Hi Chris,
    The detector is a Validyne pressure transducer modified by Dr. Chris 
Haywood at SMU.   I don't know what modifications were made, and have borrowed the 
detector to see if I could record anything of interest with it.   There are 8 
inlets into a small volume inlet box.  A metal diaphram measures pressure 
variations differentially with respect to a reference pressure in a larger 
volume.  The bridge circuit  electronics is contained within the detector and is 
powered by 12 volts furnished by an external power supply located about 50' from 
the detector.  It has an internal 1 Hz low gain cutoff.  I have no specs on 
the unit.  I am only using two of the inlets, connected to two 50' porous hoses 
extended  inline from opposite sides of the detector.  Because of space 
restrictions, the hoses are doubled back on each other at a length of 25'.  
    What type instrument are you using, and have you recorded any 
quake-related events?
    Best regards,
    Al




Hi Chris,
    The detector is a Validyne pressure transduc=
er modified by Dr. Chris Haywood at SMU.   I don't know what modif=
ications were made, and have borrowed the detector to see if I could record=20=
anything of interest with it.   There are 8 inlets into a sma=
ll volume inlet box.  A metal diaphram measures pressure variation=
s differentially with respect to a reference pressure in a larger volume.&nb=
sp; The bridge circuit  electronics is contained within the detect=
or and is powered by 12 volts furnished by an external power supply located=20=
about 50' from the detector.  It has an internal 1 Hz low gain cutoff.&=
nbsp; I have no specs on the unit.  I am only using two of the inl=
ets, connected to two 50' porous hoses extended  inline from oppos=
ite sides of the detector.  Because of space restrictions, the hoses ar=
e doubled back on each other at a length of 25'.  
    What type instrument are you using, and have=
 you recorded any quake-related events?
    Best regards,
    Al