Outlaw Audio Model 7220 7CH Amplifier Runs Cool Enough For Mr. Freeze

Alright, we understand we're paying homage to what is said to be the worst Batman movie ever (Catwomen doesn't count since it's a stand alone movie and Hallie Berry is HOT in that costume), but in all seriousness, what Outlaw Audio has done with their newest Amplifier, the 7220, is pretty- well, cool.

     

The new Model 7220 Amplifier is a class AB, fully balanced design. It delivers 220W per channel into an 8-ohm load with all seven channels driven and 330 watts per channel into 4 ohms (assuming sufficient available wall current) realistically with about 4-5 channels driven. This amp is capable of running on a 120V/ 20A line so feed it a dedicated 20A outlet if you can. Although the amplifier is rated at 1800 watts total output power, it is capable of delivering over that for a short period of time as indicated by the fact they employed two 20A, 350V fuses (one for positive and one for negative rails) for each channel tied directly to the secondary leads of the power transformers. The reality is, the 7220 is capable of delivering almost the full 120V/20A power of a dedicated line (minus efficiencies). That's one heck of a powerful 7-channel amplifier!

Editorial Note About Amplifier Power and Wall Voltage by Gene DellaSala

Many manufacturers like to tout power figures that exceed the capabilities of the wall outlet they are plugged into. It's important to note that not even Scotty from Star Trek could change the laws of physics, so don't expect an amplifier manufacturer to do so. A 120V/15A line max power output is 1800 watts while a 120V/20A line max power output is 2400 watts. The max efficiency one could expect from a Class AB amplifier is around 78%. So, factoring in efficiency, the available power from a 15A output would now be about 1400 watts and 1900 watts from a 20A line. Divide those power figures by the # of channels driven and you've got your answer as to how much power the amplifier can potentially deliver with all channels driven. In the case of the Model 7220, using a 20A line would allow the amp to deliver up to about 270 watts/ch with all 7 channels driven.

For more information see: The Amplifier All Channels Driven Test

The signal to noise ratio at full power is rated to be greater than 125dB and is said to often approach 130dB. We aren't sure if this is a weighted or un-weighted result. But, it's quite and impressive rating, especially if you translate that figure down to 1 watt where the amplifier spends most of its time, it would still be an absolute silent 101dB. The 7220 is designed to operate with virtually no DC offset, runs cooler, and still maintains a class AB operation with two robust toroidal transformers rated at 970VA (3 Ch side) and 1,270VA (4 Ch side) supplying the gut wrenching power.

So How did Outlaw Audio Do it?

To start with, it was a joint venture between ATI Amplifier Technologies and Outlaw to design a high power, multi-channel amplifier using a traditional linear topology while also using innovative methods to maintain cool operation even under heavy loading conditions. 

Thermal runway is one of the major impacts to an amplifiers reliability and performance. Transistors are used as the output devices for audio amplifiers, and temperature directly affects the performance and operation of transistors. There have been a few different design philosophies for dealing with how the excess heat, and excess bias, negatively affect the lifespan and performance of output transistors. The Model 7220 uses ThermalTRAK transistors, which employ an internal thermal sensing diode so that bias, and subsequently heat, are adjusted for in real time. This design is said to eliminate the thermal lag you often encounter in conventional designs.

Traditionally, Outlaw Audio has been opposed to using fans for cooling. Active cooling, which utilizes a fan usually creates too much noise to be used in smaller rooms and home theaters. The Model 7220 uses a hybrid system of cooling, utilizing both convection cooling, with cool air coming from below, as well as active cooling through the use of a state of the art fan. Having a hybrid system like this makes the design exponentially more efficient. This fan is engineered to have a remarkably low noise floor and operates below 24dBA. In addition, the speed of the fan adjusts based upon the temperature of the heat sinks. This means when listening to quiet movie scenes or music tracks, the fan will slow down to indiscernible levels. With the heat sinks being constantly kept cool, these fans will normally be operating at their lower, quieter speed a majority of the time.

Outlaw 7220 Amplifier Block Diagram

Fully Differential Design

The 7220 is a true balanced amplifier from input to output. It utilizes (2) 12,000uF/50V caps per channel and operates on +-45V rails. Because the outputs are in a bridged balanced configuration, this allows the amp to swing almost the full rail voltage (no ground reference) yielding massive amounts of power (up to 4X compared to a single ended design) while operating on relatively low rail voltage. Each fully differential amp channel is actually two separate channels, each driving either the positive or negative signals, with the signal bridged at the output as seen in the block diagram above.

Some Advantages of Differential Amplifier Designs:

• More efficient use of the power supply. Each rail of the power supply is used at 100% duty cycle.
• Very high Common Mode Rejection. This helps to lower Noise and Distortion.
• Dual servos for extremely low DC offset.
  

Conclusion

As far as we know, the 7220 is the least expensive fully differential multi-channel amplifier on the market. That is quite an impressive feat for Outlaw Audio and we are always thrilled to find companies pushing the envelope of performance while still comfortably maintaining the value aspect to keep a product of this caliber in the reach of most audiophiles.

The Model 7220 is still a beast at 93 pounds so you may actually need Arnold Schwarzenegger to move it into your home theater room. It is designed to effortlessly drive speakers with moderate power demands but should still be fully capable of running systems that require significantly more power. For most of us, even with speaker upgrades, this will be the one home theater component that should remain constant in an industry of ever changing technologies. The Model 7220 comes with a 5 year warranty, though with ATI's reputation for durability, you likely won't need it.

That 220 watt/ch rating x 7 with such a large power supply means it will likely put out a lot more power with just 1 or 2CH driven. Outlaw amps have always been conservatively rated unlike some of their competitors. The Model 7220 looks like a great deal for its asking price and I absolutely love the fact that it's a fully differential design from input to output. This is how the very best amplifiers are designed whether you're doing telecom communications requiring very low noise floor and distortion, or to extract all of the resolution from the very best home theater systems.

- Audioholics President, Gene DellaSala

The build quality, brand reputation, enormous power ratings, and cool running capacity of the Outlaw Model 7220 makes it a serious competitor to amplifiers costing far more. The Outlaw Audio Model 7220 is on sale for $2,149 (free shipping) now until August 12th and then will go up to $2,299. If we get our hands on the 7220 for a formal review you can bet "We'll be back..."

Unless otherwise indicated, this is a preview article for the featured product. A formal review may or may not follow in the future.