how do i use this analog multimeter?

[Twistid 5,000+ posts]

ok i got a sperry sp-10A analog multimeter that i found in some box somewhere

i want to test the pre-outs on my headunit to see if they work ,

it has a rotating knob thing that has diff sections in it , like the first section is in red and is called "ACV" it then goes from 500, 250, 50, 10, then the next section is called "DCA and only has 250m on it, the next one is B.TEST and has 9V and 1.5V , the next one is DCV and it has 10, 50, 250, 500, the next one is "ohm" and it hsa Rx1, Rx10, Rx100

hmmm im totally stumped

Click to read more...

 

[JimJ 5,000+ posts]

Ah, analog meters //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Those bring back good memories. And by good, I mean horrible.

Set it to ACV (AC voltage, I'm assuming). Try it on the 10V setting, parallel to the circuit...you may need to use a shunt resistor to get the meter in the proper range, but try the lowest setting first.

 

[Twistid 5,000+ posts]

ok, i should have the headunit on when testing the preouts right?

 

[JimJ 5,000+ posts]

...

Yes.

 

[squeak9798 5,000+ posts]

Not just on...you have to play a 0db test tone to measure the preamp output voltage.

Deck volume up all the way

 

[Twistid 5,000+ posts]

ok i went and turned on headunit, tested preouts, nothing at all happened, it was on ACV - 10, then i put it to 50, then 250, nothing at all happend, the needle dident even move...

 

[squeak9798 5,000+ posts]

ok i went and turned on headunit, tested preouts, nothing at all happened, it was on ACV - 10, then i put it to 50, then 250, nothing at all happend, the needle dident even move...

....

Not just on...you have to play a 0db test tone to measure the preamp output voltage.
Deck volume up all the way

 

[Twistid 5,000+ posts]

by 0 db test tone you mean like the ones on bass mekanik cd where it goes like 0 cycles...

 

[squeak9798 5,000+ posts]

0db refers to the recording level of the track.

The test tones on the bass mekanik CD might be 0db tones. I don't know off hand. If not, realmofexcursion has some for download.

 

[Twistid 5,000+ posts]

hmm ok i would play some of the test tones @ nearly full volume but the needle on the voltage meter only goes up a tiny little bit like barely nothing.... crap you think my preouts are dead?

 

[sumone 10+ year member]

Your preouts are probably 2V or 4V. Check the range on the meter to see what it really corresponds to.

Do you have one meter lead on the shield & one on the tip of the RCA cable?

Also it sounds like you have the same meter I once had...make sure you calibrate it. I don't have it anymore but I think the usual process was (in resistance x1) touch the leads together, and the red circle with the lines on it is turned til the needle matches to 0 (or was it inf?).

 

[sumone 10+ year member]

OK, that yellow circle in the center (right between "sperry" & "sp-10") you have to turn that 'til the needle reads 0 on the display (when you touch the 2 leads together in rx1 mode).

Edit: oops, I mean the bigger yellow circle under the word "OHM".

 

[bimma85 5,000+ posts]

No offense, but you have been here for two years and never read the gain tutorial? Go read it //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif.

 

[sumone 10+ year member]

I think he just made a thread basing it off of this thread. He's trying to see if any signal comes off the pre-amp outputs by measuring the voltage. Cause you don't really need to measure the voltage of the RCAs for setting gain. You could use it to see at what the HU clips at...but you'd need an o-scope for that.

 

[Twistid 5,000+ posts]

OK, that yellow circle in the center (right between "sperry" & "sp-10") you have to turn that 'til the needle reads 0 on the display (when you touch the 2 leads together in rx1 mode).

Edit: oops, I mean the bigger yellow circle under the word "OHM".

THX ALOT //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif

and yea i have read the gain tutorial, that has nothing to do with what im talking about //content.invisioncic.com/y282845/emoticons/eyebrow.gif.fe2c18d8720fe8c7eaed347b21ea05a5.gif