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General Discussions => The Lab => Topic started by: dspruill on July 25, 2009, 09:23:49 AM

Title: vu buffer amplifier power supply
Post by: dspruill on July 25, 2009, 09:23:49 AM
Hello all, I am working on a RCA tube mic pre. It is the BA-2C circuit. I want to put a VU meter on the output and I was thinking of getting a buffer amp for it from JLM. My question is what would be the most elegant way of powering it?  It requires 9-30 volts. Would just putting in a separate small power supply be easiest? Or maybe just a power jack in the rear for a wall wart?

Thanks,
David
Title: Re: vu buffer amplifier power supply
Post by: substitute on July 25, 2009, 10:31:18 AM
I'm not familiar with that circuit, but if you could tap off the low voltage for the heaters and step it up a bit you could avoid needing another transformer.
Title: Re: vu buffer amplifier power supply
Post by: JohnRoberts on July 25, 2009, 12:54:50 PM
If you are series about the meter tracking like other professional VU meters don't scrimp on the PS voltage with mechanical VU meters. I once tried to use a 12v lamp supply to power drivers for console VU meters, hoping that allowing it to clip on large transients wouldn't make a significant difference to average level, but the experienced studio customers saw a tracking difference, that cleaned up when I increased the rails.

JR