introducing the black hole

[kevin gilmore]

So it turns out that the lme49830 is pretty much a dynafet on a chip, with

diamond buffers driving the fets. SO... combine with the semelab-tt

lateral audio mosfets, and the result is something super sweet, and

easy to build, about $50 in parts per channel. Combine 4 channels

with my balanced preamp, and have one serious kickass thing

guaranteed to drive anything, he6's and k1000's included.

At about 2 orders of magnitude less distortion than that other thing.

And more than 10 times the available output current.

at... 20hz to 20khz...

.1mw .05% thd (most of which is noise)

1mw .01% thd

100mw .005% thd

1w .0003% thd

many watts <.0001% thd

http://gilmore.chem....u/blackhole.jpg

Works great at +/- 30 volt supplies, But also works all the way

up to +/-100 volt supplies. 30 volt supplies highly recommended

especially balanced, because lets face it, enough is enough.

Suitable for driving say ten thousand pairs of sr-009 at the same time

(400 volts peak to peak)

A bit more work to do, but getting close now.

3.2 x 3.6 inches plus required external heatsinks.

Edited December 10, 2011 by kevin gilmore

[n3rdling]

Small and powerful like a blackhole Would this be suitable to drive speakers?

[spritzer]

Well pretty much anything can drive speakers (M3 even) but yeah, it can. This thing can swing 400V P-P into a 8ohm load with a massive PSU to match.

Edited December 10, 2011 by spritzer

[cobra_kai]

Well pretty much anything can drive speakers (M3 even) but yeah, it can. This thing can swing 400V P-P into a 8ohm load with a massive PSU to match.

Lol, that's 2500 watts or so. Absurd. So it can swing pretty much all the way to voltage rails and isn't current limited into low impedances? In that case even a +/-40V or so power supply for 4 channels would drive almost any speaker pretty well.

[ujamerstand]

Very cool. How does mute work?

[justin]

Very cool. How does mute work?

darkstar mute function, turn it up until you're deaf: mute.

[spritzer]

Ehh on this one I believe you just short to ground and the chip shuts off the output. Most chip amps have something like this.

[Shaman]

At about 2 orders of magnitude less distortion than that other thing.

Erm, does that other thing happen to be group buy material at that other place?

[chinsettawong]

Looking forward to spending more money.

Wachara C.

[slwiser]

Sorry for my lack of technical understanding but is this to be another Electrostatic amp or an amp that can power any headphone depending on its power supply?

Thanks

[spritzer]

Erm, does that other thing happen to be group buy material at that other place?

No, that would be a certain commercial amp designed to explode your headphones. I think that is the only thing that explains that crap design...

Sorry for my lack of technical understanding but is this to be another Electrostatic amp or an amp that can power any headphone depending on its power supply?

Thanks

This is for dynamic and magneto planar headphones and a way of getting close to a balanced Dynafet performance for not a whole lot of money. So while this can in theory swing enough to drive electrostatics nobody would build it like that (save for somebody wanting to upstage Krell). Recommended PSU is +/-30V.

[n_maher]

Kevin,

Any plans for an accompanying, simple bipolar PS?

[kevin gilmore]

The new dynahi power supply seems simple enough. Most of the size is due to the

electrolytics anyway. If you really want to use this as an integrated amp, a much

more massive power supply is going to be required. And then the size is mostly

capacitors and the transformer anyway. This thing actually works just fine on

a completely unregulated power supply which is what i'm testing it on now, because

i don't have a regulated supply that puts out 5 amps.

[skullguise]

This sounds exciting.....I'd be in....errr....to buy one that someone talented can build

[luvdunhill]

darkstar mute function, turn it up until you're deaf: mute.

I think I've found a market for the Dorkstar. It's mil-spec, of course:

http://www.google.com/patents?id=UZzxAQAAEBAJ&printsec=abstract&zoom=4#v=onepage&q&f=false

[kevin gilmore]

That has already been patented before in slightly different forms. The army had a version that

did very low frequency at obscene volume levels, guaranteed to make you think you drank a few

gallons of dulcolax. That version was not portable however.

[bhjazz]

dynafet + black hole = DynaHole

I'm in once I get through my current top-shelf builds.

Cool stuff, Kevin!

Edited December 16, 2011 by bhjazz

[Mister X]

Mute has me scratching my head as well.

The datasheet sez:

If there is between 130 μA and 2mA of current flowing into the MUTE pin, the part will be in

‘play’ mode.

Must be one of those "A bit more work to do" things?

[kevin gilmore]

Like i said, its not done yet. resistor and zener to turn off the mute.

And a better way to get the output off the board. etc...

Plus you can tie all the mutes together and wire it to

the protection board.

Edited December 16, 2011 by kevin gilmore

[justin]

does it play the brown noise?

[kevin gilmore]

it plays the full spectrum of noise.

i'm not really happy with the 530101b00150 heatsink, need

to find something else.

[Mister X]

How about the Ohmite R series?

http://www.ohmite.com/catalog/pdf/f-r-sink.pdf

or Mouser page 2078

http://www.mouser.com/catalog/catalogUSD/644/2078.pdf

[kevin gilmore]

Need to get rid of about 1 watt max. Width of chip is .75 inch.

Would like a single sided thing with circuit board mount pins

that is about 1.5 inches wide, .5 deep and 1.5 inches high.

[n_maher]

We could always mill down stock heat sinks.

[Mister X]

The Ohmite C series is pretty close to what you have described but they have a spring loaded, cam lockable, clip deal.

http://www.ohmite.com/catalog/pdf/c-sink.pdf

Digi-Key # C247-025-1AE-ND

( http://search.digikey.com/scripts/dksearch/dksus.dll?vendor=0&keywords=C247-025-1AE-ND )