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

Fisher 400 - Rebuilt but sounding muddy

Discussion in 'Fisher' started by healyc139, May 6, 2018.

  1. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,829
    Location:
    Glen Burnie Md.
    I don't see anything wrong in the front end. Except the fact that the guy who rebuilt it loves those silver colored caps (vitQ? or K-40-Y?).

    Healy. If you can lift one side of one of the DALE's you can get the value with a meter. Then solder it back in. Or just try with the meter and the resistor connected. You'll probably get the rest of the circuit involved too but it's a shot.
     

     

    Please register to disable this ad.

  2. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,829
    Location:
    Glen Burnie Md.
    Try moving your speakers away from corners and walls a little, say a foot or 3. Test again. Did wife change curtains, furniture in room, etc.
     
  3. healyc139

    healyc139 New Member

    Messages:
    30
    Location:
    Chicago, Illinois
    I'll try speaker placement also, but nothing changed from a surroundings standpoint. The receiver really sounded amazing for a couple of weeks and then I noticed it became muddy. And ya he sure did like using those, do you think those are worth replacing or just putting heat shrink over them? I'll check the Dale's tonight.
     
  4. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,829
    Location:
    Glen Burnie Md.
    What Brand/model spkrs are you using?

    We don't know if the caps were just installed right before you bought it or they had been in it a while. If they are K-40-Y Russian's they can change slightly, usually opening up in the mid and high ranges. Vit-Q's I've never heard. But using one type/brand/model cap tends to impart the cap's tonal qualities(I hear it more in a paper in oil cap) on the unit they are installed in. This is one of the reasons I mix up the caps between DME's, IC yellow mkp's, and Original ERO-FOL's.
     
  5. healyc139

    healyc139 New Member

    Messages:
    30
    Location:
    Chicago, Illinois
    I have Klipsch Quartets with Bob Crites Crossovers. Love em.

    Looks like the caps are K-40-Y's. What would you use for those if you were going to replace them?
     
  6. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,829
    Location:
    Glen Burnie Md.
    Replace the output couplers with Illinois Capacitor mkp's (yellow caps @ AES). .068uf 400v. test. If no change it's further back in the chain. Tone controls, C81 & 82 off V11, I'd use Cornell dublier DME's @ 600v rating. Don't change the value here. Test again. If no change I'd think your tubes need looking at. Especially the output's. What are your outputs and the 12ax7's at V10-V11-V12-V13.
     

     

    Please register to disable this ad.

  7. sberger

    sberger Hard Core Geezer Subscriber

    Just a comment on the 7868 tubes. I'm currently running a restored Fisher X-100-B integrated with 7868's, and that amp has a lot more bottom end/grunt(maybe some would call it boominess, I just consider it a very typical, early 60's tube sound. And I love it. Contrast that with my restored 500C and it's 7591 tubes and that is much more neutral, less bass, not quite but almost solid state sounding. Perhaps your 400 was breaking in over the course of a couple weeks and what you're now hearing is what it's signature sound is. I haven't owned a 400 in several years but I definitely remember it as not being as dry as the 500C is. I also had a X-101-C (7591) for awhile and it too was more neutral then my X-100-B.
     
    Last edited: May 30, 2018
  8. healyc139

    healyc139 New Member

    Messages:
    30
    Location:
    Chicago, Illinois
    Sorry guys, had to take a bit of a break on the project.

    @sberger - That is good input. I will definitely keep it in mind for after these minor updates are complete.

    @larryderouin - I have a shopping list of all the capacitors I'll be buying for the rebuild. Looking at the screen resistors - the Dales say RN60D, so I think they are 1/4W 1%.
     
  9. healyc139

    healyc139 New Member

    Messages:
    30
    Location:
    Chicago, Illinois
    Hey so I ordered what I thought would be a good replacement for the out couplers - they are .068uf 400v but they look really tiny, not sure sure if they're what I needed. Anybody mind giving input? They are CDE Film Capacitors
     

    Attached Files:

  10. RUmad

    RUmad AK Subscriber Subscriber

    Messages:
    940
    Location:
    New York
    Looks like you got exactly what Larry said to use. Should be good to go.
     
  11. healyc139

    healyc139 New Member

    Messages:
    30
    Location:
    Chicago, Illinois
    It might also be worth mentioning that these are MMP, just noticed that. Not MKP, does that make a difference?
     

     

    Please register to disable this ad.

  12. gadget73

    gadget73 junk junkie Subscriber

    Messages:
    36,764
    Location:
    Southern NJ
    Should be fine.
     
  13. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,829
    Location:
    Glen Burnie Md.
    No. They are roughtly equivalent to the Illinois MKP's.
     
  14. healyc139

    healyc139 New Member

    Messages:
    30
    Location:
    Chicago, Illinois
    Ok, good to know. Also, they sent me 630v for3 c81 &82, any cause for concern? I ordered 600v, and the pouch they came in said 600v so they mustve mixed them up. I'll hold off on that if its a huge difference
     
  15. larryderouin

    larryderouin Turn it UP, POP? PLLUUEEEZZZZZEE Subscriber

    Messages:
    21,829
    Location:
    Glen Burnie Md.
    IT's not a problem except maybe for size, but axials tend to be long. Add some spaghetti tubing or heatshrink tubing to the leads.
     
  16. gadget73

    gadget73 junk junkie Subscriber

    Messages:
    36,764
    Location:
    Southern NJ
    630v is the usual modern voltage rating. It also won't make any difference vs 600v.
     

     

    Please register to disable this ad.

  17. healyc139

    healyc139 New Member

    Messages:
    30
    Location:
    Chicago, Illinois
    Thanks guys - all the work I had planned is finished. I posted some pictures with light blue dots on top of the capacitors replaced.

    AUX Sounds amazing, haven't tried Phono yet. The Radio still sounds a little flabby, wondering if there are any other areas that would stand out there? It's not imperative that it plays radio, but I want it to be functioning as well as I can get it to.
     

    Attached Files:

Share This Page