# amp suggestions



## o89canucks (Dec 4, 2003)

ok heres my deal - ive got a 12" alpine type S dvc sub, I was using a 2 channel profile amp to run. problem was that the profile amp wasn't 2 ohm stable so the amp would overheat and shut off. Now I just bought a infinity reference mono amp that is 2 ohm stable, but the amp is clipping and heating up pretty good as well. My question is does anyone else have this sub, and if you do, does it just take a massive amount of power to run it? Im about ready to just break down and go buy a precision power, any suggestions?


----------



## captain_shrapnel (Sep 10, 2004)

I haven't had any experience with that sub, but I believe its a decent midgrade speaker. However your amps are not up to snuff, either one. Look into a hifonics brutus bx500d. Goes for about $250, pushes 250 watts at 2 ohms rms. I just had a discussion with some of the other gurus here and the general consensus is Hifonics has decent bang for the buck. Here is a link:

http://www.acaraudio.com/product_info.php?cPath=22_36&products_id=1138

Good luck, and let us know how it goes.


----------



## sr20dem0n (Mar 19, 2003)

if the amp is clipping and getting hot, you need to lower the gain


----------



## Binger (Aug 29, 2002)

yes...turn the gain down


----------



## funkpacket (Feb 13, 2004)

second on the hifonics recomendation. Viper monoblocks will blast that sub as well for a tight budget option


----------



## Punkrocka436 (Jul 8, 2003)

remember, the gain is NOT a volume knob...you turn it up until you hear distortion and back off 1/8 of a turn. Turning it up all the way is a good way to blow an amp


----------



## o89canucks (Dec 4, 2003)

bass boost is down all the way, and gain on the amp is maybe only at 1/3. amp literature states it pushes 347 watts rms @ 2 ohms stable, and the sub is rated at 300 watts rms. in fact the sub isn't distorting at all, the thd on the infinity is a lot lower than on my old profile, so you can really tell a difference in the clarity - its got a lot cleaner sound and the xover has a lower setting so it his lower notes without sounding muffled. the infinity ran right at $250 as well, but i think im gonna still shop around.


----------



## sr20dem0n (Mar 19, 2003)

1/3 gain might still be too high

what is the range on the gain and what is your signal source (aftermarket cd player (if so which one), stock cd player with a LOC (if so which one), etc)?


----------



## Azgrower (Oct 1, 2004)

Here is another option for the sub:
http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=13126


----------



## captain_shrapnel (Sep 10, 2004)

Azgrower said:


> Here is another option for the sub:
> http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=13126


Holy sh*t, thats cheap!


----------



## Twiz (Aug 24, 2004)

I had no idea you had to adjust the gain... the gain adjust has a 0.5V on it about 70% up... is the gain too high ? I just set it to max and there's no distorsion... just the sound made by the trunklid separating from the car


----------



## Twiz (Aug 24, 2004)

That's not cheap you're getting ripped off

same amp I bought for $149 and $6.95 shipping (price went up a bit since then)

http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=12398

http://www.caraudioimage.com/index.cfm?fuseaction=product.display&product_id=8&mfg_account_ID=1

You might want to look at the reviews for that site first

http://www.pricegrabber.com/search_getprod.php/masterid=602378/search=mrv-t420/


----------



## Twiz (Aug 24, 2004)

I went and adjusted the gain what's 1/8 backturn gonna do ?


----------



## sr20dem0n (Mar 19, 2003)

Twiz said:


> I had no idea you had to adjust the gain... the gain adjust has a 0.5V on it about 70% up... is the gain too high ? I just set it to max and there's no distorsion... just the sound made by the trunklid separating from the car



yes that's too high, that's one of the most important controls on your amp. The instruction manual for the amp is in there for a reason, in every single one that I've ever read there is a huge warning saying "WARNING: THE GAIN IS NOT A VOLUME KNOB", and then it has instructions on how to set it properly. I've written more walkthroughs on this process than I can count, if you run a search you're bound to run across a couple of them.


----------



## Twiz (Aug 24, 2004)

Quote: "Set the input gain to minimum (4V) position. Using a dynamic CD as a source, increase the head unit volume until output distorts. Then, reduce the volume 1 step (or until the output is no longer distorted). Now increase the amplifier gain until the sound from the speakers become distorted. Reduce the gain slightly so the sound is no longer distorted to achieve the optimum gain setting." Okay I'm sorry what gain setting do you recommend ? I set it to half (NOM) and it sucks... the bass doesn't kick that nice there's no way you can distort two 4 ohm type-R's woofers. 2 ohm might be a bit too harsh for your amp maybe that's why is heating up. I checked mine and it's hardly ever warm.


----------



## Punkrocka436 (Jul 8, 2003)

your amp is too small for your subs if you have to run it at more than half gain to get the desired output


----------



## captain_shrapnel (Sep 10, 2004)

The theory of gain is to match the amplifier's output power scale to what is going into the amp. Generally, you could max the gain on the amp but have to cut the volume knob on the HU way down to prevent distortion. Conversely, you could max the HU 's output and minimize the gain on the amp to acheive the same effect (in theory). Ideally, the most signal strength should be had by the first processor in the chain; the HU. Once ideal signal level is acheived, the gains on everything else should be MINIMIZED as much as practical to reduce noise, and increase dynamic range, headroom, and transient response. By maxing out the gain on the amp, you also max out the noise picked up by everything along the way. If gain structure is set to unity (meaning signal is consistent in level from source output to amp input) and you feel the sound is too quiet, you need more amp power, NOT gain.

A good analogy to this is the engine performance part known as the Viper 400. The 400 claims to improve engine response hugely through mysterious means. Independent testing revealed the 400 to do nothing more than alter the throttle position sensor's signal, by tricking the car into thinking the gas pedal was pushed down much farther than it actually is. The perception is that at part throttle enormous response is acheived, but the reality is that the power was always there. Only your perception changed. The gain knob has a similar effect on volume. The power of the amp is still doing what it always does, but with the gain pumped up it does it much sooner.


----------

