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Everything posted by kevin gilmore
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Sure. Lower noise
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I use 10k pots for everything. makes it simpler
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http://gilmore.chem.northwestern.edu/currentamps.jpg
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the stax mafia are definitely planning on a multibit dac. Problem is finding switches good enough (and fast enough) to do 24 bits, 1/2 lsb
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http://gilmore.chem.northwestern.edu/g9f21766.jpg
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https://en.wikipedia.org/wiki/Joe_Alaskey
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Expensive and/or raved-about headphones that actually suck!
kevin gilmore replied to Bjorn's topic in Headphones
I got my hands on the old Tektronix all tube curve tracer, the high voltage version goes to 1700 volts. I tested about 50 6ca7 tubes, no 2 indentical. not even close. did the same thing with c2m1000, and to the resolution of the screen, fairly easy to get bunches of matched quads but there is still some variation. -
Expensive and/or raved-about headphones that actually suck!
kevin gilmore replied to Bjorn's topic in Headphones
Is that how it works. I've been doing it wrong all these years. -
its not like a voltage amp, so a balanced version is still the same output current. other than the cast output circuit i'm unaware of any balanced transconductance amps.
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Expensive and/or raved-about headphones that actually suck!
kevin gilmore replied to Bjorn's topic in Headphones
alcohol AND diy, especially electrostatic power amps. at the same time. usually entertaining, and possibly deadly. -
and now for something completely different part 3
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
overkill? ME? NO, never. the resistors i picked are actually 1.5 inches long, the layout is 1.8 inches. So you can use the concrete resistors. i don't like the sound of protection circuits. So this amp is capable of about 30 amps into .1 ohm. Its just so much simpler this way. -
you are buying the 10m90 from mouser right?
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susy is low impedance input, so you can't use a 50k pot. 10k pot max!
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Group Buy - Digital Attenuator (Kevin Gilmore)
kevin gilmore replied to sorenb's topic in Do It Yourself
the attenuator resistors are not actually 10k, they depend on attenuation per switch and total impedance. -
Group Buy - Digital Attenuator (Kevin Gilmore)
kevin gilmore replied to sorenb's topic in Do It Yourself
partial schematic suitable for checking http://gilmore.chem.northwestern.edu/attenuatorv2.pdf board pictures http://gilmore.chem.northwestern.edu/attenuatorsmtv42flipground7.pdf -
Group Buy - Digital Attenuator (Kevin Gilmore)
kevin gilmore replied to sorenb's topic in Do It Yourself
payment sent -
and now for something completely different part 3
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
I think it's closer to a 6U as a stereo balanced the board is 4.35 inches high and 11.55 wide the transistors take up a bit of extra space past the board so say 10 inches X 15 inch heatsinks -
if people really want, I can probably flip the tubes to the other side to make stuff like this easier.
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and now for something completely different part 3
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
if you want a fully balanced amp, then you need 2 amp boards per channel plus one input board plus 2 goldenreference boards one set for 40v and the other set for 30v plus a very large transformer, a pair of 25 amp diode bridges and some really honking large power caps and mass quantities of heatsinks. if you ever saw the original levinson monoblock class A amps, those were 18 watts (really about 30) This is 100. you can also build the unbalanced version which is still pretty silly and less parts. And still stable into 1 ohm. -
if you don't already have the boards, there are new shorter versions of the boards that make doing the c2m1000 much easier
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and now for something completely different part 3
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
the opamp blows up at +/-40V would have to check the other parts, but +/-30V should absolutely work speaking of power... unbalanced/balanced/cast to balanced input block for all sorts of things, but mainly the uberamp, just need to find a way to get it into the box will probably involve splitting off the driver section. Uses GR power supply +/-30V for the front end and another GR power supply +/-40V to run the regulated output voltages to the output amp. If i add zeners to the servo amp, can easily go to +/-50V and as shown, its 100 watts of pure class A, and something north of 225 watts A/B front end NO feedback of any kind, .0025% thd at 20khz, 2nd harmonic. 3rd harmonic not measurable. output amps are current feedback. i think i have created a monster -
goldenreference low voltage power supply
kevin gilmore replied to kevin gilmore's topic in Do It Yourself
It does about 1.5 amps there will be a higher voltage one soon that does 6 amps -
not a liquid.
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pure ethylene glycol. I use it by the gallon to cool the xray cameras. slightly toxic.
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the tidbits i post over there are an attempt to get people to turn their fucking brains on. It rarely if ever works. Like the bit about which of my children (amp designs) i like more. They clearly don't fucking get it. and isn't it chang 3.0?