Results 1 to 10 of 10

Thread: no Can Capacitor on Leslie 122_Help needed

  1. #1
    ppp Pianississmo boxstreet's Avatar
    Join Date
    May 2018
    Posts
    3

    no Can Capacitor on Leslie 122_Help needed

    I own a Hammond A-100 and a Leslie 122, I moved the organ recently
    and am checking the Leslie (a separate problem I might deal with
    in another post), while doing that I noticed that the Leslie Can capacitor was
    missing and as far as I can tell always was, so it looks like Iíve been using it as is for many years...

    So my question is and please pardon my ignorance on the subject, is that bad?Ö
    I'm not very knowledgable beyond basic maintenance, replacing basic parts and soldering 101
    so I'm very aware of my limitations ...

    just to be clear itís the piece that should be on the COND spot on the 122 Tube Chart,
    it's referred to as a Leslie amp filter can capacitor also.

    Iíve used my A-100 &122 over the years for recordings
    without much issues but the usual maintenance & occasional service
    but Iím wondering how important it is to get one, Iíve seen places to get the part:

    https://www.tubesandmore.com/product...f-electrolytic

    is it something you can just install yourself much like a tube?

    any enlightenment about what it does also would be super.

    Thanks.

  2. #2
    ff Fortissimo muckelroy's Avatar
    Join Date
    Jun 2011
    Location
    Austin, TX
    Posts
    1,244

    1 members found this post helpful.
    Most likely, some “clever” technician installed caps underneath the chassis instead of installing a can capacitor.

    In most cases where I have seem this done, the work was total crap quality, but occasionally it is nicely done.

    Remove your Leslie amplifier and post a photo of the underside, please.

  3. #3
    ppp Pianississmo boxstreet's Avatar
    Join Date
    May 2018
    Posts
    3

    Thanks a lot,

    Will do, this will be my first time removing the Leslie amp, any things to watch out for ?

  4. #4
    fff Fortississimo David Anderson's Avatar
    Join Date
    Apr 2011
    Posts
    3,520

    1 members found this post helpful.
    I've done caps under the chassis on jobs where I wanted increased reliability on a amp that was going to be subject to the rigors of touring. It's all in how you do it. The can cap makers are simply not on the cutting edge of electrolytic capacitor manufacturing anymore. They may use Mallory's machinery, but they're not Mallory -- or Nichicon, Panasonic, or United Chemicon.
    I'm David. 'Dave' is someone else's name.

  5. #5
    p Piano Jyvoipabo's Avatar
    Join Date
    Nov 2016
    Location
    South Groland
    Posts
    260

    1 members found this post helpful.
    Capacitors having 4 sections give 2 advantages
    - Only one ground point.
    - Fits exactly the existing hole.

    But also a very big inconvenience.
    -The price if you add the shippment outside US is dissuasive.

    For this reason, some technicians keep the can in place, disconnect and replace only the failed capacitor. This is the cheapest solution.

    If the 4 capacitors have been replaced by quality capacitors and if this has been done properly do not worry too much about that.

    JP

  6. #6
    fff Fortississimo David Anderson's Avatar
    Join Date
    Apr 2011
    Posts
    3,520

    Quote Originally Posted by Jyvoipabo View Post
    Capacitors having 4 sections give 2 advantages
    - Only one ground point.
    Actually, if you want to run the grounding of the power supply as effectively as possible, having only one ground point can be a disadvantage, not an advantage because all four sections unavoidably share the ground return path with the first stage power supply ripple. This is not a big deal in Leslie amps, but can be in higher-gain amps.
    I'm David. 'Dave' is someone else's name.

  7. #7
    ppp Pianississmo boxstreet's Avatar
    Join Date
    May 2018
    Posts
    3

    Great info from everyone, especially for a novice like me.thanks a lot.

  8. #8
    ff Fortissimo Tim_at_Jonas's Avatar
    Join Date
    Feb 2010
    Location
    Indianapolis, IN
    Posts
    1,194

    Quote Originally Posted by David Anderson View Post
    Actually, if you want to run the grounding of the power supply as effectively as possible, having only one ground point can be a disadvantage, not an advantage because all four sections unavoidably share the ground return path with the first stage power supply ripple. This is not a big deal in Leslie amps, but can be in higher-gain amps.
    This especially applies in the AO28 preamp. We replaced the can caps with separates, and used a single ground point. Hum! We split the grounds as they were originally, and all was well.

  9. #9
    Moderator Wes's Avatar
    Join Date
    Nov 2011
    Location
    Inverary, ON, Canada
    Posts
    8,763

    How's that for irony. I just did exactly the same thing, to repair an AO-28 with discrete caps that had gone bad, and it's as quiet as can be.

    Thinking back, that AO-28 only had 5 caps sharing a common ground....I think there was a couple of axial 25/25s or something mounted on the tag board. Maybe that's what made the difference.

  10. #10
    ff Fortissimo Tim_at_Jonas's Avatar
    Join Date
    Feb 2010
    Location
    Indianapolis, IN
    Posts
    1,194

    One of the sections in the can behind the expression box is C26, the cathode bypass for the 12BH7 output stage. I suspect that it didn't like being grounded at the same spot as the first three supply stages.

Similar Threads

  1. Yamaha Electone FS-200 39P styrol capacitor needed
    By odinsky in forum Electronic Organs
    Replies: 0
    Last Post: 11-21-2017, 05:00 PM
  2. New Leslie - No Filter Capacitor?
    By prunenoveggie in forum Leslies, Tone Cabinets, Speakers, & Accessories
    Replies: 2
    Last Post: 09-25-2016, 10:01 PM
  3. Capacitor question in Leslie amps
    By JoeyB3 in forum Leslies, Tone Cabinets, Speakers, & Accessories
    Replies: 11
    Last Post: 05-29-2016, 04:50 PM
  4. Leslie 122 Capacitor explosion
    By geoelectro in forum Leslies, Tone Cabinets, Speakers, & Accessories
    Replies: 22
    Last Post: 08-30-2013, 02:36 AM
  5. leslie 25 capacitor
    By starshiptrooper in forum Hammond Organs
    Replies: 33
    Last Post: 03-23-2011, 06:58 PM

Tags for this Thread

Bookmarks

Posting Permissions

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