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Help me Recap a Vibro Champ

Discussion in 'Amp Central Station' started by Josey, Oct 27, 2016.

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  1. Oct 27, 2016 #1
    Josey

    Josey Tele-Meister

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    So I've been searching for a while and finally scored an all original '65 Blackface Vibro Champ. (I'll post pictures later) It does function properly however the tremolo sounds weak and there isn't much response from the tone controls. I know a full cap job is in order but I'm asking for advice on component values and manufacturers in order to get the most out of this great little amp. Also where is the best place to get parts? I want to keep everything stock for the most part but if I can change a value or component here or there to get more response from the amp then I'm all for it. Any guidance would be greatly appreciated. If you need any readings or more info to help with your suggestions then let me know and I'll get you what you need. Thanks.

    P.S. I'm also looking for suggestions on the speaker replacement. I want to keep it at 8" and box up the original.
     
  2. Oct 27, 2016 #2
    muchxs

    muchxs Doctor of Teleocity

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    Antique Electronics Supply is the only place to get the original style cap can.

    https://www.tubesandmore.com/products/capacitors?page=2&filters=Brand=CE Manufacturing

    Go 20/20/20. It's easier on your rectifier.

    https://www.tubesandmore.com/products/capacitor-ce-mfg-450v-202020-f-electrolytic

    They're on sale through Monday. Grab one while you can!


    Bypass caps: I use 22uf / 50v, 10uf / 50v and 47uf / 50v starting at the preamp.

    Nichicon caps are readily available at Radio Shack, that is if you can find a Radio Shack. The stock bypass caps are 25uf / 25v (two) and 10uf / 25v. Rat Shack has 35v, perfectly acceptable.
     
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  3. Oct 27, 2016 #3
    tjnies

    tjnies Tele-Holic

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    You'll get a bunch of responses for speakers. It kind of depends on the voicing you prefer. Myself, I tend to like alnico magnet speakers in VCs (Weber 8A125 is excellent). Others like the chime of ceramic. There you have many choices: Jupiter is inexpensive and highly thought of. So is WGS (who actually builds Jupiters).
     
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  4. Oct 27, 2016 #4
    Outcaster

    Outcaster Tele-Holic

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    What soldering iron ya got? My Weller 140/100 wont make a dent in those cap cans. They need something pretty hefty (by the way, I'm open to suggestions)
     
  5. Oct 27, 2016 #5
    peteb

    peteb Friend of Leo's

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    I got a weller SP120 for this job.

    It gets those cap can tabs off in seconds

    A big tip is part of it

    The sp120 has the 1/2" chisel tip.

    The 100/140 is a soldering gun, a soldering iron is the right tool. Probably don't even need a 120, an 80 would probably work.
     
    Last edited: Oct 27, 2016
  6. Oct 27, 2016 #6
    keithb7

    keithb7 Friend of Leo's

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    Josey, what is your experience working on high voltage circuits? Tell us about your soldering experience.

    Before I share my thoughts I'd like to be sure you have your personal safety in mind. As well, that you have developed some needed skills.
     
  7. Oct 27, 2016 #7
    Josey

    Josey Tele-Meister

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    Thanks muchxs! I've got the cap can ordered and on its way. Ran by the only radio shack that I know exists in the state of Alabama and scored some nichicon's for the bypass caps. (Those 35v caps sure are small) Grabbed a can of DeOxit and some de-soldering braid as well. Was hoping to score a heavier wattage resistor for the bias section but 1/2 watt was as high as they went.

    Outcaster I may have to borrow my amp mentor's iron for the cap can job. It's a "hog leg" from the 1800's but still gets the job done. The cheap tool warehouses like Harbour Freight usually have cheap high wattage irons that could probably work for you. They may only work once but how often will you need it? lol
     
  8. Oct 27, 2016 #8
    BobbyZ

    BobbyZ Doctor of Teleocity

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    When I do a cap can. I plug in Big Bertha an old 200 watter. She's a BUG (big underwear girl) so the lights dim for a while. While she's warming up I can pretty much get all the "little" stuff done. Then it's "wham bam thank you ma,am" and the old cap cans out before the chassis has time to heat up. That big chunk of copper for a tip must be the key.
    If there's alot of old solder left I just melt it quick and wipe it off fast. Then put the new one in bend the tabs and solder it quickly.
    Don't take long!

    I'd rather not talk about doing them before I found old Big Bertha!
     
  9. Oct 27, 2016 #9
    Josey

    Josey Tele-Meister

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    Here's a few shots of me just working around the house for reference.

    High Voltage:

    Soldering:

    Safety is of the upmost importance:

    I've got mad skills:
     
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  10. Oct 28, 2016 #10
    Thin69

    Thin69 Friend of Leo's

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    IMG's don't work.
     
