kevin gilmore

well its 2016, soon to be 2017, and it might as well be 2009/2010 because lampizator is round 2 of singlepower. I was waiting to get a picture of the board so that I could disprove just about everything lampizator has said, and found it. here it is The balanced output board is more of the same, its clear that the output tubes are a common cathode design, simple diode rectifiers and cap for the filament power, resistor plate load etc. This is an OUTPUT stage! Not a I/V converter. Not anything else either. Output capacitors are connected to the board and mounted with left handed skyhooks (also known as air) to the output connectors. Some recent lampizator complete lies all but one completely disproven by pictures birgir has 1) the soekris dac is modified to be a current output dac, and the tube stage is the I/V converter OK, flat out lie, the pictures shows that the voltage output of the soekris module is wired directly to the input/attenuator board. In fact there is absolutely no way to modify a R2R ladder dac to be current output, you need a multiplying dac, or a stack of current switches. 2) the soekris dac is modified by removing the +/-4V power supplies and driven with a super fancy (as in pair of 3 terminal regulators) power supply, truth is that board up front is just a +/-12V simple power supply that also supplies power to the attenuator board. 3) the one I can't verify, that lampizator programs completely custom and proprietary firmware into the soekris. No maybe a few filter changes, but the bulk of the firmware, not a chance. But really, the chance that this idiot can program something like that, you gotta be kidding. TRUTH! The soekris dac is used as both pcm and dsd, its hard to call something chipless with lvc595 shift registers as the output switches. The output of the soekris dac goes directly to the attenuator board, the attenuator board goes directly to the tube output stage. unregulated High voltage power supply also reminds me of Mikhail. etc. and people are paying up to $20k for this, pretty soon some will be comparing the various kinds of wood used on the base of this thing.

Here is what I have to say for all dac's these days. Even though this has been going on for 25 years or more, there is still so much to be done for both the hardware and firmware/software. I'm sure that people 20 years ago that sunk >$25k in to the krell sbx64 stack are kicking themselves for doing so, as today's price on that pile is just about a giveaway. For R2R discrete dacs, you have your choice of 2's complement dacs (basically 1 ladder per channel per side) with associated issues with switching around virtual 0v and sign magnitude dacs which are twice as many parts, and can generate interesting new distortions when the 2 sides are not perfectly matched. then there is the firmware and associated iir, fir, closed form etc filters, everyone tries to make theirs proprietary, until someone open sources this, it will continue. So spending $5k or more on something that may have been close to $20k seems like money dumped into the trash can. Especially stay away from lampizator, in my opinion, the new singlepower. Buy a holo spring and sit on it for 2 years when all sorts of new everything should show up. or if you are pcm only and going to stay that way, buy a yggy. part 2 more and more people are doing upconversion from pcm to dsd128 and dsd256 and like me seem to like the sound a bunch better. Its so much easier to design one switch per channel (and match the rise and fall times and exactly control the off and on voltages) than it is to design 24 or 28 (2's comp) or 48 or 56 switches (sign magnitude) per channel, then double that for balanced.

http://bbs.audio-gd.com/dispbbs.asp?boardid=2&Id=30313 audio-gd version, 8 for balanced sign/magnitude

pars needs an 8.5 digit dvm!

the 4 tube DHT version pictured last is definitely NOT srpp.

the lampizator site clearly states that the tube stage does the I/v conversion. but the pictures clearly show the voltage output of the soekris dac (there is no current output) going directly to the attenuator modules, there are 2 because its balanced. there seems to be no discussion of the actual tube output stage, and rarely have I seen cathode followers done as dht, so its probably a low gain plate output stage likely with a plate resistor. Also the pictures would otherwise show 4 separate filament windings (well 5 counting the diode rectifier) if it was cathode follower. even Mikhail would have a hard time building a piece of crap like this.

And the bottom of the thing is wood. Would love pictures under the board with capacitors in parallel or series attached to nothing. Even mikhail never did anything in wood (that I know of) although there was a partial wood front panel. for more amusement there is a company out there modifying teac products replacing regulators with some other regulators and some capacitors with some other capacitors and charging more for the upgrade than the thing cost in the first place.

won't make any difference

a lot of times it is so much easier than that. many of the chips in dac's have unique footprints and are easy to identify without having to resort to more unique measures. The firmware in them however is much much tougher to extract, which makes sanding off the chip numbers even more stupid. Unless they are using super cheap junk opamps etc. or 5534 chips for the i/v conversion.

I think it should work as is. may have to adjust the value of a trimmer pot to get to zero volts output

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