Tubes for BAT VK60. Need help

Which fuse? The fuse on the back panel next to the power cord or one of the 4 fuses underneath the tubes? If underneath the tubes...it's likely tubes arcing and failing. That is common. New tubes and a new fuse from Radioshack. Make sure it's the same type and value.

I'm pretty sure Kevin Deals 63CC tubes are really 6C33cb's. I've retubed my VK60 from him once. Tubes sounded great.

If it's the main fuse. That maybe a issue somewhere, I can't comment there...

john

Good John, many thanks.

RE - K. Deals' 6c33'S
I was hoping that to be the case. Though I did see a .pdf Tube Data sheet that showed both it and the 33c-b as two different tubes. Looking at the pics of both hasn't helped. They spec differently too.

RE - fuses
"Underneath"

...according to the owner which had that experience (s). his thoughts pointed more to the application and use to the Thor pre IN CONJUNCTION WITH, rather than the BAT VK60'S '6SN7S' alone. Some reverse synergy I guess.

We are soon to find out for sure.

BAT's tech guy, 'Dan', said to that account, "the SN's need have the 600v rating to avoid that and usually it is a bad tube causing it, arced, or to low a voltage value most of the time."

As best I can remember, Dan also mentioned rolling tubes in the amp isn't a bad thing, but one runs the risk of blowing fuses and/or tubes, if the plate voltages aren't in keeping with the design parameters... saying some NOS tubes just weren't on that level years ago.

Andy of VTS said the safe bet given that info is to keep to the military grade of NOS 6sn7's.... 5761? Syl, Tung, or RCA.

have you or anyone found placing the speaker being used cables onto taps other than the speakers suggested imp load, effective, better, or no diff? (like putting a 8 ohm spkr onto the 4 ohm taps, for ex.)

I've not had any issues with my amp blowing fuses other than once during an output tube failure.

Andy's advice is good, as is Dan's. The commercial grade NOS stuff is the best place to look for 6SN7 replacement. I replaced the front two positions with RCA red base 5962s from Andy some time ago and they are still rippin.'

Best bet about the output taps is to swap 'em and see what floats your boat. I've tried connecting the 4 ohm taps to my VR4jrs, but to my ears, the presentation was a tad more effortless using the 8 ohm taps.

"...the peak power will occur into a 3 Ohm load (in the case of 4 Ohm taps) and into 6 to 7 Ohm load (in the case of 8 Ohm taps)." The jrs are nominal 6 ohms.

Dgarretson
I'll sure bear that tube integrating idea in mind. I would freak right out if upon installing a set of tubes they were to arc out on me.

Loonytunz ... You bet, thanks. try any of the Tungs or Sylvanias?

Andy had merely mentioned the Syls being way more extended on top, tungs having better body by a fair amount, and the reds being the more warm sounding but still with fine detail and imaging.

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.