Is there a way to find out your preamp/RCA voltage with a multimeter? - diyAudio
Go Back   Home > Forums > General Interest > Car Audio

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 10th March 2008, 07:24 PM   #1
Flyin11 is offline Flyin11  United States
diyAudio Member
 
Join Date: Sep 2007
Default Is there a way to find out your preamp/RCA voltage with a multimeter?

Ok...I know how to try and set your gains with a multi-meter but I was wondering if there is a way to use it to find out what voltage your RCA's/preamps are putting out? I know I had a discussion a while back about my headunit voltage and how you wouldn't really see 5v unless you had it maxed out in volume. So, I might be looking at another amp and don't want to get into a situation with it if it says 4V max input sens and my HU has 5V. Although I had this setup with a Alpine amp before and had no issues. Just wondering though so I can test and make sure....
  Reply With Quote
Old 10th March 2008, 07:43 PM   #2
cuibono is offline cuibono  United States
diyAudio Member
 
cuibono's Avatar
 
Join Date: May 2006
Location: City of Angles
I don't deal with car amps, and I don't know what this has to do with input sensitivity, but if I wanted to know the output levels of something, I would get a recording of a 440Hz sine wave (long enough to be useful, a couple minutes?), and play it. Then with the voltmeter set to AC, just read the terminals. You might not want to have you speakers on, it would probably be loud.

You should be able to find a test tone like the one above on the net somewhere. I'd try and avoid a higher frequency tone because your meter might not be accurate higher up..

Enjoy
  Reply With Quote
Old 11th March 2008, 12:26 PM   #3
Flyin11 is offline Flyin11  United States
diyAudio Member
 
Join Date: Sep 2007
Thanks but that's not what I was referring to. That's how to set up your gains. I was wondering if there was a way to find out the voltage coming out of your RCA's from your headunit. I saw on another site someone said that you can set your multimeter to read AC voltage and use the positive probe and touch the pointed part of the RCA and then use the negative and touch the outer round part of it and it gives you the voltage coming off the RCA. Someone then replied though and said to be extremely careful cause if you touch one of the parts incorrectly you can burn out the RCA's in the headunit. I would want to be careful so I was wondering if anyone knew anything about this or if there's a way to do it? I'm wondering what mine is sending as I don't have my volume up max at all and never come anywhere near it so I don't really believe the 5V rating Kenwood gives me in the manual as you probably won't hit that unless you are at full power and you still might not get 5V out of it.
  Reply With Quote
Old 11th March 2008, 12:39 PM   #4
luka is offline luka  Slovenia
diyAudio Member
 
luka's Avatar
 
Join Date: Sep 2005
Location: in Slovenia :)
Send a message via Skype™ to luka
Hi

MOst units give 2v, so there is good chance your's does too. If you still want to, best way would be with scope, if you will try with DVM usetest tone, 50 or 60Hz tone, + of DVM does to middle or RCA, - to outside, no plastic there, if you put it on plastic you won't read nothing
__________________
home page @ http://www.classdaudio.tk/ @ 24/7 all year long
I FEEL SLOVENIA
  Reply With Quote
Old 11th March 2008, 01:12 PM   #5
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
I'd agree, 50-60hz will probably give the most accurate reading unless you have a true RMS meter.

I'm not sure about other head units but most Pioneer head units will produce the maximum undistorted output at 1 step below the maximum volume (using a 0dBfs tone). For it not to be driven into clipping, you will have to have all EQs and bass/treble settings at 0. The loudness coutour will have to be off.

There is no danger of damaging the RCA outputs unless you allow them to come in contact with a power source (uninsulated 12v wire, speaker outputs of the amplifier...).

This is a 60Hz tone. Burn it to a disc and use it for testing.
http://bcae1.com/temp/60hz60seconds.zip
  Reply With Quote
Old 11th March 2008, 02:28 PM   #6
Flyin11 is offline Flyin11  United States
diyAudio Member
 
Join Date: Sep 2007
Thanks Will give it a go later on. Tried a 60hz tone before and it didn't sound great to me after I started playing my music again so I've been using a 28hz tone and get a much better bass response. My system seems to like either 25hz or 28hz. Will stick that back in again and see what the RCA's are reading.
  Reply With Quote
Old 11th March 2008, 04:10 PM   #7
jol50 is offline jol50  United States
diyAudio Member
 
Join Date: Nov 2007
Default Re: Is there a way to find out your preamp/RCA voltage with a multimeter?

Quote:
Originally posted by Flyin11
and don't want to get into a situation with it if it says 4V max input sens and my HU has 5V.
You should not have to worry about that. Not 100% but I don't know if a HU can even put out its full rating playing music. Ones I have measured on RCA before I got a good dmm were millivolt. But it should not matter as you really should never turn the HU all the way up, and should never have to turn the amp gain all the way up either. Back in the 80s we ran 5v line drivers with no problems. Don't recall there being more than 2v HUs then.

You use a 50-60hz tone because odds are the meter can read standard AC current Hz better, it should have no effect on your system what you test with since RCA will not be hooked up anyway if you are reading voltage of it. Also, any numbers printed on an amp pot for crossover frequency or gain level...don't trust they are accurate. Better to set crossover by ear or with tones than what most amps say, even some crossovers.
  Reply With Quote
Old 11th March 2008, 05:39 PM   #8
luka is offline luka  Slovenia
diyAudio Member
 
luka's Avatar
 
Join Date: Sep 2005
Location: in Slovenia :)
Send a message via Skype™ to luka
Hi Flyin11

Its no the point in using 28Hz coz your meter won't show it right, and if it you do it by ear, there is not point of using it anyway, wrong reading is the same as none...If you do it by ear do all by ear...
__________________
home page @ http://www.classdaudio.tk/ @ 24/7 all year long
I FEEL SLOVENIA
  Reply With Quote
Old 11th March 2008, 06:48 PM   #9
Flyin11 is offline Flyin11  United States
diyAudio Member
 
Join Date: Sep 2007
Yeah, I know...The meter fluctuates and doesn't really give you a solid reading but I just judged it by when it stops fluctuating and stays still longer than when it is fluctuating, just for a second or 2, that's where I stop and get it to where I want it. I'm not complaining, I know that it's not totally accurate that way but it sounds great anyways and I like how it is sounding. I can't go 60hz or over anymore...It just doesn't compare and I don't get the sound I'm looking for
  Reply With Quote
Old 11th March 2008, 06:54 PM   #10
diyAudio Member
 
Join Date: Nov 2003
Location: Louisiana
Why are you having problems with 60Hz?

It's not supposed to sound good, it's simply the frequency that's most likely to be accurate on a meter that doesn't read true RMS.

The readings should be rock solid and shouldn't vary more than a few thousandths of a volt.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Very Low Voltage Preamp lumanauw Tubes / Valves 8 30th July 2008 06:21 PM
regulating voltage for preamp alizawi Chip Amps 56 12th May 2006 12:47 PM
6DJ8 preamp voltage? needtubes Tubes / Valves 1 2nd April 2004 09:06 AM
How low should PSU ripple voltage be in a preamp? DrewP Tubes / Valves 5 6th February 2003 07:43 PM


New To Site? Need Help?

All times are GMT. The time now is 10:09 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2