POLL--Thread Idea: (Ginormous Tube Amps)

[agedhorse]

Good point!
IIRC (this was over 10 years ago) peaks were +40v, troughs were -40v.
The actual peak-to-peak swing was 80v

That’s still 200 watts RMS or 800 watts PPMP.

 

[NecroticImbecil]

Formerly owned this guy:

Also owned a Sunn 300T, if that qualifies. No pic of that one. The 2 big tube amps we aren't talking about also. Eventually settled on this little fella:

Played it out exactly once. It was great though. Now it's in the practice space.

I love these things like I love old muscle cars, the difference being I can afford to own one of these.

 

[LetItGrowTone]

Hasn't anyone built a tube power amp with one of these newfangled switching power supplies (I know nothing about them), to cut most of the weight of the power supply transformer?

 

[walterw]

Hasn't anyone built a tube power amp with one of these newfangled switching power supplies (I know nothing about them), to cut most of the weight of the power supply transformer?

yeah, i think peavey did a while back

also, blackstar has that setup but in the guitar world, a 50w tube guitar amp with what looks like a desktop computer power supply in it instead of a power transformer, with the result that it's lighter than a lot of solid state guitar amps

 

[hbarcat]

If size, weight, sound volume, and cost, were no objects, then I'd be rocking a 400 watt tube head every time and I'd need plastic surgery to remove the insane looking grin from my face.

But they are, so I don't.

 

[badinage]

...the insane looking grin...

I applaud you for at least maintaining a focus on worthwhile goals.

 

[Wasnex]

Hasn't anyone built a tube power amp with one of these newfangled switching power supplies (I know nothing about them), to cut most of the weight of the power supply transformer?

Not sure about tube power amps. I know of two heads, Peavey VB-3 and VB-MA. AFAIK they are pretty much the same except for graphics and the VB-MA has an added blend control to mix the clean and drive channels.

This looks like it could be interesting:

 

[J Wilson]

I'd not be interested because I'd be leery of the ginormous problems of finding the right tubes (a whole shoebox full), the money involved for buying them, plus dealing with an experienced electronic tech (and there's several here in Nashville, not a problem finding them) . . . for something I can't really hear a compelling difference over tube front/ss power in back, or for that matter, all solid state.

Just ain't got a dog in this scuffle.

 

[Aussie Player]

Used to own one of these, Marshall 2001, 375W, with 13 tubes.
Less than 100 made, I had the first one in Australia but the built in compression unit went sour and completely sucked the output power out of it, so it became useless for live work. I believe Cliff had one in AC/DC as well. Not sure if he had the same iasue.

Jim Marshall was visiting Sydney at that time and wanted to buy it back as he wanted to scrap them. Can't be many still out there theae days........

Got to love a man who stands by his product and strives to keep you happy.

 

[rufus.K]

Another strange behemoth. Also 1000 watts...
http://www.chambonino.com/construct/const9.html

I'm intrigued.

Check out that tone stack

 

[mikeswals]

I'd follow the thread just for the pron of it if there were lots of pics and gig pics...

 

[Lance Bunyon]

View attachment 5224364

So hot

 

[Bill Whitehurst]

I checked the 400+ box because I am interested in them,
playing, seeing, hearing
just NOT moving them.

Do a search for the BAGA project.
It has some insights into what is involved in building a truly high powered tube amp.

 

[bassguitarist85]

Not sure about tube power amps. I know of two heads, Peavey VB-3 and VB-MA. AFAIK they are pretty much the same except for graphics and the VB-MA has an added blend control to mix the clean and drive channels.

This looks like it could be interesting:

That is my video! A few points from the video detail...

Yes the SMPS module removes over 50+lbs of weight by not having a heavy power transformer. The OT is rated at Class M rather than Class F, meaning it can be physically smaller, operate at a higher temperature, and still handle the wattage of Class F if not more. The SMPS is very precisely designed, regulated 500VDC for the plates, and regulated 6.3VDC for the filaments, unique as the filaments are normally VAC, but with an SMPS its all DC. It also has the unique feature to operate at 120-240VAC automatically. The main fuse however would need to changed to accommodate the proper amperage.

The VB-3 has two 12AX7s and one 12AT7 in the preamp. Power amp section has one 12AX7, one 12AT7, and a matched octet of either 6L6 or EL34/6CA7 valves. I personally fun a full complement of EHX valves in the preamp and 6CA7 Beam Tetrode power valves.

