Isemcon have a line of ICP (4 mA constant current) microphones that are P48, in fact also P24 and P12 compatible. They claim that they can be used with no degradation of performance with 12 to 48 V phantom power. The adapter is a straight connection of pin 2, while pin 3 is simply grounded.
This is the data sheet. The information is the most detailed for the 7001 model, but they are all electronically the same:
https://www.isemcon.net/ashop/datasheets/iSEMcon-IEPE-CCPmic.pdf
This is an independent review of the ICP mic and the real P48 version that comes with an XLR connector rather than BNC. The ICP version was tested with aid passive adapter:
https://www.isemcon.com/datasheets/iSEMcon EMM-13D082.pdf
It shows that ICP version used with P48 has 10 to 18 dB higher harmonics in the range of 100 - 120 dB SPL. Beyond that, there is little difference, with the P48 version being only about 1 dB better.
I get that the built-in 6.8k resistor with P48 can be seen as a constant current source, and if the drive electronics in the mic have sufficiently low output impedance (< 10 R in this case), there will be little degradation of the signal.
I also get that the sensitivity is slightly higher if the CCS is set to a higher current because this means the ampflification of the internal source follower is closer to unity. And I get that sensitivity decreases towards P24 and P12 because there is a lower current and because the feed resistor is lower than with P48.
But why would the mic care about the compliance range of the CCS? This is specified at 18 - 30 V. I get that you don't want too high an upper limit because it may blow the mic amp on startup. But why would the sensitiity depend on the limit? The output will stabilize at 7 V +/- 2 V. At that point the amp won't know whether the CCS compliant is to 18 V or to 30 V, and 18 V should be sufficient to insure +/- 6 V signal swing.
The marketing gibberish is of little help: The built-in prepolarized microphone cartridge controls an AC/DC-Zener Diode circuitry with an output impedance as low as 10 Ohms
This is the data sheet. The information is the most detailed for the 7001 model, but they are all electronically the same:
https://www.isemcon.net/ashop/datasheets/iSEMcon-IEPE-CCPmic.pdf
This is an independent review of the ICP mic and the real P48 version that comes with an XLR connector rather than BNC. The ICP version was tested with aid passive adapter:
https://www.isemcon.com/datasheets/iSEMcon EMM-13D082.pdf
It shows that ICP version used with P48 has 10 to 18 dB higher harmonics in the range of 100 - 120 dB SPL. Beyond that, there is little difference, with the P48 version being only about 1 dB better.
I get that the built-in 6.8k resistor with P48 can be seen as a constant current source, and if the drive electronics in the mic have sufficiently low output impedance (< 10 R in this case), there will be little degradation of the signal.
I also get that the sensitivity is slightly higher if the CCS is set to a higher current because this means the ampflification of the internal source follower is closer to unity. And I get that sensitivity decreases towards P24 and P12 because there is a lower current and because the feed resistor is lower than with P48.
But why would the mic care about the compliance range of the CCS? This is specified at 18 - 30 V. I get that you don't want too high an upper limit because it may blow the mic amp on startup. But why would the sensitiity depend on the limit? The output will stabilize at 7 V +/- 2 V. At that point the amp won't know whether the CCS compliant is to 18 V or to 30 V, and 18 V should be sufficient to insure +/- 6 V signal swing.
The marketing gibberish is of little help: The built-in prepolarized microphone cartridge controls an AC/DC-Zener Diode circuitry with an output impedance as low as 10 Ohms
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That sounds like it won't work at all with old equipment that has a phantom supply with a single 3.3 kohm resistor to a centre tap on the primary winding of a microphone transformer, instead of two separate 6.8 kohm resistors and no transformer. DC coupled inputs also won't work with 7 V of offset.
Regarding the compliance: no idea, maybe they just measured it with three different supplies, got results that were the same within the measurement accuracy and just reported the numbers.
Regarding the compliance: no idea, maybe they just measured it with three different supplies, got results that were the same within the measurement accuracy and just reported the numbers.
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