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Hirsch2k

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Posts posted by Hirsch2k

  1. On 12/13/2019 at 11:18 PM, mwl168 said:

    The hum is present with the Carbon amp OFF?

    Positive. I suspect ground wiring issues outside of the amp but not sure yet.

    On 12/14/2019 at 7:41 PM, UFN said:

    A toroid transformer that's audibly humming is normally either badly made, overloaded or miswired. Does it hum without load as well? Also, you do know about shorted turns on toroids, right? https://www.bicronusa.com/resources/tech-guide-toroidal-power-transformers

    Will test the no-load hum as well as the efficiency and the power consumption. Maybe I have a short somewhere?

     I can sort out the shorted turn since nothing is connected to the top metal plate.

     

  2. I was a bit involved "in real life" in the last couple of weeks, so only now got back to the Carbon. Both channels are working but I have a nasty ground hum. It is present with the Carbon turned off and no input device so it´s not the transformer and probably not a loop. I suspect the crappy electric panel in my workshop. I will finish everything up and take the Carbon to my listening spot, I hope it is better there.

    Also, my torridial is very audibly humming. It has a metal plate on the top and a screw in the middle which I screwed into the metal baseplate of the housing at the bottom. I hope I didn´t short it with the two metal plates.

  3. So I have finished the boards and adjusted Current, Offset and Bias but Oh Boy is this a fiery beast. I have mounted 3mm thick aluminium under the SiCs and it is at 100 C after a minute. Just to make sure that I do not have a short somewhere, this is expected behaviour right?

    I thus don´t feel comfortable giving it a real test run without the proper heat sinking.

  4. On 8/12/2019 at 5:42 AM, hyperma said:

    Really hate lead-free......

    Ok that is understadable... The fat C2M, Caps and Heatsinks are probably not very enjoyable with lead-free. 

    I am collecting more components for my second mouser order and thinking about the on/off switch on the front. What do you think, is it critical or will transients and spikes be completely filtered in the PSU and one can workwith an ordinary push button switch?

    I thought about ordering the Amb epsilon 24 with transformer but that will set me back  ~40 dollars in shipping alone ?

  5. On 8/10/2019 at 6:37 PM, hyperma said:

    Replaced STTH512 by infineon IDH10S120 on PSU ..... Hmmmm.....no output voltage.

    I'v chosen this diode for making a "more carbon version KG Carbon", and the performance of IDH10s120 way better than STTH512 on paper but donno what happened.

    1.jpg.c2ea30a2e3c29a718eabbd983d0d3b4e.jpg

    I bought some SMT version of 2SK389 for better thermal coupling and way cheaper......hope it works.

    2.jpg

    Those solder joints need a bit more love ;)

  6. 18 hours ago, mwl168 said:

    A few things to consider.

    I don't use soft start with Carbon and my other solid state electrostatic amps but I use a thermistor in the primary winding of the PSU transformer to damp the inrush current at power on which provides somewhat of a soft start in my mind.

    Good point, the inrush current with those caps is probably substantial

    10 hours ago, kevin gilmore said:

    or a seperate switch and a rolex

    ?

    Ok, no delay it is. Thanks a lot!

  7. 20 hours ago, mwl168 said:

    The 600R and the CPC1117N on the back of the board are for the soft start. Don't populate these two parts if you don't need the soft start.

    Thanks, I guess I´ll try without, or it there a good reason to have soft start in the Carbon?

  8. On 6/12/2019 at 10:21 PM, Pars said:

    Thanks guys!

    And does anyone have an actual full schematic for these?

    Hi Pars,

    the pictures you posted look like the following:

    Full credit goes to Kevin of course

    kgsshvpssicfetsinglenewleftfatsws.zip

    kgsshvpssicfetsinglenewrightfatsws.zip

    I am building the PSU at the moment. Is the marked 600R for the soft start circuit?

    As I understand it, the soft start is mainly important for tube designs and there is no need to populate 600R as well as the CPC1117N in solid state designs?

     

    Thanks

    Screenshot_.jpg

  9. I am still in the process of sourcing for a KGSSHV Carbon build. Unfortunately I was send one wrong board and I can´t reach the seller any more ?

