Palomar SL41 microphone

Does it squeal then you reach up and touch the metal part of the mic jack where it plugs I to the radio?

Just a shot in the dark.

 

What’s a radio without a talkback ? It’s like driving a truck without straight pipes.....

 

Yeah just turn TB down until the squeal stops. Very simple

 

When it comes to fidelity, the components probably aren't the only contributing factor. The directional ECM's, ( I believe) tend to distort more than the omni-directional ones. The ECM's that I had purchased are omni-directional, mainly because I am using them on my base station radios, where the external noise isn't such a problem. Omni-directional would probably be more of a problem in a noisy big truck, than a uni-directional element. Unless, you had the noise canceling material added to your microphones housing. I noticed that the ECM on the data sheet shows it to be noise canceling, not sure if that would induce some distortion in the mic element or not.

 

OK that might be part of the reason they are using the extra components, for a little more amplification in the circuit for the ECM element. Most ECM elements run between 1 and 10 V. The higher the voltage, the more audio gain (louder), the element has. That maybe part of the reason for additional circuitry, since they are running a 1.5 volt battery, probably due to its smaller size. The 9 V battery is really handy for the higher gain, if there’s room for it.

 

The amplification from the electret element might not be as strong as you think, especially while only using a 1.5 volt supply voltage.
Its been said that paralleling 2 ECM elements will provide a 40% gain in audio. They will have a little more money involved redesigning the plastic to hold the 2 elements. Maybe Eric could name it the SL-42...lol.