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About prosigna

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  • Location
    Greeneville, TN
  1. I was adding my subs to an installed system in the local colleges theatre for a ballet. The installed system is composed of a pair of Peavey PV-112 mains with no subs, some Realistic speakers hanging in the lighting rig above the stage as monitors. All run by a pair of Peavey CS-800x4 4-Channel amps and a small Mackie mixer in the booth. Since the ballet has a very fine selection of music the lack of bottom end in this system has bothered me and I volunteered to add my subs. My subs are a pair old Peavey SP-118 driven by a PV-1500 amp in bridge mono using the internal crossover of the amp. I took the amp up to the alcove where the theatre's amps are and tried to figure out how to patch into the system. There are two patch panels in this alcove - one is a typical 1/4" TRS patchbay normalled passing the signal between different line sources and the 8 amp channels. The other is a 1/4" TS speaker patching panel attaching the amp outputs to the various 1/4" locations backstage and in the orchestra pit. I plugged a bannana-to-1/4" adapter into the amp in bridge mode, plugged a 12-ga 1/4" speaker cable from the adapter to the "A" speaker patch point going to the pit and began studying the signal patchbay. Pretty soon there was an oder, smoke, light inside my amp (where there are no LEDs), protect lights were bright red, then flames. A resistor on each channel's board burned up. I shut it off, metered the jack I had patched into, and it measured OPEN. Went home and grabbed a dinosaur CD-800, the really heavy ones from the early 80's. Patched it in and got the subs working but with a serious hum. Lacking adapters or more cables I put off tracking down the hum until the next day - it didn't seem to bother anyone in the production other than me..... Returned with many adapters, solder station, cables, the who tool kit for finding a ground loop and fixing the hum. Now when fired up channel B's LED would glow bright RED and channel 1 on one of the installed PV-800x4's began to glow bright green. This channel has no input signal and should NOT be flashing. I began to isolate the hum but then the output to the subs was much lower than earlier. These subs with this amp in this empty room should thump when AC/DC Thunderstruck is played. The Technical Director for the college is a great friend, a true artist, set designer, and lighting guru. He is not a sound man but he has wired up the whole system. I am beginning to help him understand where to lift pin 1 and also to NEVER CUT THE EARTH GROUND OFF THE POWER PLUG. I am very concerned that the speaker patch panel has fried two of my amps. This panel is a steel panel with standard panel mount 1/4" TS jacks. It dawned on my this was connecting the Neg. post of all the amp channels together - all 8 channels of the CS-800x4s and whatever amp I patched into the jacks leading to the pit. Also, in the pit the jacks are all panel mounted to the patch panel. Connecting the negative is in best case - it assumes no one flipped polarity between the speaker output and the patch point. Would y'all agree the speaker patch panel causing community between the negative posts is "bad" and possibly fried my amps?
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