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30W stereo Amp $19.95 (wierd looking)

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Originally posted by: takeru
i wonder what will happen if you chain say 100 of these together...
Click to expand...
You'd get EXACTLY 30 more dB of output, as in it takes EXACTLY twice the amount of power to get 3 more dB of Volume.

Something like this would be cool to mount inside a case. I have a small portable LAN box I built, and really wanted to put a set of small speakers and an amp inside it, dosen't have to sound great, but passable for low volume. Maybe something like the small full range Harmon-Kardon's in the imac's with a small subwoofer. hmmmm....
rolleye.gif
 
Originally posted by: mattyrug
Originally posted by: takeru
i wonder what will happen if you chain say 100 of these together...
Click to expand...
You'd get EXACTLY 30 more dB of output, as in it takes EXACTLY twice the amount of power to get 3 more dB of Volume.

Something like this would be cool to mount inside a case. I have a small portable LAN box I built, and really wanted to put a set of small speakers and an amp inside it, dosen't have to sound great, but passable for low volume. Maybe something like the small full range Harmon-Kardon's in the imac's with a small subwoofer. hmmmm....
rolleye.gif
Click to expand...

Uhhhh, 30dB??? You might want to check your math. Using 10 * log(dB1 / dB2) and inputing 1 and 100 for the change in power factors, you get 20dB, not 30dB. It would require 1000 times as many amplifiers to give a 30dB gain. And, you are not taking into acount driver power compression or the fact that hardly any driver could even take 100 of those.

Also, I would not mount those inside a computer case, as the heat is already quite high in there, and the amplifier will create even more.
 
not attempting to hijack or be a retard or anything but.....

what exactly does adding an amplifier do? i have a creative cambridge FPS2000 digital sound system with my audigy. would adding an amp do anything?

sorry for the stupid question, im curious.😱
 
Since your FPS2000 speakers already have an amp built in, it wouldn't do any good to put another one between your soundcard and your speakers...if that's what you're asking.

Speakers with amps built in are designed for a certain range of input power. It's pretty low or else you wouldn't need the amplifier...you would be able to just connect the speakers to the input that goes to the amp instead. 😉

Putting a speaker-driving amplifier in front of another amplifier is kind of a bad idea. Once you turn it to high, you would probably blow the pre-amp stage in whatever you were connecting whether it was a pre-amp, receiver, powered speakers...pretty much anything that isn't just a passive speaker.

I guess it *could* be okay if your soundcard has an incredibly weak output AND you are careful when you're rigging it up. 🙂
 
Originally posted by: ObiDon
Since your FPS2000 speakers already have an amp built in, it wouldn't do any good to put another one between your soundcard and your speakers...if that's what you're asking.

Speakers with amps built in are designed for a certain range of input power. It's pretty low or else you wouldn't need the amplifier...you would be able to just connect the speakers to the input that goes to the amp instead. 😉

Putting a speaker-driving amplifier in front of another amplifier is kind of a bad idea. Once you turn it to high, you would probably blow the pre-amp stage in whatever you were connecting whether it was a pre-amp, receiver, powered speakers...pretty much anything that isn't just a passive speaker.

I guess it *could* be okay if your soundcard has an incredibly weak output AND you are careful when you're rigging it up. 🙂
Click to expand...

yeah.

 
LOL- This thread is funny, I have to admit, many people do not understand these ratings and what they really mean
I have had so many peeps come to me to listen to their car stereo's ( I seem to be the only one in my circle who knows about this stuff)
and they got this 500 watt "rockwood' or "jensen" or "Audiovox" type crap and they crank it up on me............
yeh, it sounds loud but......pretty crappy and only "hits" around the 60-80 hz "sweet spot"

after this, I am supposed to be impressed with their "hit,romp, or beat" so I then take them on over to check
my modest system with a 50x2 zapco on the fronts(Aura 6 1/2 components) and a Zapco 100x1 for bass
which is a 12" Aura force12 guess what? My sh*t blows them out the water with spl and most importantly without your
ears hurting from the distortion ;P now this is usually followed by looks of disbelief that their 500watt monster amp
could be so sh*tty and a very tiny 100watt amp could be so good. I then proceed to tell them some of the same things I see you guys discussing here, ie the numbers don't mean anything. you gotta look at the context of the measurements for the "true" power
ratings. things like slew rate are important and damping factor
(this is what controls the motion of a speaker directly after a signal is sent through it)
also the range of frequency that the measurement is taken on ie 10hz-100khz is typical of quality gear
also you gotta kinda know the names in the biz too that are known for quality like ZAPCO for instance




 
Originally posted by: nugglife4me


I then proceed to tell them some of the same things I see you guys discussing here, ie the numbers don't mean anything. you gotta look at the context of the measurements for the "true" power
ratings. things like slew rate are important and damping factor
(this is what controls the motion of a speaker directly after a signal is sent through it)
also the range of frequency that the measurement is taken on ie 10hz-100khz is typical of quality gear
also you gotta kinda know the names in the biz too that are known for quality like ZAPCO for instance
Click to expand...

