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OTL Asylum OTL, Output Transformerless Amplifier User Group. |
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In Reply to: 6SN7 posted by fred.hammersmith on March 18, 2010 at 20:54:38:
My experience with 6SN7s has been with pairs of ASL Hurricanes, ASL 845-based SETs, and M-60 Mk.3.1s maybe a half-dozen years ago. (I sold those after a few months of trying to drive the upper-eight octaves of Vandersteen 5As, NOT a good match.)
As I now recall, early in my 'N7 life, I eventually determined that RCAs were the nicest-sounding 'N7s of random batches of inexpensive tubes purchased thru eBay, sounding a little richer in the lower frequencies and not lacking anywhere else. Then I found that Ken-Rad VT-231/6SN7GTs had just a little more of that really nice-sounding richness*. Then I heard the Tung-Sol roundplate 'N7 (hereafter TSRP) and stopped looking for other 'N7s. The TSRPs have a tonal balance that is even more beautiful and rich and natural, just the way I want my reproduced music to be and which is so difficult to find. Starting pursuing those, ended up with a few more than 20, but then slowly sold all the equipment that used them. Sold a few to friends and stopped with 15 in the drawer.
I now have a new pair of M-60s coming this week from my buddies at USA Tube Audio, and over the last couple weeks have bought four more TSRPs, carefully selected from the stuff on eBay. Paid c. $290 delivered for the four, and all test good-enough** to excellent, and they turned out to be a mechanically-matched quad with NO brown spots on their tops and with two having the same date code.
I expect to use 2 of these TSRPs in each amp, since (probably) I'll be using the gain-reduction plugs in the V2 positions* and ought not to use them in the V4 cathode-follower position due to Voltage requirements. After I get at least 48 hours of warm-up time on the new pair of amps plus some hours of listening thru them, I'll start moving some 'N7s around.
One other thing I discovered was that Herbie's tube dampers...
http://herbiesaudiolab.net/rx.htm
...do really well at reducing or eliminating any residual 'nervousness' resulting from microfonics in tubes...and ALL tubes are microfonic, and the more gain being squeezed out of a tube, the more likely you can hear the microfonics.
Oh ya...I bought a carton of Winged-C 6H13Cs (6AS7Gs) from an eBay seller radiohouse...
http://www.ebay.com/itm/111933819746?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
They arrived promptly in perfect condition.
More later.
* I looked for them on eBay recently and OH MY--are they ever expensive now, almost to the Tung-Sol roundplate level!
** I learned with my three 'N7-using amps that they do NOT require high-testing tubes to sound excellent.
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Follow Ups
- Any more-current experiences with 'N7s in A-S amps? - jeffreybehr 04/3/1615:42:43 04/3/16 (0)
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