Best coil for pick-up EMF fields (in a amplifier)? Telephone Pick-Up Coil, DIY?

[Tobias Claren]

Hallo.

There are "telephone pickup-coils".
But in different versions.
For example:
"CP-22" with 20x22mm:
Coil DCR : 390ohm+/-10%
L=112mH +/-10% @1Khz
Q=1.5 +/-10% @1Khz


"CP-36" with 36x25mm:
Pick up coil DC resistance (DCR) approx : 250?+/-10%
L= 120mH +/-10% @1Khz
Q=2.1 +/-10% @1Khz


"Q" = Quality?

Are there other qualities?
Better quality? Higher than "2.1"?

Better to solder yourself?
Higher sensitivity on many frequencies.


Thanks,
Tobias Claren