How to figure pre-amp voltage

[Mr Bojangles 10+ year member]

I'm trying to set the gains on my amp correctly and I need to figure out what the pre-amp voltage on my head unit is.. I don't see the specs on the pioneer site.. Anyone?

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[Rich B 5,000+ posts]

You will need to say which Pioneer headunit you have before anyone can tell you the preamp output.

 

[Mr Bojangles 10+ year member]

I was just wondering in general how to find out.. Like if there was some kind of test with a volt meter or something..

 

[nauc 10+ year member]

there is a trick using like a 0db tone and a -3db tone

they should be a certain amount of voltage difference between them when not clipped vs when clipped

cant remember how it went

maybe someone else knows, think TheChris at CAF told us

 

[GrnEydDvl 10+ year member]

I'm trying to set the gains on my amp correctly and I need to figure out what the pre-amp voltage on my head unit is.. I don't see the specs on the pioneer site.. Anyone?

You can hook up a DMM and measure the AC voltage on your preamp outputs. Of course, ths won't tell you when they start to clip, just what the voltage is at whatever frequency you are playing, at whatever volume point on the headunit you have selected, at whatever dB's the test material was reorded at..

Best bet is to buy a decent, cheap o-scope and find out at what point it is clipping. Or you can ask here with a model number and perhaps someone has done this test already for that model.

Why did you want to know the exact voltage in the first place? Knowing it doesn't mean a lot unless you are trying to compare it to another headunit. Specs are fudged by manufacturers and as long as you are beyond a minimum voltage from the HU, you can drive your amps just fine. Knowing it won't help you set your gains any easier.

 

[thch 10+ year member]

yes, you should be able to measure Volts AC for each setting on the HU, using a 0db tone.

then meausre the same, but use a -3dB tone.

for each setting, the ratio of these two results should be constant. as clipping sets in, the ratio approaches 1.

algebra shows that each result could be converted to a logrithm, then these results subtracted -- giving a constant. basically converting each measure into a dB-ish value, then subtracting to get a constant value is (pseudo) dB's.*

*to be dB's, a scaling factor would be applied. but this isn't needed to get results.