kevin gilmore

Do not under any circumstances remove the lemo like connector on the end of the headphone cable. You will need to get the matching connector. And then wire that connector to a stax male plug. You are not going to like the price of the lemo connector. (something like $75 if i remember right)

OK, here is a little more sillyness. You know those 3 channel amps with the active ground, How about this. Channel 1 is made up of R - L Channel 2 is made up of L + R Channel 3 is made up of L - R The left channel is channel 1 minus channel 2 == (r - l) - (l + r) == -2l The right channel is channel 3 minus channel 2 == (l - r) - (l + r) == -2r 3 wires, yet balanced...

If you have not figured out whether or not i am insane yet, nothing i can do will help you any further. You need ground cheaters because the center of that bridge amp is almost certainly connected to earth ground. Connecting the earth grounds of 2 amps together, and the minus terminals of the bridges together is going to result in lots of broken parts. OK, lets see if you can answer this one. You can buy those really big subwoofers generally for the automotive wars. Many of those drivers have dual voice coils. You can certainly wire the 2 coils in series, and now you would have what you would call a balanced dynamic driver. But you can also wire them in parallel, and what do you have. But really the difference is the same, the voice coil adds the forces from each coil together and turns that into a single force that moves the speaker cone. Does the speaker cone know whether it is being driven balanced or not, of course it does not. All that matters is the total electromotive force.

Here is a twist... Take 2 balanced output monoblocks (OK, don't do this unless you really know what you are doing) Tie the output minus terminals together and wire to 3 wire (as in common ground headphones). Make sure you use ground cheaters on the power cables. Now use 1:1 audio input isolation transformers at the inputs to the amplifiers. Is it balanced Sure is... It is just a matter of what you consider your reference to be.

There are lots of monoblocks that are not H bridge amplifiers. All of the older marantz and parasound amplifiers for example. There are monoblocks that have rca inputs only but are bridge output amplifiers. (crown, mackie et all) The easiest way to tell (with the power off) is measure the resistance between the rca ground and the minus terminal of the amplifier. If the resistance is very close to zero, then it is NOT a bridge output amplifier. All of my electrostatic amps are in fact H bridge amplifiers. Certainly not complementary but in fact dual push pull. If you replaced the heaphone with a large value resistor, (and eliminate the bias) it would look just like any other bridged amplifier, other than the very large voltage swing. Not counting the bias, electrostatic headphones are 4 wires just like dynamic headphones without a common ground. The fact that the resistance is almost pure reactive means little.

see you are mixing up words that mean nothing. unbalanced headphones are the same as balanced headphones with a common ground. The load (in this case the headphones) cannot possibly know how it is being driven. But if it is being driven from a balanced (really bridged source with no ground) then it has to be 4 wire.

OK, a phono cart is a 2 wire source. It does not know whether it is balanced or not, and does not care. What does make a big difference in this case due to the very low output voltages is how much noise and hum is added to the signal due to the cables and connectors. A 2 wire rca connector and standard coax references one side of the cart to ground, and does so thru the cable shield. Way better, an i know this for a fact is to use 3 wire coax, connect the 2 inside wires to the cart, then if you have to, at the rca end, connect one of the wires and the shield together. Way better, but still an unbalanced signal. Even better is to actually have a balanced input front end which in general requires twice as many parts, but can if done right get an additional noise level 3 to 6 db lower than a non balanced front end. Ray's piece of shit phono preamp does this. At the output ray uses a drv134 to convert the unbalanced signal to balanced. In fact this really does absolutely nothing. The 5 wire connect is clearly desirable, but really only usable with a true balanced phono section. Now balanced output is a similar yet completely different animal and for a different reason. Take a 200 watt rms amplifier into 8 ohms. Bridge the thing. Given enough heatsink and power supply you instantly have an 800 watt rms amplifier into 8 ohms. Plus you get absolutely matched rise and fall times. In fact you can take 2 lousy amplifiers (as in quasi complementary) and put them together this way and get something that sounds really excellent, as in the crown macro reference monsters. The reason krell et all do the balanced (as in bridged) output is because of the lack of quality pnp output transistors past about 135 volts. Its the only way to get huge amounts of power and retain the rest of the characteristics everyone desires.

Ray has sold more than 800 of them at $295 each. === $236k Thats the biggest and only plus point i can think of. Unity gain and less power than what you hook it up to...

Ray is one of those people that likes to count his chickens before they hatch. And he likes to sell at least 500 of a portable before he moves on to the next one. So if he could sell 500 @ 425 that would be $212K justin is eating into that at a rate of more than 50% so ray will be lucky to sell 200 @ 425 and that would be $85k. So ray is by the way he measures stuff at least $127k in the hole.

My guess is that one of those two vendors is not happy at all.

Yes the prototype is in the basement. But really it was so much easier to buy a pair of bigass krell monoblocks. The older i get, the less i build stuff especially if i can buy it instead. Which means justin owe's me at least 4 more amplifiers. (all electrostats)

Design of the B24 and my uberamp of about 6 years ago, virtually identical. Especially the cross coupled feedback with all the benefits from that. Uberamp scales very nice up to about 800 watts per channel into 8 ohms. With appropriate parts and +/-125 volt rails the B24 will do the same thing. Plan on many square feet of heatsink. And a power transformer that requires 2 people to lift it. As shown it is good for at least 100 real watts rms per channel into 8 ohms.

