can one amp run all my speakers?

[Monkeyman]

It is much easier to ruin a pair of speakers with to little power than with to much power. If you don't have enough power, then the speakers are playing with little control. The speakers voice coil won't mover over the bobbin properly, and will brush up against it causing friction and as a result heat. This heat will eventually damage the coils windings and the bobbins circular shape to be ruined.

If you buy speakers and they claim 100 watts RMS, then any amp you buy to power them should be AT LEAST 100 watts RMS (it is usualy a good idea to add 10-30% amp power over the speakers RMS rated power, so for this example Speaker=100 watts so amp should be at least 110-130). This is known as "Power Headroom."

Always use RMS output power figures, and NEVER "max" power figures for amplifiers. Many companies claim outrageous "Max" numbers as a sales lure, but their amps can only supply that power for a fraction of a second at EXTREMLY HIGH distortion numbers. Consider Max to be a number which will occur only if lightning strikes it (because that's what it is).

Here are some basics for buying an amplifier:
1) Make sure the THD numbers are LESS than .1% (your ears will thank you).

2) Make sure the amp has an RMS output power rating equal to or above that of the speaker(s) it will power.

3) Do not use Class D amplifiers for full range, bandpass, midrange, or high range speakers (class D does provide more power than A/B and WAY more than class A, but the distortion is significantly higher). If you can afford a Class A amplifier with enough RMS power for your speakers than you should buy it (unless you like the sound of a class A/B amplifier more).

4) This is not absolutley nessisary, but if you can afford an amplifier with a dampening factor of less than (or around) 50, than buy it. With a lower dampening factor and a high voltage output from your head unit you need to be carefull that your RCA inputs are securely plugged into your amplifier, because damage will occur if an RCA disconects while the stereo is on (sudden extreme change in electrical resistance). Amplifiers with dampening factors >50 also tend add less coloration to the signal, resulting in a cleaner, clearer, warmer sound. Some examples are: Celestra VA series (www.celestra.it); Audison HR-100, Thesis HV-214 (www.audison.com); and the McIntosh Labs MCC602TM (www.mcintoshlabs.com).

Hope this helps,
David

[theprodigy79]

Here are some basics for buying an amplifier:
1) Make sure the THD numbers are LESS than .1% (your ears will thank you).

Preferably you will find an amp with significantly less than .1% THD... Considering this is actually the audible cut-off, you also have to keep in mind that every other component in-line with your system contributes to the overall THD... So if your headunit is rated at .05% THD and your amp is rated at .08% THD, you're well over the audible level (not to mention, your speaker wires and anything else in-line add distortion)...

3) Do not use Class D amplifiers for full range, bandpass, midrange, or high range speakers (class D does provide more power than A/B and WAY more than class A, but the distortion is significantly higher). If you can afford a Class A amplifier with enough RMS power for your speakers than you should buy it (unless you like the sound of a class A/B amplifier more).

Where are you getting Class D providing more power than A/B and 'way more' than Class A? This is non-sense... I am currently running two pure Class A amplifiers; one rated at 1000W RMS at 12.5V in 1 Ohm Bridged, 1/2 Ohm Stereo, 1/2 Ohm bridged or 1/4 Ohm stereo, and the other amp rated at 600W RMS at 12.5V in 2 Ohm Stereo, 4 Ohm Bridged, 1 Ohm Stereo and 2 Ohm Bridged... That's 1600W CONTINUOUS underrated at only 12.5 Volts with two pure Class A amps...

All the classes represent are the ways the signals are processed from in to out... They have NOTHING to do with power ratings... Class A provides a continuous amplified signal from in to out. 100% of the signal is used in this format, and therefor it requires more power draw to perform... If you can supply the current in, it can match any amp's current out... Class B amps only amplify half the input wave cycle, and are therefor twice as efficient, however they add a ton of distortion... Class A/B is a hybrid between the two formats, essentially amplifying 50%<X<100% (X representing the signal)... It's more efficient than Class A but not as efficient as Class B, however it doesn't introduce as much distortion as Class B amps (therefor it's a reasonable settlement for most people). Class D amps power using 'on/off' mode, using a sequence of fixed amplitude pulses and MOSFETs. They are very efficient amps, but they also introduce a large amount of distortion... Also, Class D does NOT mean "digital" (contrary to what several people around this forum believe)... It is simply to designate the type of amplifier, following Class A, Class B, and Class C... and followed by Class E, etc... The output waveform may resemble a pulse-train of digital symbols, but a Class D amplifier merely converts an input waveform into a continuously pulse-width modulated analog signal. (A digital waveform would be pulse-code modulated.)

Sorry for rambling... but just felt that a couple things needed clarification...

-James

[Monkeyman]

Should have clarified:
Class D produces MORE OUTPUT POWER FROM LESSER INPUT POWER.

Something tells me I am going to have to respond to a whole lot more of these......

I give general discriptions so that all who read it can make sence of it.

I am surprised your reaction was to the class D statement and not the Damping factor statement. That damping factor numbers I provided were for the system as a whole, and not for the amplifer alone (Damping factor is the ratio of speaker impedance to the output impedance of the amp). To make sure things are clear: http://www.sweetwater.com/expert-center ... pingFactor

I don't believe it is a good idea for me to provide every detail I can in a response, it takes up to much space, and would confuse those who don't have a strong background in audio (or electrical engineering).

Hope this is a little clearer,
David

[theprodigy79]

Sometimes backing up certain statements is a good thing... Either that or throwing in the entire statement as you did above (it just took completing one sentence)...

I left the damping factor statement alone because I couldn't tell what you were going for with the last paragraph and I'm too tired to try to make any sense of it... Your statement flat out told people to purchase amplifiers with extremely low damping factors, and then you listed high class companies that manufacture amplifiers with damping factors well over 200... Yeah, it threw me off a bit... Glad you clarified that the numbers you gave were for the system as a whole, cuz if people actually followed that statement verbatim they'd run out and load up with Pyramid sh!t...

People on this site aren't morons. If you give everyone a bit more detail and clean it up a bit, instead of just trowing out a generalized (or only partial) statement that may be mistaken to mean something only partially true, or even completely false (such as the damping factor stuff), they can probably get a lot more out of it...