Question about Groove Tubes The Brick Preamp / Direct Box Microphone

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Dirty signal from a groovetube brick di

Bad hum and hiss when I plug in any 1/4 cable to the di. Tried the ground lift. Doesn't do anything.

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C1000s hum/buzz on phantom power

possibly the microphone needs more power than your sound card can supply although I cannot imagine as the duet is a good piece of equipment.
Is the duet USB bus powered?
Have you tried another cable? Possibly one wire is defective which means that phantom power will superpose the audio signal. In this case you might hear a hum. By the way this results in 6dB of signal loss. This is why XLR plugs have 3 wires. If connected with a 1/4" jack it has to be a stereo plug (tip, ring, sleeve)

Mar 26, 2014 | AKG Audio Players & Recorders

1 Answer

My sm58 has a low level buzz or hum. how should I proceed to diagnose and repair. I am assuming a loose wire or a frayed wire grounding out.

This could be any of several things. IF the audio output of the mic is at a normal level then the first thing to check is the mic cable. I have several things to discuss so read all of this and then test.

First, I found six BRAND NEW XLR cables were wired wrong... the vendor had 13000 of them in stock and was going to have to check them all. The cables appear to work, but had the shield and one signal wire in the wrong place so the line was NOT a twisted pair balanced as required, but instead a plain coax. I had to repair these at a venue when I discovered the problem. Please google the correct XLR configuration. The pin numbering is NOT what one would expect. You cables (open the ends and look) should have the shield tied to pin 1 which is one of the side pins. Mine they had the shield on the middle pin or apex of the triangle.

Second, there are COUNTERFEIT Shure SM58's being sold. Read about that at google... If you unscrew the screen and find a label on the side of the element, the mic is a fake... Now there are two qualities of fakes... some perform ABOUT as good as the genuine, and others don't even have the balancing transformer.

If the hum is only there while handling the mic, the ground to the shell is not connected... this is mainly a mechanical connection. You can extract the XLR male plug from the bottom of the mic by removing the side screw and gently pull out by grabbing one of the pins. Also you can verify the wire colors as the fakes use the wrong color wires.

Noise problems are my specialty so if you need further help send a comment to me.

Mar 25, 2011 | Shure SM58 Professional Microphone

1 Answer

I love the UHF-5800, but I have a hum coming from it now. I had the original power supply short out and replaced it with a different power supply. It orignally takes a 13v 800ma supply but I could only...

The hum could be for a number of reasons
  • The slightly low voltage / current handling of the power supply won't help. You could probably get away with up to 15v without difficulty - many laptop universal power supplies are capable of generating the higher voltage so might be better than normal multi-voltage transformers that only go up to 12v - they will also be more stable in output.
  • The polarity of your power supply could be the wrong way round - check the symbols on the case near the power input socket - it matters with some brands and not with others.
  • Move the wireless receiver away from any other sources of interference - anything with a large electro-magnetic field (CD or DVD players, tv, hearing loop amplifiers, mains transformers) or any large lumps of metal that may attenuate the signal.
  • Only use balanced (xlr) cables to connect receiver to amplifier mixer and make sure they do not run parallel to any cables carrying mains electricity.
  • Turn the signal gain on the receiver up and the sensitivity on the amp /mixer down to improve the signal to noise ratio.
  • If the set allows try switching to a different frequency

Feb 27, 2011 | Vocopro UHF-5800 Professional Microphone

1 Answer

I am getting some humming from the speakers when I

Yes, use balanced cable to the PA system and use a DI at the computer end.

The DI is known as a "direct box" or "direct input" and converts the UNBALANCED computer output to balanced to send toe the PA system.

Feb 01, 2010 | Peavey Escort 2000 Microphone

1 Answer

My shure radio mike has a bass hum

This usually means that the ground wire has broken. Try a new balanced XLR microphone cable and see if the hum goes away. If it doesn't then the problem is either the microphone or the jack that you are plugging the cable into. If you are plugging into a mixer, make sure that the ground pin has not been removed from the power cord. Same thing with the amp that the mixer is plugged into etc. If you think it is the microphone have a look for a small hole on the side of the base of the microphone where the cable plugs into it. Use a small flat bladed screwdriver to tighten that screw in a counterclockwise direction. This will stop the jack in the microphone from wiggling. It also provides a ground for the body of the microphone. If that doesn't help, Try turning it in to remove the jack and examine the wiring. Do this gently. There should be 3 wires on this jack. It is an XLR jack. The wires should be 1= ground, 2= hot and 3= cold. SAme with the plugs on the cable. Hope this helps.

Oct 22, 2009 | Shure SM58 Professional Microphone

1 Answer

How to connect XLR plug to Combi-Connector socket

You need a D.I. (direct interface) box. Most have XLR to 1/4" . You have to go from the 1/4" to your size jack. Remember your taking a low impedence device to a high impedence input thats why you need a D.I. you just can't make a cable to do that. Also I think you mean a 3.5mm jack.

Apr 11, 2009 | Audio Players & Recorders

1 Answer

Low Mains hum

Definitely sounds like a ground issue, try plugging it into an outlet on a seperate house circuit, or you could always live on the edge and clip the ground on the plug via an adapter plug.

Jul 11, 2008 | Audio Players & Recorders

1 Answer

Sony ecm 989

This is a wonderful microphone that I used for years without any problems. Then it developed a background noise (a hiss, or buzz, or sound like a bad ground; it's been too long and I don't remember the specific sound now). I checked the integrity of the ground and other wires in the cable and didn't find any problems so I replaced the old cable with a new cable, but I still had the noise.

I use the microphone with the microphone head separated from the microphone body, so I have a cable that runs from the head to the body and a separate cable that runs from the body to my inputs. I don't have either an electrical or logical explanation for why the following solution got rid of my noise, but it worked for me.

On the cable that connects the head to the body, simply take an insulated wire, strip both ends and with electrical tape, tape one bare end to the metal plug shell on one end of the cable and then do the same with the the metal plug shell on the other end of the cable. You can add some tape wraps along the length of the cable so it doesn't look so funky and is a little less cumbersome. I didn't do anything to the cable that runs from the body to the inputs. This got rid of the noise for me. REALLY. THIS IS NOT A JOKE. I DON'T KNOW WHY, BUT IT WORKED FOR ME. Maybe it will also work for you. It's certainly easy enough to try. Good luck. Bob

May 04, 2008 | Sony ECM-DS70P Stereo Recording Microphone...

1 Answer

Audio technica at 4040 constant ground hum noise

you can test the cable from connection to connection for continuity from end to end. There should be no resistance( a complete short) If the cable is good, there is a bad or broken connection inside the mic. Good Luck

Jun 23, 2007 | Audio Technica Audio-Technica AT4040...

1 Answer

Hissing from one of the two NT5 mikes

have you concluded that it is 1 of the mics?if mics are ok you need to purchase a mic pre.

May 28, 2007 | Rode NT5 Professional Microphone

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