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Helium

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Posts posted by Helium

  1. The ultimate DIY? A Stax SRM-T2!

    in Do It Yourself

    Posted · Edited by Helium

    Thanks, I've already start thinking angle grinder FTW to butcher my nice completed T2 PCB.

     

     

    angle-grinder-aeg-wsa-1780s-dirty-3d-model-low-poly-obj-mtl-fbx-stl-blend-dae.jpg

    Just kidding, I would do it on CNC if that happened. Kevin, so how do I wire, simply each PS board to each channel (=half T2 board)? I'm afraid I will encounter heavy ground loops.

  7. Technical Assistance/Advice Thread

    in Do It Yourself

    Posted

    Just wanted to share one of my most favorite acquisitions among hundreds of manual and electric tools.

    Heinrich deep throat is capable to punch holes in the center of 400mm panel (hello large enclosures like Modushop Slimline).

    No burrs, very clean holes, any hole is perfectly perpendicular to surface, and waaayy more accurately positioned than made by drill bit as you can never avoid drill bit wandering. Precision is close to CNC milling.

    I also use smaller punch Roper Whitney XX with smaller throat.

    IMG_20180826_183811_1.jpg

    • Like 2

  9. KGSSHV Carbon Build Thread

    in Do It Yourself

    Posted · Edited by Helium
    typo

    1 hour ago, AngelWing said:

    2. 2 Golden reference HV and LV Boards

    You will need 1 x HV board with bias section and 1 x HV with +/- 15VDC  low voltage section. If you populate +/- 15VDC low voltage section on one of HV boards, you don't need separate GRLV board. If you go with separate GRLV board (more luxury solution), you can use either single GRLV board producing both positive and negative 15VDC, or split boards, each producing +15VDC and -15VDC.

    Also, if you go with separate GRLV board, you can do with 2 x HV boards with bias section (saves money if you order boards at PCB house). You need to populate bias section on one them only.

    1 hour ago, AngelWing said:

    3. 2 KGSSHV Carbon boards.

    Correct.

    1 hour ago, AngelWing said:

    1. It looks like KGSSHV is a balanced input amp. What will it require so that I can run it unbalanced?

    Nothing required. It will accept unbalanced input as well, sound volume will be less.

    1 hour ago, AngelWing said:

    2. This image here: https://www.head-case.org/forums/uploads/monthly_2015_12/IMG_1617.JPG.8b2de600707a2057508ca7688eae8dd6.JPG has what it seems like 7815 linear regulator and no GRLV so is GRLV really required? Ignore the shoddy wiring(will not follow it).

    7815 is noisier than GRLV. GRLV presumably produces cleaner +/-15VDC. Piece of advise: go with amb's Sigma22 for low voltage. Much cheaper than GRLV to buid.

    1 hour ago, AngelWing said:

    3. This seems to be using a GRLVDual of some sort:https://www.head-case.org/forums/uploads/monthly_2016_04/571e4255cfd2c_P_20160425_2358271.jpg.ee96baecdcf1a5953c86c401e05d2bdf.jpg is it as good as using 2 GRLV?

    That is single +/- GRLV. You can go with split positive and negative GRLVs, as mentioned above.

    1 hour ago, AngelWing said:

    4. Can I keep my ODAC amp in same enclosure maybe shielded ? Is ODAC good pairing?

    Not recommended IMHO. What if you need to upgrade your DAC in the future?

    1 hour ago, AngelWing said:

    5. What are Opto servos?

    Not needed for Carbon (=no tubes). Leave unpopulated.

    1 hour ago, AngelWing said:

    6. Lastly a loaded question. What will be the best way to make GRLV and GRHV so as to use least amount of components and not sacrifice lots of quality? It seems there are various designs of the PSU and I would like to save some money if possible.

    Use GRHV onboard low voltage section, if you want to cut costs. Or use Sigma22 instead of GRLV, and order 2 x HV bias boards instead of 1 x HVbias + 1 x HV w/low voltage.

