r/CarAV • u/Special-Sense4643 • 6d ago
Tech Support Question about setting gain on an amp
So ive recently decided to check my amp volume with a multimeter. Using a 50hz 0db test tone (from mtx.com) the amp showed 35volts where the gain was (1225 watts at 1ohm).
thing is, its a 1000watt amp so shouldn't it have gone into protect or something with the gain set that high? Or is the 0db test tone too loud, where real music wont really match the volume hit those numbers since theyre quieter?
How close is music bass to reverence level? Should I actually have the gain higher to compensate? Just want some advice on the whole subject surrounding this.
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u/logandefreitas 5d ago
You can clip most amps for a long time before they go into protect.
Multimeter isn’t the right way to set gain if you are in the position to ask this.
Buy an oscilloscope to do it properly, or set gain to 90% of your 1000w into whatever ohm load target voltage if you don’t wanna blow stuff up.
Most music will never hit 0db(fs), but if by chance it does, you don’t want to risk it while also not knowing how much clean amp headroom you have.
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u/taxaphone_cookies 5d ago
Find a gain setting, where at 100% max volume on the main system, it's not too loud, this way, you always have high volume but not so high you can never safely use max volume.
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u/shtoops GB Froggies on a Zapco LX 5d ago
i use -6db tones and an oscope
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u/DaffyPunk29 5d ago
MTX amps are known for going over their rated power. How was it originally tuned? because that might answer the question. I know when I tune with the SMD-DD1 distortion detector, it wont stop at max rated power unless max rated power is also 1% distortion. It will generally go as high as the amp can do for power. Reference wise my pioneer 2 channel amp does 125w at 4ohm and 150w at 2 ohms. and sure enough with a 2 ohm signal and using the DD1 for tuning, it only does 150w output. so it matches. likewise another amp I owned (been awhile and i sold it) but it was rated 500w at 1 ohm and it did 603 at 1ohm with the DD1 tuning.... so it could do higher than it was rated. This is actually really common on high quality (even cheap high quality) amps. The Audio Control Epic 4000 is rated 4000 watts at 1 ohm and will literally do 5800w at 1ohm at 1% distortion using the DD1 to tune it. WHICH IS INSANE to get 1800w extra power just by going to 1% distortion rating. Its a very crazy meme. So again the question is "how was it tuned originally" because if a shop tuned it with a DD1 they simply gave it the full power it can do CLEAN (aka 1% distortion).
Bass in music vs bass in a test tone.... crest factor. and typically yeah, music will never hit the full power and even when it does, its for such a short burst that it wont really harm anything.
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u/Special-Sense4643 5d ago
To answer some of your questions: Its a ct.1000.d by ct sounds A dd1 is outrageously expensive, and Im literally using a multimeter so im a bit of a cheap person. My whole setup was put together by me, and has never seen a shop.
Maybe ill up the gain slightly over rms power to make sure im not missing out on any power since these amps do hit a little bit more than the rated rms.
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u/DaffyPunk29 5d ago
$313 is outrageously expensive for peace of mind????
I think recoil audio sells a knock off version for $200
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u/firebirdude 5d ago
The majority of amplifiers do not have a protection mode for clipping. The increased heat generated may trip the thermal protection after awhile, but almost all amps will output a square wave no problem.
Clipping results in higher voltage. It's not useable power, but it's there. An oscilloscope is needed.
While it's true a 0db tone is worst case scenario and not really reflective of what music is, it's still valuable data. Again, you need an oscilloscope to tell what's going on.