Sylvania 6550 NOS Matched Pair

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I found these in my temperature/humidity controlled storage room this past week along with several other tubes (listed on Audiogon!) I did not recall I had. 

I have graded this pair as 8/10 due to pure external cosmetics.  They are pure NOS, it is just the original warehousing of these wherever they were made them less visually clean and neat.  Also, the OEM boxes were not in salable condition.  The loss of silk screening on Tube 1, and some hard glue substance on the base of Tube 2 do not affect the electrical characteristics or sonic results of either tube, however,

These are a VERY hard to find Sylvania 6550 matched pair in white boxes.  Some shootouts have placed them just behind the venerable Tung-Sol Grey Plate early 1960's 6550 in terms of overall performance.  Lively, dynamic(!), open and pure with deep tight fast bass and open extended airy highs.  Midrange the classic NOS vacuum tube 6550 sound very, very close to the Tung-Sol.  This is why the Sylvania's are as hard to find in any decent condition any longer as the Tung-Sol's are.

Test Results:

Test Date: 01/01/2023

Tube 1

PC: 33.10
Gm: 4.16


Tube 2

PC: 32.70
Gm: 3.98

Matched to within 2% PC and 5% Gm!

Please see photos.  These are the classic three getter (two top, one side) Sylvania 6550 vacuum tubes with some visible silk screen lettering still on them and still in white boxes.

When one can find these, they're going for $300/each!  I know of only one tube seller that still has any stock left and he knows it. 

This pair is listed for a lower price than the two listings I have for Sylvania 6550's in OEM boxes due to the cosmetic issues noted above and lack of OEM boxes.

I have three listings (see other two on Audiogon) of pairs of these beauties and when they're gone, they are gone. 

Seller pays shipping in USA (I do not ship outside USA).

Please see my feedback and buy with confidence.

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