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Entry  Tue Nov 17 21:10:35 2009, rana, Summary, Electronics, Busby Low Noise Box: Photos and Upgrades IMG_0217.JPGbusby-noise.png
    Reply  Wed Nov 18 00:38:33 2009, rana, Summary, Electronics, Voltage Noise of the SR560's OUTPUTs (the back panel) sr560.png
Message ID: 2288     Entry time: Wed Nov 18 00:38:33 2009     In reply to: 2286
Author: rana 
Type: Summary 
Category: Electronics 
Subject: Voltage Noise of the SR560's OUTPUTs (the back panel) 

I've measured the voltage noise of the SR560's lead acid battery outputs; they're not so bad.

Steve ordered us some replacement lead-acid batteries for our battery powered pre-amps (SR560). In the unit he replaced, I measured the noise using the following setup:

SR560                              Busby Box

(+12V/GND) -------------AC Input      Out  ----------------   SR785

The SR785 was DC coupled and auto-ranged. The input noise of the SR785 was measured via 50 Ohm term to be at least 10x less than the SR560's noise at all frequencies.

sr560.png

Its clear that this measurement was spoiled by the low frequency noise of the Busby box below 10 Hz. Needs a better pre-amp.

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