accoustic pickup/pre amp noise

[J Wah]

I have and a L.R. Baggs RT pickup with no built in preamp that I run through a L.R. Baggs Para Accoustic D.I. playing a Guild DV-52. I just got a Mackie VLZ 1202 Pro mixer and was setting up last night. I ran the Guild to the D.I., out the XLR and into the Mackie preamp. It sounded great at low volumes but as soon as I turned it up there was a lot of noise ("SSSSSHHHHHHHH"). If I turn the gain down on the channel it is quiet. I had a pretty hot mic on one channel with very little noise. I turned down the adjustable gain on the D.I. but when the gain was increased on the mixer to get the same level, the noise was back. I am not talking about high levels, this was comfortable levels through headphones on the Mackie. The other thing I noticed was when I touched the D.I. like to invert the signal, I was hearing the touching through the headphones.

Any ideas where the noise is coming from or what I could do?

Thanks alot

J

 

[Tom Hicks]

That stuff was designed for live sound,where a little extra noise isn't as big a deal.For recording purposes,a small diaphragm condensor mic is the way to go.A condensor mic will give you a more accurate reproduction than dynamic mics.Small diaphragm responds faster (less mass) than large diaphragm to better capture transients of guitar attack.

You could have a bad ground in the DI box.A possible explaination is that when you touch the metal box it is grounding through your body.Just a guess based on your symptoms.

Tom

 

[J Wah]

I think the noise when I touched the D.I. was do to a bad input connection. I am still getting alot of "hiss". I have tried new cables, different channels and about anything else I can think of. It has probably always been there but I am just now noticing it with the new Mackie. I am using most channels and this is the only one I get noise from. Does anyone use the L.R. Baggs Para Accoustic D.I.? Do you get any noise from it? Maybe its the pickup? They are both supposed to be clean and quiet. Help! The hiss is driving me crazy!

 

[Opus]

Yeh sure but....

Tom is absolutely right, the noise you hear when you touch your DI is caused by either a bad earth or bad sheilding. If this is the case I would take it back to the shop you bought it from and let them listen to it, if you're lucky it might be a warranty job!

However, if this is an active pre-amp then you're going to get noise at high gain settings no matter what you do. Try adjusting the input gain on your mixer using the PFL setting if it has one, basically you want the input signal to peak at zero on your meters when viewing it pre-fade. You'll notice a similar noise when you play a bass with a built-in active pre-amp, it's just the nature of the beast unfortunately. I know with basses you can sometimes change the op-amp IC with a better quality chip and this will remedy the problem to a point, possibly the same applies with your equipment.