kevin gilmore

the big yellow caps are the output caps, the 2 analog devices chips are likely the dac chips (can't read the numbers) then discrete solid state buffer then tube output stage with what seems to be a current source for the plate. 2c51 a better choice than most tubes. only one resistor mod in the lower right corner. depending on how much it costs, possibly a decent deal.

no this is the krell/Marantz style of doing unbalanced to balanced via the low impedance - cfa input. Marantz still does this in products today. differential gain way less than .1db, look at the graph. schiit has trademarked this as "schiit pivot point" my unbalanced/balanced/cast input board does the same thing. if cavalli was not such an idiot, he could have done the same thing with his liquid cabon instead of a cheap front end opamp. By the way, liquid gold is the same fucked up mess.

pabbi1 at canjam2010 drove my T2 into clipping. you could hear it across the room. He was very happy. Everyone else was scared there were others that stopped by my office and roughly the same thing.

so what function do tubes do in a dac? unless you plan on building a modern version of an eniac, the answer has to be the output buffer. Everything up to that buffer has to be solid state. So you get your choice of a tube cathode follower, or a tube driving an output transformer. The cathode follower is going to have a fairly high output impedance, something like 10k ohms so it might have trouble driving some cables, and the transformer output will have a low output impedance, and a bit more second harmonic distortion. your other choice is a solid state buffer of some kind. all 3 are going to sound different, some people are going to definitely like one over the other. the solid state buffer is likely to have less thd and more ability to drive long cables. if you have a solid state dac, and want some tube goodness add one of these http://schiit.com/products/saga

I almost forgot the most important bit. djs welcome to headcase! where the woman are strong, all the men are good-looking and the children are above average were you going to say something or just repost my pictures? edit: needed to get the quote correct

I can't find the power supply pics, but here are some of them. sloppy evidently going all the way back to 2007, looks like djs designed much of this too. definitely like the hand drilled hole on the preamp boards.

a transformer doing that? completely unheard of but an amp without any feedback of any kind is going to contribute to this. Even at 15 watts per stator driver

its a numbers game. the output of the amplifier is balanced, so is it 6500 ohms per output, or 6500 ohms total if its 6500 ohms per output then the rolloff just due to the resistance and the load makes it -3db at 103khz which is -.167db at 20khz so the amplifier would be rolling off faster than that. all of my amplifiers have 5.1k output resistors on each stator driver. and before those resistors the amps have a much wider frequency range than that. AND is that 6500 ohms include the required 5.1k safety resistors to prevent the headphones from sudden death, or is that the real output impedance of the amplifier. Because if its the later, its as bad as another product we know of around here

I was referring to audio transformers in the audio path. And i'm sure you know this. I have tested a number of lundahl input transformers, and besides being very sensitive to even the slightest amounts of dc, they have 2nd harmonic greater than the .05% you state, just by themselves. I like transformers in power supplies, and rf isolation. At work, lots and lots of 400mhz,500mhz, 600mhz and 5,10 and 35 ghz where striplines turn into transformers real easily without any ferrite. Take a look at that picture again, the hanging electrolytic and flying resistor at the left side. Is this the kind of quality that MSB produces, if I was a customer and bought something in this price range that looked like that I would be mighty pissed. OH wait someone did it for me and sent me a MSB platinum dac. with lots of hidden cuts and jumps and hanging parts on the bottom sides of the dac modules. I posted the pictures, but i'm too lazy to look for them. At this price range the audio jewelry has to be absolutely perfect inside and out. D'Agostino power amps pass the test, Boulder, not so much. Krell has fallen very far in the last few years. Whats going to happen to levinson and revel now that Samsung owns them is going to be really horrible. I'm clearly not the target customer for msb products, I absolutely have the money to write a check for the pair, but would never do so. Even if I had 100 times as much money as I do now, I would still not buy the msb pair. Nor would I buy the sennheiser Orpheus 2, or the hifiman. On the other hand a 2019 Z06,ZR1, or C8 as my retirement vehicle (complete with tennis balls) is a done deal. Back to numbers, 440 VRMS. is that stator to stator, or stator to ground. seems like stator to stator to me. So 600v peak to peak stator to ground. maybe that is why you don't want it clipping? A number of people I know listen at more than 440 VRMS. Even though they should not. These are the same people who hate srm323 because they clip so easily.

