The Jazz Guitar Chord Dictionary
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  1. #76

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    Quote Originally Posted by Max405
    GT, All this Polytone talk has gotten me curious. I want to open my amp and investigate the loose Reverb tank. But while in there, can you recommend some tweaks that can can make myself that will reduce the hum that I get?
    JD
    I had a hum with my Mini Brute IV. Thought that it would be something about old caps.

    I did not want to take tha amp to the tech so I recorded the hum for 30sec or so. Then I sent the clip to the man attached with an e-mail.

    Tech said that it does not sound like cap job but failed grounding. I tried first to ground the reverb tank to the chassis of the preamp and — voila, now it is silent as ... anything.

    I have to buy a bottle of wine for him someday!

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  3. #77

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    I agree with assessment above. I suspect that both your problems are actually one. Get the reverb tank secured/grounded and you should be good.

  4. #78

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    Mine doesn't hum but has that weird digital kind of sound with note decal where it gets a little fuzzy. I have no idea how to describe the sound and even though it is not digital that is the only way I can describe it. My Cube 30X has the same thing. In real life on the bandstand it is not noticeable but if you pay attention to it at low volumes then you can hear it.


    Sent from my iPhone using Tapatalk Pro

  5. #79

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    Quote Originally Posted by rio
    Mine doesn't hum but has that weird digital kind of sound with note decal where it gets a little fuzzy. I have no idea how to describe the sound and even though it is not digital that is the only way I can describe it. My Cube 30X has the same thing. In real life on the bandstand it is not noticeable but if you pay attention to it at low volumes then you can hear it.
    Buzzing when notes fade away? Is there difference in the anomality between treble and bass notes?

    First I would suggest to check the tubes – but I guess You don't have tubes in these amps!

    Then it can be something else inside the circuit or the speaker.

    I had some months ago a Greenback speaker that functioned normally but from the low A to low E the notes had a loong buzzing tail. The coil had gone to a wrong position during the shipping. Usually it is difficult of impossible to cure but I succeeded with a help from a tech.

  6. #80

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    Quote Originally Posted by Greentone
    I agree with assessment above. I suspect that both your problems are actually one. Get the reverb tank secured/grounded and you should be good.
    Quote Originally Posted by Herbie
    I had a hum with my Mini Brute IV. Thought that it would be something about old caps.

    I did not want to take tha amp to the tech so I recorded the hum for 30sec or so. Then I sent the clip to the man attached with an e-mail.

    Tech said that it does not sound like cap job but failed grounding. I tried first to ground the reverb tank to the chassis of the preamp and — voila, now it is silent as ... anything.

    I have to buy a bottle of wine for him someday!
    if that is the problem, I am gonna do cartwheels! I want badly to love this amp. I know it's pedigree and so many of my bro's here love it. I'm gonna play around with it.

  7. #81

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    I gigged last evening at an outdoor venue to an audience of about 500-750 with the MBII. Ordinarily, I would use my MBIV or my Lab Series L5 for that setting. Well, the II worked well and my guitar duo partner was all smiles and compliments. The tone with my Telecaster was excellent. Fine amp.

  8. #82

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    Hi Greentone,
    do you think that all the MB2 have the same power ?
    The blue tolex seems to have more power than the diamond tolex
    No ?

  9. #83

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    Phil,

    The very earliest ones have 90 watts. (These are the Mini Brutes with the white baffle boards and the felt cabinet covers. They date from the 70s.
    Polytone Mini Brute II - A Good Choice for Jazz?-polytone-mb-iv-rear-label-jpg
    Later, they went up in power.
    Polytone Mini Brute II - A Good Choice for Jazz?-my-mbii-back-label-jpg
    The blue ones from the 90s have 135 watts in/100 watts output power:
    Polytone Mini Brute II - A Good Choice for Jazz?-mb-iii-90s-label-jpg
    In practice, they are all about the same in terms of acoustic volume in my experience.

  10. #84

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    Quote Originally Posted by Guido_59
    Hello I'm Guido from Italy

    There is a member in this post MilesPG selling his Polytone, i have nothing to do with him whatsover,

    if you can grab the Megabrute if in good condition, powerfull small 8" and it has that sound trust me i have a few, i have DV Mark Little Jazz Orig Cubes Orange 1978 Polytone kills all, they are easy to fix,
    the Sonic Circuit is not that great

  11. #85

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    I agree with Durban. The MegaBrute is, along with the Baby Brute, my favorite. The 8" speaker is maybe the best tone engine ever for the archtop guitar.

  12. #86

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    Quote Originally Posted by Greentone
    I agree with Durban. The MegaBrute is, along with the Baby Brute, my favorite. The 8" speaker is maybe the best tone engine ever for the archtop guitar.
    I think the speaker size itself makes a huge difference. 8" sizes seem to be far less depending on decent room acoustics. Whenever i get into an acoustically problematic environment, choosing the 8" is usually an easy way out of muddiness. Withe a 10" i would often need a low frequency filter (like on the clarus) to tame it. Therefore i generally prefer to use my Mambo 8" to the 10".

  13. #87

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    I guess it was inevitable. I purchased the Mini Brute II new at a local music store for $237 in 1978. About 15 years ago the reverb quit but otherwise the amp sounded great and was relatively portable, so it fit-the-bill. I do have a Fender Twin Reverb I bought in 2005 to replace the one I bought in 1987, which was a replacement for the one I purchased in 1964 when I was 16 years old. But a strange thing happened; the "Twin" got heavier as I got older.

