Monitor amps, a little help

[Rick Collins]

Try to make this short. We were using one 2 channel amp for 6 monitors, 3 on each channel. we bought 2 new Crown XLi 1500 amps so we can put one monitor on each channel. Now it seems we can't get anything on one channel. we have s signal coming into it. Can see the level lights when we talk into the mike, just won't come out. Did we buy a bad amp or is there something we are or aren't doing right ??
we even have taken the speaker line from the other channel and switched around. also what seems weird is the INput side of lead that works says ch 1 but the sound is coming OUT on ch 2 !!

 

[MNicolai]

Check all the settings on the back of the amp. It sounds like you're running it in Parallel instead of Stereo. Look closely at your switches near the input connectors.

 

[Rick Collins]

Yes, we have checked the parallel switch. didn't help.

 

[FMEng]

Check the wiring of the speakon connectors. Perhaps your cable was wired for bridging on the previous amp.

 

[TimMc]

Try to make this short. We were using one 2 channel amp for 6 monitors, 3 on each channel. we bought 2 new Crown XLi 1500 amps so we can put one monitor on each channel. Now it seems we can't get anything on one channel. we have s signal coming into it. Can see the level lights when we talk into the mike, just won't come out. Did we buy a bad amp or is there something we are or aren't doing right ??
we even have taken the speaker line from the other channel and switched around. also what seems weird is the INput side of lead that works says ch 1 but the sound is coming OUT on ch 2 !!

Okay... The input mode switch MUST be in "stereo" mode. The switch is probably in the Bridge or Parallel mode if you are sending a signal to channel 1 only, but seeing signal lights on *both* channels. While you're at it, make sure the input level switch is set to 1.4V as well.

Reduce the number of variables.... connect only 1 signal to the amp, using channel 1. You should have an output only from channel 1. If you have output from both, re-check the input mode switch position. DO NOT change this switch while powered on. IF you have channel 1 correct, then physically move the input connector to channel 2 on the amp and verify proper operation, i.e. audio only from channel 2 output.

If you had both inputs to the amp wired up, it's possible you were sending signals to both channel from your mixer. You can bypass the mixer by using an SM58 or similar dynamic mic and plugging directly into the amp. It won't be loud, but there will be enough output level to drive a loudspeaker sufficiently to verify operation of the amp.

 

[Rick Collins]

OK, figured out what the problem was. For WHATEVER reason, the Speak-on plug for one or the other (channels 1 or 2) will Not work at the same time. BUT, if we use the banana plugs on them all it works fine. Something wrong in the amp itself and we aren't going to worry about trying to get it exchanged.

 

[FMEng]

Like I said, a miss-wired speakon cable connector. The amp "Channel 1" speakon includes both channels, so there is easy opportunity for it to be wired wrong and cause unusual behavior. The "Channel 2" speakon is just that one channel. This info is well described in the manual and screened on the back panel.

 

[Rick Collins]

The miss-wiring was not what we did attaching the connectors. It's INSIDE the amp. All our connectors/speakers work. The speak-on female ends in the amp are not right.So we are just staying with the banana plugs.

 

[DrewE]

The miss-wiring was not what we did attaching the connectors. It's INSIDE the amp. All our connectors/speakers work. The speak-on female ends in the amp are not right.So we are just staying with the banana plugs.

It would be extraordinarily strange for there to be miswiring of the speakon connectors inside the amp, as they are directly mounted to a PC board. I'd go so far as saying it's virtually impossible. Having an open connection is probably more likely, but would still be highly unexpected from a new amplifier that presumably went through some QA testing. It sure sounded like your cable, or at least the one(s) you tried, had the speakers connected to the second channel on the speakon rather than the first channel that the amplifier was intended to use (well, unless you want to access both channels from the channel 1 speakon connector).

At any rate, there's nothing wrong with using the banana plugs, and of course no sense in spending much if any time mucking about with what you now have working.

 

[Ben Stiegler]

Banana plugs - ugh bad - wait til something tugs the cable during showtime and it pulls loose. Takes 5 mins to open the speakon shell and visually verify that it’s wired correctly.

 

[MNicolai]

It would be extraordinarily strange for there to be miswiring of the speakon connectors inside the amp, as they are directly mounted to a PC board. I'd go so far as saying it's virtually impossible.

Agreed. The one caveat I'll put on that is that I have seen the Bridge/Parallel/Stereo switches go bad, so it's not outside of the realm of possibility that you're set to one mode but the switch is activating a different mode, but it's nearly impossible that the internal wiring of the NL4's are bad. Cable connectors are much more likely, whether that's at the amplifier end of those cables or at the speaker end -- or both.

As @FMEng pointed out, the pinouts are a little different on the connectors by design. This is so you can you use the amplifier either as two separate NL4 connections with one channel on each 2-conductor cable, both cables wired to 1+/1-, OR you can use a 4-conductor cable and have 2 channels delivered on the same cable. The common use cases for this are if you have bi-amped speakers and are separately driving the LF and HF drivers, or if you are using speakers in a "Mix Top/Sub" configuration where the tops might be wired to 1+/1- and the sub might be wired to 2+/2- so you can deliver one cable to the sub and then loop through up to the top speaker.

If you must use the bananas, then go for it -- but I would be highly suspicious of the NL4 pinouts of your cabling between the amplifier and the speaker.