General Electric GE 6201 12AT7 ECC81 Vacuum Tube Valve Industrial Variety Triple 3 Mica NOS NIB For Your Univalve Perfectly-Balanced

General Electric GE 6201 12AT7 ECC81 Vacuum Tube Valve Industrial Variety Triple 3 Mica NOS NIB For Your Univalve Perfectly-BalancedThis new old stock, new in box, industrial grade GE triple mica 6201 (12AT7 ECC81) dual triode was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. It measured an absolutely, incredibly super rare, perfectly balanced 70 70 where minimum (65%) is 50 50 and 100% is 77 77. This happens perhaps once maybe twice per decade! This variety has copper support rods; gray plates; two additional, vertical

This lot of three new old stock

Tube shield dimensions are as follows:

3 rather than 12

All were made by Sylvania although one is labeled "Philco

This Tung-Sol 9BR7 tube tested to spec on our Paul Hart-calibrated TV7/U

2 milliamps' plate current while Tube Two drew 40

They measured (from left to right): 56

Fortunately the libretto is present and in great shape

beefy black plates: three mica spacers for improved mechanical stability and low microphonics

They measured 93/80 for Tube One and 94/82 for Tube Two where minimum (65%) is 57/57

5 volts with adapters (not included) and they sound tremendous even though they are running with slightly-starved cathodes

These three CBS 6K6GT tubes were tested on our Maxi Matcher 2 with 325 volts on the plates and a bias of -36 volts for shorts