gepardcv

On that link, click through to the CMF60 data sheet (http://www.vishay.com/doc?31018), which shows the maximum working voltage: 500V. I use RN60D for everything that calls for conventional resistors (i.e., not the high-power ones or for exotic builds like the T2).

I tried a modded HD800 at the last Bay Area meet, and didn't care for it. It did reduce treble harshness considerably, but at the expense of a significantly reduced bass. Maybe it just wasn't a great mod, not sure. The 800S is intriguing.

Your custom order form doesn't have a shaft diameter parameter, but other than that, that looks excellent! (Sending you a PM shortly.)

I'm looking for a volume knob that would work with an RK50 on my Carbon build, with the pot mounted on the front of the case. A 48 or 50mm diameter knob, 25 or 30mm deep with an 8mm shaft would work well, in plain black anodized aluminum with an indicator dimple. Does anyone have a good source (or have some available)?

Paid. Thanks, Soren!

It says carbon v5 on the spreadsheet but v6 in the thread here. Which is it?

Received my boards yesterday. Thanks! I don't see any obvious defects, so I guess I didn't get the tainted board. Please let me know if I need to reimburse you for any additional shipping costs.

I've had good luck with iTEAD's prototyping service. Others have reported good results with Seeed Studio. PCBs from these manufacturers are not quite as nice as the PCBNet ones, but work fine for me on other builds. Just send them or upload Gerber zip files from KG's site (http://gilmore.chem.northwestern.edu/boards/). It's relatively inexpensive.

FWIW, this OP27 works on my Dynalo build: http://www.mouser.com/ProductDetail/Analog-Devices/OP27GPZ/?qs=sGAEpiMZZMvtNjJQt4UgLalm6EXZly/yGRc8RxRIZuM=

Not 10k for stat amps, though, right?

I use a DY294 to check zeners (and other semiconductor parts the tester supports) before soldering them in. For fuses, I use a 3.15A slow-blow on my KGST and KGSSHV builds (for North America 115V). Could probably go down to under 3A, but I figure the onrush current is likely to blow the fuses annoyingly often. Some people on the KGSSHV thread have recommended thermistors and lower-current fuses, but things seem to be fine with my builds as is.

That heatsink looks a lot like the Aavid 531302B02500G (Mouser part 532-531302B25).

Thanks, Kevin. This is kinda sick and tempting at the same time. I'm not good at estimating heatsink size for the power dissipation requirements, but could the balanced version be built in one large (4U or 5U) chassis, assuming heatsinks with 50-75mm fins (I'm sure Fischer sells something useable), or would it require monoblocks?

Trying to understand the inputs and outputs: does each channel need two uberamp boards?

I have the following transformer from Toroidy, based on prior discussions: 150VA primary: 2x115V secondary: - 2x 335 VAC at 200mA - 16-0-16 VCT at 500mA Not enough for a Carbon at 20mA, you think?

Sent. Thanks!

I tried and reversed the mod on my new 007A. Used the mod for a week before giving up. It made the headphone fart intolerably, just from moving my head, which ruined the whole listening experience. FWIW, I really the stock sound on the latest 007A anyway.

About the B+/B- output: the zener strings as specified do produce +/-400V rails. If you want +/-350, change both zener strings to add up to 350. I suggest you actually use a zener string adding up to 340 or slightly less, since zeners tend to run at a higher voltage when warmed up, i.e., if you make them add up to 350, you'll probably end up with 360 or more. I also hand-match zeners so they really do add up to the rated voltage, since they're normally within 5% tolerance, but's probably overkill. Not sure about the -20V line.

Yeah, there was a startling amount of hate for Stax and the special KGSS at Tyll's Big Sound. Different strokes, I suppose. I did notice that Kevin occasionally posts a tidbit of information on HF that I didn't notice here on HC. (Hats off for having the patience.)

There's certainly more to a KGSSHV than to the cmoy, but as long as you can make clean solder joints, clean flux off finished boards, take basic precautions for working with high voltage, and understand the wiring (which people here on HC are really helpful with), you can build it. If you like tubes, the KGST is a bit simpler to make, and I think sounds quite nice. Electronic parts are inexpensive, it's the casework that kills you (but I like mine really nice). Of course you have to discount labor costs to 0, but DIY is fun.

I usually unplug my headphones when powering on the KGST, because I measured the offset at +/-350V (the DC rails, essentially) for the 1-2 seconds it takes for the heaters to kick in and the tubes to start working. It's probably unnecessary to do that, but I don't plan to conduct a controlled experiment to find out.

It would at least be interesting to get a new 007A to @Tyll Hertsens for measurements. The graphs of the Mk1 and Mk2 are quite different and I'm pretty sure the new one is much closer to the Mk1 than to the Mk2. Not sure I can stand to part with mine long enough to make the trip, though.

If we go with Jim's PSU, should the GB also include a bias power board?

In for 1 amp board and 1 of Jim's PSU.

I am in for a couple of boards if you guys do a run.