- Joined Feb 7, 2021
Back in another life I helped built a TV station and designed/built/rebuilt several remote trucks.
A VU meter has a defined set of ballistic parameters. That is, the amount of needle overshoot that happens at a sharp transient increase in volume is standardized so all VU meters show the same effective volume level. The ballistics and damping are calibrated when the meter coil is loaded with a specific non-zero impedance. My guess is that it is 3.6K ohms for this meter, so you want the coil to see 3.6K ohms as the source impedance no matter what the input signal level is. A common way to do this is a variable gain opamp stage followed by a 3.6K resistor in series with the meter.
Alternatively, 3.6K might be the impedance of the meter when it is applied to an external circuit. However, the 3.6K loading impedance rings a faint bell...
I don't see any diodes on the on board, so the meter must have it built in. This means it is a true VU meter, not just a meter with a VU scale.
1.734 V = 1.228 V (0 dBu) x 1.414 (sqrt 2). It is the peak value of an input sine wave that will produce an indication of 0 dB.
Hi Ak ,
I currently have 'Vu meters' that can be found everywhere on eBay like the Nissei TN-73.
I don't see any diodes or 3.6k resistors inside the VU, the meter doesn't have it built-in. this means they are not a true VU meter, just meters with a VU scale like you said.
And I wonder how can we turn them into real VUmeter with its true law.
Do you have any idea how to do this step?
Thank you very much
Moderator edit: New thread created from here.