Jump to content

Ariamella

Returning Member
  • Posts

    46
  • Joined

  • Last visited

Posts posted by Ariamella

  1. On 7/4/2018 at 10:22 PM, Pars said:

    Documentation? heh

    Which amp? This is a confusing thread because there are at least 3 amps discussed here, maybe more (Kevin or others, correct me if I am wrong):

    1. CFA2 (CFP) - current feedback amp. Each board does 1 channel SE, so 2 for stereo SE, 4 for stereo balanced. Kevin later did a mod to this adding current mirrors feeding the servo. People who had built the original noticed that the servo was audible as to quality of opamp. The schematic in Kevin's archive is the older version.
    2. CFA3 - current feedback amp for balanced. Not sure if anyone ran boards for this one. Basically a pair of CFA2 amps and ubal-bal board on one pcb. Schematic does not show the current mirror mod as in 1 above
    3. uberamp - seems to be a power amp; I've never quite figured this one out :)

    Here are the schematics for the CFA2 (current mirror version), and the CFA3. I also attached my BOM for a CFA2. Amp quantity shown is for stereo SE. If going balanced, double it. It should reflect the later current mirror version. You'll also need some GRLVs or other power supplies, etc.

    cfa2cmirror.pdf

    cfa3production.PDF

    CFP2_BOM_update2018march.xlsx

    EDIT: I also ran across another schematic on Kevin's site which I hadn't seen before: currentsourceamp2.PDF. This seems very similar to the cfa2cmirror schematic, but is described as a transconductance amp.

    Your BOM has 1k specified but I can't find that anywhere in the schematic. Is the 1k necessary?

    Edit: here's the mouser BoMs for the CFA2 and GRLV I created:

    CFA2

    GRLV (30v)

    I think they're both correct but if there are any mistakes please let me know...

    • Like 1
  2. 3 minutes ago, PretentiousFood said:

    Mouser's finest!

    I'm not sure about the hfe grade as I can't find the receipt. The package says FCE. FCE is not an hfe grade, but E is the highest and sounds like something I would buy.

    Shoot me a PM if you'd like.

    image.png

    This is the hFE chart on the datasheet of the KSA992 (and should be identical to the grading system on the KSC1845).

    image.png.e1e7cc6a0fab90a1886905f41590ff1d.png

    @kevin gilmore, do the 2SA1145/2SC2705 on the ss dynahi boards I have need to be matched?

  3. I was wondering about the transistors used on one of the older versions of the susy dynahi boards being obsolete, and after searching online I think I've found replacements for all of them that seem to be drop in. I'm just wondering if these are fine or if I need to find something else or try and source NOS or used parts.

    • 2SA1358/2SC3421: KSA1220AYS/KSC2690AYS
    • 2SA1145/2SC2705: MMBT5551/MMBT5401LT1G
    • 2SA1349/2SC3381: matched pairs of KSA992/KSC1845
    • Matched pairs of 2SJ74/2SK170: matched pairs of LSJ689/LSK489 or LSK74/LSJ170 (both seem to be rare/expensive!!)
  4. 5 hours ago, gepardcv said:

    Yeah, those are the numbers from the Gerbers I used for my boards. SMT and MJE output sand. No idea about sizes for any older revisions, but if you get me the Gerber for it, I could try to figure it out for you.

    Ok, thank you anyways! The older revisions are probably close enough that the case I plan to use can fit them all...

  5. 2 hours ago, gepardcv said:

    @Ariamella: I pulled the following numbers from the Gerbers, and I think they match the produced boards:

    - ssdynahibalsmtm.zip: 215.9×115.3mm

    - goldenreference6.zip: 93.3×109.9mm

    Thank you very much! Is that the newest SMT version of the dynahi? Sorry to be a bother but do you happen to know what the dimensions are for the V1 Susy Dynahi boards are?

  6. 49 minutes ago, MASantos said:

    I remember Salas saying how having the reg on the same board as the phono was a big influence on the great sound of the FSP. You could use the GRLV before the shunt, some people used a jung super reg as a "pre regulator" for the integrated shunt. 

    Hm that could work at some point, but I doubt I'd be able to afford both of them at the moment...:p

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.