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Outlaw Model 7140 7 Channel Amplifier Review

amirm

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#1
This is a review and detailed measurements of the Outlaw Model 7140, seven (7) channel home theater power amplifier. It is on kind loan from a member. The 7140 seems to have come out a few years ago and is shown as discontinued. At the time it was out, the cost was a reasonable US $1,100. The new replacement series, 7000X looks just like this so not sure what they have changed.

The 7140 is a beast of an amplifier, nearly breaking my back carrying it up to my lab:

Outlaw Model 7140 7 channel Power Amplifier Audio Review.jpg

The design is highly modular with a massive toroidal transformer powering 7 independent amplifiers, each with their own power supply on board. The heatsinks are rather beefy with plenty of distance between them and top of the unit. The feet are also quite tall allowing better ventilation from bottom to top.

The back panel shows the inclusion of XLR inputs which I appreciate:

Outlaw Model 7140 7 channel Power Amplifier Back Panel Connector Audio Review.jpg


The inclusion of a grounding terminal was interesting. It did no good in my testing with XLR inputs as it should not.

During use, the 7140 was quite stable, never complaining, shutting down or anything as Audio/Video Receivers (AVRs) tend to do. Clearly then this is a more robust solution than internal amps in those units.

Power Amplifier Measurements
As usual we start with our dashboard view of 5 watts into 4 ohm load using a 1 kHz tone:

Outlaw Model 7140 7 channel Power Amplifier Audio Measurements.png


I was surprised to see such high mains hum at 60 Hz. A prior review of another unit with just RCAs complained about the same thing and recommended a ground terminal on the unit which they have added. But as I mentioned, it made no difference. I have to think this is magnetically coupled into the amplifiers.

Fortunately or unfortunately the distortion spike from 2nd harmonic is bit higher still so didn't impact measured SINAD (combination of noise and distortion relative to our main tone). As it is, the 7140 lands below the average for all the amplifiers we have reviewed so far:

Best Stereo Amplifiers Tested.png


Frequency response is flat enough:
Outlaw Model 7140 7 channel Power Amplifier Frequency Response Audio Measurements.png


32-tone signal to resemble "music" shows the typical rise of distortion with frequency:

Outlaw Model 7140 7 channel Power Amplifier Multitone Audio Measurements.png


And rather high noise floor which could be caused by that power supply hum.

Here are the noise figures for 5 watt and full power:
Outlaw Model 7140 7 channel Power Amplifier Signal to Noise Ratio Audio Measurements.png


We are not clearly more than 14 bits or so at 5 watts so not very quiet.

Here is our power versus distortion and noise at 8 ohm:

Outlaw Model 7140 7 channel Power Amplifier Power into 8 ohm Audio Measurements.png


We see the elevated noise and distortion relative to our reference amplifier. Power produced is right on the money at 146 watts.

Here is the same at 4 ohm:
Outlaw Model 7140 7 channel Power Amplifier Power into 4 ohm Audio Measurements.png


The above tests are at 1 kHz. Here is what happens when we sweep the frequencies, aiming to measure power at 1% THD+N

Outlaw Model 7140 7 channel Power Amplifier Power Sweep Into 8 ohm Audio Measurements.png


Outlaw Model 7140 7 channel Power Amplifier Power Sweep Into 4 ohm Audio Measurements.png


Quite a drop in power with both loads when we get down to 20 Hz. The power supply capacitors are likely too small to keep up with the slow rate of change at low frequencies.

We see a similar view when we look at sweeps at different frequencies:

Outlaw Model 7140 7 channel Power Amplifier THD vs Power vs Frequency Audio Measurements.png



Finally, some people like to see intermodulation distortion of 19 + 20 kHz tones so here it is at max power:
Outlaw Model 7140 7 channel Power Amplifier 19+20 kHz intermodulation Audio Measurements.png


Conclusions
The Outlaw Model 7140 has a very sturdy build. It produces good power per specifications provided from manufacturer (at least in two channels). The down side is too much ground/mains leakage and distortion+noise that is slightly below average. Paying more (a lot more actually) will get you sharp reduction of such problems.