    Really not many options to save money. Most expensive parts are main filter caps (40 USD/ea, and you need 4 of them), balanced potentiometer of your choice, transformer(s) and casework. None can be dropped out.

  11. The Multi Amp aka Dynalo Mk2

    in Do It Yourself

    Posted · Edited by Helium

    For me it doesn't look like IC (THAT) related issue. Does the hiss increase as he turns the volume up? If yes, then it's likely to be some grounding issue. Otherwise it may be oscillation (though I don't know if dynalo is prone to oscillation). Let him try to temporarily fasten hinged ferrite cores on either headphone cable or input cables or both and see if it makes difference.

  14. The ultimate DIY? A Stax SRM-T2!

    in Do It Yourself

    Posted

    There is plenty of 1N4007 diodes. P/N E3/54 you provided is just a package type. Search another one, this generic diode cannot be out of stock for sure.

    https://www2.mouser.com/ProductDetail/Vishay-Semiconductors/1N4007-E3-54?qs=sGAEpiMZZMtbRapU8LlZD0HbIjlpuZ44RKYLoMCkjXw%3d

    Same for 0.1uF 50V. There are tons of alternatives. If you would like to stick to Kemet, try searching Kemet 315, 320 series as well. 100V is OK also. Just mind lead spacing. 

  15. The ultimate DIY? A Stax SRM-T2!

    in Do It Yourself

    Posted

    8 hours ago, swampsong said:

    Yes i would second that, i read through this thread twice and having those early pictures would be great.

    My new boards should be here in a week or so and i can finally begin... I probably could have started with the old ones but why not spend more money... lol

    -James

     

    Here are pics

    A83741D6-2D8C-482E-8AD7-040F92E41BC3.jpeg

    What's wrong with these boards? By new boards do you mean published a week ago?

  20. Part Sourcing Assistance/Advice Thread

    in Do It Yourself

    Posted

    Stupid question. Now searching for tube socket for KGST, GG and BH.

    Lot's of options. Aside from the material they are made of (bakelite, ceramic, teflon), I'm stuck at terminal type.

    https://www.ebay.com/itm/301444050005

    https://www.ebay.com/itm/301838302161

    Are these gold pins really intended to be soldered into PCB? Will solder adhere to gold plated surface?

    Or better look for sockets with leaf terminals?

  23. KGSSHV Carbon Build Thread

    in Do It Yourself

    Posted

    On 29.06.2016 at 5:33 PM, spritzer said:

    But you just install a switch which grounds the - input for SE.  Hell, just make two XLR plugs with pins 1 and 3 tied internally. 

    Can anyone confirm please that output power is the same in case of using SE inputs? Any drawbacks?

  24. KG Balanced Dynahi build discussion thread

    in Do It Yourself

    Posted

    6 hours ago, penmarker said:

    I turned the lower left/right trimmers all the way down again and turned it back on, and the offset was only 1mV. Then I tried biasing them back up to 270mV and the bias stayed low. I switched it off, and then after a few minutes switched it on again and the offset shot back up to around 3-4V and drifted down to several hundred mV. I repeated this with min 140mV bias, switching off/on, working all the way up to 200mV where the offset stayed low without displaying the erratic behaviour.

    Why are you biasing to 270mV only? With off-board heatsink, dynahi must be biased to 750mV (and even more if you like and as long as temperature is OK). With onboard heatsink, half of that (375mV) or more as long as temperature is OK.

  25. 2018 PCB Group Buy with TKD pots

    in Do It Yourself

    Posted · Edited by Helium

    On 14.03.2018 at 12:42 AM, steefdebruijn said:

    If they all are mentioned in the first post, I think we miss the board files for the "Unbal/Bal Tube w PSU". The PSU is there (grhv100v) but the Unbal/Bal board itself seems not.

    But did anyone confirm that they are good for order (no errors ets.)?

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