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Polytone mini/teeny brute -- HELP!!

Discussion in 'Amps and Cabs [BG]' started by KrisKraft, Apr 11, 2009.


  1. KrisKraft

    KrisKraft

    Apr 11, 2009
    This amp is blowing fuses. Any quick fix? If not,I need SCHEMATICS to repair it. It's 100 Watts, 2 input, diamond vinyl, serial# 13718.
     
  2. Lia_G

    Lia_G

    Oct 27, 2005
    I don't have any answers for you, but the guys at Condor Electronics in Seattle re-capped a Teeny Brute for me 5 or 6 years ago. Perhaps someone there has the schematic:
    http://www.condor-electronics.com/

    Good luck,
    Liam
     
  3. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Not to be the bearer of bad news, but...

    A lot of the earliest Polytone amps used a particular power amp design which had a specialized IC from National Semiconductor, controlling the output transistors. Trouble is, the IC was prone to failure, it could take out one or both transistors, and cause other damage down the line, and... the magical IC is obsolete and ridiculously hard to find. Also, the power amp is entirely enclosed in the cabinet, so there's nowhere for the heat to escape.
     
  4. Lia_G

    Lia_G

    Oct 27, 2005
    Yep. And my IC is bad now. Had fun after the recap until the IC went bad though! Now it sits in the corner of the basement. Might turn it into a cab someday, who knows.

    Liam
     
  5. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    I'd be tempted to forget about the IC and stick a Hypex power amp module in there.

    I also have a dead Polytone in my basement.
     
  6. johnk_10

    johnk_10 vintage bass nut Supporting Member Commercial User

    Feb 16, 2008
    Thousand Oaks, CA
    John K Custom Basses
    i ran into the exact same problem years ago, so i have a dead one in my storage unit.
     
  7. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Dead Polytone Club:

    1. KrisKraft
    2. liam_g
    3. fdeck
    4. johnk_10

    :D
     
  8. johnk_10

    johnk_10 vintage bass nut Supporting Member Commercial User

    Feb 16, 2008
    Thousand Oaks, CA
    John K Custom Basses
    +1!!! :)
     
  9. Jim C

    Jim C Is that what you meant to play or is this jazz? Supporting Member

    Nov 29, 2008
    Bethesda, MD
    Wow,
    I had one break a million years ago, had it fixed, then sold it a few years later.
    Started reading this thinking that I should have kept that amp (mine had what looked like black felt on the cabinet).

    About time something I sold years ago was a good decission!
     
  10. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Mine has the black felt. Actually it belongs to a dude who brought it to me for repair. He toured with it forever before it broke. When the foam speaker grille disintegrated, he found a cookie cooling rack at Saint Vinnie's for 25 cents, spray painted it black, and screwed it on the front of the speaker. I plan on measuring the speaker response curve for posterity.
     
  11. Lia_G

    Lia_G

    Oct 27, 2005
    Hah, mine is also black felt and with the wonderful disintegrating foam (but not completely disintegrated yet). When Condor Electronics recapped it, they also replaced the blown speaker with an eminence model (forget which one ... whichever non-neo one it is that works well in sealed cabs).

    I like the dead polytone club! ;)

    Liam
     
  12. Lia_G

    Lia_G

    Oct 27, 2005
    JohnK, this is sorta crazy ... but would converting it into a little sealed 110 cab and pairing it with one of your V4B's make a good studio rig? I wonder if the sound would be anything like a "quiet SVT" for recording ...

    Liam
     
  13. Jim C

    Jim C Is that what you meant to play or is this jazz? Supporting Member

    Nov 29, 2008
    Bethesda, MD
    As I remember either those speakers were expensive to recone or I was particularly broke at the time. Had about a 1" tear at the surround that was fixed with toilet paper and clear finger nail polish. Sounded fine; wonder what ever happened to that one.
     
  14. Bassman822

    Bassman822

    Sep 1, 2007
    Bessemer, AL
    If I recall , Polytone offered a retrofit kit at one point. If the company is still around, it might be worth a shot
     
  15. 62bass

    62bass

    Apr 3, 2005
    Polytone is still around, but barely. They aren't too helpful when trying to service old gear either. You can try phoning them. They have a website with contact information.

    Not many people are willing to try to fix Polytones.

    I had a MiniBrute in the 70s that I liked a lot. I sold it about 1983 and it was still working fine. Great recording and very small gig amp, but there are many, better little amps today for bass.
     
  16. jgsbass

    jgsbass

    May 28, 2003
    Floral Park, NY
    I think the weakest link in the Polytone story is the cabinet. It was made to be small. It doesn't really throw the sound very far. The amp part is fine, the cab is a little limited. We used all sorts of strategies to increase the sound spread. Some people added cabinets( which cut out the internal speaker), some people put a cabinet and put the cable into the extension speaker jack part of the way to get both speakers going ( at the cost of a mismatched impedence load) and some used to turn the speaker to face a solid wall, angle it up slightly, and use the room as a big cabinet. On its own the speaker cab is just too small to sound real good. Back when it came out, its selling points were good sound and portability, but its competition was a B 15 and it was way more portable.
     
  17. chadds

    chadds

    Mar 18, 2000
    +1 on the cabs weaknesses. I've had several over the years. The last had the ext cab. I played my SWR SM-400 through it and guess what? It sounded exactly like the internal amp of the Polytone. I gigged regularly with a 101 which looks like a short Vintage Fender Bassman. 1x15. I know they later added a couple of 5"s or 6"s. The 1x15 sounded so good because the cab was larger. I would use a Y cord turn the bass eq up and treble dwn on one channel and the opposite on the other and blend the volumes. Really nice. Played San Francisco's Golden Gate Park with it through a giant PA with the best side fills I've ever heard. It's in the foothills of the Sierras now.
     
  18. staccatogrowl

    staccatogrowl Savoring the spinning, shimmery aquasphere Supporting Member

    Jul 14, 2006
    I could have applied for a member number for the dead Polytone club.

    Instead, I took my felt Mini Brute II to Al's Diner (Repairs Well Done), just outside of Ann Arbor, MI.

    Aside from being a very cool cat, he's an authorized Fender, Mesa, and Peavey service provider. He fixed my amp for $40. :eek:

    He has schematics on hand to do the work.

    His email is alsdiner@comcast.net .

    Just so you know, I am not affiliated with his business, and I am not a family member.
     
  19. jgsbass

    jgsbass

    May 28, 2003
    Floral Park, NY
    The 101 was a great amp. The Polytone series was designed to be portable more than anything else. Upright players loved it because it satisfied the criteria for being an amp, and they hated using amps. There were no real good transducers for basses available at the ( late 70's, early 80's) time, and they knew they would sound like poop, through any amp: Polytone filled a niche. It was also the easiest amp to transport on a subway.
    If you think the 101 sounded good, you should have seen the 220. 2 101s on the same chassis as separate amps or bridgeable to use both amps with one set of controls, driving 4 10s. This was an amp designed in the 70's to be loud which wasn't Polytones strong suit or reputation. I played one at a rehearsal space for a year: I begged them to sell it to me then. It was expensive at the time and discontinued pretty quickly, but what an amp. 220 watts, 4 10" combo.
     
  20. ItsNotMeTalking

    ItsNotMeTalking

    Feb 16, 2005
    hi, anyone has any schematic or manual for a teeny brute (first edition i think,.. without midcontrol) thanks...
     

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