VU meters

[PhilMcL]

how does one hook VU meters on to an amp? is it just on the positive end of the speaker outs? or something inside, in the circuitry?

does adding a vu meter color the sound in any way?

thanks.

 

[Manitoulin]

If you are using a standalone VU meter, in most cases the meter has to be protected. Most meters work with milliamps (unless they have a shunt attached); your amp will push out amps of current.

You will need exact specs on the meter to calculate the correct resistor to drop the excess power from the amp so you do not fry the meter.

 

[tennisdude]

If you are using a standalone VU meter, in most cases the meter has to be protected. Mormally meters work with milliamps, your amp will push out amps of current.

You will need exact specs on the meter to calculate the correct resistor to drop the excess power from the amp so you do not fry the meter.

what's mormally meters?

 

[Manitoulin]

what's mormally meters?

Was supposed to be normally... I have edited it for clarity

 

[drspiff]

Nah, Manitoulin is pulling your leg. "Mormally meters" are like D'Arsonval meters, only different.

 

[shrinkboy]

does tennisdude have enough posts to be taking cheap shots like that? doncha have to have, like, 100 posts or so before you get cheap shot privileges?

 

[sorenj07]

lol i know both him and phil, tennisdude is just fooling around

 

[PhilMcL]

does tennisdude have enough posts to be taking cheap shots like that? doncha have to have, like, 100 posts or so before you get cheap shot privileges?

:yes: :yes: :yes: :yes:

 

[tennisdude]

Was supposed to be normally... I have edited it for clarity

yeah mang I know, I'm jus' foolin'

:yes: :yes: :yes: :yes:

:tears:

 

[PhilMcL]

what does anyone know about it coloring the sound? eh?

 

[sorenj07]

it can't really, all it does is evaluate two different currents, there's no circuit that runs through it to be colored... you're in the clear for that.

 

[Strawman]

What kind of meters? I have the Rat Shack AMP 100 and 200's in a systems. No change in the sound as all it's doing is measuring the current, not changing it.

 

[Sam36]

where can i buy a meter? hopefully the shunt kind

 

[sorenj07]

the 'bay, where else

 

[Mark W.]

Well, Now lets see my Heathkit Audio Control Center which has a very nice pair of output meters is a pass through design where the speaker conductors go into one set of connectors and come out a different set of connectors and then on to the speakers.

My Radio Shack APM-200 meters require a lead all there own so you would run a lead from the speaker connections on an amp to the meters (where it dead ends) and another set of leads to the speakers themselves.

I guess it would depend on the meters.

 

[sorenj07]

possible source for VU meters, though it purportedly measures amps... would this work the same way?
http://euphoniaaudio.netfirms.com/e...d=151&osCsid=5e09e064a481e8c840ac4de31a3ffa9a

 

[drspiff]

From what little I remember that I gleaned during my instrument technician apprenticeship, the difference between a "normal" meter and a VU meter is that the VU meter has weighting applied to it. This weighting, either internal or external, makes the meter respond in a dB scale. A typical D'Arsonval meter movement is linear across the meter movement. If you have a 50 millivolt Full Scale meter, 25 millivolts will cause the meter to deflect to mid scale. A dB weighted meter uses a logrithmic scale. We know that a 3dB increase represents twice the power, and the VU meter is calibrated so that it shows this log relationship rather than a "normal" linear relationship. How this is done escapes me.

 

[sorenj07]

so basically this thing is linear and we want logarithmic? makes sense... i just wonder why they would offer linear meters at an audio diy place ...

 

[drspiff]

Perhaps they figure that you have the weighting part and just need a new meter movement. Or maybe they got a great deal on the meters and are now asking themselves "Hmmm, what do we do with these things, now?"

 

[Leroy]

does adding a vu meter color the sound in any way?

According to Heisenberg uncertainty principle the act of monitoring a signal will affect the signal being monitored. Whole different thing is if the difference can be heard... Use some badly improvised circuitry and maybe you may add some kind of noise. But normally the meters should be connected so that they measure sort of a copy of the signal that goes to yer cans and the actual signal you hear isn't going through the meters