The least he can do is send me front and rear panels for the amp, and maybe a cardboard box for the power supply...

Here is one for you, that you might not expect It is the only DAC/amp combo that i have tested (and i have tested a number of them including a couple of 2704 versions) that works with a SunBlade 1500 and Solaris 10. Which is very convenient for me... Not sure why the others don't work.

No i have not said anything to Ti about this. He either should know about it, or will soon. Ti ==== Ti Khan. TI ==== texas instruments There was a very long thread on the nelson pass forum at diyaudio.com which i'm sure is still there about how TI desperately tried to stear clear of nelson's patents on a particular chip, but were unable to do so and ultimately licenced nelson's patents. I think that nelson is a reasonable person, and for diy like things (as in virtually no commercial potential) he is likely to give his permission. I have seen him do so in the past. But if you don't ask first, well....

Yes it is sweet. However it absolutely violates Nelson Pass's SuSY patent. (in fact so does my Uberamp) So if he wants to sell boards, he had better talk to the man and get permission first. TI ended up paying nelson big bucks to buy his intellectual property on this issue. I still think i can show prior art and that nelson's patent is null and void, but that is a legal battle i would never want to fight.

Dac's both powered from the usb port. Both units run from batteries to avoid any possible ground loops. Same intel based computer used for both. I think i know what all the IMD crap is on the predator, but until i get some time to test and verify, i won't say anything. Lets not forget that jude absolutely loves the predator. Can anyone continue to trust jude's recommendations at this point? Slightly biased maybe, no never... I think it is the same problem where the predator makes lots of hiss on some laptops... All i have to say is Induced Harmonic Compensation. Yeah, that's it... Ray is copying Rudistor. Truely classic.

Actually this is exactly what you would expect from a tle2426 (or compatible) rail splitter that has to fight a low impedance load. Ray decided to seriously lower the values of all the feedback resistors on the opamp such that at medium and high gain positions each channel puts about 120 ohms of internal load to ground. That is 60 ohms that the rail splitter has to drive before you actually add any headpones. So without any tantalum low impedance caps on the output of the rail splitter where they would actually do some good, the output of the rail splitter is going to sap up some of that seperation.

Done by a 3rd party who happens to own both units. Someone I trust who has no hammer to pound with. I see no reason not to post this, as it should be clearly duplicatable by just about anyone. http://gilmore.chem.northwestern.edu/picovspredator.htm

I'm not done yet, more sillyness to follow. Since i have a NC lathe at my disposal i was thinking of making some bells to ring with the hammer. Turns out the science for making bells is very complicated.

Got to start watching those cut and paste's... Actually with the glass shop at northwestern university shut down, i have stashed one of the 3 glass lathes. So i do in fact have the necessary stuff including bakeout ovens and turbo pump down systems to actually build tubes. Even have a 50 year old RF generator suitable for flashing the getters. The nichrome wire and the rest of the stuff is easy except if i want to do thoriated filaments or indirect cathodes. The cathode material is nasty. Getting new getters probably not so easy either. The bug and butterfly were cloisene'd enamel.

with that video of a home made tube going round these days... (and it turns out that guy was someone i worked with back in the midwest hifi days 30 years ago) I figured i would show a picture of a tube i made by hand in 1976 (at zenith) Has a couple of bugs in it. (actually a bug and a butterfly) http://gilmore.chem.northwestern.edu/tube1.jpg http://gilmore.chem.northwestern.edu/tube2.jpg Proving without a doubt that i was nuttier, longer than just about anyone. (made from picture tube necks)

I managed to get one of those hd-dvd players at wallmart for $99. Did not even have to wait in line. Just for chuckles i bought it. Filled with software bugs like i've never seen before. Won't even play one of the startrek remasters (which are glorious by the way) all the way thru, you have to go back to the menu and play it title by title. Think the blu-ray players are any better, think again. Go to avsforum and look at all the titles that various players won't play, or do stupid things with. Its not the price for me, i want something that works right out of the box and not have to install firmware every week for the next year. Plus some of the firmware fixes allow some disks to play, and then break others. So if you want to watch disk A you need this rev of firmware, and this disk you need a different rev... But evidently you can't go backwards in revisions on most of the players. The only player that works perfectly is the PS3. Very sad. By the middle of this year you will see lots of blu-ray players for $299 or less. In fact you can buy a blu-ray computer drive for that now...

I started counting headphones in that picture, came up with at least 21, probably more like 30. Then i started counting everything in my house, dynamic and electrostatic, and can come up with almost that many. What i'm obviously sorely lacking is enough closet space to do that. I would have to throw out half my wardrobe (ahem) to pull that off. Damm

Thanks billy, It really means a lot to me. Maybe I'll let you play with my new hammer. (i just got a couple of miniature pumpkins) http://gilmore.chem.northwestern.edu/hammer3.jpg