gepardcv

That file imports cleanly into Fusion360. Grab it from the Mac App Store and register for a free "hobby" license. Its all-"cloud"-all-the-time data management system leaves much to be desired, but in brief, you need to (1) create a project in the data panel, and (2) upload the .dwg into the project. Post-processing the design into something you can manufacture is the usual can of worms. I recommend at least splitting each panel (currently all in the same file) into separate part files. Fusion360 can export STLs if that helps. If you have (access to) a CNC mill with Fusion360 drivers, it should "just work."

I made an honest attempt to read this article, but couldn’t get past the author’s snooty preachiness. Is it just the old streaming-pays-artists-nothing argument salted with the-ignorant-masses-don’t-appreciate-real-music? (And never mind that in the good old days, nearly all musicians also weren’t well paid because labels pocketed all money and no one bought self-published CDs, and as for musical tastes — I’m sure there’s material for at least a dozen PhD theses buried in the subject.)

Yeah, those are the numbers from the Gerbers I used for my boards. SMT and MJE output sand. No idea about sizes for any older revisions, but if you get me the Gerber for it, I could try to figure it out for you.

@Ariamella: I pulled the following numbers from the Gerbers, and I think they match the produced boards: - ssdynahibalsmtm.zip: 215.9×115.3mm - goldenreference6.zip: 93.3×109.9mm

That looks pretty nice, @astro. I don't have an answer for your question, but I have another question for the wider audience: shouldn't the Mean Well PSUs use fuses on input for this circuit? I know these IRM units have some protection built in, but I don't understand how robust it might be.

The advice I heard is a piano student should be able to easily play Bach’s Inventions and Sinfonias collection before studying the organ. Real pipe instruments are obviously huge, rare, expensive, and hard to get practice time on. Digital ones with nice consoles and pedal boards are accessible but still pretty large (not much worse than a grand piano, though less acceptable as living room decor). There is the small matter of adapting to the vastly different tactile feel of an organ keyboard, of course... As far as testing audio equipment goes, Marie-Claire Alain’s recordings are a standby for me (not least because few other instruments actually produce low frequency sounds). And if you like BWV 565, try 582 and 537.

Where are you sourcing the heatsinks?

Then you’ll suddenly decide it’s a good idea to build a T2...

A favorite misspelled catchphrase of astrostar, burned into my retinas from back when I paid attention to the Stax thread on HF. As I recall, he extolled the virtues of tube DACs, and sported an Audio Note build. This might be him, trolling here with a sock puppet account.

I heard good things about Auralic Aries. Connect it to your network, stream either your own content or whatever providers it supports (supposedly including Tidal), plug it into a DAC, and that's it. The industrial design isn't for me ¯\_(ツ)_/¯.

Great work. Did you find that the bias current drifts at lower rails voltages also?

Good grief. I posted about trying this pile of feces at a meet earlier. It could barely make a sound. At max volume, it sounded like a Carbon at about 9:30 o’clock. I made the mistake of plugging my 007A into it, and yanked out the cable about 90 seconds later when I realized that, considering it doesn’t work as an amp, that it probably got the bias circuitry wrong, too. Which seems indeed to be the case. How much damage do you figure I did to the diaphragms? ?

From long-term memory: the 280 is that lovely combo of hot treble and boomy bass that makes everything sound like a wood screw to the eardrums. I used it with a 2nd-gen iPod at the office (didn’t have fancy amps at the time), so it may improve with moar power (but I doubt it). It lived on my desk and I treated it well — the piece which snapped was the plastic extension on the inside of the headband next to the ear cup. It could not withstand the strain all headphones endure in that spot when you hold the cups apart while putting the unit on your head.

I had a 280Pro about 12 years ago. Piece of junk. It’s brutally uncomfortable, painful everywhere it touches after 15min of use. It also causes listening fatigue within 30min if you can sit through the pain — probably hot treble, but I blocked it out of my mind. To add insult to injury, the cheap plastic where the cups connect to the headband will snap and break within the first month, as it can’t survive the strain of being put on and taken off the wearer’s head.

Oh, I already have CFA boards... I thought you meant that you already ordered boards for the IRM PSU. If no one has those, I'll probably sit down and lay them out myself within the next few weeks, but I'm not very experienced at PCB design, so that might take a few tries before I get it right.

@UFN: Yes! Would you mind sharing your boards?

I was thinking about how to shrink the PSU for a small-chassis CFA build, and remembered @Kerry's mini-Dynalo. He used two Mean Well IRM-15-24 modules. Would that work for a 24V CFA?

Fascinating unit. Please post an update when you try it out.

Nice work, @Blueman2! One thing I observed: the ODAC (which is what I assume you mean by "O2 DAC") clips. At least, mine does. It only works properly (for some loose definition of "works" and "properly") with digital input volume on the source dialed down to ~50% (and no, I'm not sure that it doesn't throw away bits of dynamic information in this state). The clipping is substantial and easily audible compared to every other DAC I have available. I don't know much about tube swapping, but make sure your DAC is not causing you any grief first.

@penmarker: Your transformer is really close to your amp boards. Mind the shielding and the wiring, or you'll have EM interference. I did the same thing, and I'm still working through some noise problems. (Though with recent posts on this thread, I'm now wondering if the THATs are partially to blame.)

I used 300×100×40mm sinks for my Carbon, and they don't get very hot at all at 20mA. I guess that with lower current I could get away with sinks a quarter of the size. You will retain the through-hole Cree SiC MOSFETs, right? Designing the boards so the devices attach directly to sinks rather than through angle brackets should help with dissipation also.

I want to know, too. Was thinking of trying this to replace the THAT parts: https://diyaudiostore.com/collections/parts/products/linear-systems-matched-jfet-pairs-grade-b

@mypasswordis: Does that mean you have SMD Carbon boards to share??

Kimiko Ishizaka's just-released recording of the Art of Fugue: http://music.kimiko-piano.com/album/j-s-bach-the-art-of-the-fugue-kunst-der-fuge-bwv-1080

That's because RN60D resistors have (1) fairly high-wattage ratings for their size, (2) high availability in many values, and (3) low cost.