kevin gilmore

file server down till sometime tomorrow when the electricity comes back

not without making the board a bit bigger, its just about as small as I could get it

10k input resistor to ground, or relatively low impedance pot required, will up date board in a bit.

here is the soekris output section http://gilmore.chem.northwestern.edu/dac.pdf notice that the top set of switches is wired to +4 and ground, and the bottom set is wired ground and -4v (this is how you get sign/magnitude without any dc on the output. each audio-gd board is half (less than half) of a soekris single output. how you put two boards together to get rid of the dc is unclear. I see no way to wire one set of switches to ground and -vcc. soekris is sign/magnitude, audio-gd in single board form is definitely 2's complement switches look the same soekris does dsd by using just the 3 segment bits

goodies from the iceland

zsa zsa gabor died at 99 years old. rip

looks like a standard Hammond case to me and no pictures of the insides available. Stay away.

don't I know it. in 10 years I doubt we will be able to continue to run 9 nmr magnets, 3 mri, and 5 ft's, plus all those low temperature epr experiments. luckily I will be retiring in 2.5 years or less there are 400mhz superconducting liquid nitrogen magnets, but those are toys.

I pay $45 a gallon for liquid helium I get back $16 a gallon for the equivalent gas generated from a gallon of liquid helium The new liquefier we bought to recycle the recovered helium gas was $500k which did not include the raw gas compressor ($130k) the storage bag ($15k) and the storage torpedo's which are still in use from world war 2, and $20k for a 2000 liter storage dewar. To continue to get government grants we are required to recycle helium.

actually my price for a gallon of liquid N2 is $1.60 a gallon of milk is about $4

left 3 top and bottom blue resistors are the segment bits 5.11k 02C resistors and all the other blue ones in that row are 10.2k 69B resistors and the other blue ones in that row are 5.11k 130 is 13 ohms top switches v- = ground bottom switches vcc=ground

No schematic for the power supply that Kerry did. Unless he has it.

the cavalli liquid helium definitely sounds a lot like daffy duck.

note: liquid hydrogen is stupidly dangerous. besides which you are unlikely to get anyone to sell it to you. liquid nitrogen is better, and very cheap. been there, done that many times, no difference can be detected. cryo'd cables,cd's,tubes, flowers,bananas... liquid helium is even colder, and very expensive

that picture is not the holo dac. its something else. the holo dac has only a few caps.

actually the MIT cables are more than a resistor to ground. There is all that hot-glue. Dripping piles of hot-glue. And a couple of very small value caps. the guy at double-helix cables clearly has absolutely no understanding of electrostatic anything. Unlikely to have ever opened a quad56 or quad63 because if he had he would know that there is a reason why the wires are so thick. and so goes with his fancy silver wire in a high capacitance dielectric. Go to his website and count how many turns on the braiding and figure that the capacitance of his cable would be at least 3 times that of a stax cable. and then the BS about not plating the silver with gold because gold "slows down the signal" and yet all his connectors are cheap gold plated crap. etc. No one should help idiots like this mess up other peoples stuff.

not high enough resolution to see what is going on. like whether its sign magnitude etc. and the power supply box obviously does not have enough capacitors. This is overly goofy. Especially if one cap shorts out, repair could be just about impossible.

that one might be really good, real and matched cmos switches instead of digital outputs. But its pcm only, the cmos switches are not fast enough for dsd

well this guy clearly has no clue, and does not understand capacitance. or the voltage ratings on the wire. and i'm not going to sell him any 5 pin stax plugs reminds me of the idiot that made a krell ksa5 power cable filled with magic pixie dust and managed to get the wiring wrong and did a number on that amp.

yep, upsampling. plus if you are going to keep the original samples you need higher resolution to extrapolate the pieces in between. so at least 20 bits. one of the main reasons is filtering. for 16/44, you really need a multi pole output filter to prevent aliasing, and all the analog filters that have been used in the past have significant phase shift among other issues. so you bump it up to some very high frequency, then a simple single pole filter way outside the audio band, say 100khz. then no phase shift at all in the audio band. and you make perfect discrete high power pure class A switches.

its one of the things i'm thinking about

its a cfa and the gain is high enough that trimming is probably not necessary. But i will look into it

found this gem on lampizator website •DHT triodes in single ended anode follower configuration as Lampizator signal tubes (45 or 2A3 or 101D) really? i did not know that tubes worked that way. And something he does not say for the SE units, they invert phase. for the calculated power and voltage levels depending on the tube, 5% thd second harmonic. 275V top of plate resistors, 130V on the plate, 55 volts on the cathode. Not a lot of room to work with with this gain.

no way to set the midpoint, on congo5's unit, it is about 5v (well there is, but its a pain, have to trim resistors)

the flavor of the month is clearly r2r discrete dacs MSB,dCS,Soekris,Lampizator, T+A, Totaldac, DSC1 (an interesting variant),new audio-gd, Holo Spring and probably a bunch of others coming. the 20 bit multibit that schiit uses is the highest resolution monolithic integrated circuit part available. (no dsd) everything else is delta/sigma stuff