SWR 900 set up wrong? Long post.

[AltGrendel]

I'm trying to figure out if I missed something or if there was something wrong with the head. Just trying to learn here, so please play nice.

I was working as a stage hand at a out door jazz gig (5 bands) and was helping set up the back line. The bass rig was a SWR-900 (brand new) and two Goligth cabs, 4x10s. The bass player asked for some help and I was volunteered as "the bass guy" to help. The bass was a '62 reissue and was plugged into a DI that was running to FOH and to the passive input on the SWR. He wasn't getting any sound from the rig. I checked the back and the cabs were plugged into the X-over outs. I powered off the amp and plugged one each into the parallel stereo outs. We had sound for about a minute, then it cut out and wouldn't come back no matter what I changed. Powering off each time I made sure the stereo/mono switch was set for stereo, tried the X-over outs again. Nothing worked and we wound up using a different head entirely.

I couldn't check the fuses (no multi-meters around) and there weren't any Speakerton cables of that size around. The Goligths were set for 0db and worked fine with the replacement head. Knob tweaking on the front panel made no difference. I can't think of any thing else I could have tried.

Any ideas what I may have missed?

[murphy]

Does sound like a fuse issue

[IvanMike]

were those speaker level crossover outputs or line level? If they were line level and meant to be wired to the inputs of the poweramps they "Saw" far less impedance than they "wanted" hopefully just a fuse but you could have fried some internal components.

If they are the same as the old swr units the fuses are a fast blo and a slow blo that you can simply screw out and visually examine and replace as needed.

[bandl]

You need to plug the speakers into the speaker output jacks, not the crossover outputs. Those are line level signals that are generally routed to the effects return jacks for using the internal amps for biamping.

[IvanMike]

ahhh what i thought. my guess is you may have fried something with the impedance mismatch.

[AltGrendel]

Originally Posted by bandl

You need to plug the speakers into the speaker output jacks, not the crossover outputs. Those are line level signals that are generally routed to the effects return jacks for using the internal amps for biamping.

That would explain everything. Thanks.

Originally Posted by IvanMike

ahhh what i thought. my guess is you may have fried something with the impedance mismatch.

I was afraid of that.

Couldn't visually check the fuses, they were the ceramic kind (you know what I mean).