Need help with vu meters

[skulltronix]

I need help hooking up two TR-35 VU meters to a Lepai amplifier.  I try to run wires from the speaker outputs to the meters and I only get very erratic movement around the 3/4 volume level. Anyone know what I'm doing wrong?
Thx
Pls email response to [email protected]

 

[pucho812]

you cannot just hook up meters to anything and expect them to work willy nilly.  There is plenty of information about meter buffer amps and what is needed to make meters work. a little searching will go a long way.

 

[PRR]

> very erratic movement

Rectifier.

 

[sodderboy]

Plus, you don't want to connect them to the output of a power amp.  They are commonly used in the line level signal path, and there they should be properly buffered.
A power amp with VU's is measuring line level into the amp section and not the actual output.
Mike

 

[Brian Roth]

In the far/distant past, I recall connecting "real" VU meters (Dixson maybe?...but they had internal rectifiers) across the outputs of a Crown power amp.  But, part of that setup included a resistor pad between the output of the amp and the input of the meter.

Best,

Bri

 

[pucho812]

What would be the point to having vu meters read the output of a power amp?

 

[Brian Roth]

The Crown amps had input pots, so hanging the meters across the output ensured the amp was actually producing an output (or not, if the pots were turned off, speaker load was shorted, etc).  This was for a friend's small PA system.  IIRC, there were four VU meters since the system was stereo bi-amped.

Bri

 

[pucho812]

ah interesting.

 

[CJ]

special recitifers used back then, small black squares with 4 small leads, wait, they all loke like that,  ??? probably supplied thru simpson,


maybe an attempt at a schotky response?

never seen too many, got a few from doc hoyer to run the fairchild 670m vu's,

don't know where he got them, probably from his basement in wisconsin,

 

[Sredna]

special recitifers used back then.......

Selenium rectifier maybe? 

(copper oxide, germanium)