kevin gilmore

i was going to use the .47uf 600v caps, those are definitely too big

that might be a bit low, certainly the 1uf caps are too big for the current board size

you need some power supply cap, and the wima's would make the board too big

build it, put it in a super fancy box, and sell it for $37k betcha it sounds better than the high priced spread, at least no stupidly expensive and useless input transformers. its a push pull amp, so it might actually sound a bit different. besides which its winter what the fuck else are you going to do.

i'm sure you can use a c2m1000 as long as you find a way to add some heatsink

really, first I have heard of it on the second board, output transistors facing in, and under the board as well as the 2 surface mount. might be possible to move the mounting hole another .1 inch

djs name all over every board in the dac except for one. take a look. So he has been there since at least 2003 and probably a lot longer. only one other name on one of the boards JLG. fact is that the holo spring dac probably trounces every single msb product made and only costs $1500 to $2200 and is far better built. The power supply on birgir's dac is a massive hunk of crap.

http://www.diysoundlab.com/ is the attenuator $395 yikes at $10.5k

a little cleanup, and .6 inch from center of output device to mounting pins. board file posted

pbhv9560 and pbhv8560 are matched transistors for the front end, both 600v. better idea 2.6 inches, don't see how that can possibly happen unless I flip the outputs around and mount inside and under the board. would be impossible to work on if something blew up 2.7 x 3.7

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.