The problem is, the slew rate and damping factor can be manipulated along with the power ratings of an amplifier. Damping factor is just the ratio of the output transistor resistance to the load being driven. You can substitute a higher impedence loudspeaker to make the number better. Not to mention, adding the speaker wire will usually have more resistance than the amplifier output transistors, making the damping factor meaningless again. And besides, the loudspeaker being driven is usually the weakest link. A factor of 10 or higher is usually considered inaudible.

Here is a great link on truth in damping factor: http://www.trueaudio.com/post_013.htm

As for slew rate, its basically meaningless. As long as the amplifier being used has low distortion at the top of its frequency range like 20khz, at full power, the slew rate measured on paper doesnt mean a thing.

As for the frequency range, first, you dont need an amplifier that goes much higher than 20khz, and second, almost any switchmode power supply based car amp has the bandwidth available to play 20hz to 20khz, which is what our ears can detect - even the cheap pyramids and legacies.
 
any switchmode power supply based car amp has the bandwidth available to play 20hz to 20khz, which is what our ears can detect - even the cheap pyramids and legacies.
Click to expand...
Using cheap amps to drive subwoofers make for sloppy bass though.
I had a 4-channel Rockford Fosgate amp bridged to 120wx2 running a pair of subs. It was a pretty nice amp. However, when I switched it out for a 75wx2 Earthquake amp the difference was like night and day. I had a lot more lower-bass extension with all other equipment remaining the same.
So, if you're going to run a pair of decent subs don't cheap out. If it's for a set of door speakers, knock yourself out. 😉

Yeah, I know that the cheesier a name sounds, the worse the equipment usually is. Earthquake happened to be the exception though. At least when I bought mine! 🙂
 
Originally posted by: ObiDon
any switchmode power supply based car amp has the bandwidth available to play 20hz to 20khz, which is what our ears can detect - even the cheap pyramids and legacies.
Click to expand...
Using cheap amps to drive subwoofers make for sloppy bass though.
I had a 4-channel Rockford Fosgate amp bridged to 120wx2 running a pair of subs. It was a pretty nice amp. However, when I switched it out for a 75wx2 Earthquake amp the difference was like night and day. I had a lot more lower-bass extension with all other equipment remaining the same.
So, if you're going to run a pair of decent subs don't cheap out. If it's for a set of door speakers, knock yourself out. 😉

Yeah, I know that the cheesier a name sounds, the worse the equipment usually is. Earthquake happened to be the exception though. At least when I bought mine! 🙂
Click to expand...


That is rather ironic that you write that, as I have never heard of anyone complaining that an amplifier was no good for bass, but great for midranges. Distortion is much harder to detect at lower frequencies that at higher ones. Not to mention the power needs of lower frequencies are typically higher than that of high frequencies. Can you explain what "sloppy bass" is?

The reason you probably had more lower bass extension was that the Earthquake might have a bassboost built in. Neither of those companies typically overrate their equipment, so I would imagine the Rockford would allow for 3 to 6dB more output in a car.
 
I bought one of these about six months ago. There is no way in hell this little ah heck is 30W RMS. But then again, RMS has been pretty much dropped for many types of amplifier, and we're back to "Peak Power", just like with early 70's Emerson junk.

But, it is absolutely perfect...really...for what I wanted. I picked up a Samsung 32" stereo TV with no speaker outputs. It does have variable audio out, though. So I plugged this little amp in, set the volume at about 90%, and connected my rear speakers to it. Presto, I have a huge increase in sound quality and spatial effect, with zero complication (my S.O. can still adjust the volume with the remote and not have to fiddle with a separate amp. The amp matches the TV's own almost perfectly...figure 3 to 5 watts RMS.

YMMV!
 
Originally posted by: Harvey
Originally posted by: ConnCarl
But then again, RMS has been pretty much dropped for many types of amplifier
Click to expand...
WHAT!!! Did someone cancel reality again?
rolleye.gif
Click to expand...

Seriously peak rms, whatever, its meaningless! Read above! There are too many factors you need to include for an accurate representation of power output.
 
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