Page 1 of 3 123 LastLast
Results 1 to 10 of 26

Thread: Capacitors in tone control circuit

  1. #1
    Forum Veteran 62vauxhall's Avatar
    Join Date
    May 2014
    Location
    Greater Vancouver Area. BC
    Posts
    1,257
    No such things as bad days, just bad moments

    Capacitors in tone control circuit

    In the hopes it will fix a dead and or weak channel as it did before, I spent the afternoon re-capping a second APT Holman preamp that came into my possession. With only a few left to go (there are 41 of them), I pulled one in the tone control circuit and thought to ask before replacing it with one I have on hand.

    I've been routinely using capacitors with voltage ratings one level higher than what I removed. What was in the tone control circuit is 16v 22mf but I have no 25v of same but I do have 50v.

    My hesitation to use those is due to something I read recently whereby using a capacitor of higher voltage provided the capacitance rating is the same makes no difference in most cases but it can have an effect in some circuits with a particular design intent.

    My understanding is that the guy who designed this pre-amp was a bit of a tweaky fellow so I was looking for opinions whether installing a higher voltage capacitor in a tone control circuit is safe to do or should I wait until Tuesday and get some 25V or even 16V.

    I can't remember what I used in the first pre-amp, probably the 50v and I didn't notice anything amiss. As a matter of fact I think I recall that being so because the local shop didn't have any 25v or 35v 22mF when I re-capped the first pre-amp so that may be why I came to have these 50v in the first place.

    EDIT: I was told once that in these pre-amps, there are only two electrolytics that the signal passes through but damned if I know which they are.
    Last edited by 62vauxhall; 08-06-2017 at 11:23 PM.

  2. #2
    Forum Veteran WOPL Sniffer's Avatar
    Join Date
    Aug 2015
    Location
    Arizona
    Posts
    2,690
    Screw it
    The factory used higher voltage ratings when they ran out of the correct ones. I see it in Carver stuff and a few others. I also do it. No harm, no foul, just stick with the farad rating (iffn you aint an engineer and know what can be tolerated).
    I had the nations problems figured out one night while on blah blah blah........ huh?

    Big amps
    Kenner Close N Play

  3. #3
    Forum Veteran Netfly's Avatar
    Join Date
    Jul 2017
    Posts
    228
    ---
    Use shouldn't run into problems using higher voltage caps. It's just a max rating that the cap can handle. You can however run into problems if you change the type of cap in some applications. Say using an electrolytic to replace a tantalum or ceramic. This can be related to polarity, thermal or reliability issues. Worse that can happen is the cap may pop. Mind the polarity for the electrolytic, don't change types and you should be ok.

  4. #4
    Forum Veteran 62vauxhall's Avatar
    Join Date
    May 2014
    Location
    Greater Vancouver Area. BC
    Posts
    1,257
    No such things as bad days, just bad moments
    Thanks and 'twas as I thought so I'll use what I have.

    I dug around a bit and found what I'd read about signal going through electrolytics and it wasn't those 22mf. They were 100mf's and I've already replaced those.

  5. #5
    Forum Veteran WOPL Sniffer's Avatar
    Join Date
    Aug 2015
    Location
    Arizona
    Posts
    2,690
    Screw it
    Quote Originally Posted by 62vauxhall View Post
    Thanks and 'twas as I thought so I'll use what I have.

    I dug around a bit and found what I'd read about signal going through electrolytics and it wasn't those 22mf. They were 100mf's and I've already replaced those.
    uf (micro farad?)
    I had the nations problems figured out one night while on blah blah blah........ huh?

    Big amps
    Kenner Close N Play

  6. #6
    Administrator Gepetto's Avatar
    Join Date
    May 2011
    Location
    Sterling, MA
    Posts
    6,584
    Old 'Arn Enthusiast
    Quote Originally Posted by WOPL Sniffer View Post
    uf (micro farad?)
    Yeah Perry, the old school was mF for uF and mmF for pF. You are way to young to be familiar with that though.

  7. #7
    Forum Veteran WOPL Sniffer's Avatar
    Join Date
    Aug 2015
    Location
    Arizona
    Posts
    2,690
    Screw it
    Quote Originally Posted by Gepetto View Post
    Yeah Perry, the old school was mF for uF and mmF for pF. You are way to young to be familiar with that though.
    Musta been WAYY old school. Even the old navy manuals for our ancient radios used uf......
    I had the nations problems figured out one night while on blah blah blah........ huh?

    Big amps
    Kenner Close N Play

  8. #8
    Administrator
    laatsch55's Avatar
    Join Date
    Jan 2011
    Location
    Gillette, Wyo.
    Posts
    52,609
    Halfbiass...Electron Herder and Backass Woof
    Hence the "way to young".....
    taking something that's already good, and making it better...........and for the knowing smiles that cross their faces.......Nando-2011...

    "Silence cannot be Misquoted"--Lazarus Short-2012 "

    " I Just Collect Smiles Craig......Cheap Smiles!-----Fishoz-2017

    "anything can be done, it's finding the easiest way that's hard"-----Bobbysdad--2014

    " Synth percussion is deadly to children, house pets and shitty power supplies"---Stephen Evans 2014

    " You have not reached the point of diminishing returns, you've just ran out of money

    " The Pioneer U-24, unfortunately, is just too expensive and rare to find. That's why I have one."--Nando-2014

  9. #9
    Administrator Gepetto's Avatar
    Join Date
    May 2011
    Location
    Sterling, MA
    Posts
    6,584
    Old 'Arn Enthusiast
    Quote Originally Posted by laatsch55 View Post
    Hence the "way to young".....
    My first Lafayette short wave receiver kit used the mF and mmF nomenclature as did my first Eico amp kit so I guess that makes me old school

  10. #10
    Forum Veteran Netfly's Avatar
    Join Date
    Jul 2017
    Posts
    228
    ---
    You'll sometimes see mfd too. As you probably know it's actually f, not uf. Mu being the greek letter generally associated with micro.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •