1. Time for some upgrades in server hardware and software to enhance security and take AK to the next level. Please contribute what you can to sales@audiokarma.org at PayPal.com - Thanks from the AK Team
    Dismiss Notice

B-2101 repair project.

Discussion in 'Exclusively Sansui' started by BigElCat, Jan 2, 2018.

  1. SansuiJavier

    SansuiJavier AK Subscriber Subscriber

    Messages:
    139
    Location:
    Valencia (Spain)
    "The manual is incorrect, the first one, as mentioned before, is the photo of the amplifier in the manual, the GND test point of the F-4619 is the farthest point of the heatsink, not as indicated in Photo (4.2 top view). The second one refers to the setting of BIAS, KVR3 and KVR4 are inverted in the adjustment page of the manual."

    this is what I noticed in my recap, but please check if the same thing happens, mine was a 2102 ...
     

     

    Please register to disable this ad.

  2. BigElCat

    BigElCat Mmm Hmm Subscriber

    Messages:
    7,894
    Location:
    South of Kansas City
    I can't source a side adjust 470 ohm Bourns for the F-4618 boards.

    I'm thinking I'll just put a used Sanken in for now and re-do the adjustments.

    The Sanken that's on its way is a 3519A rated at 180 volts instead of 160 volts.

    How much of a difference will that make ?
     
  3. Hyperion

    Hyperion Roobarb & Custard Subscriber

    Messages:
    48,611
    Location:
    Hertfordshire, UK
  4. BigElCat

    BigElCat Mmm Hmm Subscriber

    Messages:
    7,894
    Location:
    South of Kansas City
    Tell me about the signal path...

    Is the F-4618 Drive Amp circuit board in the path ?

    What about the F-4619 Power Amp circuit board ?
     
  5. Hyperion

    Hyperion Roobarb & Custard Subscriber

    Messages:
    48,611
    Location:
    Hertfordshire, UK
    Yes it is - definitely
    Yes, of course.
     
  6. BigElCat

    BigElCat Mmm Hmm Subscriber

    Messages:
    7,894
    Location:
    South of Kansas City
    So I should use Silmic IIs or Fine Golds ?

    Of the two which would be better ?
     

     

    Please register to disable this ad.

  7. Hyperion

    Hyperion Roobarb & Custard Subscriber

    Messages:
    48,611
    Location:
    Hertfordshire, UK
    I'll answer here, but maybe I shouldn't, but I am trying to help you so here goes... I really don't like Elna Silmics, although I know they are very popular and are reputed to sound great.

    I tried some once and I didn't like them - but maybe I simply didn't wait long enough for them to settle in? - thus my vote will always be for Fine Golds.
     
  8. ManyMoonsAudio

    ManyMoonsAudio AKA paul79 Sponsor Subscriber

    Messages:
    3,064
    Location:
    Tulsa Ok (C-Ville)
    Interesting John. I find the Silmic II's to be quite good in all signal path/coupling applications I have tried them. I don't like them for any other application though. Strictly in the signal for these.

    You might try to revisit, trying them only in the signal path, however, your FG's are some great sounding caps as well.
     
  9. BigElCat

    BigElCat Mmm Hmm Subscriber

    Messages:
    7,894
    Location:
    South of Kansas City
  10. BigElCat

    BigElCat Mmm Hmm Subscriber

    Messages:
    7,894
    Location:
    South of Kansas City
    Connector locations on the F-4618 Drive Amp Circuit Board (right channel).

    DSC00446.JPG
    DSC00447.JPG
    DSC00448.JPG
     
  11. Hyperion

    Hyperion Roobarb & Custard Subscriber

    Messages:
    48,611
    Location:
    Hertfordshire, UK
    KA's are very good - I like them :)
     

     

    Please register to disable this ad.

  12. BigElCat

    BigElCat Mmm Hmm Subscriber

    Messages:
    7,894
    Location:
    South of Kansas City
  13. Hyperion

    Hyperion Roobarb & Custard Subscriber

    Messages:
    48,611
    Location:
    Hertfordshire, UK
    Strongly recommended, an absolute lifesaver. :)
     
    smurfer77 likes this.
  14. smurfer77

    smurfer77 AK Subscriber Subscriber

    Messages:
    1,485
    Location:
    San Francisco
    A DBT is strongly recommended. I use only a variac and a current monitor (which I monitor closely but is probably not as obvious as a bulb glow, but I see fine details in current draw that help me trouble shoot and analyze) but this provides no current limiting beyond blowing the variac fuse. A DBT limits the current if your gear has an issue causing it to draw unusually high current (such as a supply rail shorting to ground via shorted outputs)... and if you physically are somehow a part of the circuit that could save your life. Another option would be an isolation transformer but that is more expensive. if you work mainly on solid state gear, a DBT is the way to go, if you work on tube gear sometimes I reckon a variac + dbt.

    About the caps, I agree with all John said. I like the nichicon over the elna but as John says it might just be a matter of settling in or personal preference. Also, as you get use to reading schematics you will get use to spotting which caps are in the signal path; on one board in the signal path, you will still have caps not in the signal path here and there. Selection of caps for signal path is quite different to power supply and so on so it's good to spot the differences. You will see folk use audio caps on power supply all of the time, whereas you can get much better caps for such roles.
     
    Hyperion likes this.
  15. BigElCat

    BigElCat Mmm Hmm Subscriber

    Messages:
    7,894
    Location:
    South of Kansas City
    Here's a capacitor list for the F-4618 / F-4619 boards; quantity needed total for both channels is in (parentheses).

    Nichicon UKA's, unless stated otherwise.

    (6) 10uF 35V (Silmic IIs)
    (2) 10uF 50V (UFGs)
    (4) 100uF 6.3V
    (2) 100uF 35V
    (2) 100uF 25V
    (4) 470uF 50V
    (4) 470uF 35V
    (2) 220uF 10V

    I hope this is correct because that's what I'm ordering. The FG's and Silmics were substitutes because the KA's didn't go that small.
     
  16. BigElCat

    BigElCat Mmm Hmm Subscriber

    Messages:
    7,894
    Location:
    South of Kansas City
    I have a variac. I'm off to get parts for a dim bulb tester.

    Tell me about fuses. I blew the a 5A 250V AG fuse. I can only find a 5A 250V AGC fuse. Is this an ok substitute ?

    The filament is a different style. Original on top.

    DSC00450.JPG
     

     

    Please register to disable this ad.

  17. Hyperion

    Hyperion Roobarb & Custard Subscriber

    Messages:
    48,611
    Location:
    Hertfordshire, UK
    I think these fuses are the same functionally 'AG' means 'Automotive Glass' and 'AGC' means Automotive Glass Cartridge. ;)
     
    smurfer77 likes this.
  18. BigElCat

    BigElCat Mmm Hmm Subscriber

    Messages:
    7,894
    Location:
    South of Kansas City
    Last edited: Jan 10, 2018
  19. ManyMoonsAudio

    ManyMoonsAudio AKA paul79 Sponsor Subscriber

    Messages:
    3,064
    Location:
    Tulsa Ok (C-Ville)
    Good stuff. What sold me on the Silmic caps was my preamp. It has a back to back pair at the output of the line stage, the only caps in the signal, and they absolutely sing here. They replaced the previous Black Gate caps I had there, and did better in every way, most notably in transparency and body.
     
    pete_mac likes this.
  20. BigElCat

    BigElCat Mmm Hmm Subscriber

    Messages:
    7,894
    Location:
    South of Kansas City
    Which preamp are you referring to ?

    I have a C-2101, all original, and still sounds good.
     

Share This Page