headinclouds Posted January 27, 2015 Report Posted January 27, 2015 (edited) Parts and layout looks a lot like a KGST (KGSSHV front end) with SiC replacing the tubes..... Great looking development gentlemen, keeping the hobby electric. I know it was comically named in the other KGSShv thread but should it be KGSC, Carbon , or KGSiC (!) Well perhaps not KG sic. Edited January 27, 2015 by headinclouds
DHTGUY Posted January 30, 2015 Report Posted January 30, 2015 <a href="http://imgur.com/vRrgpVj"><imgsrc="http://i.imgur.com/vRrgpVj.png?1" title="source: imgur.com" /></a> Need some help - shoud this be left open or should there be a link ? I am building the 450v version, nearly finished. What does 100ms mean on the board?
DHTGUY Posted January 30, 2015 Report Posted January 30, 2015 sorry - I think this should be the correct image
insanity Posted January 30, 2015 Report Posted January 30, 2015 I guess it should be 100mA, This is the fuse you need, if you build the 500V version. As you are building the 450V version, you don't need to populate this part.
spritzer Posted January 30, 2015 Report Posted January 30, 2015 Yup, that's why it has 500V in brackets next to it.
DHTGUY Posted February 7, 2015 Report Posted February 7, 2015 Thanks. PSU is now finished, 1st amp board getting along nicely. Amp board version 0.63 has the 18v zeners -D5 and D6 below - marked with an M - I assume that they are not populated for the C4686A, just for the 05n100m? There is nothing in the schematic suggesting they are left out for the C4686A On the PCB: Top right, marked B, between the 1K and 1M is a link when using the C4686A - left open using the 01N100D Mosfet? Thanks
spritzer Posted February 7, 2015 Report Posted February 7, 2015 Anything marked B is for the BJT's and anything M is for the mosfets. The mosfets should never be used really (outside the CCS), the performance is pretty much terrible.
llamallama Posted February 11, 2015 Report Posted February 11, 2015 I have a grounding question relating to the the XLR ground (Pin 1). Earlier in the forum it’s mentioned: “… XLR pin 1 should not be connected [to star ground]. it should be connected to the chassis through the shortest path possible.” Similarly, in johnwmclean wiring diagram, each XLR Pin1 is connected to the chassis by itself. What I wanted to clarify: Can the two Pin 1 wires be soldered to the same spot on the chassis? In the diagram they are connected at two different spots What’s the reason for not connecting Pin1 to star ground? I.e. All ground wires into one point
johnwmclean Posted February 11, 2015 Report Posted February 11, 2015 If XLR pin 1 is the shield, the chassis should act as an extension of that shield, the best way to do this is to connect pin 1 via the shortest wire at the entry point of the chassis. This is all explained in rane notes.
mwl168 Posted February 13, 2015 Report Posted February 13, 2015 Need some advice here. Can the KGBH mini PSU that many have used to power the KGST be used to power the KGSSHV Mafia version? Would it compromise the performance of the KGSSHV? Your thoughts and advice are much appreciated.
nopants Posted February 13, 2015 Report Posted February 13, 2015 I was able to use the KGST mini PSU @ 350V with kgsshv amplifier boards, with no modifications whatsoever. The one thing I noticed was that the DC offset tended to settle at -15.x V You can probably zero it out with a single resistor change
spritzer Posted February 13, 2015 Report Posted February 13, 2015 I've built a few dozen HV's like that so yeah, no a problem. Just be very careful with the mafia boards, they aren't the most forgiving PCB's we've ever designed.
mwl168 Posted February 13, 2015 Report Posted February 13, 2015 Thanks nopants and Birgir for your help. Hi Birgir: Can you elaborate what you mean by the Mafia version not being a forgiving PCB? Are you referring to the potential arcing problem resulting from less than careful soldering job and flux residual? Also, for the Mafia board, can I replace the 2SA1968 in the current source with ixtp01n100d? I know this is possible with other version of KGSSHV boards but involve chaning a few resistors as well. Best!
guzziguy Posted February 13, 2015 Report Posted February 13, 2015 It means that if you ever break the code of silence, Birgir will find you and make drink red vodka until you pass out. You'll awaken in a women's lavatory.
spritzer Posted February 14, 2015 Report Posted February 14, 2015 Well that plus the soldering technique has to be perfect due to the compact size of the board. All leads neatly trimmed and the board properly cleaned of all flux residue. Also the top center hole, if that is used for mounting (which I do) it has to be properly insulated. The mafia board is 2SA1968 only and any attempts to try and make it work for the IXYS parts would probably end badly. There is another slightly larger HV board design which can take both parts. It's never been tried but it should be problem free.
