Re: [Harp-L] Mic impedance into a PA

["Vern Smith" <jevern@xxxxxxx>]

Whenever you plan to use sound equipment that is not your 
own, you should take adapters.

You have two things to consider:
Jacks and XLR connectors...mechanical compatibility.
Hi Z and low Z...impedance match.

Usually, XLR is Low Z  and the jack is Hi Z
Some PAs and mixers give you your choice of Female XLR Low-Z 
or Female jack hi-Z on every input. You should be so lucky!

I always take two transformers..available at Radio Shack or 
Guitar Center, etc. for < $20 each.
See:
http://www.radioshack.com/search/index.jsp?kwCatId=&kw=microphone%20transformers&origkw=microphone%20transformers&sr=1

1. Hi-Z female jack in to Low-Z male XLR out.  This is the 
one you may need with a Hi-Z mic and a PA system.
2. Low-Z female XLR in to Hi-Z  male jack out.

With these, you should be prepared to deal with any PA 
inputs.
I have never noticed any perceptible degradation of the 
sound attributable to a transformer.

Most likely, the PA will have Low-Z XLR inputs.
You can plug your Low-Z mic in directly.
You will probably have to use the transformer (1. above) for 
your Hi-Z mic.

Vern


----- Original Message ----- 
From: "Paul Routledge" <kingley@xxxxxxx>
To: "Harp L L" <Harp-l@xxxxxxxxxx>
Sent: Wednesday, July 22, 2009 1:12 PM
Subject: [Harp-L] Mic impedance into a PA


> If I plug a Hi-Z mic direct into the PA, it acts as an 
> unbalanced Low- Z signal. Am I right?

You probably won't hear anything at all from the mic.

> If I am would it be better to use an XLR-XLR lead, or use 
> the channels  instrument socket and use an XLR-Jack lead?

That would take care of the mechanical compatibility of the 
connectors but not the impedance match.

> If I used a DI box and ran the mic into that then into the 
> PA it would  be a balanced Low-Z signal. Am I right?

> Would either way be of benefit tonally to the mic and it's 
> frequency  curve?
>
> The reason I'm asking is because tomorrow I have a sit in 
> on a local  gig, but as it's only for a couple of tunes I 
> would rather go direct  into the PA than take my amp.
>
> I plan on taking a Shure 545SD wired to Hi-Z, I also have 
> an RE10  (that obviously is Low-Z so is fine) that I may 
> also take.
>
> But I think as it's an unknown situation the 545SD may be 
> a better  choice with the on/off switch. Just in case the 
> feedback monster  raises it's ugly head.
>
> Paul
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