NOS Tung Sol 6550 VS Tung Sol 6550 New Production

Has anyone had experience with the new Tung Sol 6550 new production power tube. If so how does it compare with the NOS Tung Sol 6550 ones. I want to replace my stock Sovtek 6550 in my ARC Ref 6 . But from what im seeing the NOS Tung Sol 6550 is way up in price of about $ 350. And the new Tung Sol 6550 new production power tube is about $ 35 from the Tube Depot. 
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I also have the ARC Ref 6 and thought I would try the NOS Tung-Sol.  I like a rich, sweet midrange, which is what the stock Sovtek has.  I did not like the Tung-Sol.  It has more extended highs, a deeper, tighter bass and is more dynamic.  However, the midrange is sacrificed for these qualities--all in all I did not find it musical.  I much preferred to original Sovtek; it has a very sweet, rich midrange.  I thought there might be an issue with break-in time, so I did put 50 hours on the Tung-Sol with only a slight improvement.

some people who have answered you here seem to have only read your title line, then didn’t read what you actually are asking -- which is these titled tubes used in an ARC Ref 6 linestage...

the 6550 position in the Ref 6 is in the rectifier section, it is NOT used as a power tube in the signal chain at all, so its impact on the sound of the unit will be somewhere between minimal and none...

so I would not worry so much about using these ungodly expensive NOS USA 6550’s from the 1950's and 1960's and stick to what ARC suggests to use in terms of modern day produced 6550’s for the specific purpose in your unit

you may want to direct this query to greg christensen at arc (technical / service manager) -- ask him whether they have done usage and listening tests using old stock american 6550s in the Ref 6 rectifier circuit and what they have found

this is one of the hazards of posting a question like this on a forum like this... you give people license to wax lyrical on stuff they have feelings about, but they are not answering you on your specific application -- details matter!

good luck

you may want to consider the Shuguang KT88-T nature sound series. among the best sounding 6550/KT88 I have heard, in a power amp, but do not know what it would sound like as a rectifier.
@jjss49 -     "schubert ....what do u mean .....Never listen to Sylvania 6550s from the 1950s?"      As for myself; that was the question I answered and (as stated), simply with my take on Schubert’s post.        Just a guess; I’ll bet the OP found his tube replacement, long before this dead thread was resurrected.        Not that anything you posted was incorrect, but, at times; dates are also relevant details.