Fostex M88RP, M55RP impedance

Measured with Escort impedance meter (a DC ohmmeter should never be used on ribbon mics).


Fostex M88RP s/n209087, lower Z version
Zo=238Ω
It sounds bassier than the 600Ω? version
At of course it interacts differently (less treble sparkle or more bass) with the Pleiades (130Ω,40mH) than when the 600Ω mic version is used.


Fostex M55RP
Zo=274Ω
By rotating dials (see a previous post) a Pleiades filter of 70Ω,40mH sounded bright and nice.


How would these mics sound stepped up to more than 800Ω by the Western Electric 1:2 transformer and then terminating the higher Z with the Pleiades (130Ω,40mH) filter?
Later addition:
They sound great and sparkling bright
Signal path, setup:


Male voice singing the intro of the (Power of Love - FGTH) - mic at 2-3in - WE 1:2 transformer - Pleiades (130Ω,40mH) - Sony TC-D5 Pro - Sennheiser HD 580

mic in above setup:
M55RP slightly louder than M88RP low Z
Beyer M119 louder than all, least noise, more forward
M88RP possibly smoother from all



Note: The Sony ECM-250 sounds great too with just the Pleiades filter and no 1:2 step up. A bit more hiss than other mics.