Buzzing sound with my new preamp

[astro21]

Hey all, here is my setup:

- R0DE NT2-A (just got it...)
- ART MP Studio preamp
- Monster cables
- BOSS BR-600

Here is my problem: I can hear a buzzing sound when the NT2-A is plugged in. This buzz appears when I raise the recording and mic levels on the BR-600, the more I raise them, the louder the buzz. On the other hand if I keep the recording and mic levls on the BR-600 on the low side (like 10-15%) and raise the input and output levels on the preamp, the buzz doesn't seem to be there. (or at least it's very very quiet) To get decent vocals and not hear almost any buzz, I would thus need to set the input and output levels on the preamp to about 75% while keeping the recording and mic levels on the BR-600 very low.

Is this normal? I'm assuming that the buzz comes from the preamp, not from the NT2-A. It doesn't come from the BR-600 because the incorporated mics don't cause any buzz at all.

It's really annoying me. While I know that the ART MP Studio is one of the cheapest preamps available, I didn't expect a buzz.

Could someone tell me what's wrong and how to make it right? Should I just stick to my formula of high input/output levels on the preamp and low recording/mic levels on the BR-600 and be content with that?!

Thanks.

A.

 

[tmix]

It is called "Gain Staging".

Basically in non technical terms what you are hearing is the electronics / impedance/ whatever interaction of 2 preamps. (the one on the Boss and the ART)

The simple answer is is you are going to have to use your ears to set the amount of gain that gives you the most level with the least noise.

If you are looking for clean, I would start by monitoring through the boss, plugging every thing in and on with all the gain settings down.
Turn the gain (on the Boss) to a quiet, lower setting that is appropriate for a line level (like a keyboard) setting, turn it down if noisy. then start with the output gain of the ART, turning it up till you here a sweet spot. The noise will sometimes dissappear for a second then come back louder , sometime it is linear starting out nonexistent and getting constantly louder. Then turn it back a little. Then bring up the Arts input gain till you start to hear noise and back it off to quiet.

It takes a little effort , but it is worth it.

 

[crazydoc]

Hissing type noise is normal with poor gain staging. Buzzing is not. I am assuming this buzzing is some type of 60 or 120 cycle hum.

Does it only occur when the mic is plugged in? If there is no noise when the mic isn't hooked up, but the gain is turned up in the preamp, then the problem may be with the cable or the mic. Have you tried changing cables? Have you used a different mic?

If the noise persists when the mic isn't hooked up, then the problem is probably in the preamp or the cable/connectors from the preamp to the recorder.

I am also assuming you are connecting the preamp to the line input of the recorder, and not the mic or guitar inputs.

 

[astro21]

Thanks for your replies and help. I'm a newbie, as you certainly noticed.

The preamp is connected to the mic entry of the BR-600, not the Line In. I assumed that because it is a mic that I'm plugging in that's where it should go. Should I plug it in the Line In instead, and if so why?

 

[crazydoc]

Thanks for your replies and help. I'm a newbie, as you certainly noticed.

The preamp is connected to the mic entry of the BR-600, not the Line In. I assumed that because it is a mic that I'm plugging in that's where it should go. Should I plug it in the Line In instead, and if so why?

This is very likely your problem. The mic input is to directly plug a mic into - it has the high gain needed to amplify the low level (low voltage) electrical signal put out by a microphone. It is actually a preamp. When you plug the mic into your ART preamp, it amplifies the signal to "line level" (about 1 volt) which needs to be connected to a matching line level ("line") input of the next device.

By plugging a line level output (the ART) into a mic input, you are not only overamplifying the audio signal, but you are amplifying any noise in the signal also.

If you hook up the output of the ART to the line input of the BR-600, everything should work fine. Or, if the recorder has phantom voltage, you could plug the mic directly into it. (Edit: it doesn't seem to in the specs I just looked up.)

