03-25-2010, 06:35 PM
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Pretty much everything you need to know about amplifiers
Pretty much everything You Need to Know About Amplifiers:
Lets start off by saying that you can hook any amplifier to any speaker you desire as long as you do not exceed the minimum ohm rating of the amplifier. For example if your amp says the lowest ohm load you can run is 4ohm mono then you do not want to put anything lower than a 4ohm speaker(s) load on the amp. Yes a 10 watt amplifier will play a 5000 watt speaker.
Important: The speaker does not have the ability to tell the amplifier "I handle 1000 watts". The amp does not have the ability to read what kind of power a speaker can handle. So when you here someone ask or say "will that amp push that speaker", it is a dead end question. Of course it will push the speaker, it's just that if you have a 10 watt amp and 100 watt speaker, the speaker is just able to handle more power than the amp can deliver. This will not hurt the amp or the speaker but PLEASE PLEASE PLEASE read about clipping and distortion.
What the specs mean:
THD= Total Harmonic Distortion (measured in %, the lower the % the better. Lets say you are playing a 100hz note, THD is where you may encounter at 200hz note at the same time. Lets say your THD is .05%,
this means that only .05% of that 200hz note will play at the same time as the 100hz note, thus, the lower the number, the cleaner and less distorted the sound at any level.
S/N Ratio= Signal to Noise Ratio (Just like it says, how much true signal (audio) do you have vs. noise in the signal. The higher the number the better. For example, if the S/N ration of your amplifier is 100db, you will have perfectly clean signal.
RMS and PEAK power= (Let me start by saying that if you are looking at an amp that specs an amplifier in Peak power, beware, as an amplifier does not have a peak power, it just has power and nothing more. It's not like it can somehow pull extra power out of nowhere. They should be rated in "Power" or RMS Power, not Peak power. An amp will only do
what it is able to do and no more unless you drop the ohm load the amp sees from the speakers, then the amp will send more power but this is not "Peak" power. Read about rms and peak power in this tech page to fully understand this.)
Damping factor= This is how tight the sound is in a way. Imagine a big ol floppy rubber band, this is a low damping factor. Now imagine a tight rubber band, this is a high damping factor. The higher the
damping factor the better. When a signal is applied to a speaker, the speaker moves and then after the signal is finished the speaker moves back to it's setting position. The time it takes for the woofer to get back into setting and ready position is damping factor. Amps like old Kenwood basic or Adcom or Crown K1 or K2 (not the cheap junk on their bottom line) will have a damping factor of 1000 or so and that is awesome! A good damping factor is around 400 to 500. An average damping factor is around 200 and anything less is defiantly cheap. High damping factor is achieved through the use of extra output transistors in parallel. If the amp you are looking to buy does not spec THD, S/N ratio and damping factor, beware because obviously the manufacturer doesn't even know anything about the amplifier they are selling. These are important specs and all amplifiers have them.
Headroom= just that "headroom" Some amplifiers are over built and that is a good thing. Like old Carver or Phase Linear or the Crown K1 and K2 series amps have massive headroom. Basically, these type of amplifiers use an over sized or n-regulated power supplies so that when there is a huge draw of power, the power supply can handle it. However, they must also have the output transistors to back them up. Extra transistors in parallel will give you the higher damping factor and an oversized power supply will give you the headroom. (please read about clipping in this tech page).
Frequency response and bandwidth= This is the frequency range the amplifier will play. Sound is in octaves and for example; when a 15khz note is struck and played through amplifier, the amplifier needs to be able to play out to 30khz because 30khz is one octave higher than the 15khz note that was struck. Most decent amplifiers should play out to
Slew Rate= this is the measurement in milliseconds of how fast the amp can go from 0 volts to max volts (output). The slower the amp, the lesser the quality.
Matching ohms: This is so important and the cause of half of all blown amplifiers. So many people do not understand this and will tell you bogus information. If the amp can handle at max a 4ohm stereo load, that is the lowest ohm load you can put on it. If it says 4ohm mono or bridged (same thing), that is the lowest ohm load you can put on it. If you do otherwise, you run the risk of blowing the amplifier and nobody will warranty that kind of abuse.
Do's and Don'ts:
1. Always turn down the gains before you turn the amp on or off.
2. Never disconnect or connect electronics or speakers to the amp
while it is on.
3. Never get the amp wet or spill anything on it.
4. Never take the top off and mess around inside the amp unless you have been authorized by the manufacturer or it is just some old amp you bought used.
5. Don't plug the speakers into the "Inputs" of the amplifier, plug them into the speaker outputs.
6. Try to keep your amplifier in a well ventilated area.
7. Avoid driving the amp too hard causing clipping on output signal. You can't always hear clipping before it does damage. Clipping will damage both the amp and especially the speakers. In fact, it is the cause of 75% of all speaker damage. In fact most speakers are blown from using too SMALL an amp.
8. IF YOU HAVE A QUESTING ABOUT WHAT YOUR DOING, THEN ASK!