[kevin gilmore]

3 more pages coming when i'm in the mood.
(Cpu, Servo and Transformer/diode bridges)

The ultimate headphone amp

800 watts rms per channel into 4 pairs of grado's (8 ohms)

http://gilmore.chem.northwestern.edu/uberpage1.jpg
http://gilmore.chem.northwestern.edu/uberpage2.jpg
http://gilmore.chem.northwestern.edu/uberpage3.jpg
http://gilmore.chem.northwestern.edu/uberpage4.jpg
http://gilmore.chem.northwestern.edu/uberpage5.jpg


Happy Holidays

 

[Zanth]

YOU ARE A GOD.

 

[grinch]

now i just need to find three more pairs of hp-1's and i'll be all set.

your continuing involvement with the community is highly appreciated kevin. very interesting stuff.

 

[eric343]

Now I know what John Grado used to drive his Gradospeakers.

I take it this isn't the crazy watercooled one? (IIRC that one put out 400W more)

 

[kevin gilmore]

Yes this is the water cooled version.

It always was 800 watts per channel into 8 ohms.
Exactly double that for 4.

 

[kelly]

Thanks for posting these. Sorry for jumping the gun in the other thread. I edited to include a link to this thread in case anyone finds it in a search.

So... who's going to be first to build one?

 

[puppyslugg]

Quote:

Originally posted by kelly So... who's going to be first to build one?

I would, but I don't have nuclear reactor to power it.

 

[kevin gilmore]

You will notice that this is very similar to many of my
other designs.

Fully balanced input and output. No capacitors anywhere
in the signal path. Low overall gain. Current sourced everything.
Regulated power supplies, everywhere. Dual tracking too.
Pure class A (cpu controlled sliding bias thing).

Maximum distortion at 800 watts at 20khz into 8 ohms
right around .01%. No wimpy maximum output current
like the halcro either. 50 amps, no problem. 1 ohm load
no problem either.

A few other details, 50 ohm input. My preamp drives it perfectly.

So many of the trendy cables out there regardless of
advertising sound different not for the stated reasons, but
rather that of improper loading. All cables are transmission
lines. To drive them with a low impedance output and
terminate them into 100K is just plain wrong.
(read article in stereophile about 6 months ago)

You can certainly scale this down to only a couple of hundred
watts per channel easily.

The water cooling is a mighty nice convenience, but the
unit can certainly be built as an air cooled unit.

morsel has graciously given me parts librarys for the expresspcb
schematic program. I'll get a round toit sooner or later.

 

[kelly]

Would you be willing to take a stab at say...

About how much would the parts total be for the 800 watt version? (per channel?)

And then a 200 watt version?

And then the water cooling?

I know labor on these is very exhaustive, I'm just trying to get some ballpark of the parts.

 

[eric343]

Quote:

Originally posted by kevin gilmore Fully balanced input and output. No capacitors anywhere in the signal path. Low overall gain. Current sourced everything. Regulated power supplies, everywhere. Dual tracking too. Pure class A (cpu controlled sliding bias thing). Maximum distortion at 800 watts at 20khz into 8 ohms right around .01%. No wimpy maximum output current like the halcro either. 50 amps, no problem. 1 ohm load no problem either.

Absolutely brilliant... I love it

Quote:

A few other details, 50 ohm input. My preamp drives it perfectly. So many of the trendy cables out there regardless of advertising sound different not for the stated reasons, but rather that of improper loading. All cables are transmission lines. To drive them with a low impedance output and terminate them into 100K is just plain wrong. (read article in stereophile about 6 months ago)

Hmm... good idea.

 

[HD-5000]

I wonder how this compares with mega-buck amplifiers?

 

[eric343]

By the look of it, a more appropriate statement would be "I wonder how much this kicks the butt of mega-buck amplifiers"

 

[BoyElroy]

The Uberamp sounds like a perfect match for my Apogee Stages. I'll make a giant sized headband and hang them off the top of my head, kind of like oversized AKG K1000's

BTW, will the Uberamp have balanced and single ended inputs?

 

[ServinginEcuador]

OOOOOOOOHHHHHHHHHH!!!

Five smileys for Gilmore and his incredible amp that will take ther world by storm!!! Maybe this one will get featured in Stereophile and get interest up and orders coming in. It's just finding a suitable power sourse to supply the 50 amp draw it's capable of!!!

 

[eric343]

Yeah - building a 3250W power supply isn't that easy

BTW, for those with smaller-than-21" monitors, I went through and resized them to about 1024x768; they're still readable but you don't have to scroll around as much:
http://www.drsue.net/images/uberpage1sm.gif
http://www.drsue.net/images/uberpage2sm.gif
http://www.drsue.net/images/uberpage3sm.gif
http://www.drsue.net/images/uberpage4sm.gif
http://www.drsue.net/images/uberpage5sm.gif