The VB-MA adds an additional 12AX7 in the preamp section to accommodate the blend channel, but no optical tube compressor like the VB-3. The power section is the same. Still the stock China Ruby tubes for now. As one can imagine, rolling new tubes at this quantity is mad $$$$

Each power section can handle 300W RMS. Basically balls like a brass monkey!

Finally each amp weighs 37lb with their foot switch's. Remove the wooden top box and the amp itself in its metal shell only weighs 22lb!!

There are very specifically designed special parts to suppress the switch mode noise on the PSU outputs. It is not easy to design. Between the complexity of this SMPS and the high cost/scarcity of power valves, I don't expect we will see high power tube amps with an SMPS like this ever again sadly, but I could be wrong.

IMHO it seems like a waste to design a lightweight SMPS powered valve amp and only have it power a pair, quad or sextet of power valves. Go big or go home!!

Thanks for referencing my video!

 

[agedhorse]

That is my video! A few points from the video detail...

Yes the SMPS module removes over 50+lbs of weight by not having a heavy power transformer. The OT is rated at Class M rather than Class F, meaning it can be physically smaller, operate at a higher temperature, and still handle the wattage of Class F if not more. The SMPS is very precisely designed, regulated 500VDC for the plates, and regulated 6.3VDC for the filaments, unique as the filaments are normally VAC, but with an SMPS its all DC. It also has the unique feature to operate at 120-240VAC automatically. The main fuse however would need to changed to accommodate the proper amperage.

The VB-3 has two 12AX7s and one 12AT7 in the preamp. Power amp section has one 12AX7, one 12AT7, and a matched octet of either 6L6 or EL34/6CA7 valves. I personally fun a full complement of EHX valves in the preamp and 6CA7 Beam Tetrode power valves.

The VB-MA adds an additional 12AX7 in the preamp section to accommodate the blend channel, but no optical tube compressor like the VB-3. The power section is the same. Still the stock China Ruby tubes for now. As one can imagine, rolling new tubes at this quantity is mad $$$$

Each power section can handle 300W RMS. Basically balls like a brass monkey!

Finally each amp weighs 37lb with their foot switch's. Remove the wooden top box and the amp itself in its metal shell only weighs 22lb!!

There are very specifically designed special parts to suppress the switch mode noise on the PSU outputs. It is not easy to design. Between the complexity of this SMPS and the high cost/scarcity of power valves, I don't expect we will see high power tube amps with an SMPS like this ever again sadly, but I could be wrong.

IMHO it seems like a waste to design a lightweight SMPS powered valve amp and only have it power a pair, quad or sextet of power valves. Go big or go home!!

Thanks for referencing my video!

View attachment 5224902 View attachment 5224903 View attachment 5224904 View attachment 5224905 View attachment 5224906 View attachment 5224907

Surely you are kidding about saving 50 pounds with the SMPS. The power transformer doesn’t even weigh close to 50 lbs!!!

 

[bassguitarist85]

Surely you are kidding about saving 50 pounds with the SMPS. The power transformer doesn’t even weigh close to 50 lbs!!!

Well if we are talking say a Classic 400 tube amp or Ampeg SVT, then yes that weight is close. Either way its a significant weight reduction.

 

[LetItGrowTone]

With an "output transformerless" (OTL) circuit (a niche, usually hifi related), the output transformer could be avoided too. I know nothing about it, but it was a real thing.

 

[agedhorse]

Well if we are talking say a Classic 400 tube amp or Ampeg SVT, then yes that weight is close. Either way its a significant weight reduction.

No, it’s not. Add in the weight of the amps and there’s no way to save 50 lbs.

I work with both technologies as part of my day job.

 

[Wasnex]

No, it’s not. Add in the weight of the amps and there’s no way to save 50 lbs.

I work with both technologies as part of my day job.

Perhaps SMPS could shave off 20-25 lbs?

 

[Wasnex]

The Peavey VB-3 is 37lbs and the VB-MA with SMPS is 38lbs; both rated for 300w.

For comparison, the Mesa Strategy Eight:88 is 49lbs and rated for 465W. The Prodigy Four:88 is 29lbs and rated for 250W.

All pretty remarkable IMHO. Too bad they are all discontinued .