Valvo 12AT7 ECC81 Vacuum Tube For Your Univalve Zenith 7476 7678 This hardcover book -- and

This hardcover book -- and its dust jacket -- is in very good condition

They are dead quiet when the CD player is muted and have excellent frequency response

This new old stock-testing RCA 6CG7 / 6FQ7 dual triode tested a perfectly-balanced 2600/2600 micromhos on our Hickok 800

I have listened to this entire album and It has light to lightly-moderate surface noise audible in quiet passages and barely-audible in voice-level passages

Tube One measured 42 while Tube Two measured 42 as well where minimum (65%) is 31

Valvo 12AT7 ECC81 Vacuum Tube For Your Univalve Zenith 7476 7678 This hardcover book -- andThis Valvo 12AT7 ECC81 dual triode was tested on our Paul Hart calibrated TV7 U for shorts, gas and transconductance. There were no shorts or gas. Transconductance measured an underwhelming but well balanced 40 42 where minimum (65%) is 50 50 and 100% is 77 77. This tube has nice silkscreening; a flared base; sutured tops and excellent flashing. It sounded great in my Bottlehead, though is not recommended for this headphone amp which was designed for