Behringer vt100fxh not powering on.

[Four]

So I just got a brand new 212 from avatar with Eminence Delta Pro 12a's in a stereo config. I plug my head in and get all sorts of rattling coming from the cabinet I just got. The volume wasn't much past 4 or so. It always seemed the rattling would happen on the bass somewhere around C in the 8th Position, the chord was something like a 1,3,7. After re-wiring the speaker with the correct stereo back plate config and thinking everything is cool, I still get the rattling. After some research on the speaker I found its resonate freq is about 51 Hz. No matter if it was clean or dirty I always got the rattle around the same spot on the guitar with the same chord. Out of curiosity I start to move around the room and as soon as I get close to the amp head it powers off. My initial thought was the fuse, I got replacements and still no power. I would test a fuse before installing and flipping the switch, the fuse would be good but as soon as it goes in the head, the fuse is dead. The culprit may have been cables, but while not an expert I'm getting signals all over the preamp(?) and there definitely seems to be a signal running from the main input to the head's output, so I'm not sure if something is shorted or completely screwed. Nothing "looks" burnt but there is a weird acidic burning smell. Unfortunate this seems to be a "Legacy" product and it is Behringer, so finding a schematic may not happen. I always know these things are hit and miss over the internet but any assistance is appreciated.

[Enzo]

Sounds like you have a resonant buzz/rattle in the cab. Probably nothing to do with the amp. It always happens with the same notes, because they are at the frequency of the resonance. Something is probably loose inside. Speaker mount hardware, cabinet hardware, loose wood joint in the cab body, handles, etc etc. Wiring won't change that.

As to why the amp won't power, that is separate. If it is blowing fuses, then it has something shorted - power tube or transistor, rectifier, something...

[olddawg]

It's a 100 watt SS amp. If you blew a speaker to a dead short you could have killed the output devices in the amp as well. First thing I would do is plug a cord into the speaker cab and measure the DC resistance tip to sleeve at the other end. You can also test cone movement with a 1.5 v battery. If it isn't a dead short (Should measure around 7 ohms for an 8 ohm cab), try a different amp but be careful. A rubbing voice coil could kill the next amp. If either are under manufacture's warranty, call and bitch like hell. They will probably resolve the problem.

[Four]

Sounds like you have a resonant buzz/rattle in the cab.

This was a guess of mine as well.

Something is probably loose inside. Speaker mount hardware, cabinet hardware, loose wood joint in the cab body, handles, etc etc. Wiring won't change that.

I did a quick glance inside for this when I re-wired the cab and everything seemed super tight and and well assembled. The thing I can say is there isn't any kind of bracing or "kludge" inside. I'm not sure if these are less common in 212s?

As to why the amp won't power, that is separate. If it is blowing fuses, then it has something shorted - power tube or transistor, rectifier, something...

I plugged in an old(ten years?) 25w 110 solid state combo and the 212 cab seems to work fine but I haven't tried "pushing" the cab yet with the 110. I'm gonna do another exam of the cab, try to get some more advice and call avatar. So as of this moment it only seems to be the amp that's malfunctioning but I guess I won't really know till I can do some more testing of the cab. I've also heard that sometimes when SS amps don't power up it can be the power switch but I tested that to the best of my ability and that seems like it transmitting something. The only thing that seems unresponsive is the power transformer.

[Four]

It's a 100 watt SS amp. If you blew a speaker to a dead short you could have killed the output devices in the amp as well. First thing I would do is plug a cord into the speaker cab and measure the DC resistance tip to sleeve at the other end. You can also test cone movement with a 1.5 v battery. If it isn't a dead short (Should measure around 7 ohms for an 8 ohm cab), try a different amp but be careful. A rubbing voice coil could kill the next amp. If either are under manufacture's warranty, call and bitch like hell. They will probably resolve the problem.

Thanks for the advice. I'll google how to test cone movement unless you could explain it easily here, otherwise I'll see what I can find. From what I can tell so far the cab is at least functioning. Again I'll have to do some exact tests to be sure.

[Four]

I should also mention the cab is closed back.