Jump to content

bbest

Returning Member
  • Posts

    81
  • Joined

  • Last visited

  • Days Won

    1

Posts posted by bbest

  1. 7 hours ago, simmconn said:

    The closest sub for LT1021 is the LT1236. As far as I know they only differ in long-term drift specs. There are other shunt mode 10V references but none come close to the noise performance of LT1021/LT1236.

    Unfortunately LT1236 has also insane price.

    SUPSIC produces GC2M1000170D  100% the same specs as C2M1000170D, costs 1.5$.

  2. Repairs.

    Of cause it was some problems (for T2 this is normal, nothing special). It was successful first run. But after some modifications I had bad connection for tubes filaments 6.3V.

    * so fried couple times 2SK216 + went to rip 4-6pcs LTL-4221NLC. Silent dead, no sparks.

    * PSU lines -500V, +500V (not alone here, other members had same problems):  zener 24V, 2n3904, fqpf8n80c.

     

    Thanks all who helped in repairs.

  3. Hello everybody!

    Almost finished T2 started in 2022. It was very funny and pleasant build, very interesting. For base I took PCB developed by jamesmking in 2020. For me it was most convenient layout, it is possible to rearrange in case two channels. Plus no absolete elements.

    In this build changed:

    * DC offset resistor R64 from 510 to 649Ohm

    * 2SJ79/2SK216 on TTA004B/TTC004B

    * FQPF8N80C on STP8NK80Z

    Some pics

    Amplifier.

    A1.thumb.jpg.2fded5dfb7a3c00a78331718581d09bf.jpg

    A3.thumb.jpg.0fe02cf44e493206855cfc8685fca9cc.jpg

    TTA004b/TTC004b

    A11.thumb.jpg.781cf28881518791b6ed73864f85ff9b.jpg

     

    And PSU

    P9.thumb.jpg.ba74bc91619e251b940636fcc570751a.jpg

    P6.thumb.jpg.ee92b70b15210be0fa0cab27325f2730.jpg

    More pics here https://cloud.mail.ru/public/mHh6/ktC6SknZ5

    Thanks jamesmking, JoaMat and other guys for help in assembling.

    • Like 4
  4. On 8/2/2023 at 10:36 AM, jokerman777 said:

    Wanted to buy some FQPF8N80C seems uk rs-online only let me enter UK address, is there a way to get them ship worldwide?

    Hello all!

    Same question - how to replace it or where to buy?

    May be something from this:

    * FQP8N80C

    * STP8NK80Z

    * STP7NK80Z

    ?

  5. 6 hours ago, Pars said:

    I personally prefer the CFP3 to a Dynahi, but I have only compared SE directly. The CFP3 is probably my favorite dynamic amp, but my SE Dynafet is awfully close (and better than an SE Dynahi in my opinion).

    I've never built a Beta22, but have heard them at meets (10 or more years ago). I don't recall being particularly impressed then, even though I have a lot of respect for Ti.

    And what difference between CFA3 and Dynahi? My balanced Dynahi seems more rude, more simpler then beta22. Last one very close to electrostatic sound.

  6. Assembled my balanced Dynahi old version of 2004.

    dynahi1.thumb.jpg.9632310a5338b6b4cb24f0dc2d2bad14.jpgdynahi2.thumb.jpg.9ce7736d1afbf644f16eef6c51181585.jpgdynahi3.thumb.jpg.8ef36b344966f7e086335b76311f5160.jpgdynahi4.thumb.jpg.399c6dbde8c512780115ff58a99f024c.jpgdynahi5.thumb.jpg.8e40994a17efe9bd264bb93adf6b0e61.jpg

    Using it with HiFiman HE-6. Sound: entertaining, opened, dancing cheerful. Compared it with beta22.

    Have only couple of questions:

    * does it make sence to change main capacitors from Panasonic FC 470uF on Nichicon KG 680uF

    * DC offset without opamp +-10mV, with opamp OP27 +-2mV. Is it ok, left as is or try to make it better by changing on opa134 or something like this

    * does it make sence to make some other mods

    What you think?

    • Like 4
  7. On 2/24/2023 at 2:21 PM, MLA said:

    I've sucessfully used stn0214 as replacement for ksc5026M as per JoaMat's recommendation in several other builds. Don't know the heat dissipation requirement for the position where they are used in KGSSHV, but someone more knowledgeable than me might chime in here. 

    Not so far ago it was expected in JUL-23 on mouser, but now shift to 19-Aug-24. So only stn0214.

    Quote

    btw I think I'm going to use STP8NK80ZFP instead of the obsolete FQPF8N80C, at a glance the specs looks very similar other than a different Id rating and speed.

    here said https://www.mouser.com/PCN/onsemi_Generic_PD24419ZB.pdf it could be replaced on FQP8N80C, but mouser also suggested STP8NK80ZFP

  8. On 2/6/2023 at 4:22 AM, jamesmking said:

    Here the latest T2 psus, I have modified the layout to provide more space around the rather hot R11 3W resistor and added vent holes to the pcb. The pcbs, transformers etc still fit inside a 400mm deep case without issue.

    ...

    This pcb is 220mm wide by 137mm deep and contains the -260V, -560V and +250V rails

    image.thumb.jpeg.ba35ce04c9d132e09c2874113890c141.jpeg

     

     

    tiny mistake: FQPF8n80s -> FQPF8n80c. But anyway, FQPF8n80c completely obsolete. May be it make sence to change it on FQP8n80c.

    PS: compared to previous gerber version

    fixed wrong silk for IXCP10M90S: KAG -> GAK, good 👍

    • Like 1
  9. 20 hours ago, Craig Sawyers said:

    It's an ONSemi part. I really don't know what has happened with ONsemi. They bought Fairchild and Sanyo, and have obsoleted most of the really useful audio parts. Anything remaining has ended up on ridiculous lead times.

    We're well beyond the Covid excuse, and I'm left with bungling corporate incompetence as the only explanation remaining

    so may be find some analog for KSC5026MOS, on Aliexpress some shops try to sell 1pcs for 24$ 🤔

×
×
  • Create New...

Important Information

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