What is the physically largest amp you have ever built?

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So I was at a HiFi shop the other day and they had some huge kt88 PP monoblock hooked up that sounded pretty damn good. That got me thinking about how big I would reasonably build an amp. Well I have to say that I would probably build a set of huge monoblocks if I had the time and money but I haven't yet. So far my biggest amp has been an F5 and it was not really that big. So what has been the largest amp you have built (pics help)?
 
Does adding a one ferrad cap bank to a 100W sub amp count? It was a 16 x 17 x 12 inch box with the amp, a CM Labs, mounted in the rack above it, and a box with a bank of 60W light bulbs for my slow start on top. All told, about 2 and a half feet of rack space. Yes, young and stupid, but had access to surplus caps.

Being a lot older, big no longer has any attraction. Only sound. It's bad enough to run two HCA 1200's with a crossover and Furman sequencer and still need the AVR for the center and rears. I would gladly switch to pint sized digital if they did not sound like garbage to me.
 
Well, I never completely assembled it, but this is the prototype for the monster. A SE vacuum tube guitar amp that made 200 W RMS. The plate power transformer alone weighed 75 pounds. The complete power supply (removed from a tube powered Motorola UHF base station weighed over 100 pounds. The filament transformer and the OPT weigh about 20 pounds each. The small transformer for the driver supply weighs 8 pounds. A moment of sanity ocurred that kept me from putting it all together. I realized that I couldn't lift the assembled amp, and had no real use for it. Several years have passed and my sanity is waning. I have since acquired a smaller power transformer from a Harris radio transmitter that produces more voltage and I might just have to put it all together.

I once build an amplifier that occupied an entire 4 foot rack, but it wasn't an audio amp. It was a HF ham radio amp that put out 1200 watts from a single 4-400 tube operating just a wee bit over spec. I could lift it though.

I built a solid state amp back in 1971 that produced about 1200 watts. It was large, but light since it had only one tiny audio isolation transformer on the input. The amp had 24 X 2N3773's mounted on a large circular heatsink with a fan on each end. The heat sink with transistors was US Air Force surplus. It ran directly off of rectified wall outlet and drove four 4 ohm speaker cabinets in parallel. We know not to build things like this today, but I was 18 and invincible then. The cabinet was bigger than the 100 Watt Kustom PA head that drove it, but largely empty. It was finished in the same tuck and roll vinyl that Kustom used, and made bigger, since bigger is better! It was used by a rock band for outdoor concerts for at least 10 years.
 

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For me, it was an OTL that Murray Zeligman and I built about 30 years ago. 32 tubes (6528) per channel. Four chassis construction. Pitiful efficiency (40 watts/channel into 8 ohms, maybe 3000 watts of heat, 2000 of which was heater supply alone). Enough heat to scorch the walls and drive us out of the room. We may have used it for half an hour before we admitted that, despite the investment in parts and labor, it was a terrible idea. No pix, but if anyone has copies of the old Audio Update magazine from that time, it was on the cover of one of them.
 
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An F5. Not that big but for a tube guy pretty big. I'd never build a tube amp like the one in the second picture. That's not big, that's huge and crazy and awesome....and kinda stupid too. Dr Frankenstein was mad, you know....
 

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The top of the line NYAL OTLs, the company of the late Harvey Rosenberg, were sufficiently large. 4 large rack units, for two channels, two regulated power supplies and two OTL amplifier chassis... iirc. There is probably a picture somewhere. That was back in the 1970s...

The ML-2 Levinson was fairly large too... going historical.

There is/was also a WE/IPC rack thing...
Multiple channels.

But I did not build those.

_-_-bear
 
An F5. Not that big but for a tube guy pretty big. I'd never build a tube amp like the one in the second picture. That's not big, that's huge and crazy and awesome....and kinda stupid too. Dr Frankenstein was mad, you know....

Looks like Dr. Frankenstein should have invested in some non-marking wheels for his super tube amp thingy...

check out the very bottom of the pic!

301439d1347673845-what-physically-largest-amp-you-have-ever-built-lm-212amp.jpg


-Charlie
 
Those Chinese wheels can't take that load! Just imagine a flat tire.

Recently the Big Dumb Blonde One stacked about 150 seven pound OPT's on a small flatbed cart. I got them into the house and almost to their destination when I got the "flat". After the OPT's were scattered all over the floor, the label was obvious "maximum load 350 Lbs". The failure was shearing of the pin that is the axle for the tire, followed by the bending of the base plate.
 
A 20 output device MJ15023/24 746 watt Leach inspired amp, with plus and minus 120 volt rails from 2 Dunlap Clarke 1000 transformers. Ramped up with a 25 amp Variac. It had 4 8 inch 20,000 uf 250volt GE caps on each rail. I wish I had a picture to see this myself right now. While testing it would scramble up the uhf band on my kids TV. It took me a while before I realized the amp was causing the interference.
 
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