Microamp Meter for VU

[thecr4ne]

I'm building a (drip) Fairchild 670, and rather than dropping the cash on the "right" meters, I picked up a pair of Simpson  17503 "Century" series meters on the cheap. These are microamp meters with a scale of 0-200uA, which, I understand is what the Fairchild meters were.

Should I be aware of any other technical differences? I can't find any info on the rise time for the  17503s, should I even worry about it? Any intricacies I need to know about converting the scale from uA to VU or can I just make 0uA=-20VU and 200uA=+3VU?

Here's a few other things I'm considering:
-swapping the housing with those from Model 27 meters, though I understand the construction is not the same.

-Replacing the scale card with a VU A scale. Not sure how I want to go about that yet, trying to find one, or DIYing it.

-Hacking in lights. The  17503s aren't illuminated.

Thoughts?

Thanks.

 

[gyraf]

Ballistics will (should) be quite different on a real vu-meter than on a current meter..

But that may not be a problem for you.

Jakob E.

 

[thecr4ne]

I had a feeling. I did however, come across this quote from :

Take a standard "real" VU meter and remove the diode bridge.  This will give you a 200 uA (microAmp) meter which is about what you need.  That's also what the Fairchild meter was. 

in reference to an Altec 436C meter question here:
https://groupdiy.com/index.php?topic=52204.msg665396#msg665396

Any truth to this or is it an oversimplification?

 

[Michael Tibes]

True, but maybe not the point: a VU is a 200uA meter, but not any 200 uA meter is a VU because of different ballistics. Like it was mentioned, it might not matter in real life. I use cheap 'VU's in my 1176 and I'm happy with them. They move and I don't care about  a mathematical exact metering.

Michael

 

[JohnRoberts]

VU meters (even real ones) are pretty much worthless for serious metering... 

If all you are looking for is eye candy, try it. If it is too something, tweak the circuitry.

JR

 

[gyraf]

If it is too something, tweak the circuitry.

...nice tagline..  ;D

 

[emrr]

If it's a high speed meter it will not be damped, and will jiggle all over the place.  Like this, which is what meters looked like before the VU standard came along.  Not a lot of useful info there.  You get all sorts of overshoot which is purely meter ballistics, not related to audio. 

https://www.youtube.com/watch?v=c2S9kFq-mmA

 

[Gold]

VU meters (even real ones) are pretty much worthless for serious metering... 

If all you are looking for is eye candy, try it. If it is too something, tweak the circuitry.

JR

If I could only have one meter type it would be  VU meter. Not a PPM, not Dourough not some fancy combo meter. I look at meters all day every day and I rely on them. I'm not the only one.

 

[JohnRoberts]

If I could only have one meter type it would be  VU meter. Not a PPM, not Dourough not some fancy combo meter. I look at meters all day every day and I rely on them. I'm not the only one.

That's why I invented a meter (decades ago) that displays more than one characteristic (Peak, Ave, and even crest factor from difference between the two).

People who learned on VU meters have figured out how to apply windage and accommodate widely ranging crest factor sources. When tracking it was common practice to record high crest factor musical sources cooler than the VU meter level indicated because that was not actually cooler to the tape.

The customer is always right (even when wrong). When I sold multitrack consoles with all VU meters, I added peak LEDs in addition to the VU to reveal headroom status.  I still question the ability to scan 24 VU meters at once and get a good reading of what is going on level wise in all channels.  At least with the peak LEDs they could easily see really hot tracks.

I repeat my comment for "eye candy" try whatever mechanical meter you have. If you never used a real VU meter I doubt you will be bothered by the difference. BTW real VU meters are not cheap.

I cannot imagine printing audio to digital media without some form of peak meter. I suspect most digital platforms incorporate peak metering.

JR

 

[Gold]

For individual sources like a bass drum or a vocal the ideal meter type would vary.  I still think a VU meter is better than a 12 segment PPM. I’d take a plasma PPM though. For stereo program I think VU meters tell you what you need to know better than anything else.