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NOS Tubes - Ecstasy or Agony

I have been running tube amps for many years and have built a number of SETs and other tube amps, kit's mostly.  My main power tubes have been 2A3's and 300bs and I have used mostly new manufacture tubes including JJ's and EML 300b's (great tube btw).  I did use NOS driver tubes and headphone amp tubes.  Never really had a problem.

I just transitioned to a Don Sach's 6sn7 based preamp and McCormack SS power amp.  The preamp is very nice and sounds great with Shugang tubes. Of course, I wanted to try some NOS tubes, went online and did my research.  Now the DS2 is a great preamp, the drawback is it uses 4 6sn7s and so I need to get pairs.  Would  have love to get my hands on the Dehavilland, uses one tube!

First Pair - I ordered some Sylvania's from TC Tubes. Advertised as 50's vintage, ,when I received  them they were marked 60's. Hmmm.  So I tried them and they sounded pretty darn good except after a couple hours one of them developed a high pitched hum, like a florescent bulb. So I sent them back.  

Second Pair - ordered from Brent Jesse - has a good rep online and a really informative website.  Received them and one was dead on arrival, they were also clearly of different construction. So they are going back.

Next will try Andy at Vintage Tubes Services, he also has a solid  reputation so hopefully I can get something that works.

I am curious what experiences others have had. Maybe its COVID, or are these dealers just unreliable, or is just 6sn7's?  Really thought I could just buy some NOS tubes and experiment, I can't even get two to work.

I don't really want to disparage these dealers but I do think all the claims of testing are maybe overblown.
drewh1

Showing 4 responses by daveyf

daveyf's avatar
daveyf
3,012 posts
 
Some NOS tubes I have seen have clearly been used in some kind of electronics for decades. If you look at the tube pins, they are not only corroded, but also generally not that straight! The only 'New' thing about them will be the new owner who acquires them in the sale! Luckily, it seems that a lot of the better 'NOS' euro tube manufacturer's made tubes with enough quality to last for multiple insertions and hours....Too bad this doesn't seem to be the case with today's manufacturer's. 
daveyf's avatar
daveyf
3,012 posts
 
Interesting thread. I am in the middle of listening to a number of different NOS and not NOS tubes in my preamp. They range from Telefunken to Valvo's to Siemens to Amperex to Brimar's, etc. 
The question I always wonder is what does NOS mean to folks...to me New ( and there's the key word!) Old Stock (NOS) should be a BRAND new tube that has been in stock, unused, until purchased by you...the consumer. Unfortunately, this nomenclature doesn't apply to almost all of the tube suppliers...as their new( sic) is everybody else's either a) gently used, b) heavily used or c) maybe used..maybe new! 
To that, we see discrepancy in how tubes are tested and what a passing grade is for the tube...some of these very same folk believe that 80% of new is new...some believe that so long as the tube has ok microphony, gain balance and no gas issues--it is new! 
Then we have the protocol of how the tube is tested( or not) and what tube testing gear is being used...and lastly what is the expertise of the tube tester in his ability to read/understand and utilize the tester. ( When was the tester last calibrated etc.,). Many questions and not too many answers. OTOH, I am always pleasantly surprised that these NOS tubes really give one a very nice boost in SQ over the current production tubes that are available. ( At a cost in $$).


daveyf's avatar
daveyf
3,012 posts
 
To add to my post...
I do suggest that taking advice from tube re-sellers as to what is best sounding is probably not the best idea. Many of these folk have some experience ( if we are being kind here) with listening to a tube in their own gear, which in some cases (most?) will either be a) less resolved than yours, b) as resolved as yours...but totally different in regards to the set up and c) not your level of expectation when it comes to tone and timbre. While I do believe that a general idea as to what the tube in question sounds like...whether it is a little bright, unable to really dig deep in the bass etc., is accurate, the true SQ from any tube is going to be up to the end user and his particular gear and taste/expectation.
Only way to know is to place the tube in your gear and listen.
As to issues with noise and other factors...like drewh1 found out, best to deal with a reputable dealer/re-seller...and pay their up-charge.
daveyf's avatar
daveyf
3,012 posts
 

RCA's can sound great. I rolled in a pair of Clear top 12AU7's into my amp and the soundstage increased considerably. One thing I have found is that IF one can source an organ re-brand, which these tubes are ( Hammond) then they are a little less noisy than the original labels. Not always, but mostly.

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