kevin gilmore

tympanni 1's were about 1974, so the patent would have run out 1992 or so... Got to be public domain now.

any details of the lawsuit? those patents have to be way out of date by now.

looks like i'm going to have to learn ltspice... wonder what happens if i put in something fast. I'll try that when i feel a bit better... stomach flu and high voltage probably don't mix.

probably NSFW luvdunhill will appreciate. http://www.youtube.com/watch?v=Fow7iUaKrq4?version=3

what does that moron's opinion have anything to do with the price of tea in china. I really like the lcd2, but there are things that i don't like also. Some of those resonances need some work. And besides, motional feedback sure seems like a great and easy thing to do with dipoles... These guys could learn a lot from how magnaplanar does stuff.

anyone ever heard a phillips david?? Probably way before most of your times... But it would be interesting to put a capsule mic inside the audeze, and do active balancing of frequency response with feedback just like the phillips did. Turn the thing ruler flat in a jiffy. Would be super easy as the thing is a dipole.

Outstanding. I would have no idea how to make a chassis like that.

A little too much inductance in the cable could possibly do this. I kept mine rather short because i was running out of 10 colors of wire. Eventually i was going to make a much longer pair. I just do not understand how ST can make crap like the 7912. I finally got a couple of these, and no matter what i do, even in the most simple of circuits with 100ma of load, they just don't fucking work.

You better look at the -15 again... If you put in a 12 volt regulator, then you forgot to flip the one diode. Not that it probably matters, but if the diode is in wrong, then its gong to be about -18.

Its hard to tell from the picture, but you did use the ceramic washers right?? at least on the non-isolated parts.

In general the distortion goes down, not up. As long as both sides are well matched. impedance does go up, but compared to the impedance of the wire feeding the headphones it makes little difference for things like dynahi,b22. slew rate doubles. noise cannot be determined, but probably goes up.

I think that is right, but if you have the 100 volt windings, don't hook them to anything.

you can certainly power it up without a load, but make sure the angle brackets are attached otherwise the current source that drives the zener to power the opamp gets very hot very fast.

And then you really abuse them like singlepower does, and they really do burn up.

So both hammond and plitron are worthless... You would think that companies making this stuff for the last 75 years would have a clue.

Schematic updated with note from Inu. I'm using vintage parts, because with the amount of stuff i have in stock, i don't actually see the reason to buy more. Inu's mod increases the open loop gain of the power supply feedback. So the new versions of the op27's must be a different process or gain from the old ones. Completely makes sense. Now i'll spend the rest of the day synthesizing it, trying to find a better op27 model.

+/- 10 volts in any direction is just fine. You can get it to zero but it won't stay there due to the unregulated power supply. Has to work.

First time i've even heard of 8cg7's in an 007t. if the unit really was set up for the 8cg7's then the filaments of 6cg7 would be way high. In any case unless the tubes are competely toast, if they bias right, then they pretty much have to work. In fact if the tubes are toast, they would not bias correctly. offset to make the difference between the tubes zero bias to make the difference between each tube and ground zero.

The specs on the transformer was to deliver 130ma on the high voltage line DC. SumR calculates however they calculate from there. With all the problems i had with plitron, i made sure that he understood the current requirements. 60ma on the 285 volt winding and 60ma on the 75 volt winding. I did actually use the minus transformer for the 60 volts, but switching to the other transformer is definitely an OK idea. As people can attest to that visited CJ, the thing was on all day, and was definitely HOT, but not untouchably hot.

The -500 volt supply should be the current of the +500 supply plus the current of Q26,Q27,Q34 which is about 25ma. On my amp i measured 50ma on the +500 line, and 75 ma on the -500 line. Ultimately the current on the +500 line is controlled by the led's that do the current sources. If the supply is noisy or oscillating, a small cap across R41 (say .1uf) should shut it up. Or you have a bad opamp or a noisy zener on the power lines. Now why the transformer is getting hot, i don't know. The transormers were spec'd at 140ma i think. (have to look when i get home)

I was talking about the 7 pin socket that fit the current circuit board holes. The connex sockets can't do that. tom has sent me some more tubes, one of my tubes definitely has a problem, as tested on my tube tester. I did not test them before i used them however... So when they show up, i'll listen again.

you got 2 of the 3 numbers right...

Nope, not a DAC.

you gotta love engrish translations... http://gilmore.chem.northwestern.edu/dsc_1550.jpg

The wiring diagram is on the schematic. Each of the channels is seperate and has all the wires to run that particular channel. For the one extreme lunatic out there that wanted dual mono power supplies. Ac and dc all on the one connector. Interchangable. Also easier if there is a problem to troubleshoot one channel at at time.