Car audio Rumours
50 Watt CAFz'r
Joined: Nov 2008
Posts: 223
Lol your obviously joking. And I know you wouldn't be so dumb but I can't speak for some of the others on here. But that's why wer here right. To help the others.
Last edited by mustaine4prez; Oct 2, 2009 at 12:15 PM.
Regarding the Gain vs volume debate:
This is from BCAE: I think both sides are correct depending on what you have or have used or are referring to;
Note (rant):
There have been many people who have said that the gain controls were not volume controls and they are right, to a point. Some amplifiers' gain controls are used precisely like a volume control (one end of the potentiometer connected to ground, the other end connected to the pre-amp signal and the wiper connected to the amplifier's front end). This configuration will allow you to reduce the output to nothing at the minimum gain position. These are not very common but they HAVE been used on some amplifiers. I know because I took the cover off of a few amps to see why they had absolutely no output (Doh!). Others are connected similarly but there is a small amount of resistance between ground and the formerly grounded terminal of the potentiometer. This small resistance prevents the gain control from reducing the output to zero output. These are very common on amplifiers made in Korea and China. There are other amps that use the potentiometer to pull the signal toward ground. The pot is the lower half of a voltage divider and may use only 2 legs of the potentiometer. This type of gain control was used on at least one brand of Japanese manufactured amplifier. You can also put the potentiometer in the feedback loop to control the overall gain of the amplifier. The point to all of this is... There are many ways to use a potentiometer to control the output of the amplifier. Some are used precisely as volume controls and others are not. You can not make a blanket statement such as 'gain controls are not volume controls'.
This is from BCAE: I think both sides are correct depending on what you have or have used or are referring to;
Note (rant):
There have been many people who have said that the gain controls were not volume controls and they are right, to a point. Some amplifiers' gain controls are used precisely like a volume control (one end of the potentiometer connected to ground, the other end connected to the pre-amp signal and the wiper connected to the amplifier's front end). This configuration will allow you to reduce the output to nothing at the minimum gain position. These are not very common but they HAVE been used on some amplifiers. I know because I took the cover off of a few amps to see why they had absolutely no output (Doh!). Others are connected similarly but there is a small amount of resistance between ground and the formerly grounded terminal of the potentiometer. This small resistance prevents the gain control from reducing the output to zero output. These are very common on amplifiers made in Korea and China. There are other amps that use the potentiometer to pull the signal toward ground. The pot is the lower half of a voltage divider and may use only 2 legs of the potentiometer. This type of gain control was used on at least one brand of Japanese manufactured amplifier. You can also put the potentiometer in the feedback loop to control the overall gain of the amplifier. The point to all of this is... There are many ways to use a potentiometer to control the output of the amplifier. Some are used precisely as volume controls and others are not. You can not make a blanket statement such as 'gain controls are not volume controls'.
Administrator
Joined: Feb 2006
Posts: 16,860
Ah, but that is not the myth. In fact the myth is quite the opposite: Vented boxes don't sound as good as sealed - which, fortunately, we all know to be preposterous! 
Ok, so you are trying to run your system off only the cap then?
The power supply of a car amplifier is not a static load like a lightbulb. It takes it's power in pulses. A capacitor of sufficient quality and size should be able to supply the required current for the pulse and recover before the second pulse. We're talking milliseconds here. This is why RC poo-poos on the giant carbon caps. They are too slow to recover.
I like to use a toilet analogy since most people are familiar with a toilet and it's operation. The reason your toilet has a tank on it is the pipe feeding the toilet cannot supply water fast enough to flush it. The pipe can, over time, supply a virtually endless amount of water, but just not fast enough to flush the bowl. Very similar to how an alternator can supply virtually endless amounts of power, but sometimes not fast enough. Now, when you flip the lever on your commode, the tank has enough reserve to flush the bowl. Then you have to wait until the tank fills again. Not a problem unless it was chilli night... Then you may come to realize that your tank has a limit on how often it can be utilized before you simply outrun it's capacity. If you had a larger tank, or a larger supply you would be able to cycle more often. In the same way, your amp has caps on the circuit board to support the power supply for general usage. Most of the time we drive around listening to a handful of watts. Heavy usage though means needing to add outboard capacity or your performance will suffer. If you "like chilli", you may need a LOT of extra capacity. That capacity can come from a capacitor (or a battery).
Caps are convenient and compact but I never said they were cost effective. That is something completely different.
Personally, I don't add a cap to achieve better sound. I add it to help stop my lights from dimming. In this capacity (lol, pun) they work great.
The power supply of a car amplifier is not a static load like a lightbulb. It takes it's power in pulses. A capacitor of sufficient quality and size should be able to supply the required current for the pulse and recover before the second pulse. We're talking milliseconds here. This is why RC poo-poos on the giant carbon caps. They are too slow to recover.
I like to use a toilet analogy since most people are familiar with a toilet and it's operation. The reason your toilet has a tank on it is the pipe feeding the toilet cannot supply water fast enough to flush it. The pipe can, over time, supply a virtually endless amount of water, but just not fast enough to flush the bowl. Very similar to how an alternator can supply virtually endless amounts of power, but sometimes not fast enough. Now, when you flip the lever on your commode, the tank has enough reserve to flush the bowl. Then you have to wait until the tank fills again. Not a problem unless it was chilli night... Then you may come to realize that your tank has a limit on how often it can be utilized before you simply outrun it's capacity. If you had a larger tank, or a larger supply you would be able to cycle more often. In the same way, your amp has caps on the circuit board to support the power supply for general usage. Most of the time we drive around listening to a handful of watts. Heavy usage though means needing to add outboard capacity or your performance will suffer. If you "like chilli", you may need a LOT of extra capacity. That capacity can come from a capacitor (or a battery).
Caps are convenient and compact but I never said they were cost effective. That is something completely different.
Personally, I don't add a cap to achieve better sound. I add it to help stop my lights from dimming. In this capacity (lol, pun) they work great.
500 Watt CAFz'r
Joined: Jan 2008
Posts: 537
Originally Posted by JordyO
Not at all... I was more using it because this was the number that had been thrown out there so it was for the sake of continuity in this discussion
Originally Posted by jstoner22
i think he was referring to our debate on whether the gain control on amplifiers is the same as a volume ****...
It's funny how you can produce evidence to support your opinion, no matter what the debate, and someone will spin it back on you. You guys do know that gravity is a myth right?
