Is A12 supposed to sound like this? Audio clip inside

[brad347]

I have an older A12 that I built several years ago. It always seemed to behave normally. However, in my tests today, up against my N72, J99, and any other preamp I can get my hands on around the house (Mackie mixer, old Yamaha PM-180 rack mixer), the A12 sounds thin and almost high-passed. I don't remember it sounding like this before, and I feel like I would've noticed, but who knows.

I recorded the following clip using an Audio Technica 4033 that happened to be sitting on my desk. I was at close range to maximize proximity effect-- my mouth was practically touching this cardioid mic.

First you hear the A12, then the N72, and finally the J99.

The A12 seems band-limited on the low end compared to the other two.

Rest of recording chain: Lynx Aurora at 48kHz, 24 bit. All 3 samples normalized for level matching.

Would love to hear your thoughts of where I should start looking to troubleshoot this. Thanks!

http://www.soundsdifferent.com/music/preamp_test_A.mp3