ELAM 251 polar patterns

[ghiatorino]

Hi folks,
I just finished an ELAM 251 clone and I am puzzled about the sensitivity change between polar patterns.
I have good frequency responses over the 3 patterns, omni is nice and fig.8 perfectly symmetrical, with usual zeros on 90deg.
Polarizing voltage is 60V.
What I am not sure is that the overall sensitivity drops around 6dB when in fig. 8, and about 3dB in Omni.
The original manual seem to claim the same sensitivity for the 3 patterns.
Any info would be very appreciated.
Cheers
Rino

 

[kingkorg]

What I am not sure is that the overall sensitivity drops around 6dB when in fig. 8, and about 3dB in Omni.

This sounds perfectly normal to me, the capacitance of the capsule that tube 'sees' rises in omni and f8.

 

[Tim Campbell]

Yes I checked my vintage ELA M251 and it is indeed quieter in fig 8 and omni than in cardioid.