How to check amp voltage

Is this amp OK?
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squidfingers729
Posts: 70
Joined: Fri Mar 28, 2008 6:00 pm
Location: Lafayette, La

How to check amp voltage

#1 Post by squidfingers729 »

I'm pretty new to using a multimeter. When I say new, I mean I just opened the package for the thing. Would someone be kind enough to explain this in baby language for me, from what settings to put the meter on, to where to stick the business ends of the meter on my XTI2000? I just don't know where to make contact with the speakon connectors.


My meter: http://i.walmartimages.com/i/p/00/04/21 ... 00X500.jpg

Grant Bunter
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Re: How to check amp voltage

#2 Post by Grant Bunter »

Sure thing,
Read the manual for your new toy because you're going to play with electricity.
That's not being sarcastic.

From that, work out where the red and black lead plug into the unit and set it on AC 200. Heads up, with an amplifier you're working with AC voltage.

You don't need to go near the speakon(s) because the XTI, at least according to the manual, has binding posts. So black lead to black binding post and red to red, the probes need to contact the metal in the middle of the binding post to get a reading.
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
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squidfingers729
Posts: 70
Joined: Fri Mar 28, 2008 6:00 pm
Location: Lafayette, La

Re: How to check amp voltage

#3 Post by squidfingers729 »

Hey thanks for the response, it helps a bunch!

Just curious, but where do you make contact on amps with just 1/4 jacks?

Grant Bunter
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Re: How to check amp voltage

#4 Post by Grant Bunter »

squidfingers729 wrote:Hey thanks for the response, it helps a bunch!

Just curious, but where do you make contact on amps with just 1/4 jacks?
You plug in a 1/4" jack, either with "bare tails" (ie the wire to tip and the wire to sleeve are stripped and separated so they don't touch), or a 1/4" jack without cables attached, and put red on tip and black on sleeve.
At least that is convention, but it always pays to check with a manual (or sometimes a flow chart printed on the amp cover) for any amp to check that convention has been followed...
Built:
DR 250: x 2 melded array, 2x CD horn, March 2012 plans.
T39's: 4 x 20" KL3010LF , 2 x 28" 3012LF.
WH8: x 6 with melded array wired series/parallel.
Bunter's Audio and Lighting "like"s would be most appreciated...

miked
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Joined: Fri Oct 23, 2009 4:18 am
Location: San Antonio, TX

Re: How to check amp voltage

#5 Post by miked »

Unless you really know what you're doing (and you don't b/c you're new to this) do not stick multimeter probes directly into a 1/4" output jack. You will short circuit things and possibly destroy your amp. BTW, what amp do you have that ONLY has 1/4" output jacks and no binding posts or Speakons? Speakons are "relatively new" but binding posts were around before 1/4" jacks.

Grant gave you a 100% correct walkthrough on how to take a reading w/binding posts.

Charles Warwick
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Joined: Mon Mar 09, 2009 1:25 am
Location: Ames, Iowa

Re: How to check amp voltage

#6 Post by Charles Warwick »

I have an Xti2000 and you do indeed just stick the probes into the appropriate binding posts, don't mess around with the speakon jacks, just use the binding posts. I unscrewed them, put the probes into the holes, and loosely tightened them back down.

Agreed with everything else mentioned, don't try to measure directly from the jacks. If you have to (i.e. there aren't binding posts) do what Grant said.

Michael Murphy
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Location: Trinidad

Re: How to check amp voltage

#7 Post by Michael Murphy »

Great responses. Squid you know you are going to play a tone of some sort to give the amp some thing to amplify right?
If you dont have a tone generator, download a free tone generator from the web set it at say 50hz sine wave, connect headphone pc out to mixer, mixer to amp and amp to meter (as previously described) start generator and see what happens. You may need to increase the headphone output and/or the mixer to achieve max readings on the meter and/or also the amp gains. Android phone makes it very simple btw.

According to your amp spec its 475w @ 8ohms, using

http://www.sengpielaudio.com/calculator-ohm.htm and inputting those values in the relevant fields your amp is good for 61v

Your testing should mesh with this value +/- a volt or 2

pumpsfast

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