I just bought this amp on ebay for a good price. I couldn't find any reviews on it on the net. Does anyone have any experience with their amps. Are they overrated? Is it a decent company? This amp is rated a 600rms at 4ohms and 1200rms at 2ohms.
Any info would be appreciated.
Its a decnt company bu thtere stuff is a bit overrated.It may put out 600 w rms but at what voltage? How much did you pay? As long as it wasnt too much id say its worth it...phil
i have an MA audio high current amp, 1300 watts RMS...frankly it kicks ass. Its nearly toasted almost every sub i hooked up to it, audiobahns, kickers, alpines. damn thing is too powerful.
thanks for all the info, I'm not sure about the voltage. 600rms is plenty for me anyway because I'm just running a single audiobahn that is rated at 400rms. I guess I'll be careful not to blow my sub. Also its says that its a class a/b amp what does that mean?
CLASS A
This is the easiest class to understand, so it leads the list. The positive and negative output transis-
tors each handle 100% of the audio signal- they are biased so their zero-signal output current idles
halfway between zero and maximum. When the audio current in one transistor increases, the
current in one transistor increases, the current in the other decreases; as a result, their voltage
move together. Each transistor can, therefore, deliver a faithful replica of the signal all by itself,
except for the large idle current.
If we were to connect just one transistor to the loudspeaker, we would hear fair-quality sound, but
that would force the cone way off center and would probably overheat the voice coil. When we
connect both transistors to the load, the idle current from one transistor is absorbed by the other
(rather than going through the load), but the audio currents reinforce each other and appear nicely
in the load.
The primary advantage of class-A operation is inherent lack of distortion. The full waveform is
preserved in the positive and negative transistors, so there is no trick to combining their currents.
However, a serious flaw is the extreme heat loss at idle. The transistors actually run hottest while
“standing still”- sort of like controlling a car’s speed with the brakes while keeping the throttle
mashed down. Naturally, amplifier designers have looked for other ways to ensure low distortion
without such wasteful operation.
CLASS B
If we are careful, we can let each transistor control only its half of the waveform. When the wave-
forms are combined properly, we still get the complete output waveform, but we have eliminated the
large idle current. The amplifier runs much cooler because no power is used until it’s needed.
The trick, of course, is to get seamless combining. If the waveforms don’t joined together perfectly,
we get zero-crossing distortion (frequently called crossover distortion). This kind of distortion is quite
objectionable because it results in a slight gargling or rattling sound during quiet parts of the pro-
gram, where the signal is near zero.
Fortunately, there are a number of ways to eliminate this problem. One popular method is to com-
promise between class A and B and operate the amplifier in class AB. Bu permitting a small idle
current to flow, we get a small amount of idle heat, but we eliminate any chance of “dead space”
between the positive and the negative waveforms.
CLASS C
When each transistor controls less than 50% of the waveform, we call this mode class C. This mode
is not usable for audio because of the large gap between the waveforms, which causes severe zero-
crossing distortion. Class C is used where such distortion is unimportant or can be tuned out by
other circuitry. In some amplifiers, the output transistors are run in class C for less idle heat, with the
driver transistors filling in the gap. This method is called class ABC.
CLASSES D, E, & F
These classes apply to switching amplifiers, which will be explained in the second half of this article.
CLASS G
This mode uses two or more sets of output transistors connected to different supply voltages. The
goal is to reduce the heat loss in class A or B amplifiers. Remember the example in which we had a
100V power supply but we only needed 40V into the load? We had a lot of waste heat because
there was 60 “unused” volts wasted in the output transistors.
In a class G amplifier, we have on set of transistors connected to a lower voltage supply, say 60V,
which supplies all output voltages up to this value. We then transfer to a second set of transistors
connected to the 100V supply. With this method, the ”unused” voltage for a 40V output is cut from
60V to 20V, dramatically reducing the waste heat. Because an amplifier spends most of its time
supplying only a fraction of its power, the average losses can be cut by 50% or more.
The main problem is to ensure seamless transfer from the low-voltage to the high-voltage transis-
tors to avoid any small glitches similar to zero-crossing distortion. QSC Series Three and the origi-
nal MX series amplifiers used this technique quite successfully.
CLASS H
This class uses a single bank or output transistors connected to a low-voltage supply, along with
some means of switching them to a higher-voltage supply when required. This method has the
same thermal benefits as class G, but it avoids the second bank of output transistors, thus reducing
the size and cost of the amplifier.
The QSC EX series uses this technique to pack more power in the same chassis. (The EX4000 has
twice the power of the old MX2000.) The new MXa series uses the same technique to simplify the
construction and to improve reliability.
Most of these methods require some alteration of the audio signal as it is broken apart and reas-
sembled. Not surprisingly, these alterations result in errors in the reassembled waveform. In Part II,
we’ll discuss how error-correction circuitry, protection circuitry and other design features allow the
amplifier to perform its function without altering the waveform.
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"About Buddha: Just how in the hell does a 600-lb fat man have the nerve to preach about self control???"
wow thanks for the info cyberdoberman. With all this said should I be careful with the amp to make sure it doesn't overheat or do most companies build a good enough cooling system that it won't be an issue.
Also since there is little noise distortion is it better to have a A/b class amp as opposed to a d class amp for sq?
thanks
nice copy and paste....
I've had the amp before, it's okay..... Didn't blow my mind with power but seemed to push the subs rather well. That and it ran very good at a 1 ohm resting load for me, but seemed to get rather hot there, while at 4 or 2 ohms it didn't seem to get hot at all.
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http://www.sounddomain.com/id/davesexplorer2
hey man i got a ma audio amp rated at 2000 watts rms and the only prob. i have with it is on hot days if i leave my backseat down (where amp is mounted) its kicks into protect for awhile becuase its to hott
