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Everything posted by kevin gilmore
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you know that its possible that the hifiman amp has output transformers in which case the 300b would actually work as push pull. If so, what is that massive heat sink in the middle for. Still completely stupidass.
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SE to balanced is what you probably mean, and you can do that. you can also do SE output, but then why?
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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.