For typical home theater duty, the 7140 should do the job fine. It just isn't something to get excited about from pure performance point of view.

------------
As always, questions, comments, recommendations, etc. are welcome.

Folks, I was not kidding when I said this amp nearly killed my back to carry it upstairs to my lab. To keep testing these things, I need to get one of those staircase elevators old people put in. And that costs serious money. I appreciate you all donating to get me one of those things to save my back using: https://www.audiosciencereview.com/forum/index.php?threads/how-to-support-audio-science-review.8150/
 

confucius_zero

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#3
outlaw... steve guttenberg's favorite brand :p
 

Ilkless

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#7
BTW, I read some place ATI made this amp for Outlaw. Anyone know for sure?
Yeah, and also Monoprice Monolith. I can confirm this because I looked at Monoprice's internal pics and it has ATI's name printed on the toroids; ATI has in-house toroid winding capabilities for iirc higher-spec OEM builds/their own stuff. Testing the 7-channel Monolith and ATI might be very interesting to see of they are all spec'd differently.
 
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Blumlein 88

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#8
Glad to see you include the twin tone IMD at 19&20 khz.

Now I'm going to raise an issue. Frequency response......good enough???.............I doubt it. I believe with a truly flat amp, you'd be able to abx this easily. Yes it isn't much, and it is mostly at extremes, but it droops the entire upper octave. In close short comparisons I've found that droop easy to hear on music even though my hearing probably stops at 15 khz now days. I think we are obsessing over SINAD numbers that aren't important with music while glossing over minor, but audible FR issues that would give one device a bit of character vs another. And that is before we connect it to a complex speaker load.

Which btw, any progress on a more complex speaker load to test power amps with?
 

audimus

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#9
Glad to see you include the twin tone IMD at 19&20 khz.

Now I'm going to raise an issue. Frequency response......good enough???.............I doubt it. I believe with a truly flat amp, you'd be able to abx this easily. Yes it isn't much, and it is mostly at extremes, but it droops the entire upper octave. In close short comparisons I've found that droop easy to hear on music even though my hearing probably stops at 15 khz now days. I think we are obsessing over SINAD numbers that aren't important with music while glossing over minor, but audible FR issues that would give one device a bit of character vs another. And that is before we connect it to a complex speaker load.

Which btw, any progress on a more complex speaker load to test power amps with?
I am not sure what exactly you claim to hear with the “droop” but people pay good money to get room eq that pulls higher frequencies over a broad range down much more than this as sounding better with their target curves. :)

Sure, you can have a perfectly flat amp with room equalization to make the flatness irrelevant or you can have an amp that is closer to that curve to start with. Seems like a distinction without a difference for the result. As an academic engineering criterion, sure.

This amp came out before the room eq caught on. I would not be surprised if some amps were tweaked to be “less bright” to either compensate for higher harmonic distortion at the high end or to appeal to people that prefered a “warmer” sound and differentiate from the often tinny sounding mass market brands.
 

audimus

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#10
External forum posts have noted that some channels have more “noise” than others relative to their position to the power supply. I wonder how the different channels would measure in modular amps like this where any module can be used for any channel (rather than what is pre-labeled if any). This is an important criterion in multi channel amps that tests should possibly look at.
 

Neddy

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#11
Thanks Amir!
VERY Timely - I just received what I think is the 5 ch variant of this amp, previously also (apparently) offered by Outlaw and perhaps Carver.
The one I bought:
https://www.outdoorspeakerdepot.com/5-channel-amp-180w-osd-audio-xa5180.html
The Outlaw variant:
https://www.audioholics.com/amplifier-reviews/outlaw-5000

This amp replaces a perfectly functional Emotiva UPA-500 for surround duty - for the simple reason that it is a (net) cheaper and simpler route to having balanced inputs (as well as unbal, in this case) than buying 5 XLR baluns adapters for the Emo!
Certainly the near 80lb shipping weight and disc surgery is a bad combination - I dang near dropped the thing getting it out of the box.
It was however well packed, shipped quickly, delivered without any dropping or damage, and appears to be sturdily built.

