kevin gilmore

fuck me. but what else is new i think there are fairchild equivalents, but maybe not same pinout.

so for entertainment I was looking thru the SR price list. Sure enough 394A Mercury Thyratron... $250... Now to go and find some with the socket. Must have the blue shinny

anything >+/-12 and < +/-35 the amp works fine with 15v or 20v power supplies i am using the power one linears, in 15v mode they typically can be turned up to 16.5 which works fine and you can't build anything for the price of those. or in a bigger box you can buy the 20V units (24v, turn down to 20)

that circuit flat out does not work for balanced amplifiers especially with dacs that have output dc. you want this http://gilmore.chem.northwestern.edu/boards/protect3.zip

yep

where is Ray Samuels and his magic military solder and wire when you need him. OH wait, the guy finally retired.

now that I see the tubes, major stupidity. but really, what did you expect. The one on the left is a standard low voltage high current mercury rectifier. filament and plate anode. The one on the right is a grid pulse thyratron with the plate disconnected and the grid used as the anode. Basically both are driven as equivalent 30v say 10 watt zeners. Then the dc is applied to the shield wire of the cable. Same trick as audioquest cables that use the 24 volt battery Does not do anything. Never did anything Evidently Mikhail built something very similar. But look at the blue shinny.

volume and balance now working with the real attenuators http://gilmore.chem.northwestern.edu/dsc_0626.jpg something else could be used to feed the serial port with an infrared or web based controller.

That hurts. True, none the less.

i've started working on the 4dsystems 3.2 inch touch lcd again. I think its the right answer whether you use it standalone, hooked to a arduino, or raspbery pi, beagleboard etc. still looking for an easy solution that combines this display with a wifi enabled web page controller. (yep i'm lazy) will publish the 4dsystems standalone code when i have time to test it.

srmXh the same as the srm212 schematic http://gilmore.chem.northwestern.edu/srm212.gif also this http://gilmore.chem.northwestern.edu/srmxh.jpg yeah i know its old

One of the variants of the "rabbit out of the hat" sketches has Bullwinkle saying, "Don't know my own strength." I already have an es1 I rebuilt, pictures were posted. Mine is a 2 box because the amp box was much shorter. But really I did not need 2 of these. The SS1 rebuild was it for the monster singlepower disasters.

you have to use the servo on this amp. not designed to work without it. you would have to very carefully match the input fets

there is no way that is a T2. for a start the transformer is way to small and no way to stuff all those parts in a box that size

garbage in, garbage out. but the 10khz dac output is really messed up

finally putting the single ended version in a chassis http://gilmore.chem.northwestern.edu/squarewave4.jpg

probably should work. double the filament current, so account for that.

the update on the board was for the mpsw06 transistors because the 2sc1815 are hard to get now. otherwise no difference

I don't think the JT has a constant output impedance. But I will analyze to make sure. My attenuator has both a constant input impedance and a constant output impedance. need to break the delete key on birgir's keyboard!

lsk170 and 2sk170 have the gate in the middle, not the either end like the dual.

notice that 2sk170 or lsk170 are not pin for pin, you have to bend the pins to get the correct pinout

measuring that is very tough. Need a screen room, a very heavily filtered mains supply and expensive meters designed for this kind of thing. Mine is a keithley ac microvolt meter. And you have to block the DC first. Film caps work for this.

is lsk489 any easier to source? a pair of lsk170's or 2sk170's also works

there is no 60hz unless there is excess current being drawn by the headphones the 500V version of the kgsshv takes the voltage directly from the main unregulated supply, so no chance of hum even with the headphone drawing much more current than it should.

so the bias supply is a voltage multiplier directly off the ac line, and its really high impedance. So anything that might load it even a little bit is going to cause 60 hz hum. if the diaphram slams hard against the stator, its going to discharge the bias a bit.