Vacuum Tube Snake Oil Salesmen

Not to beat a dead horse - but I was getting low on 12AX7s so I ordered some Mullard reproductions from Vivatubes. Given what has happened recently I decided to get 2 matched pairs of Psvane Horizon 12AX7 from Amazon to compare.

Vivatubes rated each matched 12AX7 in the 96.5 (plus or minus a couple tenths) for gain as marked by hand on the box. All results were unique.

Psvane were simply stated tubes as matched with no test results marked on the box.

RESULTS with MaxiPreAmp II:

Vivatubes average reading 97.5 (plus or minus a couple tenths) with either side of the tube within a couple tenths of each other. All exceeding the 92 target gain.

Psvane tubes ranged from 84.2 to 91.7 for gain. None met the 92 target. None were well matched for either side of the tube or for the pair in each box.

For what it is worth...Vivatubes appears honest and accurate (deviations due to different test equipment). Mullard reproductions are either much better made or much better QC than a competing brand.

I will thank Amazon in advance for their good customer service in accepting back the Psvane 12AX7s.

@calieng. Funny I had the exact opposite experience with some 6sn7’s purchased from Viva.  It’s been a while so I don’t remember how the test results were noted, but suffice it to say the tubes did not match.  Viva also took the tubes back without question. Moral to this story, test the tubes yourself no matter who you buy from, which really doesn’t speak too well to this part of our industry.

Well gain is different than transconductance.

Remember that the vast majority of these testers only test a tube at one operating point and these point vary from tester to tester. 

Apples to apples only if the seller uses the same tester as the consumer.

The thing to ask yourself is if you would pay much more for tubes which were matched using numerous operating points from a vendor willing to spend the time and money to do it correctly.

Most, I think, would not.

clarifying my earlier post, 

@psvaneaudio has been busted sending out fake test results with their top tier tubes enough to make it like that they just arent testing them. 

theyve been selling dud horizon tubes for a good while. at one time the return rate was bad enough that their exclusive retailer,  amazon, posted a "frequently returned item" warning on some of the @psvaneaudio listings. 

ive seen on several forums customers bring this to their attention, as how theyre testing these and receive bot-style non-answers in stead of a legitimate response. ive written @psvaneaudio about this and gotten a nonsense response. 

Apples to apples only if the seller uses the same tester as the consumer.

@audition__audio 

That’s sort of true in the absolute sense; but relatively speaking, matching tubes should match when measured against one another.

The thing to ask yourself is if you would pay much more for tubes which were matched using numerous operating points from a vendor willing to spend the time and money to do it correctly.

Most, I think, would not.

Interesting. So, you already paid much more for tubes which were supposed to be matched but were not, now the question is would you pay much more than that for tubes which were actually matched?