how to calibrate a VU meter at preamp output ?

[emrr]

Remember American broadcast used +8dBu. 

I agree it's arbitrary decoration these days, especially for non-program work. 

There are plenty of old old preamps that won't drive a +4 VU high enough to be of any use too.  They might approach zero in near-audible overload.  The VU would be of use with the following program amp. 

 

[madswitcher]

"Most of the studios I worked at used 0VU = +4 dBu and, if they had BBC-spec PPMs, 0VU = PPM 4"

I thought that on a steady tone,  0dBu was BBC PPM4, so 0VU =which is +4dBu = PPM5 ?

Mike