Ampex Meter Assembly, pn 4010098-01, Sold Out.

These rack mount meters are completely passive, with the A and B Channel A3Fs (inputs) and A3Ms (outputs) wired in parallel.   The XLR Pin 3 is connected to the TIP of the 1/4" jacks through a 1KΩ resistor.  The 1/4” jacks (front and rear) are TS.

There is no isolation between the jacks and XLRs except for the 1KΩ resistors. 

For practical purposes any one of these connections could be used an input or output, which could lead to some odd results if different signals were connected to the same channels XLRs and 1/4” jacks.   

The meters are calibrated, and the photos were taken with a +4dbm 1KHz signal looped through both the A and B channels.  

Each meter has 2 incandescent lamps that are switched from the front panel.  The backlighting requires AC power to operate, but the meters work without or without any AC power.  Everything works fine, and there are 3 Calibration settings for Zero VU; +4,+8 and +12 dbm.  

There's a 3 pin Ampex style power cord included.