The GUTZ

[tINY]

-tINY

[tINY]

-tINY

[Wavebourn]

hi tINY;
that ump is too complex.
Look here: 3 tubes only, 300W peak power (for continuous 300W power bigger output tranny and heatsink are needed). Very clean sound. I've found a golden mine!

[tINY]

Actually, there's 3 amps and an active cross-over in there (about 800w output). And it fits in a small speaker cabinet.

I appreciate the old way as well.



-tINY

[Wavebourn]

Originally Posted by tINY

I appreciate the old way as well.

But it is a completely new way: 10W tubes on MOSFET steroids.

Very simple and very linear.

[tINY]

That looks like a neat trick. I see the transistors burried there now.

You drive Tubes with the Mos-FET, right?



-tINY

[Wavebourn]

Originally Posted by tINY

That looks like a neat trick. I see the transistors burried there now.

You drive Tubes with the Mos-FET, right?

No. Opposite. MOSFETs driven by tubes with "sneaky local feedback"
Later adding more MOSFETs I got 300W from the same tubes, but need bigger heatsink and output transformer (they were too hot after 10 seconds of measurement)

[zmix]

Originally Posted by Wavebourn

No. Opposite. MOSFETs driven by tubes with "sneaky local feedback"
Later adding more MOSFETs I got 300W from the same tubes, but need bigger heatsink and output transformer (they were too hot after 10 seconds of measurement)

Sounds like the Frank Van Alstine patented "Fet-Valve" topology:

The Fet Valve amplifiers are our highest expression of hybrid design, blending the best of vacuum tube and solid-state technologies. All of the basic design concepts are uniquely ours with sixteen allowed patent claims. We design and build these lush, wonderfully transparent, and outrageously dynamic amplifiers to satisfy those who have never been satisfied with solid-state alone. The sound stage is life-sized and the performers are real.

Our hybrid vacuum tube design sounds so real because it lets the individual gain parts each work in optimum environments. Vacuum tubes are great at manipulating voltages-you can play with 200+ volt signals where transistors would go up in smoke and flames. So, we use vacuum tubes for all voltage manipulations. Vacuum tubes, however, cannot drive difficult loads. They have very limited output current and get in big trouble trying to drive feedback loops, stray internal capacitances, and connection cables. So, we don't let our tubes see any loads at all. They operate in an idealized mode amplifying voltages only, and do it perfectly.

Power MOSFETs are super current amplifiers. They can control great gobs of current without stress, and when properly selected and used, they perform without needing external compensation, thermal tracking circuits, or VI limiting and protect circuits. So we use all power MOSFETs for current-amplification duties. There is simply no roughness or compression in Fet Valve amplifiers.

[Wavebourn]

Originally Posted by zmix

Sounds like the Frank Van Alstine patented "Fet-Valve" topology:

No, their patented thingies are straightforward: tube ams and solid state voltage followers. All of them claim to blend together best of 2 worlds, but more often they blend worst Clichéa of both words like typical opamp with tube input differential pair and solid state output emitetr followers.
In my amp tubes and MOSFETs work in parallel driving the same load, where FETs deliver higher portion of output current getting input from tube's cathode and delivering feedback to it's anode.

I believe if somebody ever dares to patent such topology Sir Darlington have to sue them!

[tINY]

I don't think Darlington's pattent is still enforceable...




-tINY

[Wavebourn]

Originally Posted by tINY

I don't think Darlington's pattent is still enforceable...

...so, somebody can get patent on his invention again?

[imacgreg]

I'm stoked to finally have something to share in this thread! Attached are a couple (new) pics of the Level-Or(TM). My Standard Audio partner Thom and I are very proud of this box and glad to show off the gutz! Enjoy!

[pan60]

cool pix Ian!!!!
thanks for posting these!

[imacgreg]

Originally Posted by pan60

cool pix Ian!!!!
thanks for posting these!

Hi Pan60,
We haven't forgot about ya! We've got a demo earmarked for you; our #1 goal has been getting production units out to those who purchased them. We will get something to you sooner rather than later. I'll keep in touch.

[pan60]

Originally Posted by imacgreg

Hi Pan60,
We haven't forgot about ya! We've got a demo earmarked for you; our #1 goal has been getting production units out to those who purchased them. We will get something to you sooner rather than later. I'll keep in touch.

the customer should always come first!
i am looking forward to getting one in the mad lab here!
we will stay in touch.

[gevermil]

Found these behind the toilet .

[Lynn Fuston]

Originally Posted by gevermil

Found these behind the toilet .

Can you say "retirement?"

[Scott LaChapell]

Do these state VF-14 on them?

Originally Posted by gevermil

Found these behind the toilet .

[Halfmoon]

Originally Posted by gevermil

Found these behind the toilet .

And where might that toilet be?

[jdg]

Originally Posted by Scott LaChapell

Do these state VF-14 on them?

i can see one that does.

holy hell.

[ulysses]

Originally Posted by gevermil

Found these behind the toilet .

Are they real? Or are they old octal cans with new printing and Nuvistors stuffed inside?

[gevermil]

And under that , I found these - Man I never clean back there

[nobtwiddler]

Inside of an Aurora GTM - 822 Mini Mixer

[vineyardgray]

Guts Pics and a MYSTERY -- see notes below...


OK, so here is the power supply and channel # 3 (this is a 3 channel unit):




And here are channels #1 & 2 and the additional boards that someone has added in. I would have guessed that they were balanced ins, but there are still only two ins (on a barrier strip). Any other guesses?

[Wavebourn]

DC/DC converters for 48V phantom power?

[ulysses]

Looks like a balanced input to me. The larger chip looks like a resistor array. How many connections did you think you needed for a balanced input?

[vineyardgray]

Trick question, Ulysses?

While three conductors are typical in a balanced cable - you're right, they could have tied the shield to the chassis, I suppose (or left this end unsheilded?).

So this unit is optimized for balanced inputs but unbalanced outputs, which I guess is OK since it will likely end up feeding a channel insert anyway.

One final question then, the tie ins to the + and - 15VDC are to power those chips? (OK, two questions, should I worry that the rails are +14.99 and -14.93)?

[Wavebourn]

I thought you were asking about black bricks. :)

Yes, that small boards look like preamps.

[zmix]

The unit pictured above is the 3 channel Orban 516EC de-esser. You can see that the third channel is unmodified and has a single white wire from the barrier strip to the circuit input.

THe first and second channels have been modified with a DIY perfboard input circuit. I think that Justin is correct and these are for a balanced input.

Here is the schematic Note the unbalanced input.

[ulysses]

Originally Posted by vineyardgray

While three conductors are typical in a balanced cable - you're right, they could have tied the shield to the chassis, I suppose (or left this end unsheilded?).
One final question then, the tie ins to the + and - 15VDC are to power those chips? (OK, two questions, should I worry that the rails are +14.99 and -14.93)?

The shield is strictly speaking not a requirement for balanced audio. But I would assume the reason there isn't a screw terminal for it is because this was a retrofit and there wasn't another screw terminal available. Shouldn't prevent somebody from attaching the shield though - I would bet there's a screw someplace on the rear panel you can use.

Yes, the +/-15V rails are tied in to power this circuit. The smaller chip is an op amp that needs power. The voltages you measured are not a problem. Strictly speaking, they mean you get .04dB less headroom than you would with exactly 15V rails. In other words, there's absolutely no problem.