 

[astro21]

Thanks for the advice crazydoc. I tried what you suggested, but plugging the mic into the preamp and then into the Line In of the BR-600 doesn't seem to be enough to generate enough gain: even with the input and output on the preamp set to maximum the BR-600 can barely pick up a signal!

So I might have to stick with plugging it in the MIC, and having to play with the gain of the BR-600 and the input and output level of the preamp in order to get less buzz sound... I don't think that it's the mic which is causing the buzz sound as the buzz is still there when the mic is unplugged. So it's obviously either the preamp or the cables, which are all brand new. Unless this particular preamp always creates a buzz sound? Are cheap preamps prone to do this?

 

[crazydoc]

What kind of cables/connectors are you using between the ART and the Boss? I see the Boss uses a 1/8" stereo jack as its line in, so you'll need a Y adapter to give access to each channel separately, and plug the ART line out into one of them.

 

[astro21]

Thanks for your reply, crazydoc.

I'm using an XLR cable from the ART to the BOSS, and use an XLR-to-1/4" adapter with an 1/4"-to-1/8" on the Line in of the BOSS. I don't think I would need a Y-converter as there is only one Line in (no L and R).

If I'm plugging it into the MIC, I use the same as above, just without the 1/4"-to-1/8" adapter.

 

[crazydoc]

From the owner's manual:

3. LINE IN jack (Stereo mini type)

This input jack accepts analog audio signals (p. 34).
Connect the output of CD players or other portable audio
players or other audio equipment.

This is a stereo (L and R) line input. If you are using a plain (mono) plug, you could be grounding one of the inputs, which may be causing the volume loss.

 

[astro21]

From the owner's manual:
This is a stereo (L and R) line input. If you are using a plain (mono) plug, you could be grounding one of the inputs, which may be causing the volume loss.

Hi crazydoc,

So what kind of cable would I need in order to plug the preamp into the Line In of the BR-600? I currently have an XLR cable that I can plug from the preamp to the Line In (using a 1/4" adapter). If this is a "plain (mono) plug", what kind of cable do I need for it to make it stereo? Are there stereo XLR cables out there?

Sorry if it sounds really stupid but I'm at a loss here...

Also, my BR-600 manual says: "When connection cables with resistors are used, the volume level of equipment connected to the inputs (GUITAR/BASS jack, LINE IN jack) may be low. If this happens, use connection cables that do not contain resistors, such as those from the Roland PCS series."

I'm using Monster mic cables, but don't know if they contain resistors. There's no mention of resistors on the Monster Cable website, but I don't know much about cables...

Thanks so much.

A.

 

[Carter]

Make sure the 1/4" side of your adapter is a TRS and then use something like this.

http://www.fullcompass.com/product/291749.html

Those cables dont have any resistors

 

[astro21]

Thanks Carter. Yes, the 1/4" side of the adapter is a TRS, it was supplied by BOSS with the BR-600. I'm then using a run of the mill 1/4"-to-1/8" adapter.

When you say that those cables don't have resistors, do you mean the microphone Monster cables?

I'm using the XLR output on the preamp, which is balanced. By plugging the cable into the Line In of the BR-600 (which I assume is unbalanced), could that be an issue? The 1/4" output of the preamp is unbalanced; should I be using that instead?

 

[crazydoc]

You can use a balanced system as above to input to the line in of the recorder. You will get 2 signals, each half of the original power and of opposite polarity (inverse), one to the left channel and one to the right. If you record both and try to combine them, they will sum to zero, so you can use either one but not both (unless you change the polarity of one.)

The better way (in my opinion) would be to take the unbalanced output of the preamp into one of the line in channels of the recorder, either left or right. To do this you'll need a Y adapter of some kind with a 1/8" stereo plug into the line in of the recorder, and mono jacks of whatever size needed to accept an unbalanced cable from the preamp (like this as an example: http://www.radioshack.com/product/i...no&kw=y+adapter+stereo+mono&parentPage=search and http://www.radioshack.com/product/i...+to+1/8&kw=cable+1/4+to+1/8&parentPage=search ). You'll only use one input of the Y.