  11. Oct 28, 2016 #11
    muchxs

    muchxs Doctor of Teleocity

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    Another tip: Remove the output transformer before tackling the cap can. That gets a bunch of wiring out of the way. You can replace individual flying leads from the board if you roast them. You can't replace the OT leads, not neatly and easily.

    That's another thing the "untouched solder joints and all original parts" crowd tends to ignore. The original transformers aren't worth much to me if the original leads display multiple soldering iron burns.
     
  12. Oct 28, 2016 #12
    keithb7

    keithb7 Friend of Leo's

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    Josey put the soldering gun down and slide the chassis back in, until you learn how to post images here. Lol.
     
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  13. Oct 28, 2016 #13
    Josey

    Josey Tele-Meister

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    Stupid privacy settings.:mad: How about now?

    But to answer your question Keithb7... Yes I know my way around. You and I have had this conversation before. I'm not a frequent poster and I lurk in the shadows listening to the veterans around here.
     
  14. Oct 29, 2016 #14
    keithb7

    keithb7 Friend of Leo's

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    Lol. Pics work now. Not trying be all "safety officer, superiority complex". I'm no pro either. Just wanna be sure you're good to go.
     
  15. Oct 30, 2016 #15
    Josey

    Josey Tele-Meister

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  16. Oct 30, 2016 #16
    clintj

    clintj Friend of Leo's

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    80+ watts in an iron (not a gun, those are toys) and a big fat chisel tip. The key is thermal inertia, or the ability of the iron to get hot and stay hot when presented with a big heat sink like a chassis. The heavy tip stores large amounts of heat to make that possible.
     
  17. Mar 28, 2017 #17
    charlie chitlin

    charlie chitlin Doctor of Teleocity Silver Supporter

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    Death cap alert.
     
  18. Jun 25, 2018 #18
    Josey

    Josey Tele-Meister

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    I figure since this was my thread to begin with then it's ok for me to raise it from the grave...If not I'll start another.:)

    As you can see this project started a year ago and I really, really appreciate the help and knowledge you guys freely share here. This is definitely my go to site when it comes to research on vintage amp repair and service. You guys helped me bring this little Vibro Champ back to life and I've enjoyed every minute of it. I've performed the basic maintenance such as the recap job including the filter cap can with a 20uF/20uF/20uF 450V as muchxs suggested, as well as replacing the electrolytic caps with one 10uF/25V and two 25uF/25V Sprague Atom's. While I was at it I also replaced the dropping resistors with 2 Watt Allen Bradley Carbon Comp's as well as the V1 plate resistors with 1 Watt ABCC's. Also replaced the original power chord with a 3 prong chord and did away with the dreaded death cap. I also replaced the Cathode cap and resistor with a Sprague Atom 50uf/50V cap and a 5 Watt Wire Wound 1K resistor. These changes definitely brought this little amp back to life in a way that it really doesn't seem little anymore. It has plenty of volume and headroom on tap and the tremolo is oh so sweet. It can really get slow and deep (That's what she said).:twisted:

    I'm really wanting to start recording with this little beauty but despite all the improvements it still has just the slightest of hum, and me never being one to leave well enough alone was wondering if there is something I could do to kill the hum completely. I feel 95% certain the hum has to do with the fact that the B+ voltages still read about 50 volts higher than specifications. My 6V6 is running right at 12 Watts of dissipation so I consider that acceptable but if I could drop the voltage I'm thinking the hum will go away and allow the amp to run cooler and more efficient. I've combed through the archives and found a couple of other threads that dealt with this issue and they were able to tame the hum and drop the B+ voltages by wiring one of two 5 or 10 Watt resistors inline with the First Filter Stage of the Cap Can. I've attached a link to those threads below. Seems like this could be my answer, however in both of those cases they each had the cans with the extra 20uF of filtering wired in parallel for a total of 40uF for the first stage. In my case I would only have the 20uF in the first stage. I'm sure this is a noob question but can I still apply this modification to my amp given my current level of filtering in the first stage?

    http://www.tdpri.com/threads/how-to-kill-hum-in-a-vibro-champ.358724/

    http://www.tdpri.com/threads/67-blackface-vibro-champ-restored.749372/
     
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  19. Jun 25, 2018 #19
    Josey

    Josey Tele-Meister

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    By the way... here’s a clip I recorded with my iPad to give you an idea of how she currently sounds.

     
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  20. Jun 27, 2018 #20
    Josey

    Josey Tele-Meister

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    Have all the Amp doctors and gurus left this site? Muchxs, BobbyZ, Wally... any of you guys still around?
     
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