gepardcv

I've bought LT1021 from Digi-Key in the past. Doesn't look like there's a ton in stock, but I think it comes and goes.

I wonder if there's a good way to adapt the GRHV. Crank the negative rail to -460V, keep the positive rail at +400V, and (if possible) use a voltage divider to make a +220V. Way simpler and smaller than the T2 PSU.

That is so impressively miniaturized that pairing it with the beastly T2 PSU and its three huge transformers seems just wrong.

Looks neat. What power supply did you use?

A1. The KGSSHV uses some out-of-production transistors. While you can still buy them, fakes can be a problem, and reputable suppliers (like bdent) charge a premium. The Carbon is essentially a strict upgrade from the KGSSHV, with (I believe) all current production parts. The major advantage of the KGSSHV over the Carbon is the availability of versions with on-board heatsinks, which simplifies the metalworking considerably. You might consider building a KGST instead. It’s a great amp, and aside from matching 6S4A tubes, I found it generally pretty easy to make. Also consider the SRX Plus (though I haven’t made one of those yet). Search here for threads discussing these builds. A2. Only you can decide that. It pays to try before you buy. A3. The Carbon and Megatron are no more dangerous to build than any other device operating at comparable voltages.

This is so interesting. The full-size Dynalos I built are the coolest-running amps I have. Really surprised at how much hotter all the smaller parts end up. I want to make a mini, but the heat issue worries me.

My ODAC is a piece of garbage. It clips loudly, audibly, and obnoxiously when macOS system volume is set to >50%. Maybe it's broken. Not one other DAC I tried does this, at any price point. If you want an integrated DAC+amp solution for your Carbon, you're much better off with Soekris boards. Still not recommended: (1) Carbons run somewhat hot, and I don't know if it'll take much to fry the DAC boards, (2) you'll have a much more complicated internal layout, (3) you'll need a larger case, (4) you'll have a much more complicated power supply setup to deal with. General piece of advice in addition to what others have already said: get some experience drilling and tapping external heatsinks. I destroyed the first one I worked on.

Over 3k USD for a slow-ass f/5.6 lens? I’ve had good luck with Leica glass and enjoyed rangefinders in the past, but that’s just silly.

Wait, did anyone actually determine that the heatsinks don't help cool the transistors? That's... counterintuitive.

Resurrecting a year-old post about the iESL. I've been thinking about this. What exactly is the problem of putting a cap after the ballast resistor? Is it just that having a capacitor as the last thing on the bias line would cause inrush current to surge while the cap is discharged and fry the diaphragm? If so, wouldn't the resistance still be set by the ballast resistors (5M or whatever) and so therefore still limit the current? Assuming voltage remains a constant 580V.

My stuff came in. Thank you Steve!

Monoprice posted a product page for a $700 electrostatic system: https://www.monoprice.com/product?p_id=33455. No description or specs, but the pictures look like that might be a Stax plug...

Also paid. Thank you!

I usually make my own BOMs following the board silkscreens. That way it'll definitely be up-to-date. The only non-obvious parts I remember are the LED, so use LTL-307ELC.

You mean when the drivers are made or when the speakers are assembled? I was startled when a rattle in a pair of DIY C-Note speakers I built went away after a few hours of pink noise. (And that rattle wasn't imaginary. I have the speakers set up to play with a digital piano and Ravenscroft 275. The woofers definitely made bad noise when I pressed certain keys but not others.) It would make sense if the drivers were not run when manufactured, and it would also make sense to run a speaker for a while after assembly to get rid of problems like the one I ran into.

Have you already gone through the existing Dynahi thread? There will be some dead links, but using the search function will get you pretty far. https://www.head-case.org/forums/topic/9768-kg-balanced-dynahi-build-discussion-thread/?tab=comments#comment-468974

I'm all for knocking down absurd prices, but the decision to dig in puzzles me. The product is getting dragged through the mud on every audio forum, along with Massdrop's name and reputation. Its comms/PR people, assuming they exist, have undoubtedly advised a strong mea culpa along with a solid dose of public groveling, and have so far been ignored. It doesn't even matter if the design was ripped off or not. Assuming the Massdrop-Airist contract was written by someone with minimal understanding, it would have included indemnification clauses specifically for this purpose, allowing Massdrop to ditch Airist with minimal legal fuss. Perhaps Massdrop is financially stretched, and eating the cost of the product and reimbursing the backers would be ruinous.

I've had a Soekris dac1541 since late summer last year (~9 months or so). It's really good. I made a volume-matching AB (not ABX) switching box, and I could not hear much difference between the 1541 and a Gumby. Sold the Gumby, it's not worth the desk space and it has fewer features (not to mention it has that obnoxious relay that snaps loudly at night in a quiet house when it has no USB signal lock). The original filters are pretty neat and have audible differences — admittedly with sighted testing, but that's way more than I can say for any other filter-switchable DAC I tried. I also recently picked up an RME ADI-2 DAC to play with its DSP. Very neat device. The built-in parametric equalizer works well. I've never heard a 007A+Carbon combo thump this hard after I EQed it to (as best I can without a measurement rig) match the Harman curve (based on Tyll's old measurements of the 007). On the downside, I think it increases listening fatigue somewhat, so it's probably not ideal for long listening sessions. For short periods (like 30min or so), it sounds pretty fantastic and impressive. With all DSP turned off, I cannot hear meaningful differences between the ADI-2 and the dac1541, but I must admit I didn't try very hard.

Congratulations!! Have a great time out there with Putt!

I don’t have a good sense of what speaker specs make them efficient. I have a C-Note kit waiting for assembly, and was thinking of using that with this amp (8 ohm impedance with a sensitivity of 85 dB 1W/1m). That looks to me like it’ll get plenty loud..?

I wondered about this... what is the actual audio effect of high offset? I've never wanted to experiment on my own builds, but I keep hearing about (trigger warning! ) SinglePower amps having +/-150V offsets and such... Does it just distort like crazy? Make noise? Does it clip? Anyone have measurement charts showing the effect?

Reviving an old thread, sorry-not-sorry... DIYAudio Store is running a preorder sale on Pass ACA kits, $317/pop with a dual monoblock option. Includes the works. The default build is 7Wpc (class A), the monoblocks are 20Wpc. I'm really tempted, but would appreciate advice from more knowledgable people here. I've been interested in Pass designs for a while, and this is my chance to get my feet wet reasonably cheaply. But if I don't like it, I'll end up with more amps I don't use taking up closet space (cough)... https://diyaudiostore.com/collections/frontpage/products/amp-camp-amp-kit

You mean the polarity is inverted on the drivers? That's nuts. Does it fail the wiring center/twisted test on https://www.audiocheck.net/soundtests_headphones.php? (Note the quote from the page on the subject: "That would be the last straw if your headphone's manufacturer made wrong connections, but it sometimes happens as reported with very cheap brands, or counterfeit replicas.")

It's easy. Let's stop pluralizing "headphones". Instead of saying "a pair of headphones", just say "headphone". As in, "I think the SR-009 is a slightly-bright headphone" and "Stax wants to make improvements with the SR-009S headphone". Same for the HD800 and HD800S.

If Stax currently sells every unit it has the capacity to manufacture, then it might not make sense to do any more marketing. Also, it's far from clear that Stax can scale up manufacturing if demand increases (and we definitely don't want it to respond to rising demand the other way, by raising prices).