    So, if anyone has a KG SiC PSU PCB in Landscape with +15V -15V -400V I am happy for your PM. Additionally if anyone needs a +400V + Bias PSU, feel free to contact me.

    Edit: I got an 8 Dollar coupon at JLPCB so I thougth paying 8,50 dollar for 5 PCBs is probably worth it. 

    So I will give away 4 of the +-15V -400V PCBs for cost of shipping. I am located in Germany.

  10. Quote

    Perhaps a better moral question would be the horribly flawed EU lead study which resulted in ROHS. Arguably, this has contributed to millions of tons of failed consumer electronics clogging landfills. The US military still does not allow lead-free in its equipment, and I don't use the crap either.

    ?

    I am still in the process of sourcing for a KGSSHV Carbon build. Unfortunately I was send one wrong board and I can´t reach the seller any more ?

    So, if anyone has a KG SiC PSU PCB in Landscape with +15V -15V -400V I am happy for your PM. Additionally if anyone needs a +400V + Bias PSU, feel free to contact me.

    Edit: I got an 8 Dollar coupon at JLPCB so I thougth paying 8,50 dollar for 5 PCBs is probably worth it. 

    So I will give away 4 of the +-15V -400V PCBs for cost of shipping. I am located in Germany.

  11. Transformer and wires finally arrived. Unfortunately I have two +400V GND BIAS PCBs and no 15V -400V PCBs ?

    If anyone has a spare +15V -15V -400V "landscape" board I would be happy for a PM.

    Additionally I give away a +400V BIAS PCB.

    Thanks a lot!

    Edit: I got an 8 Dollar coupon at JLPCB so I thougth paying 8,50 dollar for 5 PCBs is probably worth it. 

    So I will give away 4 of the +-15V -400V PCBs for cost of shipping. I am located in Germany.

     

  12. 15 hours ago, s_r said:

    It's a TKD 4CP-601 (50kOhm).

    I heard it is a reasonably priced replacement for the ALPS. Does anyone who lives in Europe have a spare PCB for it laying around ?

    15 hours ago, gepardcv said:

    I'm not sure how much voltage that part of the circuit sees. In any case, I had better luck ordering a bunch of extra RN60D resistors and hand-matching them to <0.1% than relying on the manufacturers' matching process. YMMV, of course.

    Thanks, I will think about that. Ordered the toroidal from audiophoncics yesterday since it was quite a bit cheaper than toroidy but they have delivery times of about 4 weeks ?

  13. @gepardcv Thanks a lot!

    Yes, that would be the specs for the 450V supply, but as you said, 400V should be sufficient.

    Here is my Mouser BOM for the GR HV: https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=eefe01ae3c

    Replaced 1N4007 with N4007RLG and 3N254-E4/51 with KBP201G as they are EOL.

    Replaced MF1/2CC2002F with CMF6520K000BEBF at R7.

    Was wondering if I can replace RN60D3903FB14 with YR1B392KCC 392K .1% since it is only rated for 250V?

    Thanks a lot!

     

    Edit:

    13 hours ago, s_r said:

    Been busy listening to this, just replacing the output resistors was enough. I suppose lesson learned is that as soon as you stop looking for rookie mistakes is exactly when they happen.

    IMG_20190606_163205.thumb.jpg.be0ceea8945151310607bac6456f43a8.jpg

    Looks super clean, which potentiometer did you use?

  14. Hi all,

     

    I would love to start building the KGSSHV Carbon. I am not an complete beginner but certainly have never tried a project in this scope. After reading for a few days in the threads I have a few questions and hope I can ask them here.

     

    I have the boards at home already and would first order the transformer. I thought about audiohonics.fr, does anyone have experiences with their custom transformers?

    I would use the GR HV supply with the LV regulator on board. On the first page I found:

    Quote
    • 2× 360VAC @350mA
    • 16-0-16VCT (anywhere from 15-0-15VCT to 18-0-18VCT should work fine) @500-700mA (the higher amperage is way overkill)

    Would this this be the transformer to use with aforementioned supply?

    Futhermore, the BOM on the first page was updated 2015 I think. Is it still usable or are there newer versions?

    Additionaly I think I will need at least one Stax socket, does anyone know where to source them?

     

    Thanks a lot in advance!

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