Roland JC120 Line Out/Speaker disable

th902

Hi folks. Just wondering, is it ok to put dummy cables into the speaker outputs while using the line out on a JC120? Or should I disconnect the speakers? It's an idea for late night practice/recording. 

Cheers!

ICBM

Depending on the version, plugging an unconnected cable into the extension speaker jacks may not turn off the speakers - on some versions they're in parallel so the speakers will remain on. On other models they're in series so it will - make certain the other end of the cable is protected or taped over so it can't short against anything.

If not and you're going to disconnect the speakers, you only need to remove one connector from each speaker, and you also must tape or otherwise insulate the loose end of the cable to make sure it doesn't short against anything or you may do serious damage to the amp.

Either way, don't crank it up too far - although most solid-state amps are fine with no load, if there is any risk it's worse with the amp turned right up.

th902

Thanks for the advice, it's very much appreciated! It works totally fine, and the speakers are quiet with the plugs in the back. I have to put the volume to about 8 to get a usable signal though, so hopefully that won't cause any problems. Cheers again. 

ICBM

th902 said:

Thanks for the advice, it's very much appreciated! It works totally fine, and the speakers are quiet with the plugs in the back. I have to put the volume to about 8 to get a usable signal though, so hopefully that won't cause any problems. Cheers again. 

I’m very surprised you have to turn it up that far. When you say plugs, do you mean just spare jack plugs?

Not shorting plugs I hope...

th902

Me too, to be honest. I think the signal from the line out might be a bit weak. It's very hissy, so have to turn it up to get it competing with that. Yeah, just a couple of those pedal connector things haha. 

ICBM

That is a bit strange - if it's very hissy relative to the signal volume that implies the level is too quiet earlier in the amp... although JCs *are* quite hissy, it has to be said! It just doesn't come out through the speakers much because there are no tweeters.

Looking at a schematic for a version with a series speaker connection, I can't see a reason why disconnecting the return ground path (which is what the switch in the jack does) should affect the Line output, so I don't think it's that. Does your version have an FX loop, or just a power amp input jack?

th902

Yeah, it's very hissy, and doesn't have the high end filtered like it would through the speakers, so it's a lot more noticeable. It's an old one that has the Main Ins on the back, but no FX loop.