Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => AmpTools/Tech Tips => Topic started by: FYL on November 07, 2010, 11:06:36 am
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Just stumbled upon a pair of vintage Sifam Director R24A meters while sorting thru some storage boxes. I had bought them second-hand years ago - they had been removed from a broadcast console, tested them, boxed them and forgot them. Yes, I know...
(http://www.aingeal.com/pix/R24A.png)
I either plan to use them in a TBB mic preamp or resell them - gosh, there's a huge demand for real Sifam meters and some people are willing to pay a very steep premium for them. Anyway, this version is nowhere to be found in my files, even the dustier ones, and the "new" Sifam is of no help.
They are calibrated for 7 dbu (1.734 V), not the usual 4 dbu (1.228 V).
(http://www.aingeal.com/pix/R24A%20Label.png)
They also use a peculiar back lighting system, with two screw bulbs mounted on a bracket and illuminating a small circular window on both sides of the motor, cf. the attached pix.
(http://www.aingeal.com/pix/R24A%20Back.png)
(http://www.aingeal.com/pix/R24A%20Bracket.png)
Does anyone have some info on these?
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> calibrated for 7 dbu (1.734 V), not the usual 4 dbu (1.228 V).
"FSD" is Full Scale Deflection. Where is full-scale on a VU meter? +3db. Zero VU is 3dB less than FSD. Therefore zero VU is 1.23V.
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"FSD" is Full Scale Deflection. Where is full-scale on a VU meter? +3db. Zero VU is 3dB less than FSD. Therefore zero VU is 1.23V.
Of course. Must have been sleeping while posting.
Thank you PRR.