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Thread: JBL 6260 power amp

  1. #16
    Tom Loizeaux
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    My guess is that there's not going to be much change in the way these amps sound over time. They have "burned in" way back when. You might want to adjust your L Pads to help get the balance you like.
    Keep us posted.

    Attached is a photo of my other JBL Urei amp box, sitting on top of my 4333s.

    Tom
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  2. #17
    Senior Member GordonW's Avatar
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    Well, if they've been sitting for over 10 years, then the electrolytic caps and such have probably oxidized and unevenly dried out inside. They will need to be re-formed (by being used at voltage for a period), before they'll work at 100% performance. Could make a very slight difference in the sound... enough to make a perceptable 'graininess', sometimes.

    Regards,
    Gordon.

  3. #18
    Member 4344's Avatar
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    6260 & 6290

    i am working hard to run the amp

    and one thing.....
    per as grumpy say : the fan isn't the quietest , but does keep the amp from melting

  4. #19
    Member 4344's Avatar
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    6290

    OMG!

    I turn the power off of both channel A & B, the clipping indicator "ON"! How come...why's that??? It can just be "OFF" after I plug out the socket?

  5. #20
    RIP 2011 Zilch's Avatar
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    There is enough energy stored in those amps for the indicator LED's to remain illuminated for a minute or so after you turn them off. Consider it a "lamp" test. The relay you heard has long since disconnected the speakers....

  6. #21
    Tom Loizeaux
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    Quote Originally Posted by 4344
    OMG!

    I turn the power off of both channel A & B, the clipping indicator "ON"! How come...why's that??? It can just be "OFF" after I plug out the socket?
    It might be good for you to read the owner's manual for the 6260 amp. Understanding how to operate these does help prevent problems and reduce anxiety.

    Tom

  7. #22
    Senior Member Jakob's Avatar
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    Hi all,

    I don't know if You experienced this, but on my 6290 it's not the fan that is the big problem, it's mechanichal noice from those big transformers! They rattle the whole amp. To reduce this I've removed the top-lid, that helps a bit to get rid of the box-resonance. However, I use them to drive a pair of 18" and never felt I needed more power. At my listeninglevel that is a remarcable thing, and then You don't hear nor the fan or the transformers

  8. #23
    Dang. Amateur speakerdave's Avatar
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    Yeah, the vibration noise can be a problem even with the smaller amps, the 6230 and 6260 (which I now have on my 4333A's--the 6230 is nice, but too small by itself). The top of the case seems to be the usual culprit--a reminder that these amps were not designed for livingroom use. I leave it on, though, for safety, etc.; I use an old paper back to dampen it, careful not to block the venting slots. A beanbag of shot would work even better.

    David

  9. #24
    Senior Member GordonW's Avatar
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    Hey, one caveat to those who have these 6260 amps (and will probably apply to the 6230 and 6290 as well):

    There are some "power resistors" (1 watt resistors) in the amp, that seem to be a bit under-sized, power-handling wise. I started to have a weird "clicking" distortion out of mine (like the output relay was "dropping out" momentarily on high-power transients), and when I went inside to inspect, I noticed about 4-5 of these resistors that had gotten hot enough to brown the circuit board!

    The 6260 is now at a very competant repair tech, to have all those resistors replaced (with 5 watt resistors, spaced off of the board about 1/4" to enhance airflow and miminize heat transfer to the board), and for a general checkout. I'd recommend you all look inside your amps too, to make sure you're not having problems with these "mini-space-heaters"...

    Regards,
    Gordon.

  10. #25
    Dang. Amateur speakerdave's Avatar
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    Thanks, Gordon.

  11. #26
    RIP 2011 Zilch's Avatar
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    Another tip:

    One of the used 6260's I received had a problem with the standby relay buzzing and being intermittant. It was obvious that a technician had struggled with the temperature sensor and capacitors in the circuit to make it half-assedly work.

    Had he bothered to look at the +/- 15V supplies on an oscilloscope (an old-school ANALOG test and measurement device ,) he would have seen substantial ripple there. The culprit? Small electrolytic filter capacitors located too close to the three-terminal regulators had dried out over time. I replaced them and restored the standby/overload circuit to factory values, which worked to perfection.

    On loan to Mr. Widget for audition, he's been driving his Sub1500's with that amp without complaint for a while now....

  12. #27
    Senior Member GordonW's Avatar
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    Quote Originally Posted by Zilch
    Another tip:

    One of the used 6260's I received had a problem with the standby relay buzzing and being intermittant. It was obvious that a technician had struggled with the temperature sensor and capacitors in the circuit to make it half-assedly work.

    Had he bothered to look at the +/- 15V supplies on an oscilloscope (an old-school ANALOG test and measurement device ,) he would have seen substantial ripple there. The culprit? Small electrolytic filter capacitors located too close to the three-terminal regulators had dried out over time. I replaced them and restored the standby/overload circuit to factory values, which worked to perfection.
    That may be at least part of the problem with mine. Same symptom, sort-of... the relay will momentarily "drop out" on high-power transients.

    I'll make sure that the tech checks that +- 15V supply... though, knowing him, he's probably already on the case, WAY before I mention it...

  13. #28
    Administrator Mr. Widget's Avatar
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    Quote Originally Posted by Zilch
    On loan to Mr. Widget for audition, he's been driving his Sub1500's with that amp without complaint for a while now....
    I am using it in my music only configuration... even when pushing it to see how crazy loud the system could go the peak indicators have not come on with these 4 ohm woofers. I am crossing them over at 50Hz, so with musical program there isn't a lot of content.

    I doubt it would work in my HT application where I have seen certain explosions clip my 660 watt JBL MPA 600 driving the same speakers!


    Widget

  14. #29
    Senior Member GordonW's Avatar
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    I dunno. Even in it's "semi-crippled" condition (the relay dropping out), my 6260 was still strong enough to make an entire storage unit building RATTLE, on just a pair of Eminence 15" drivers in 3.7 cubic foot vented cabinets. I mean, loud enough that the storage unit bays on the OTHER side of the driveway were rattling!

    IME, those 6260s and 6290s had power, quite beyond what would normally be expected for their ratings. I'd expect, though they're rated at the same power, that the 6260 has close to TWICE the "usable" power of my QSC 1400... it'll easily drive subs to near-destruction, that the '1400 would not even begin to stress...

    Regards,
    Gordon.

  15. #30
    RIP 2011 Zilch's Avatar
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    Yeah, Mr. Widget,

    Give it a try. The forum MUST know EVERRRYthing about stuff JBL!

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