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Microphone hum

All about the tools and techniques involved in capturing sound, in the studio or on location.

Re: Microphone hum

Postby Scouser » Fri Sep 18, 2020 9:17 pm

Sorry for my ignorance Sam, so are you saying you plug in the groundology and from that, there is a lead that plugs into the mix pre ?
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Re: Microphone hum

Postby Mike Stranks » Fri Sep 18, 2020 9:58 pm

What this device allows you to do is provide a ground/earth as there isn't one provided thru the mains plug.

So you power the MixPre as you normally do with your USB Mains Supply connected to the USB Port.

You connect your mic(s) as normal to the XLR socket(s).

You use the grounding plug to provide the ground earth. You plug the pseudo mains plug into any mains socket you like - doesn't have to be switched on. In Hugh's case he replaced whatever's attached to the other end of the 'Groundology' cable with a standard TRS jack plug with the plug sleeve connected to the single-core Groundology cable. I'm suggesting that you should use a 3.5mm TRS plug as there are some 3.5mm sockets that you're probably not using on the MixPre. But you still connect the single-core cable to the sleeve of the 3.5mm TRS plug.

Thus you then appear to have TWO mains connections. One is the USB Power Supply. The other is the Groundology (earth-only) mains plug connected to the sleeve of a 3.5mm jack plug connected to any 'spare' 3.5mm socket on the MixPre giving you the needed earth/ground connection.

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Re: Microphone hum

Postby zenguitar » Sat Sep 19, 2020 12:36 am

Glenn Gould wrote:I keep getting this hum in my microphone

:angel:

Andy :beamup:
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Re: Microphone hum

Postby Scouser » Sat Sep 19, 2020 10:32 am

Mike, thank you so much for your reply, really appreciate you taking the time to give such a detailed response.

The only thing I am a little unclear about, is if the groundology plug comes with the required 3.5mm TRS lead from the plug, or is this something you have to make up yourself ?

Reading through Hugh's review, talked about cutting and re soldering ! This is not something I can do, so if this the case I would need some kind of work around, if that is possible ?
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Re: Microphone hum

Postby Sam Spoons » Sat Sep 19, 2020 11:07 am

I think the plug comes with a 'press stud' type connector for connecting it to their other earthing products so you would need to modify it. To test the principle you could just take a wire (guitar cable would do fine) and touch the tip of one end to the socket nut on the Mix-Pre and the other end to either a metal chassis part of any piece of class 1 equipment (or any exposed plumbing metalwork (which should all be earth bonded but may not be).
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Re: Microphone hum

Postby Mike Stranks » Sat Sep 19, 2020 11:17 am

Scouser wrote:Mike, thank you so much for your reply, really appreciate you taking the time to give such a detailed response.

The only thing I am a little unclear about, is if the groundology plug comes with the required 3.5mm TRS lead from the plug, or is this something you have to make up yourself ?

Reading through Hugh's review, talked about cutting and re soldering ! This is not something I can do, so if this the case I would need some kind of work around, if that is possible ?

Yes; it would be a soldering job I'm afraid.

I have a 'Groundology' plug here which I could loan you (for postage costs) to see if that would work. If it does we could then decide on a way forward. PM me if you wish to pursue...

Incidentally; there's no risk of frying yourself if you do what Sam's suggested! :lol:
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Re: Microphone hum

Postby ef37a » Sat Sep 19, 2020 11:26 am

Just a couple of observations?
Mike, there is no guarantee that the 3.5mm jack screen shares a common, chassis connection with pin 1 of the XLR, though it probably does.

I suspect that the body of the mic is 'floating' or part of its internal screening is and so it might tell Scouscer more if he touched earth to the mic body? Of course, if the unearthed part is internally floating, that will do nothing to help.

Scouscer, please treat yourself (and indirectly us!) to a £20 Digital Multimeter. I know you say you have zero technical knowledge but such a meter will help you gain some! The first thing you would be able to do is test my first statement and check if the 3.5mm jack doe in fact connect to pin one of the XLR. The meter will also be invaluable for checking cables, batteries and even measuring audio signals.

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Re: Microphone hum

Postby Sam Spoons » Sat Sep 19, 2020 11:49 am

ef37a wrote:Scouscer, please treat yourself (and indirectly us!) to a £20 Digital Multimeter. I know you say you have zero technical knowledge but such a meter will help you gain some! The first thing you would be able to do is test my first statement and check if the 3.5mm jack doe in fact connect to pin one of the XLR. The meter will also be invaluable for checking cables, batteries and even measuring audio signals.

Dave.

Definitely do this, you only need to acquire a little electrical knowledge and it will repay you for life. :thumbup:
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Re: Microphone hum

Postby Folderol » Sat Sep 19, 2020 11:50 am

ef37a wrote:Scouscer, please treat yourself (and indirectly us!) to a £20 Digital Multimeter.

Just want to emphasise this :thumbup:

It is one of those things that once you have it, in a short time you can't imagine being without it. It won't make the tea, but it will check the kettle fuse!
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Re: Microphone hum

Postby Scouser » Sat Sep 19, 2020 12:01 pm

Hi Mike,

I have tried private messaging you but seem to be having problems.

Maybe you could email me here and I will get back to you scouser1968@hotmail.com

Thanks
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Re: Microphone hum

Postby Scouser » Sat Sep 19, 2020 1:56 pm

Fair enough, maybe a multimeter will help, although i'm not sure I will have a clue on how to use it, I seem to have a mental block on all things electrical, but I guess you have to start somewhere.

So which £20 Multimeter did you have in mind ?
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Re: Microphone hum

Postby James Perrett » Sat Sep 19, 2020 2:26 pm

When it comes to budget multimeters, Mark Hennesy has done some useful reviews at

https://www.markhennessy.co.uk/budget_multimeters/

However, even the really cheap £3.00 meters from CPC are perfectly usable. I've just bought this one for our 9 year old because it does auto-ranging and it seems to work well (though not as good value as the ones Mark reviewed)

https://cpc.farnell.com/duratool/d03124 ... dp/IN07444
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Re: Microphone hum

Postby Mike Stranks » Sat Sep 19, 2020 3:09 pm

PM sent.

Dave/ef37a: We'll give it a go and see what happens. Mine will be winging it's way chez Scouser very soon.

Oooh! Will it? Won't it Exciting isn't it!? :lol:
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Re: Microphone hum

Postby ef37a » Sat Sep 19, 2020 4:44 pm

Scouser wrote:Fair enough, maybe a multimeter will help, although i'm not sure I will have a clue on how to use it, I seem to have a mental block on all things electrical, but I guess you have to start somewhere.

So which £20 Multimeter did you have in mind ?

WTGR! You cannot have a mental block about "things electrical" because you are using a computer and microphone and an interface and they ALL run by LEKTRIK"!

Now, I don't do this often but when you get the DMM you can PM me if you like and I can give you some basics via email...With pictures (in crayon!)

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Re: Microphone hum

Postby Mike Stranks » Sat Sep 19, 2020 5:26 pm

Unnecessarily harsh, Dave :thumbdown:

I know the electrical basics, but haven't a clue about electronics beyond the most simple of stuff. Am I now to be 'called out' because I can't identify resistors by their colour-bands and have only the haziest of notions how a transistor works?

One doesn't need to understand how many things in life work to get pleasure and benefit from them.

But we've been around this particular circles many times before. Just accept that others aren't the same as you, but that that doesn't make them deficient or needing 'crayon drawings'.

:(
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