HI Z Microphone

[Brian Carling]

Todd if the speech amplifier is working properly, then agood D-104, Shure 444 or
Astatic N30 ought to drive that rig just fine with plenty of gain. The input
impedance of the radios is often very high,
quite a bit huigher than the mic and that is OK.

As others have said the mics are typically 25K to 100K ohms characteristic
impedance. this probably varies with frequency too.

A low impedance mic of 50 to 1000 ohms will typically not drive
these old tube rigs at all well. Conversely a modern rig with 600 ohms input
impedance is not going to do well with an old high impedance microphone either!



On 11 Jul 2003 at 8:47, Todd Orme wrote:

> Does anyone know approximately what impedance “hi Z” is implying with
> Heathkit? I have an old HW-101 that I purchased without a mic, and
> have had a problem trying to locate a microphone that works well
> consistently. I feel like I am having to eat the mic to get decent
> meter deflection and transmission. The previous owner (not able to
> provide me a mic) has indicated that he had no such problem.  Any
> assistance in this matter is appreciated.
>
> Todd, NV0T
>
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