mwl168 Posted February 14, 2015 Report Posted February 14, 2015 Well that plus the soldering technique has to be perfect due to the compact size of the board. All leads neatly trimmed and the board properly cleaned of all flux residue. Also the top center hole, if that is used for mounting (which I do) it has to be properly insulated. The mafia board is 2SA1968 only and any attempts to try and make it work for the IXYS parts would probably end badly. There is another slightly larger HV board design which can take both parts. It's never been tried but it should be problem free. Many thanks Birgir. I'll have to give it some serious thoughts which amp board to use. I have spent many nights now reading this thread to learn as much as I can to prepare for a build. I am looking at the Mafia board because I like to build a off-board heatsink version to allow some flexibility in tweaking output current and voltage swing. The Mafia version is the only off-board version listed on Kevin's site and uses current parts except for the 2SA1968. I am at page 137 of the thread now and have read about many firework and smoke shows. I may very well change my mind by the time I finish reading )
llamallama Posted February 14, 2015 Report Posted February 14, 2015 Two questions regarding PCB grounding and power PCB connection: Should I use nylon or metal spacers to secure the PCBs? Does it make a difference if I'm already running wires to a star ground point? On the power PCB (rev 0.6) there is the connector "CT AC30 AC30". Where do the CT and AC30 connect to? The transformer has secondary 16V-0-16V wires
johnwmclean Posted February 14, 2015 Report Posted February 14, 2015 (edited) You can use nylon or steel stand-offs, if in doubt it’s safest to stick with nylon. The PCB holes for the stand-offs are not connected to the circuit ground, so this won’t make any difference to your star grounding point. 16V-------> AC30 0----------> CT 16V-------> AC30 Edited February 14, 2015 by johnwmclean
spritzer Posted February 14, 2015 Report Posted February 14, 2015 Many thanks Birgir. I'll have to give it some serious thoughts which amp board to use. I have spent many nights now reading this thread to learn as much as I can to prepare for a build. I am looking at the Mafia board because I like to build a off-board heatsink version to allow some flexibility in tweaking output current and voltage swing. The Mafia version is the only off-board version listed on Kevin's site and uses current parts except for the 2SA1968. I am at page 137 of the thread now and have read about many firework and smoke shows. I may very well change my mind by the time I finish reading ) The fireworks are mostly a thing of the past as we've improved the circuit boards over the years. This is still a very high voltage amplifier so if the soldering isn't perfect and the circuit boards clean of any flux, it can blow up. I'll send the larger offboard PCB files to Kevin and if he's happy with them, he'll add them to the library.
mwl168 Posted February 14, 2015 Report Posted February 14, 2015 I'll send the larger offboard PCB files to Kevin and if he's happy with them, he'll add them to the library. That would be great. Much appreciated. I have seen an offboard version in Kevin's earlier post (#3608), it's named kgsshvampv16mini which also allow the option to use ixtp01n100d for CCS. Is this the board you are referring to? It still looks small with very little space between parts. I do remember seeing photos of a larger but similar boards with less parts in earlier posts but did not see the Gerber file for it in Kevin's library. For the Mafia boards, am I correct to assume running them at lower voltage (< 400V) would reduce the risk? Thanks!
kevin gilmore Posted February 14, 2015 Author Report Posted February 14, 2015 I posted kgsshvampv15mini and kgssmvampv16mini
mwl168 Posted February 14, 2015 Report Posted February 14, 2015 I posted kgsshvampv15mini and kgssmvampv16mini Many thanks Kevin and Birgir. What's the difference between the two versions? I tried compare the v15 and v16 boards using an online Girbir file viewer, it seems the only difference between the two is the 3.3K resistor (R43) being physically relocated to a different spot on the PCB. Did I miss something? I apologize if this was already mentioned in the thread. I just got done reading all the posts and taking notes but don't recall coming across this information.
kevin gilmore Posted February 14, 2015 Author Report Posted February 14, 2015 i'm pretty sure the only difference is the position of the center mounting hole
mwl168 Posted February 15, 2015 Report Posted February 15, 2015 i'm pretty sure the only difference is the position of the center mounting hole Thanks Kevin. Yes, now that you pointed it out, I did notice that the center mounting hole was relocated to the center location on the kgssmvampv16mini PCB. There are actually a few parts that were relocated to make this possible. The silkscreen identify this board as Rev. 0.91.
spritzer Posted February 15, 2015 Report Posted February 15, 2015 The REV numbers are pretty much meaningless. The true rev numbers are the file names but they also just tell a part of the story.
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