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  1. #26

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    Quote Originally Posted by Stringswinger
    The problem was a blown bridge rectifier, whatever that does. It was a $5 part but the repair took 2 hours @$95 per hour).
    It's at of the power supply. It's the part that takes the AC and makes it so it doesn't switch from positive to negative and then back...but just has one polarity. Typically this is done by "flipping" the unwanted side, say negative, to positive -- so you get a series of just positive humps
    The bridge part is just how it's implemented, it's an arrangement (called a bridge circuit) of diodes that does the flipping.

    In tube amps, there is often a vacuum tube taking that duty.

    It generally goes
    transformer - it lowers the voltage to something we can use internally by semiconductors. Transformers only work on AC

    rectifier - makes the voltage all one polarity (say positive) but there are still humps

    filter Cap(acitor)s - smooths out the humps into a steady DC (voltage that doesn't fluctuate)

  2.  

    The Jazz Guitar Chord Dictionary
     
  3. #27
    Thanks everyone for their input on the repair option. Over three months later and 160 bucks.... I got my Poly back from repairs. Looks like it was the Power supply, something about a vertical rectifier or something. Thanks all.

  4. #28

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    Quote Originally Posted by Dave325
    Thanks everyone for their input on the repair option. Over three months later and 160 bucks.... I got my Poly back from repairs. Looks like it was the Power supply, something about a vertical rectifier or something. Thanks all.
    voltage regulator perhaps?

    basically, it's a little part that sort of ensures the transformer is doing its job correctly...
    so if there are fluctuations in the power coming in (the transformer basically will give a factor of the voltage like say 10% so if you feed it 100V then 10V will come out, but if you feed it 120V then 12V comes out), the voltage regulator says "I don't care if you are sending me 20V...I'm a 12V regulator so I'm only passing 12V of it because that's what the circuit is designed to handle"

  5. #29

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    Glad you're back in business. Those 70s and 80s Polytone amps should be kept in rotation IMO. Folks need to hear that good jazz sound.

  6. #30

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    I'm glad for you too. Congrats!

  7. #31

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    Quote Originally Posted by Dave325
    Thanks everyone for their input on the repair option. Over three months later and 160 bucks.... I got my Poly back from repairs. Looks like it was the Power supply, something about a vertical rectifier or something. Thanks all.


    good boy, $160 is good, and you still have good amp. So you now know, they are mainly repairable

    apart from some 8" 4ohm Eminence 10 & 12 or 15" speakers are pretty easy to replace if need be. Reverb Tanks most Accutronics are available. Cosmetic things grilles foam badge harder to come by.


    I have a few. They just have it Tone Wise.

  8. #32

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    Quote Originally Posted by Jonathan0996
    This is your chance to get that wall of Pignoses you've always wanted. Just think how cool you'd look standing in front of THAT!

    Attachment 51577
    I bet most of them are empty shells

  9. #33

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    Yeah...behind them there is probably a lone IC and two jacks on a small circuit board.

  10. #34

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    That's a good result, for not too much scratch. I'm liking my MB II the more I play it. I am curious about Evans, Bluguitar and the DV Mark micro CMT though ...

  11. #35

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    I gig regularly with a very old MB II. It works great and sounds like a Polytone should.

    An Evans would be a fine modern replacement.

  12. #36

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    I remember looking for a Polytone around year 2000 or so and only being able to find one in an accordion shop.

    I didn’t know they had accordion shops.

  13. #37

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    Where did you think accordions come from? Guitar Center doesn't carry them.

  14. #38

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    Polytones were THE accordion amps.

  15. #39

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    Quote Originally Posted by sgosnell
    Where did you think accordions come from? Guitar Center doesn't carry them.
    What... You've never been to "Accordion Center"... they cornered the market on Hohner

  16. #40

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    Hard to imagine, but 60 years ago pianos, violins, and accordions were what parents had kids study...not guitars.

    Otoh, parents did sign kids up for steel guitar...at least in Socal and Hawaii where I lived.

  17. #41

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    Quote Originally Posted by Stringswinger
    I own a Polytone amp and have owned 6 others over the years. Some developed rattles that I could not fix, one had a speaker blow (and that was after Polytone had folded so I was not able to replace with a Polytone speaker), one had a reverb that quit (easy fix, $17 part, did it myself), but one died on a gig (luckily, the venue had a PA that I plugged directly into). The problem was a blown bridge rectifier, whatever that does. It was a $5 part but the repair took 2 hours @$95 per hour).

    It could cost you almost as much to fix it as it is worth. But as they say, it is the devil you know....

    Good luck.
    Most of polytone rattles coming from switch button, preamp circuit vibrations (put a piece of foam between cab and circuit), speaker screws vibration, broken springs inside reverb

  18. #42

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    Quote Originally Posted by Greentone
    Polytone was a niche piece of gear. They were designed by jazz people for jazz people. Tommy Gumina was an expert jazz musician who longed for an amp that could hold up (i.e., had the balls) for jazz accordion playing. He ended up opening up his own company and ran it successfully until his death in the early 2000s. He sold many amps worldwide on the strength of endorsements from Joe Pass, George Benson, and Ray Brown. For a couple of generations of jazz guitarists and bassists, these guys were simply as good as it gets. If Joe, George, Ray--and Herb Ellis, by the way--played your gear, your gear sold. It did.

    I have played Polytone amps since the 1970s. Other than Ampeg and Fender tube gear, I don't know of amps that I like as much. Let me add that I have tried and owned MANY, MANY different brands and models of guitar and bass amps. Evans, Henriksen, AER, and Acoustic Image amps are all excellent. I could be pleased with any of them. However, no solid-state amp has the soul and warmth of an old Polytone. The designs that Tommy Gumina employed were just fine for jazz.

    Ultimately, Polytone was a family business with no provision for succession upon the death of its founder. Things just unraveled when Tommy Gumina died. We have all seen music retail businesses do this, too.

    Aer, henriksen, etc are good machines.
    They’re cold, digital reverbs doesn’t help to warming the sound.
    Polytone is the warmest transistor for jazz.
    I also like mambo amp, and yamaha g100.
    Very good amplifiers, but polytone is the warmest.

  19. #43

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    Quote Originally Posted by Dave325
    Thanks everyone for their input on the repair option. Over three months later and 160 bucks.... I got my Poly back from repairs. Looks like it was the Power supply, something about a vertical rectifier or something. Thanks all.
    That shop must have had one heck of a backlog.

    Back when I was working repairing industrial electronics I gave myself 20 minutes to diagnose the problem. More than 20 minutes I would consult with the factory or call in outside repair. Actual repair might take several hours or days depending on parts.

    Three months I would find another repair shop.

  20. #44

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    Quote Originally Posted by Papawooly
    Back in the day, the old joke was... "What is the definition of an optimist?"

    .....

    "An Accordion player with a pager!"

    I'll be here all week ba-da-boom
    Seven years too late, but great gag!

  21. #45

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    [QUOTE=Dave325;854163. Yesterday, I flipped on the switch and BAM.. It blew the fuse. I replaced the fuse and the same thing happened.

    Regards,
    Dave[/QUOTE]

    7-8 years back I had that with two of my Polytones, i cant remember what exactly caused it but anyway its nothing much and cheap easy to fix by any repair guy,

    i looked on a couple of old invoices but zulch he always scrawls some meaningless crap, but he does a good job so cant tell what it is.

    Dont throw amp out if you like.