sorenb

is the OpAmp postive input grounded? - as I recall I shorted the trimmer

https://www.youtube.com/watch?v=jGdiE-Ssfx4

did you ever listen to a Stax SRD7 ? that will probably provide you a similar enjoyment

you can probably always do better. Building a Carbon using a KGBH PSU will still give you a good Carbon.

Yes People have different opinion in this regard. No problem in replacing with a GR later. You might consider using the BH PSU rather - it's simpler and a lot cheaper in comparison to the GRHV.

Sorry, I haven't noticed that you have mentioned that the "recipe" didn't work ... Anyways, I had a look at my notes from back then, and it seems I forgot to add a few things I did in addition to get it working; I've edit the post accordingly.

I believe you need to reconsider your approach a bit. consider having the FB local on the driver rather - makes things less complicated make the servo working at the driver (Kevin mentioned this a few posts back) - having the driver in balance with the servo working is key check the opto's on the output boards whether the emitters are pulled towards ground when the current in the bridge is rising (from your description it sounds like one or both isn't working).

from your posts I am not sure exactly what you are doing, or how you have connected the various parts. do you have ~zero out of the driver? and -15V present at the output board?

lower the current or the tail resistor ...

not sure what you are up to, as far as I remember the silk value for the tail resistor wasn't far off. 10mA or 8mA isn't day or night anyways.

you probably need to lower the tail resistor for the driver output ...or dial down the current ....anyways, you need 0 offset at output (Kevin recommends ~8mA)

remove the house from headband assembly, be careful not to bend the plastic as it is kind of brittle. there are four small Philips-screws, located in each corner beneath the pad - you don't have to remove the pad, just push/lift it a bit in the corners and loosen up the four screws. Afterwards you can remove the pad + baffle inlucing driver from the housing.

you might add to the beauty, by slicing the lemmon like this:

Don't see why it should be any different, and not sure your listening experience can be explained by adding the diode as you suggest.

how? Isn't the plate always positive in rgrds to the screen. Have you tried to increase the resistor value x2 to see if you got the same change in sound?

DC Yes: Gate - Drain - Source Can't remember ... look at PCB and you'll figure it out; the black (negative) probe goes to the tail of the CCS The @MLA suggestion is a good advice BTW

Original post

seems like a badly done write-up of what Spritzer has stated about the Carbon for the past two years or so, blended with the usual Katz-magic: a touch of EQ ... wonder if Katz is aware of what ever is being written in his corner ...

Thanks. Digital printing from ModuShop (Text and Graphics in 600dpi)

too much solder and heat might be the root cause

a pair of glasses and some patience, might be a better choice ...in rgrds to the terminal block, screw'ing too hard will never give you that kind of enjoyment (although @swt61 might object)

Might be difficult for some, anyways: Original KGSShv PSU was one board, having everything: HV +/-, LV +/- and BIAS supply (you can find a couple of version in the "I'm on a roll KGSShv" thread. Kevin did a similar one for the Golden Ref. edition, but due to capacitor size it was split into a LEFT and RIGHT and is called "split" as the full version does require a great deal of real estate. GR RIGHT is HV+ and BIAS GR LEFT is HV- and LV +/- There are two different "split" version: a "FAT", which is squarish in size, and a "SKINNY" which is rectangular in size (3" x some length). Later Kevin added the "Switch", an option for keeping the regulated high voltage low for a while (mainly for use with Tube amps), those has added "SW", or "SWS" to the name. If you get "old" boards and want the "switch" option, it can be added quite easily. Some prefer the Golden Reference low voltage to the standard 78xx one used in the FAT or SKINNY boards. Thus they use GRLV either a full board or a split version. As for amp boards the v.6 or 6g is the latest one. the latter has a full ground plane on top, which requires mounting components a bit raised. Most components can be found at Mouser except for lt1021 (Digi-key) and LSK389 or 2x LSK170 (matched Idss) can be had either directly from Linear or Trendsetter. mwl168 made a Mouser BOM you can find in the Carbon building thread. If you haven't found boards, I can probably help you out.

I never had troubles with the HV900's, and haven't had any that blew, so the following is based on what I've found useful troubleshooting/checking the regular Golden Reference HV. Often it can be helpful to work at lower voltages when trouble shooting. Paralleling the high resistor (is it 2x 450kohm in the HV900?) in the probe string to get the circuit in action at a lower output DC. If regulation doesn't work for some reason and things go bad it usually isn't really bad. Parallel the R8(2x 450k) with one ~100k (one across both) will provide some ~100VDC. Initial check: The CCS's Use a lab supply at some ~15-20V, through a DMM at mA: put the (+) at the drain (middle leg) of the 10m90, and the (-) at the bottom of the CSS where R2(100) and R1(4k5) meets ...you should get ~2mA ....if you see much more, try replace the DN2540. Do the same at the other CSS: (+) to drain (middle leg) at the 10m90, and (-) at the bottom (pin 6 at the voltage reference) ...you should get ~1.3mA ...if not the 10m90 is probably damaged. Check the current limiting CSS you added (your drawing) the same way (Kevin suggested 50mA for this) When powering up the supply, hold the variac when you reach some ~40-50VDC output, and check: the pin6 of lt1021 against "ground" (pin4) ....you should see 10V ...if not, the lt1021 has probably gone south Before raising the VARIAC further: Attach a DMM across the 2k at the bottom of the cascoded CSS ... you should see ~0V (when at ~50VDC output) and only before regulation kicks in, the voltage jumps to some ~4V; it happens just before you reach the desired output voltage Attach a DMM across the 3k at the source leg of the output CSS (right most leg) ...should be some steady ~4V

How do you "stress testing"? Which resistor do you suspect being the culprit?