Pr17, which had two. I'm still on the same set of tubes in my CT-5 for the last nine years now.

The ET5 and ET7 have a single twin-triode tube for the entire preamp; one half of the tube for each channel.

I had an ET-3 SE. Had to replace the 6922 tube every 6-8 months. I sold it and bought a Luxman CL38U SE. It has 8 tubes 3 for the phono. I've had it for 2 years still dead quiet.