Audioholics on Carver Tube Amps

Cool, thanks for sharing. They don't hold punches on the cable companies. Funny.

I don't understand either. Even if the dissipation is super low, the heater by definition generates a significant amount of heat.
This is intriguing, and interesting at the same time. But B. Carver is no joker, so I would believe it.
 
Cool, thanks for sharing. They don't hold punches on the cable companies. Funny.

I don't understand either. Even if the dissipation is super low, the heater by definition generates a significant amount of heat.
This is intriguing, and interesting at the same time. But B. Carver is no joker, so I would believe it.

I know David Berning tends to run his output tubes at some ridiculously low current, like a tenth of what you'd normally expect.
 
I've got tubes that run at low current levels, but that happens to be the right spot for best performance. My Madison-Fielding amp runs 23ma per pair on the output tubes, so 11.5 ma at some 280v is a plate+screen dissipation of a little over 3 watts. EFB setup in an otherwise pretty conventional EL84 push-pull. I'm actually using 6p15p tubes but it'll run any EL84/6bq5/6p14p/7189 you want to plug into it. By the time you figure in heater power its about 8w of heat per tube, so basically a night-light bulb. Not super hot but not something you'd really want to grab hold of for long either.

The 100w Bogens bias at I think 50ma each, at 700v on the plates thats 35 watts plate+screen on tubes rated for 60. Still pretty hot tho, between the heater and the plate its baking off nearly 50w per tube.
 
Agreed. A KT88 is 10W of heater power, and on the video the guy hold his hand on it. I wonder if the heater voltage is also reduced.
 
For those who want to skip the meaningless drivel, the comments on the Carver come at ~12:30.

Apparently, Carver claims the amps are 75 wpc. I can't imagine that would be possible if it's running at super low current / plate dissipation. And what would that look like on a tube curve graph?

Perhaps I'm wrong. Maybe some of the more technically gifted here could comment.
 
It is monoblocs so it uses 4 KT88 seems, so less than 20W per tube.

And after 23:28 is the Carver's stand talk.
 
It is monoblocs so it uses 4 KT88 seems, so less than 20W per tube.

And after 23:28 is the Carver's stand talk.

thank you, I thought I'd set the video to start at that point. That's a lot to sit through to get to the interesting part.
 
For those who want to skip the meaningless drivel, the comments on the Carver come at ~12:30.

Apparently, Carver claims the amps are 75 wpc. I can't imagine that would be possible if it's running at super low current / plate dissipation. And what would that look like on a tube curve graph?

Perhaps I'm wrong. Maybe some of the more technically gifted here could comment.

My tube mentor always said, "Forget the curves." ;-) Tubes are transconduction devices and can be used in a lot of different ways.
 
well, class B operation has the tubes idle at basically zero current. Having tubes idle at very low heat isn't a problem at all. Class B also can make a lot of power, so no issue there either. The hitch is the distortion. Class B isn't typically used in hifi stuff because of the crossover distortion you get. It may not be quite so bad with tubes if you very carefully control the grid bias though. They mention something about some sliding bias arrangement, guessing that is somehow adjusting grid bias voltage based on input signal. Basically you'd be imposing both the audio signal and the DC bias voltage on the output tubes at the same time, and relying on common mode rejection to make the bias voltage shifts vanish. You might be able to do that with a simple peak detector circuit feeding a MOSFET in the bias supply.
 
I think you are right Gadget. That's the only way.
But how can they guarantee the tube life to 25? years ? In class B, the tube will dissipate power only when music is played, like a SS amp, but still, the wear on the tubes at good listening level should take its tow. Unless he bias them very cool.
But still, the tube should be very hot when used, no ?
 
Fusing the OT is good practice IMO.
I saw the after match of a catastrophic tube failure on a Marantz 8b, which could have been avoided with a single fuse.
I since add fuses to protect the OT.

But I didn't get the impurity in the tube -> arc -> fuse blow -> replace it and all good forever.
 
But still, the tube should be very hot when used, no ?
yeah, same as an SS amp, when its jamming its going to make heat. I suppose with a bunch of tubes in parallel you might be able to minimize that somewhat by spreading out the load.

I'm not buying that it can perform any healing magic on bad tubes though, unless it comes with a regular visit from a shaman who can wave the rare healing getter crystals over it.
 
I enjoyed the video except for the fact that they loved everything (except the cables)

Will try the website

Classic comment: I loved the speakers but for $40,000 they could have done a little more
 
For those who want to skip the meaningless drivel, the comments on the Carver come at ~12:30.

Thanks for the heads up. "Meaningless drivel" was a polite way to describe it, pro commentators these two are not.

They mentioned how nice the 30k Wilson (Sashas ?) sounded but no mention of the $30,000.00 Audio Reseach ref 160M monoblocks powering them...talking heads:thumbsdown:.
Over 60 grand for a pair of speaks and amps, it should sound "good".

I'd still like to know wtf happened with Bob's partnership with Emotiva to build an entire tube line.

I read somewhere some time ago, I think it was Emotiva's site (blog), that an agreement couldn't be reached by both parties so they parted ways amicably.
 
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