what is the dumont scale?

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pucho812

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looking at this weston meter at leeds in NYC at it's labled as a 1ma DC basic movment meter. perfect for the Gssl IIRC but need to double check. anyway the meter is listed aas dumont scale meter WTF is that? I never heard of the duumont scale... Dave got a clue?
 
I laughed so hard I almost spilled coffee down my shirt.

There's no "Dumont scale." Dumont was a big electronics manufacturer back in the '50s. The meter in question is just a regular VTVM meter scale with a Dumont logo on it.

(Actually, if you've never heard of Dumont, you're probably too young to know what I mean by VTVM. It's Vacuum Tube VoltMeter).

With proper support circuitry you could use it as a signal level indicator but it won't be a VU meter. The ballistics aren't the same. It will seem twitchy compared to a real VU.
 
dave

:oops: :oops: :oops: :oops: :oops: Pardon my youngness. I just figured Allen B. Dumont had come up with his own way of metering much like bob Katz. :wink: so I had to ask...

IIRC = If I recall correctly. Gssl is well Gssl. I'm slowly getting around to building one of them as guitar amps and studio work take up all my time. But always looking for something cool. That meter in question is a 1 Ma which will work...
 
"And yes, they did have a standards department that established operating levels... In this case 0VU=1mW/600ohm where the conventional Western Electric/Bell system levels were +4 dBm=0VU due to the build-out resistor. I found this to be interesting."

But what you're missing is that it's not a VU meter. It's a VTVM meter. It doesn't say "VU" anywhere on that scale. It does have a dBM scale along with two Volts scales. 0dBM=1mW in 600 Ohms, or .775Vrms is not some DuMont "proprietary standard." It's the ol' familiar Bell Labs/CBS/NBC standard from 1939. That standard gave us the VU meter, but that does not mean that a meter that reads in dBM is a VU meter. See:

http://groupdiy.twin-x.com/albums/userpics/10031/VU-1.png
http://groupdiy.twin-x.com/albums/userpics/10031/VU-2.png

VTVM (or AC millivoltmeter) scales are pretty much the same whether the name plate says DuMont, Hewlett-Packard, Triplett, Simpson, Eico, Heathkit or even Tenma.
 
i used this same weston/dumont meter for a collins project which called for a 1ma meter (26u spec) and it works great for GR. i haven't yet installed the complete metering circuit from the 26u but i'm pretty sure it *can* be switched into VU mode. i don't have the schematic handy but will check into it.
 
fook dumont and his scale. :green:

I ended up getting a nice round 1 Ma meter from the local electronic surplus store. It's a an old bakelite simpson meter. Cost was 5 bucks and works great. It just barely fits the 2 unit rack space we making the GSSL out of. I took it apart measured the dial plate and made a meter scale using front designer 3.0 software. If you look for a current post for about front designer one can see my meter scale. or beter yet take a look at it here. The meter is for Kling st. The name of the recording studio/guitar amp making company I am slowly starting with my friends.
here is the meter pic
I like it simple and to the point but yet your average dumbass will not know how to read it.
I'll post a pic of the meter in a day or 2
SSLmeterfinal.jpg
 
Nice. :guinness:

So does the GSSL kick the meter from L to R w GR? I figured it would go R to L. Guess i'm the joker who looks at it wrong.

BTW, trying to ween myself off all-lower-case typing. Sorry if my use of the ^shift key is distractingly inconsistent today. :wink:
 
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