New true platinum select grade ARC or BAT matched for plate current and gm. This is a beautiful set, and hard to beat QUAD, four pieces.
There is a misconception that Sovtek and Electro Harmonix are no different. They are made in the same factory, the Sovtek factory. When they are burned-in and tested, the best, the very best are sent to Electro Harmonix for gold plating. They get tested again, after the gold plating, merit and for micro-phonics, before being shipped to New Sensor in New York.
These tubes were, at extra cost, retested by New Sensor in NY at our request and matched as close as possible. When we tested them on our AVO TCM 163, we re-sorted them to groups. This group has the tightest gm and current. The AVO tests these at 90vdc, bias 3.1, and filament at 6.3. Average new is 30ma at 15,000gm.These are BOOK values from the plate characteristics charts and specification sheet.
No inter-element leakage, shorts, gas, or micro-phonics.
Here are the numbers for each triode section:
15,800/34ma and 16,200/34ma
15,800/34ma and 16,000/34ma 15,400/34ma and 16,000/34ma 15,500/33ma and 15,500/34ma
This is a beautiful set, hard to beat, and hard to find