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problem with 480T

mikemorrison281mikemorrison281 Posts: 3
edited October 2009 in 400 Series General Discussion
I was doing an install at a new club last night and while using my 480T, I started noticing a weird cycling "blip" in my white noise bursts. My gain structure should've been blowing my hair back but output was just ho-hum but the signal the amps were seeing was HUGE. Almost felt like the 480 was doing a severe limit and passing a signal filled with square waves or something...while trying to tweak a mid, I smoked an amp. The noise was tracking on all speakers and amps, too, just really pronounced in the subs.

any ideas what the 480 could be doing to push a signal weird enough to put a QSC 2000 into "help, I'm on fire and I can't turn myself off" mode?

I also couldn't get a Mac or a PC to talk to the 480? Tried to download the last software update and dbx website said the page was not found...??? I know dbx is really high on the 4800 now, but isn't there some support for us 480 users out here?

thanks for any ideas,

morrison

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    GadgetGadget Posts: 4,915
    Hi,
    Sorry for the delay, but I was at school and the forum went down... That is very odd.. a line level device really shouldn't be capable of doing ANY damage to any other line level device...there just isn't enough voltage there to blow anything in any other device it's hooked to even if it were all square waves... I.E. massive clipping...HOWEVER I have heard of amps going nova and back feeding a voltage spike that wiped out whatever was before it...The fact the amps meters were going crazy input signal meter wise,
    should've been blowing my hair back but output was just ho-hum but the signal the amps were seeing was HUGE.
    and the output was only - so so - is also very odd...Is it possible that the limiters were feeding the amps a massively squashed signal that had the amps duty cycle running unusually high... or that there was a brown out power wise? Because a low voltage situation can wreak havoc on amps, low power can really do weird things, and as I write this I can't really think of anything else that would explain this phenomenon, but I have forwarded your question to tech support, and I'm sure they will respond soon.

    Please keep us informed..
    Gadget
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    DennisDennis Posts: 801
    Huge signal in and small level out sounds like a polarity issue...maybe caused by the 480. Were you getting huge movement on the speakers?

    Dennis
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    GadgetGadget Posts: 4,915
    Hmmm would explain letting the smoke out of speakers... but letting the smoke out of the amp? Also no indication that anything was changed by the OP that might lead him to believe any change had caused the problem...
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    DennisDennis Posts: 801
    it was just a thought.

    Something as simple as accidently switching amps into bridge mode but connecting the speakers in normal mode would put half the system in reverse polarity. It costs nothing to double check everything.

    Dennis
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    mikemorrison281mikemorrison281 Posts: 3
    I'm not sure, but I think the guy that was originally trying to program the 480 had a limiter in the chain and square-waved the amps/speakers.

    After another call to Jason@dbx, I did a global reset and started from scratch. So far, no more smoking amps and speakers are acting civil.

    Has anyone been successful in using usb cables with db9 adapters on a new laptop to control the 480? I had to track down an old laptop with db9 ports to tie into the 480...not fun and not convenient, at all.

    and thanks for all the responses!!!
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    GadgetGadget Posts: 4,915
    There are a few USb/serial converters that are tested and verified...Find those here ;
    http://www.dbxpro.com/Download/pdfs/RS-232Adaptors.pdf
    I still don't see how square waves would kill an amp? Maybe causing a brown power situation (sag in the line low enough to smoke the amp...)???? Hmmm
    G
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    DennisDennis Posts: 801
    There is also an old thread from back sometime in 2005 about rolling the Serial/USB converter drivers back to an older version because the newer driver was not compatible with DriveWare. This applied to several makes/models because they were all the same driver (something like "Aten" I think). The thread included a link to the old driver.

    Dennis
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    GadgetGadget Posts: 4,915
    Perhaps this is the link:
    http://www.wombatsound.com/dr260/usb.php
    I'll post that in the appropriate thread in the FAQ's as well...

    G
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    DennisDennis Posts: 801
    Yup, thats the one. It took me weeks to get my laptop to talk to DriveWare until I found that thread a few years ago.

    Dennis
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    GadgetGadget Posts: 4,915
    Good! I put it in these threads:
    viewtopic.php?f=60&t=1049&p=4351#p4351
    and
    viewtopic.php?f=60&t=1063

    G
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