    I play in the pit orchestra for a local musical theater group and last Sunday was the first rehearsal. The Mini Brute worked fine when I left home for the thirty minute drive to the Church basement where the group practices. After setting up, I turned the amp on and it started to squeal as if it was feeding back--which it wasn't since nothing was connected to it. I played around with the tone controls and was able to minimize the noise a little bit. When I got home and connected the amp the noise was worse.

    The Mini Brute owes me nothing. I used it regularly at home and anytime I played for public consumption for 40 years. After mulling over my options I ordered a Fender Princeton Reverb Re-Issue from GC. It arrived a couple of days later and I tested it out. Both Gibson Humbuckers (including one guitar with PAFs) and Gretsch Filtertrons sounded smooth, full and mellow with just a bit of natural crackle at higher volume levels. In short--just perfect for my needs and a lot easier to tote around.

    I haven't given up on the Mini Brute. I'm searching around for an amp repair person in the hopes that I can use the Polytone again as a practice amp. I'll keep you posted.

    Tony D.

  14. #88

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    Tony, good luck, you might came across a tech or maybe two etc. who will claim its un-repairable, obsolete parts yadi dadi pffffff. I have a 78 Mblll, its a simple amp and any avarage (or above) skilled tech should be able to bring it back to life. Nothing in it that cant be replaced by parts available today.

  15. #89

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    Glad you like the Fender.

    Get the poly repaired, there is practically nothing in them. A hundred bucks and change will get her going another 30 years.

    good luck.

  16. #90

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    That Princeton Reverb Re-issue is a nice amp. It would be great to re-hab the Polytone, but the PRRI is a winner too.

  17. #91

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    Hi Tony,You might miss the clean headroom in the Polytone but I would bet a nickel that you will end up liking the Princeton more. The Princeton was the best amp I ever had. The open back and tubes make the amp sound fuller and a little less hyper focused than the polytone. Good Luck buddy.Joe D

  18. #92

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    After having started on tubes I bought a Polytone a very long time ago but can't even remember why @ this point.
    When I switched back to Fenders I had forgotten how much I missed the warmth and shimmer of a good tube amp.
    And if you don't want to sacrifice cleans just use Twins like I do.

  19. #93

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    Tony, I once had a mini-brute die on me at a gig (they had a lousy PA at the venue that I finished the gig with). It cost me a bit over $200 to have it fixed (it took two hours of bench time at a top notch Bay Area shop).I still keep a Polytone in the amp arsenal. A Gibson archtop with flats played through a Polytone amp just sounds "right" to me.Good luck whatever you decide to do!

  20. #94

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    Back in the day a lot of top players endorsed Polytone, Pass, Ellis, Martino, Hall, Ray Brown, etc.
    I saw all of those guys play through a Polytone except Martino @ one time or another.
    I don't know if it was because they could get a decent clean sound in a smaller amp and not have to worry about a tube dying, etc? Don't think it was strictly for the money, I doubt Tommy Gumina was paying too much.
    Maybe free amps, a little extra cheese and a smaller package was enough, those guys made a living but weren't rich.
    Or they also might have just really liked them, lots of folks do

  21. #95

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    Tony, it would be relatively easy to replace the reverb unit. I did that back in the eighties once and the replacement (if i remember correctly) was a three spring unit which sounded ways better than the original 2 spring tank.
    Polytone Mini Brute II - A Good Choice for Jazz?-preview-jpg

  22. #96

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    These amps are classic for a reason. Nothing in them that can't be fixed if you find a tech that deals with Polytone. Although you can't argue with a Princeton reverb either..

  23. #97

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    Thanks for all the comments. I intend to have the Polytone repaired and keep it as a practice/back-up amp. I opened the back of the amp (after donning gloves and and a mask) and I was surprised by the minimalist design. I've been playing through the PRRI a lot the past few days and thoroughly love that "little amp".

  24. #98

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    Curious what your setup is in the orchestra. Are you miked? Can you plug in directly to the PA if you have a amp with a DI connection?

    Always curious about how people play in these situations with which I have no experience.

    Enjoy the Princeton btw!

  25. #99

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    Quote Originally Posted by Doctor Jeff
    Curious what your setup is in the orchestra. Are you miked? Can you plug in directly to the PA if you have a amp with a DI connection?Always curious about how people play in these situations with which I have no experience.Enjoy the Princeton btw!
    Thanks Doc. The pit orchestra usually has 22 pieces. I play through my amp with a sound level check by the conductor at the outset. We are performing the musical "9 to 5". The guitar features prominently in what is essentially a "country western" style musical. Guitar solos and fill-ins are written out. It's basically an 8 week commitment twice a year and a lot of fun.Thanks again,Tony D.

  26. #100

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    My Mini-Brute II is the only amp I have left. The reverb still works (believe it or not) but its very noisy and the springs are very loose. You can hear them clanging around when someone walks into the room while I am playing. I wanted to switch out the reverb unit, but when I opened the back I noticed it has a large capaciter bolted to it. So I just unplugged the wire going into the reverb and use the amp (sparingly) without it.
    Eventually, I will get another reverb unit for it and replace the foam grill to restore it. To me, a Polytone is a symbolistic component of the music that I love. So, for historical reasons, it is really cool to have one in my guitar room.
    I dont know know of very many electronic devices that were made in the 70's, that are still operational in 2019. Polytone Amps are amazing.
    Joe D