g'day,

i was trying to tune my gains the other day on my sax 200.4 with a test cd and multimeter i've used with several other cars and amplifiers. for some reason, the multimeter wont pick up any signal from any of the speaker outputs at all. i can turn the knob from 0.2v to 6v and not get any change off 0V, on any channel and any output. i'm using exactly the same method as i do with other cars and stereos and it's worked fine, but not with this amp. is there some trick to getting the sax 200.4 to measure through a multimeter or something? the meter i'm using is an Amprobe 5XP-A and it has plenty of battery left in it.

thanks.

did you try and get any readings on it from something else? battery, just to make sure it is still working???

make sure it's set to AC or it will read nothing.

did you try and get any readings on it from something else? battery, just to make sure it is still working???

yea the amp's fine, i had it running minutes before i tried setting them, was running on about half on each gain level, i just wanted to fine tune them cos i had the time.

make sure it's set to AC or it will read nothing.

i'm an electronics technician so i understand how it all works, there wasn't a chance of an error there cos i made double and triple sure everything was as it should be. and as i said, i've set many gains on many amps with this meter without a problem, it's just this amp that's being weird.

if it helps i can make a short video showing what's happening.

did you try and get any readings on it from something else? battery, just to make sure it is still working???

yea the amp's fine, i had it running minutes before i tried setting them, was running on about half on each gain level, i just wanted to fine tune them cos i had the time.

make sure it's set to AC or it will read nothing.

i'm an electronics technician so i understand how it all works, there wasn't a chance of an error there cos i made double and triple sure everything was as it should be. and as i said, i've set many gains on many amps with this meter without a problem, it's just this amp that's being weird.

if it helps i can make a short video showing what's happening.

Then you should understand that those speaker outputs MUST be circulating a/c current or else your speakers wouldn't be playing any music. There is nothing magical about the amplifier, either your method of testing or your multimeter is faulty.

What happens if you try to read the voltage with the speakers connected? Is the voltage still shown as zero?

umm i have had this type of issue before!

to solve this issue i just put the dmm down and tuned it by ear! I would recommend doing it by ear as now a days music is hacked up and loudest being added and such that if you use a tone that is at 0db and then you listen to music which has been ripped to like +3db you could start to clip those speakers! so over the past couple of years i have been turning this gain up and a down a bit to suit my needs with the type of music i am listening to.

hmm the only thing that I can think of is that whatever you are touching is not conductive (the screws maybe?) have you tried to stick the leads inside where the wires go in? It just seems like a/c voltage is a/c voltage and you should be able to read it as long as you are making contact with the outputs and its conductive at that spot.

I'm an electrician if that helps, so I am NO expert but I do at times have to work with meters and its the only thing that makes sense to me.

You are doing something wrong, period.

You are doing something wrong, period.

I like this one ^^

Well i tried measuring the outputs when they're connected to and playing through my speakers and it does measure, but only up to like 4 volts peak, no matter where i set the gain. I probe inside the actual speaker terminal when testing so there should be no conductivity issues. I figure it's something up with my meter, i'll put a fresh battery in it and see if that helps. Soz for not quoting replies but i'm on my phone and it'd take ages.

Try a different dmm

Fuse blown in DMM?

Or even better yet, are your leads conductive... I've seen wires get pinched off, or the tips come loose and that mess with readings.

Have you replaced the batteries in it?

Fuse blown in DMM?

That is very likely.

Fuse blown in DMM?

That is very likely.

the fuse must have blown instantly due to the output of the 200.4 lol! nicely done sundown products lol!

the fuse isn't blown. the fuse in a dmm mainly comes into play when you are testing current, the voltage stage of a dmm isn't fused like the current stage. plus, the fuse is rated at 1000V at 315mA and i wasn't testing current. my dmm can read up to 750V ac and i first tested it on the 200V scale, and i doubt even the 200.4 could output over 200V with the gain set near half. the leads are ok as well, they have never been treated roughly, i tested them and they're both in good shape. i'm charging up a fresh 9V battery to try in it cos i don't have any other 9V batteries currently so i'll see if that helps. i'll try a cheap dmm i have and see how it goes as well, idk what condition it's in though but i think it works.

the fuse isn't blown. the fuse in a dmm mainly comes into play when you are testing current, the voltage stage of a dmm isn't fused like the current stage. plus, the fuse is rated at 1000V at 315mA and i wasn't testing current. my dmm can read up to 750V ac and i first tested it on the 200V scale, and i doubt even the 200.4 could output over 200V with the gain set near half. the leads are ok as well, they have never been treated roughly, i tested them and they're both in good shape. i'm charging up a fresh 9V battery to try in it cos i don't have any other 9V batteries currently so i'll see if that helps. i'll try a cheap dmm i have and see how it goes as well, idk what condition it's in though but i think it works.

I wasn't doubting your equipment and I was aware of when the fuse comes into play... I was under the assumption that you use this meter for work as well, and that maybe you were using it for current there.)

I was just listing off things that I know get overlooked quite often.

I have a similar problem with a JBL amp, I can only measure a few millivolts on the outputs, but mine is a bit different where once I get to a certain point the outputs go crazy. I've sent the amp back to JBL and got a replacement doing the same thing sent the replacement in and am waiting on the next one.

hey I can't see where you have your leads pluged into on this video? is one on the positive terminal and one on the positive of one of the speaker terminals?

also have you tried to o'scope your RCA's? to see where or if your h/u clips at?

Edited December 19, 201113 yr by CrazyKenKid

hey I can't see where you have your leads pluged into on this video? is one on the positive terminal and one on the positive of one of the speaker terminals?

also have you tried to o'scope your RCA's? to see where or if your amp h/u clips at?

One is on the positive and the other is on the negative, and yes I have figured out where the head unit clips.

o wow that is pretty odd then I don't know what to tell you then!

I know when I used an o-scope to set my gain on the amp I also had the sub (load) plugged in all the while and i first used a tone to get it in the ball park aka an unclipped signal then I popped in a few songs that I would be demo-ing more times then not and turned it up or down as required then popped the gain knob in an away I went. O and i also found the clipping point on my h/u and turned it to that number for setting up my gain.

but that sine wave is pretty interesting it goes all over the place! lol but let me know what you find out I am interested in to what is going on there.

bromo are you sure your probe on the o-scope is good. I had my velleman o-scope read like that and the problem was the probe. replaced it with a different brand and havent had a problem since (over a year later)

velleman that is the name of o-scope I used and yes come to think of it my leads were also garbage and I had to get them replaced! good call icewall!

bromo are you sure your probe on the o-scope is good. I had my velleman o-scope read like that and the problem was the probe. replaced it with a different brand and havent had a problem since (over a year later)

Its not the leads, I haven't had a problem with any of the 5 other amps tested. It also goes haywire when the sub is connected, I can tell by the way the sub is moving. Don't want to jack the mans threads though, it was more of an example of other amps having the same problem of not being able to measure the outputs.