greed2000 Posted May 19, 2001 Share Posted May 19, 2001 My band upgraded from a 12 channel mixer to a 16. My Ampeg has stereo XLR outs, so I grabbed a couple new XLR cables and plugged 'em in. As soon as I plugged into the board, I got low noise out of my amp. We tried moving to different channels on the board, but the noise persisted. We also checked all the channels with mics and they worked fine. When I changed the volume of the amp, the noise level didn't change. Does anyone know what I could check to get rid of the noise. Or can anyone tell me how to check the XLR outs without taking it to a shop??? thanks in advance Link to comment Share on other sites More sharing options...
fantasticsound Posted May 19, 2001 Share Posted May 19, 2001 No need to check the XLR outs. It's an Ampeg. Big amp, big reputation.. for noisy DI outputs. http://www.musicplayer.com/ubb/smile.gif There is a simple fix. It's gonna cost you, though. Head to the nearest music store and buy an isolation transformer for each output. Rapco makes a little rectangle that's sturdy enough. don't forget an XLR patch cable too. The transformer will pass the signal, but not the amp noise. I'm not an electrical tech, but I'll bet if there's one in here he or she will attribute it to an poor electronically balanced output. If it were transformer balanced, you wouldn't have to add your own transformer. But that costs them more money, so... Ebtech intends to make a killing with their hum eliminators. (which you could also use. Be sure to use TRS - XLRf and XLRm patch cables. You'll understand when you see one.) Why, you ask? Because of all the Mackie boards which don't have true balanced outputs. They (Mackie boards) don't take advantage of Common Mode Rejection, one of two major advantages to balanced lines. (The other is good transmission over long cables.) Hope this helps. Neil It's easiest to find me on Facebook. Neil Bergman Soundclick fntstcsnd Link to comment Share on other sites More sharing options...
greed2000 Posted May 19, 2001 Author Share Posted May 19, 2001 Thanks for the advice. I'll definetly check out the isolation transformers. Link to comment Share on other sites More sharing options...
greed2000 Posted May 21, 2001 Author Share Posted May 21, 2001 A ground lift got rid of my hum. However, I am getting no signal to the board. How can I check the XLRs for output? Link to comment Share on other sites More sharing options...
greed2000 Posted May 22, 2001 Author Share Posted May 22, 2001 I run a Johnson J-Station into the "power amp" ins on the back of the Ampeg bypassing the Ampeg preamp section. I was thinking that maybe the XLR outs come from the preamp section of the Ampeg (which I'm not using) and maybe this is why I not getting any signal at the XLR outs. Could this be the problem? Unfortunately the map is at the practice area and not my house, so I can't check my theory until Friday. Link to comment Share on other sites More sharing options...
fantasticsound Posted May 23, 2001 Share Posted May 23, 2001 Originally posted by greed2000: I run a Johnson J-Station into the "power amp" ins on the back of the Ampeg bypassing the Ampeg preamp section. I was thinking that maybe the XLR outs come from the preamp section of the Ampeg (which I'm not using) and maybe this is why I not getting any signal at the XLR outs. Could this be the problem? Unfortunately the map is at the practice area and not my house, so I can't check my theory until Friday. You hit it on the head! http://www.musicplayer.com/ubb/biggrin.gif Inserting your J-Station after the internal pre will not connect to the DI outputs. Do you have a stereo line in for efx? A Whirlwind Q-box will allow you to monitor mic and line signals through an internal speaker or a pair of headphones. It's pricey unless you will make use of it a lot. I believe they're around $150, but check online. Do you sing as well onstage? If so, try the iso-transformer. Otherwise you may get a nasty shock from grounding the mic through your lips (if you get right on it like so many of us) to your guitar strings, when you touch them. Neil It's easiest to find me on Facebook. Neil Bergman Soundclick fntstcsnd Link to comment Share on other sites More sharing options...
greed2000 Posted May 23, 2001 Author Share Posted May 23, 2001 Thanks for your reply. I think I'm probably going to say screw it and mic the amp. I don't really want to because of too many mics on stage already, but this is getting to be too much (trying to run direct). I going to try running a mono signal to the amps guitar input sending the J-station through the Ampegs clean channel (which is basically my practice setup using a small Rocktron amp). If it sounds OK, then iso-transformers are in my future. I don't need to get lit up when slobberin' on my mic! thanks for your insight Link to comment Share on other sites More sharing options...
fantasticsound Posted May 23, 2001 Share Posted May 23, 2001 Actually, you've missed the most common way to achieve what you want. A DI. If you're unfamiliar, any DI worth having onstage has a parallel output for connecting to your amp, instrument input or power amp input. You should have a couple for your PA anyway to accomodate acoustics, keyboards, etc. that have unbalanced outputs. Since the J-station is providing the complete sound, you need only use your guitar amp as a monitor. And if you can get your own onstage monitor mix, you don't even need the amp for anything. A buddy of mine was playing with Janie Fricke (older country singer) and used a POD with no amp. This is happening a lot onstage, especially in light of ear monitors becoming widely available. Neil It's easiest to find me on Facebook. Neil Bergman Soundclick fntstcsnd Link to comment Share on other sites More sharing options...
greed2000 Posted May 29, 2001 Author Share Posted May 29, 2001 So, if I have this figured out... I can use the 1/4" outs from the J-station and go into a DI. From the DI, run the 1/4" to the amp and the XLR to the board. Does that sound right? BTW, Carvin has some very inexpensive DIs ($25). Has anyone used them and if so, how do they sound? Link to comment Share on other sites More sharing options...
fantasticsound Posted May 30, 2001 Share Posted May 30, 2001 Yes, that's the right way to set up. As to DI's, I can't speak to the Carvin's myself, but Whirlwind's IMP, DIRECTOR, and their new one (can't remember the name) are good. The new one has everything circuit board mounted, jacks included. It's cheaper to build, and theoretically more prone to damage, but if you're the only one using it, I should point out that many pedals are manufactured this way. It sold for about $25 at the local Mars. (Check www.marsmusic.com) Neil It's easiest to find me on Facebook. Neil Bergman Soundclick fntstcsnd Link to comment Share on other sites More sharing options...
greed2000 Posted May 31, 2001 Author Share Posted May 31, 2001 Thanks a million for all your help. I've learned a great deal. greed Link to comment Share on other sites More sharing options...
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