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sorenb

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Everything posted by sorenb

  1. too much solder and heat might be the root cause
  2. 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)
  3. 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.
  4. 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
  5. How do you "stress testing"? Which resistor do you suspect being the culprit?
  6. Good work JimL - don't mind the comment from the janitor
  7. ...which is what I is using since trying it out ;o)
  8. 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.
  9. 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)
  10. nice drawing. assuming the fet Kevin pointed to: the RN60 goes between gate-source, and switch the text of input/output(like you mention in your edit) and you should be good to go.
  11. ....relevant for GRLV .... this is GRHV
  12. Do you have a variac? or a lab supply? The 20k getting toasted can be caused by the LT1021 not working and/or the cascoded current source not working.
  13. I'm looking for Xicon 273-series resistors: 273-240-RC 273-511K-RC 273-240K-RC 273-820K-RC 273-62K-RC 273-390K-RC 273-300K-RC 273-91K-RC 273-560K-RC 273-6.2K-RC 273-910K-RC 273-499K-RC 273-402K-RC 273-487K-RC 273-40.2-RC 273-287K-RC 273-82-RC Seems available from Mouser, but at 5000 minimum quantity. So, any hint's on where to buy in less quantity or some who might have those in stock and want to let go of, please let me know. Thanks.
  14. sorenb

    Guitar-Case

    no original Torres, but this
  15. ...well, you certainly got it plug'ed in number two ... how's the mafia DAC comming?
  16. sorenb

    Guitar-Case

    ...only asking because I got a Torres from Spain a while back - took me a while to get use to this furious lady - but I guess you already have had that experience ;o)
  17. sorenb

    Guitar-Case

    any prior experience with hand built guitars?
  18. Agree Agree so I guess we just disagree on the importance of consistency then. Since acoustical instruments have their fundamentals associated with some complex mix of harmonics I'd say it is important to treat all those with consistency. There might be more to it though, as I didn't really hear much of a difference in my Carbon as I did on my BH ... Some might also remember the difference stated between KGSShv IXYS/fet) and Sanyo(bjt) ... most prefer the latter for some reason ...
  19. the fet (cascoded or not) will deteriorate across the audio region where as most bjt CCS does not. If you just want high numbers, fets seems to be the answer. If one want linearity bjt seems to be a better option.
  20. ...and how does the numbers look like at, lets say 4kHz?
  21. probably because Joamat is not using his T2 at full blast, thus the 10m90 will see less than1kV
  22. how do you figur that from the pics in this thread?
  23. 60ohm -> RN60D or similar If you bought the mosfet Kevin mentioned you need to flip source/drain, as it is an n-channel Also it has exposed drain on the backside - ceramic isolation and washers that goes all the way through is needed
  24. Well, that is a good point - after reading you post, I did sim the T2 CSS against the 10m90/DN2540 depletion, and although the T2 comes out with a lower impedance in comparison, it maintains it well above 20kHz as oppose to the depletion cascode ...I assume it is not only a question about doing well at DC, but also how well across the entire range
  25. I guess Jung is aware of the limitations of his test setup. Anyways, you brought up the results to support your claim - which it really doesn't. Well, the Pimm web-site isn't up anymore, so it is kind of hard to discuss. never said you did. Agree. Don't consider it a downside as such. I guess it depends on what ever you consider "good", "best" or "ultimate" ... as far as I have experience the various CSS all deteriorates at some point, some earlier(lower frequency) than others. I guess that is caused by the output capacity of the device(s) used. In that area the fet's doesn't really excel.
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