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sorenb

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Posts posted by sorenb

  1. KGSSHV Carbon Build Thread

    in Do It Yourself

    Posted

    9 hours ago, Pokemonn said:

    Can I use traditional 7815/7915 3-pin regulator IC for Carbon's +15/-15 mainboards power supply to save money?

    Yes

    9 hours ago, Pokemonn said:

    does 7815/7915 degrade SQ compare to KGGR boards?

    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.

    • Like 1

  3. Kevin Gilmore Circlotron Output, Large Enclosure [high-slew] Electrostatic Amplifier

    in Do It Yourself

    Posted

    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).

     

  8. The Headcase Stax thread

    in Headphones

    Posted

    42 minutes ago, gepardcv said:

    I started getting a rattle in the right channel of an SR-207. It's only audible in lower frequencies, like the bass shaker test on Audio Check. When the same thing happened to my HD600, I disassembled it and removed a hair from the driver, which fixed the problem. A little searching the threads here hasn't turned up disassembly instructions for Lambda-type headphones. Repair suggestions, please?

    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.

    • Thanks 1

  11. grounded grid

    in Do It Yourself

    Posted

    3 hours ago, Laowei said:

    Adding the diode stops AC thru the screens (stabilizing the potential)  and leaves it to pass only through the plates. 

    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?

  12. KGSSHV Carbon Build Thread

    in Do It Yourself

    Posted

    51 minutes ago, tomoki said:

    ... is that I should use a AC source with voltage in between 15-20VAC

    DC

    51 minutes ago, tomoki said:

    ...  the middle leg of the 10m90s 

    Yes: Gate - Drain - Source

    51 minutes ago, tomoki said:

    ...  and solder pad in between R2 and R1 (also the pin 6, for the 2nd 10m90s).  

    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

     

  13. KGSSHV Carbon Build Thread

    in Do It Yourself

    Posted · Edited by sorenb

    Quote

    Often it can be helpful to work at lower voltages when trouble shooting. Paralleling the high resistor 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:

    1. The CCS's
      Use a lab supply at some or battery ~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. 
       

    When powering up the supply, hold the variac when you reach some ~40-50VDC output, and check: 

    1. the pin6 of lt1021 against "ground" (pin4) ....you should see 10V ...if not, the lt1021 has probably gone south
      Before raising the VARIAC further:
    2. 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
    3. Attach a DMM across the 3k at the source leg of the output CSS (right most leg) ...should be some steady ~4V

    Original post

    • Like 1

  14. Bob Katz on the KGSS Carbon and Dynalo Mk II

    in Headphone Amplification

    Posted

     

    4 hours ago, mypasswordis said:

    Sadly, the article is littered with as much fake news as all the previous ones I read, and I only skimmed through like half of each. Where are all the real reviewers?

    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 ...

     

  15. kgst

    in Do It Yourself

    Posted

    1 hour ago, Pars said:

    Late post/comment. Once again, really digging the casework. I hadn't asked in the carbon thread (IIRC), but how is the lettering done. It doesn't look like engraved/infilled?

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

  18. KGSSHV Carbon Build Thread

    in Do It Yourself

    Posted

    2 hours ago, Whitigir said:

    It takes some bones to get used to, I guess I should start buying some chain mails and motorcycle helmet

    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)

    • Like 1

  19. Interested in building a kgsshv don't know where to start.

    in Do It Yourself

    Posted

    On 7/15/2017 at 7:37 PM, boinger said:

    For example I see Kgsshvcarbon v1-6 and along eith them left / right / servo / ground.  

    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.
     

     

  20. Kevin Gilmore Circlotron Output, Large Enclosure [high-slew] Electrostatic Amplifier

    in Do It Yourself

    Posted

    9 hours ago, Tinkerer said:

    Just loaded it with proper resistance the same way you did way back at the beginning of the thread. Looked like one of the CMF60's (the 100R next to the 1N4007 diode) had lost a chunk of insulation on the underside only and I didn't see it. Either that or the new SMD STN9360's were garbage. It's the only PSU that needed new ones since I had enough salvaged of the others. Also possibly the socket for the voltage reference as that seemed to have melted and soldered itself to the chip. Hard to tell what was what gave out and what got damaged afterward, especially when one of the resistors burned and covered a good chunk of things with soot.

     

    All the other three ran fine. This one got up to regulated voltage, lasted about ten seconds, then popped. All the solder joints were good and the board itself was squeaky clean before it got powered up.

    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:

    1. 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: 

    1. the pin6 of lt1021 against "ground" (pin4) ....you should see 10V ...if not, the lt1021 has probably gone south
      Before raising the VARIAC further:
    2. 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
    3. Attach a DMM across the 3k at the source leg of the output CSS (right most leg) ...should be some steady ~4V

     

    • Like 7

  24. KGSSHV Carbon Build Thread

    in Do It Yourself

    Posted

    7 hours ago, Pars said:

    Why would I want the one for 2-pole fuseholder (DD11.0124.1110) if I am only fusing the hot (line)?

    I guess you don't. I was anticipating you wanted to fuse both Live and Neutral using the two fuse container - I see you want the second fuse as a backup rather.

  25. KGSSHV Carbon Build Thread

    in Do It Yourself

    Posted

    9 minutes ago, Pars said:

    Soren or anyone,

    So with one of these, and a dual primary transformer (0-110-110), you can switch voltage from US 115 to Intl. 220 with just the correct fuse drawer?

    For US use, I have a 693-4301.1014.03 fuse drawer in my cart as well (I think this one has the voltage selector for 110/220). For the US, I believe we only fuse the hot and not the neutral. Does this look like what I want?

    Thanks!

    No, and I also only fuse the hot. For 2-pole fuse you need this rather.
    For switching between 120/240 I use "my voltage selector"  ...  ;o)

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