Actually there are a number of chips in the 2465 that are obsolete. And that goes for just about every single tektronix analog scope including the mainframe ones. Sucks. I own 4. There is a guy in Greece that repairs them and seems to have infinite amounts of stock of parts.

matching the output devices not a bad idea board file posted, new software may not be compatible with some gerber viewers, I did it in rs274x although I can do the new gerber x2 version changed a number of resistors, its less than 1db down at 20khz. about 7.5 watts per board, 15 watts per channel, 30 watts total plus the power supply joamat i'm expecting you should be able to have this done by the end of the day

WIMP! If you can't stand the heat get out of the kitchen. that said, if you are not wearing the appropriate PPE, including rubber shoes, non flammable clothing, and safety glasses, and have the appropriate training you are a FOOL. and if working on singlepower gear, add a blast shield. I saw first hand while working at Zenith Radio what happens when someone does not follow the rules, I was less than 15 feet away. And that person got a trip to the hospital and was lucky. Back when CRT's were the in thing and 25KV was the way things were done. Glad that is over now. The rest of it is marketing BS. Deliberately requiring an amplifier to use a $30k dac because if it clips it may blow up seems a bit stupid. Calling the pair a high voltage DAC when there is a transformer in the middle is a lie. You actually can make a real high voltage R2R dac, with 1500V opto isolators, its pretty easy actually, much easier than doing a low voltage version. etc.

locky must have run out of metal boxes, that is the same one just as a bare board. (not that the boxes are really very good anyway, but are needed as a heatsink) that Tektronix transistor tester is all tubes, and loads of fun to keep working. i'm sure lots of unavailable tubes inside. Still a great piece I used one a bunch

I am sure there will be value changes once I build the thing, and since the outputs will be heatsinked it's easier to turn up the bias a bit an decrease the values of the voltage divider resistors

single sided even, can add a ground plane on top if necessary, current size 3.45 x 3.7 inches, i'm sure birgir will be able to shrink it in the one direction you need 2 per channel, stack on top of each other, or next to each other. I should probably add some mounting holes.

So we actually can do it as the schematic is drawn and make darlingtons out of 2 different transistors So ksa1156 and ksc2752 for the output transistors, as the schematic is drawn they are 750mw each the driver transistors are 8mw each so definitely surface mount and the input transistors are 50mw each I think there might have been a better match for the ksa1156, someone go find it. also remember that Fairchild was bought by onsemi, so lets make sure the parts are going to be there for a while

did not notice that. bad idea on the connectors

check the link again, I added something

actually 3 hands. (updated schematic with great respect to you know who) 1 hand for turkey baster (actually making casserole at the moment) short hand for mouse 1 hand holding 50 year old single malt we will definitely be building this one

so sorenb really wanted this, so here it is http://gilmore.chem.northwestern.edu/cfaelectrostat.pdf the outputs are 300v darlington transistors just need to find a suitable npn match for the stn9360, and this can be done all surface mount tiny, fully complementary, fully dc coupled, decent input impedance (none of this 75 ohm nonsense) push pull output... edit: PBHV2160ZX looks great for the npn. so you can add one more set of outputs and run up to 500v power supplies balanced input only, and you need 4 of them

I think you all will really like this one, a current feedback fully dc coupled fully complementary electrostatic push pull amplifier. what the msb could have been if they had decent engineers. just need to find a match for the stn9360 http://gilmore.chem.northwestern.edu/cfaelectrostat.pdf

anyone that has ever listened to the koss esp950 will agree its clinical and cold. it tests pretty well, thanks to gobs of feedback. but lets look at the msb specs a bit Dynamic Range >140 dB Frequency Response 0Hz-20Khz, ±0.8dB XLR Input 75 Ohm Balanced 4Vrms Maximum Common Mode Rejection Ratio > 120dB CMRR @ 60Hz > 90dB CMRR @ 1kHz > 70dB CMRR @ 20kHz Crosstalk > 90dB Crosstalk @ 1kH > 65dB Crosstalk @ 20kHz now its obviously transformer input based, so 0 hz implying dc coupled. flat out lie. and its already down by almost 1db at 20khz meaning that its slew rate limited and likely this is into no load, once you add 120pf, its going to be worse. 75 ohm input definitely implies that transformer. that dynamic range number is at least 30db off. and where is the distortion specs. Likely the distortion specs are much worse because I don't see any opamps with piles of feedback. stupid massively overpriced crap.

it would probably have to be all surface mount, so that is a fair bit of work

unlikely. I would never use a transformer to drive a voltage stacker like they are doing, something like 900v inside that transformer and i'm sure its not designed for that.

those transistors are all obsolete, would have to be re-designed with available parts