Also find HIGHLY useful info here http://www.head-fi.org/forums/showthread.php?t=119638 , altho this site is currently down.
I had a pair of 1006/845s, the newest (black, vertical) versions and found them to be HIGHLY sensitive to the microfonics of frontend tubes. Previously I had fallen in love with the overall-excellent sound of the Tung-Sol roundplate 'N7...
...and ended up sorting my stash into 4 piles based on microfonics. Those that were quiet in the 1st position got green dots, those that were too noisy for the 1st position but were quiet in the 2nd position got yellow dots, those that were too noisy for the 2nd position but were quiet in the regulator position got no dots, and those that were too microfonic for the regulator position I THREW AWAY!!!
Here's my stash of TS RP 'N7s (on the left; those are TS RP 'L7s on the right).
I've sold ONE greendot 'N7, so of dozens I tested, only 5 were quiet enough to use in the 1st gain position, 13 more were good enough for the 2nd position, and 5 more for the regulator position. I tossed maybe a half-dozen IIRC. I'm keeping mine for a while; I suppose in a decade or 2, someone else may be willing to pay what I think these carefully selected tubes are worth.
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Tin-eared audiofool and very parttime fotografer.
http://community.webshots.com/user/jeffreybehr
