Auto everything 5lb 50w tube amp?

[tedmich]

wha?
Most Musical Tube Amplifiers by Milbert Amplifiers

the designer reminds me of George Steele the old wrestler...but he seems to have discovered a couple dozen seemingly impossible design innovations...

quote:
"# Auto-Everything™
Automatic bias; Automatic idle/standby; Automatic World Power Ready with Power Factor Correction; Automatic loading. Never adjust bias again. Fly from standby to full power instantly upon demand. Plug it in and enjoy anywhere in the world, right out of the box. Drive it safely into any load, or no load.

# Play-Any-Tube™ -- Play 4 different power tubes at once if you like. Or 3. Or just 2.
Plug in any combination of 6L6, 6V6, 5881, 6550, KT66, KT77, KT88, 6CA7, or EL34 and it just works. Mix and match any combination for sound; Obviates "matched pairs" or even matched types! Power tubes can be changed readily or removed to reduce output power; the GAGA-50 will continue playing, albeit at reduced volume, should one or two output tubes fail during performance. details

# Drive-Anything™
Single output drives any reasonable combination of speakers, cabinets or loads. Nothing to set, match, mismatch, or confuse: one output does it all. Operation is optimized for 8 Ohms loads.

# Blow-Proof™
Reasonably sustains dead-shorts or no-load / total-opens without self-destructing. No more fear or blown output transformers as with typical tube amps.

# Power-Step™
Adjusts volume level vs. output power tube distortion. Not merely an attenuator, 'power soak' or 'hot plate' but a method that wastes no sound or energy as heat. details

# Super-Infra-Sonic™
Uncommonly wide bandwidth, flat frequency response down below 20Hz at full power. Plays airy highs with harshless alacrity and infra-sonic lows approaching DC voltage. details "

hmmm a flat frequency response, just what I want in a guitar amp...

opinions?

man his web site reads like a Dr Bronner's bottle...

[teemuk]

It's a clever and innovative design but it really should have been a bass amp because conservative guitarists will never buy it.

The design innovations are not impossible. They are not features of an ordinary, simple tube amp but they can be added with a marriage of tube and solid-state devices, which is what that amp is.

The patent documents are more interesting read than the sales "brochure".
http://davidberning.com/technology/patent5612646

[raiken]

I thought it was highly innovative with the switchmode impedance converter for OTL operation. That was very clever, indeed!

[Steve Conner]

It's not OTL, the output transformer is just a pathetic little lump of ferrite, and the PT presumably is too.

I'd seen David Berning's technology before in hi-fi amps, but I'm surprised to see a guitar amp using it, for the reasons mentioned in previous posts. Personally I like it, the only things wrong with it from my POV are that it's patented and I never thought of it first! :-)

Berning's magic output transformer works clean down to DC, so it should make a fine bass amp if they can't persuade any guitarists to buy it.

If I remember right, it's basically a switchmode power supply backwards. It starts by generating rails of about the voltage that a solid-state amp would use. These are then stepped up by two switchmode DC-DC converters to hundreds of volts. These converters have their inputs hung in series between the + and - rails, the speaker is connected to the midpoint of these inputs, and each high-voltage output provides plate voltage to one of the two banks of power tubes.

The current drawn by the power tubes is also reflected through the converters to the low-voltage side, where the difference in currents between the two converters is what drives the speaker. And likewise, the speaker voltage is reflected over to the high-voltage side. The tubes don't know any better, they think they're driving the speaker through a regular transformer, albeit one that refuses to saturate.

The cleverness of Berning's idea is that the converters don't need to be bidirectional, they can be made with low-voltage MOSFETs and high-voltage diodes.

[raiken]

Yeah, I meant OTL in the sense of no heavy output transformer. Little ferrite lumps that switch at 250kHz don't count.

I was thinking the same thing: "Damn. Why didn't I think of that?" The sad part is that it is so cool, I can't even pretend to not like it. I really do enjoy playing around with class D circuits and switchmode power supplies and stuff (but don't tell anyone!). I don't know whether it sounds any good or not, but for sheer innovation, it is the bees knees!

RA

[Old Tele man]

...the perfect "dual" for a power supply, ie:

PS = AC in, smoothing, DC out
AMP = DC in, modulation, AC out

[earthtonesaudio]

Very cool.

[Merlinb]

It's is a very clever design, yes!
My only problem is that the advertisers lie by calling it 'all tube', when the switching OT clearly qualifies as a big piece of non-tube circuitry! A solid-state power impedance-multiplier if you will; an amp in itself, making the whole thing a hybrid.