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From: jfraz~cusd.edu ("Harmonica" John Frazer)
Date: Thu, 12 Sep 1996 09:46:40 -0800
Subject: loZ/hiZ debate. techies jump in

hj responds a second time to Pete

At 11:23 AM 9/12/96, Pete Brunelli wrote:

p>My goal was to clear up a few technical issues with someone who needed a
>SIMPLIFIED explanation.

hj>> XLR jacks are typically used on high impedance

p>>>devices, like crystal and dynamic mic's.

hj crystal mics are hiZ, dynamic mics are TYPICALLY loZ

p Adapters for high to low impedance
>>>(XLR to 1/4" plug), and low to high (1/4" jack to XLR)

hj I am going to go out on a linb here and say this is backwards.

>>
hj>>XLR jacks may be used on some hiZ mics, but are much more typically found
>>on loZ mics.


hj>>my understanding is that guitar inputs are not loZ

hj I admit I am not an expert on electric guitar pickups.

>
p>relatively speaking, i stick to my characterization of an inductive guitar
>pickup as a low impedance device, maybe not as low as the voice coil of a
>speaker (another form of transducer) but probably under 1kohm.

hj They are extremely inductive by nature and this raises the
impedance-though the dc resistance is relatively low.

>
hj>>1/4"phone jacks are more likely to be a hiZ input.
>
p>On modern mixing consoles you typically have high-Z XLR inputs, and Low-Z
>1/4" inputs.

hj backwards.

>
p>Again, to reference the Shure impedance bulletin, a mismatch of low-Z source
>(mic) to high-Z destination (preamp stage of board/amp) gives a gain boost.

hj Read the previous sentence and tell me again that mics are hiZ and amp
inputs are loZ


>>
p>>>It sould match your system. A SM58, with an impedance adapter (Hi to Lo),
>>>into a guitar amp = a matched system.
>>
hj>>SM58 is a loZ source. you would normally use a lo-hi adapter to change it
>>to hiZ for a guitar amp input.

hj Think about it before you argue. reread your paraphrase of the Shure
bulletin again.


>
p>A SM-58 has an impedance step-up transformer as an internal device, and you
>will be raising the impedance further by doing this

hj It only steps it up to the high side of the loZ range