I know you don't need a real fancy scope to set amp gains. I was wondering if anyone could give me an idea on minimum scope specs that would work. I also saw Madell scopes on ebay one for $250 20mhz 400 v peak input., and one for $150 10mhz (don't know peak input voltage). Would either of these be any good for gain setting. What about the Velleman hand held scopes are they any good for what I want to do.? Display screens seem hard to read on these.
Replies (7)
Ash on 12/9/2007 02:15:31
A good digital multimeter will work good for most. Seeing that you're looking for a RTA, perhaps you might want to try and look into software to run on a laptop (if you have one already). This is the most economical way as some will have both.
As both of your posts are related, it may be simpler to put them one and delete the other. This way Q&A will be much quicker in response.
cplkittle on 12/9/2007 04:20:42
http://www.datafilehost.com/download.php?file=6d26c621
Here you can download an Excel spreadsheet with an embedded 60Hz tone for setting amplifier gains by amplifier output AC voltage. All you need is a basic multimeter.
storis on 12/10/2007 22:08:31
storis on 12/10/2007 22:10:28
Sorry I have been away for a few days. OK I hear alot of people say all you need is a DMM. I can't believe that is as accurate as using a scope. How do you know when clipping starts to occur with a DMM.
cplkittle on 12/10/2007 22:35:19
A DMM will not show clipping, however, if the gains are set properly to the output voltage on the RCAs of the HU there should not be any clipping. All of this is calculated on the fact that the amplifiers are quality products.
If your budget allows, and you take alot of pride in knowing that the stereo is set up perfectly, I would say get the scope. Having worked in car audio for 6 years, I have never seen one used to set up a stereo.
Even the nicest amplifiers have cheap potentiometers for the gain settings. After a little vibration, an exact setting will change a little.
I commend you for wanting to do it right. In my opinion, these days it is like using a micrometer to build dog house.
ttocs on 12/10/2007 22:49:29
i went through tech school and used them daily, and have used them to set up a couple of systems in that the customer was picky about. In the end I want to tune a system to what sound best to my ears rather then what looks best to my eyes. A DMM will not spot clipping but your ears will. If you have access to one and want to then go for it but I would not buy one for this. I am willing to bet a local shop has one that they can help you with for cheaper if you are not too far out...
jamesp on 12/11/2007 08:37:30
I have seen a Fluke DMM with sine wave generator and true RMS feature used to check the output from the preouts from a head unit. When the signal began clipping, a square waveform was on the display as well as the voltage where clipping began and I believe the ohmage that the signal clipped.
I was under the impression that the same thing could be done at the speaker outputs with drivers attached while tweaking amp gains. The only drawback may be a limited frequency range....But Im not sure.
Replies (7)
Ash on 12/9/2007 02:15:31
A good digital multimeter will work good for most. Seeing that you're looking for a RTA, perhaps you might want to try and look into software to run on a laptop (if you have one already). This is the most economical way as some will have both.
As both of your posts are related, it may be simpler to put them one and delete the other. This way Q&A will be much quicker in response.
cplkittle on 12/9/2007 04:20:42
http://www.datafilehost.com/download.php?file=6d26c621
Here you can download an Excel spreadsheet with an embedded 60Hz tone for setting amplifier gains by amplifier output AC voltage. All you need is a basic multimeter.
storis on 12/10/2007 22:08:31
storis on 12/10/2007 22:10:28
Sorry I have been away for a few days. OK I hear alot of people say all you need is a DMM. I can't believe that is as accurate as using a scope. How do you know when clipping starts to occur with a DMM.
cplkittle on 12/10/2007 22:35:19
A DMM will not show clipping, however, if the gains are set properly to the output voltage on the RCAs of the HU there should not be any clipping. All of this is calculated on the fact that the amplifiers are quality products.
If your budget allows, and you take alot of pride in knowing that the stereo is set up perfectly, I would say get the scope. Having worked in car audio for 6 years, I have never seen one used to set up a stereo.
Even the nicest amplifiers have cheap potentiometers for the gain settings. After a little vibration, an exact setting will change a little.
I commend you for wanting to do it right. In my opinion, these days it is like using a micrometer to build dog house.
ttocs on 12/10/2007 22:49:29
i went through tech school and used them daily, and have used them to set up a couple of systems in that the customer was picky about. In the end I want to tune a system to what sound best to my ears rather then what looks best to my eyes. A DMM will not spot clipping but your ears will. If you have access to one and want to then go for it but I would not buy one for this. I am willing to bet a local shop has one that they can help you with for cheaper if you are not too far out...
jamesp on 12/11/2007 08:37:30
I have seen a Fluke DMM with sine wave generator and true RMS feature used to check the output from the preouts from a head unit. When the signal began clipping, a square waveform was on the display as well as the voltage where clipping began and I believe the ohmage that the signal clipped.
I was under the impression that the same thing could be done at the speaker outputs with drivers attached while tweaking amp gains. The only drawback may be a limited frequency range....But Im not sure.
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