Originally Posted by bishop27
Hi there, forgive my ignorance. I tried searching for this but to my knowledge, this question wasn't answered.
I'm looking at the Outlaw 7220 and the Monolith 7x200 (with XLR inputs). As I'm looking at these, they seem like very similar, if not the same power amp.
It looks like the Outlaw 7220 is fully differential, but the Monolith 7x200 isn't?
I guess, I'm wondering if there are any noticeable differences between the two, or why someone would pay $1200 for the Outlaw vs the Monolith. I've heard the Outlaw is amazing, but is it really $1200 better than the Monolith?
IMO, it frankly is difficult to justify paying any more for the 7220. The designs of the two power amplifiers are very different.
The 7220 is cooled by fans instead of passively. While fans have improved since they have been refined in PC's, it makes little sense IMO to use two mechanical fans in a full size power amplifier meant for residential applications. Power amplifiers, that usually have no moving parts, can last for decades, but fans likely won't. When a fan fails, the amplifier needs to be repaired. The fans also will suck dust into the amplifier which inhibits cooling. It is difficult to see the benefit for the owner.
The 7220 is a bridged design with two amplifiers for each channel. One amp for the (+) and one amp for the (-). These two amplifiers are driven out of phase so voltage is increased, but the ability to deliver current is not increased, and it is usually current that is in short supply. Each amplifier sees one-half the impedance, 4 ohms driving 8 ohm speakers and 2 ohms driving 4 ohm speakers. Amplifiers don't like low impedances. Normally it means higher distortion, including crossover distortion. A bridged design would be good to drive high impedance speakers, 8 ohms and higher over the audio range. Such speakers are almost non-existent. There is a lot more demand to drive speakers close to 4 ohms.
The Monolith amplifier is a Class AB amplifier, of traditional design, based on ATI designs that have been refined over many years. Measurements of the Monoliths are available on Monoprice's site and also on sites such as Audioholics. The amplifier measures well and appears to be the typical ATI solid design. It will drive 4 ohms speakers all day long and doesn't have fans to replace or make noise overtime.
There are small differences that likely make a difference overall. The two amplifiers have about the same capacitance in their power supplies. The 7220 uses two capacitors, the Monolith unit, four capacitors, with pairs in parallel. Putting capacitors in parallel cuts the equivalent series resistance and inductance of the capacitor bank in half, which is good. Resistance and inductance in capacitors in undesirable. The lower the better.
Similarly there are multiple, parallel resistors connected to the emitter of each output transistor in the Monolith unit, there appears to be one resistor per transistor in the 7720. The effective resistance is likely the same, but parallel resistors likely will have lower inductance and a larger surface for cooling.