Tubes for BAT VK60. Need help

I thini Andy's description of the 3 NOS tubes is on the money. The mil spec 6sn7 is a VT231. The idea that the Thor could cause the tubes in the amp to fail seems to me to be nonsense, but it is true that if the BAT design runs the tubes at a higher voltage, it could cause shorter tube life and premature failure, esp with "NOS" tubes, that often turn out to be only overpriced "pulls". If you are buying NOS tubes from other than a trusted dealer and do not have a tube tester, you are really buying a pig in a poke. I found out the hard way and bought a tester.

Swampwalker ...sage advice. I'm in full agreement.

Fuses more so than tubes seemed the issue with the 'other' Thor/BAT user... and i think he was using a bridged pair of vk60s as vk120's. whether that matters or not i've no idea.

we'll see soon enough.

i looked into the "tube tester" briefly. Calibration is the key. Without that being accurate in the tester even with one it’s as you said, “… a pig in a poke” .

Many I saw for sale were old, out of date, unsupported, yet said to be working and recently calibrated. Several makers of tube testers told me personally even after calibration, the return shipment can put it back to it’s previous “OUT OF CAL” issues.

How does one get past that?

More importantly, finding one that is both simple to use, with a sufficiently large view meter (3” x 3” more or less), and associated electronic text (PC viewable for settings etc), and remains in calibration or can be calibrated on site… well then I’d likely be headed that way as long as it ain’t too expensive.

I’ve had the thought that in today’s digital domain there sure should be some IC set type testing gear using chips and such inside to test tube variables with and not so prerequisite of regular calibration…. And cheap.

I’ve done some of that tube buying from hobbyists… and pros…both in my exp. Have been a mixed bag, save those I’ve bought from Andy b. his have served me well, had no issues and provided good results.

Though having a tester on site does what really? Whose tester gets the nod? Mine or the sellers? I sure see it’s value for periodic testing of one’s own supply…. But as a lie detector? I don’t know about that part.

I reckon it’d be a nice thing were I out scroungeing up tubes on my own away from retail venues though.

I’m probably better served in the long run to stick with those sellers people like you point me to than attempting to become a tube monger myself.

I'm not sure how much topology difference there is between the 60 and 75, but I switched amps a while back (still using the red bases.) That being the case, take my opinion with a healthy dose of salt. I have read lots of praise for the NOS Sylvanias and aim to snag a pair of them to try in my new(er) toy, but no practical experience with any NOS goodies beyond the reds in your amp.

The description of the reds you provided sounds plausible, but since I didn't do a side-by-side with anything other than the factory 6H8C and some standby EH 6sn7s, I don't really have a frame of reference. FWIW, to my ear, the reds are definitely a warm and articulate tube in my 75. Verrry sweet.

Thanks All.

finding one of the vendors that came recomended in the above posts being closer to me I went with him on the 6c33cb tubes. Matched Quad, + tax + ship = <$200, with 90 day warranty. A bit higher than another one or two but in stock and the quckest available.

6SN7 I'll probably get from VTS. Once I figure out which version suits me for the front two, and 5692 in the six slots of the second stage.

Regarding choice of taps, with the VK60 or VK75 you can try using different taps for t & w. I found my 8R Merlins had a sweeter treble and better bass control with t on the mid tap & w on the high tap. Just couldn't get the best of both worlds without splitting the taps.