I have no idea whether it's better or worse than the smaller Emo it replaces, but is rated for more power, and about the same listed specs, such as they are.
Since these drive relatively inefficient small surround speakers (GoldenEar SS3s), I'm not too concerned about not having high end performance (at 10x? the cost?), or less than perfect bass response!!
How does it sound? Like an amp. :)
Maybe someday Ncores will come down into my price range, but for now, this seems like a decent deal, and certainly better than an un-warrantied, amateur shipped, used Ebay purchase, with unknown history...esp for under $400.

Anyhow, thanks for confirming my 'suspicions' about performance...maybe.

I see some differences between the 5ch versions and your 7 chan one, and my understanding was that these were both made in China.
Outlaw
Outlaw Model 5000 inside R.JPG
OSD:
xa5180-5-channel-high-power-home-theatre-amplifier-balance-xlr-input-5x-180w-4ohm-120w-8ohm-72...png
 
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Blumlein 88

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#12
I am not sure what exactly you claim to hear with the “droop” but people pay good money to get room eq that pulls higher frequencies over a broad range down much more than this as sounding better with their target curves. :)

Sure, you can have a perfectly flat amp with room equalization to make the flatness irrelevant or you can have an amp that is closer to that curve to start with. Seems like a distinction without a difference for the result. As an academic engineering criterion, sure.

This amp came out before the room eq caught on. I would not be surprised if some amps were tweaked to be “less bright” to either compensate for higher harmonic distortion at the high end or to appeal to people that prefered a “warmer” sound and differentiate from the often tinny sounding mass market brands.
All true. But transparent sounding to the source it wouldn't be.
 

RayDunzl

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#13
Five Watt 4 Ohm Power supply and Distortion...

Hmm...

I don't feel qualified to comment (beyond this) until I measure my own antiques.

Does look a bit high, though.
 

amirm

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#16
Well you are only providing like a few reviews per week. What are you doing with all your spare time?:)
As I am fond of telling my wife: I eat, sleep, poop and test audio gear. :) There is no time left beside those activities!
 

suttondesign

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#17
BTW, I read some place ATI made this amp for Outlaw. Anyone know for sure?
No, I can’t say for sure, but it looks almost identical to ATI amps, and I had problems with 60hz hum with both 6012’s I had over the years. ATI makes many OEM amps. Interestingly, I find my Dutch 8c to sound cleaner, though I still prefer the. Linkwitz speaker sound overall, even if the ATI amp wasn’t as good. Problem is Linkwitz is just a fussier setup.
 

Labjr

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#18
ATI also builds multi-channel amps using Hypex Class D modules & heavy linear power supplies with lots of filter caps. I'd like to see how those compare to the Hypex based amps with SMPS.

"With rated distortion below 0.05% and signal-to-noise ratio of 123 dB"

https://www.ati-amp.com/AT52XNC.php
 
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restorer-john

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#19
Good review Amir. :)

It looks to be a competent amplifier possibly for reliable sound distribution around the home instead of HT duty, although it doesn't have any of the control connections needed for automation or any level pots. Also a pity the amps cannot be bridged in pairs as an option. (probably not enough SOA in silicon and heatsink area/cooling for that). But at least it should be physically silent with no fans, even if there is some audible hum...hmm.

Good value but not class leading.
 

Webninja

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#20
This was on my list of amps, and one by one, that list keeps getting shorter. I think only Arcam and Monolith are left.

I presume the mono Outlaws would perform similarly?

I was hoping to use an amp(s) to power the front three for both HT and music.

Thanks for testing @amirm
 
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