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Monoprice Monolith 7-Channel Amplifier Review

by March 30, 2017
Monoprice Monolith 7 x 200 amplifier

Monoprice Monolith 7 x 200 amplifier

  • Product Name: Monolith 7-Channel Amplifier
  • Manufacturer: Monoprice
  • Performance Rating: StarStarStarStarhalf-star
  • Value Rating: StarStarStarStarStar
  • Review Date: March 30, 2017 00:00
  • MSRP: $ 1,499
  • Buy Now

Monoprice Monolith-7

  • Number of Channels: 7
  • EIA 1kHz Output Power at 8 Ohms:* 250 watts
  • EIA 1kHz Output Power at 4 Ohms:* 375 watts
  • FTC Full Bandwidth Output Power at 8 Ohms:** 200 watts
  • FTC Full Bandwidth Output Power at 4 Ohms:**     300 watts
  • Input Sensitivity for Full Rated Power: 1.6 volts
  • Frequency Response at Rated Output: 20Hz to 20kHz ±0.1dB
  • Phase Response: +5 to -15 degrees from 20Hz to 20kHz at 1 watt
  • Signal-to-Noise Ratio "A-Weighted": Greater than 120dB below rated FTC Full Bandwidth Power
  • Total Harmonic Distortion (THD): Less than 0.03% at full rated FTC power
  • Less than 0.005% at full EIA power at 1kHz
  • Intermodulation Distortion (IMD): Less than 0.03% at full rated FTC power
  • Less than 0.005% at full EIA power at 1kHz
  • Toroidal Transformers: 2 (1,230VA and 1,025VA)
  • Total Capacitance:156,800µF (22,400µF per channel)
  • Load Impedance: Safe with all types of loads
  • Rated for 4 to 16 ohms
  • Power Bandwidth: FTC +0, -3dB from 5Hz ~ 100kHz
  • Damping Factor: Greater than 400 from 10Hz ~ 100kHz
  • Crosstalk: Greater than 100dB from 20Hz ~ 20kHz
  • Gain: Voltage gain of 28dB
  • Slew Rate: > 50V / µS
  • Input Impedance: 28 kilohms (nominal)
  • Remote Trigger Voltage: 3.3 ~ 24.0 VDC at 5mA or greater
  • DC Output Offset: Less than ±5mV
  • Input Power: 120 VAC (nominal)
  • Chassis Dimensions: 17.0" x 7.0" x 16.5" (432 x 178 x 419 mm)
  • Net Weight: 93.2 lbs. (42.3kg)

All power ratings listed above and provided by Monoprice are measured with all channels driven.

* EIA 1kHz Power refers to maximum average power in watts at 1kHz with 0.005% THD and noise.

** FTC Full Bandwidth Power refers to maximum average power in watts from 20Hz to 20kHz with 0.03% THD and noise.

Pros

  • Astounding, real-world power that exceeds published specs
  • Incredible if not ridiculous value and price/performance ratio
  • Dual toroidal transformers ensure rated power with all channels driven
  • Truly tank-like build quality
  • Rigid binding posts and rear connectors
  • Trigger power on/off capability for integration with home automation

Cons

  • Really, really, really heavy
  • Confusing front power light
  • Front power light cannot be dimmed or defeated
  • + and - speaker terminals too closely spaced together
  • No balanced (XLR) inputs

 

Monolith-7 Introduction

We’ve all heard it before. “They don’t make amplifiers like they used to.” When someone utters those hallowed words, Krell’s name is inevitably invoked like a hallowed deity. The conversation then normally closes with a formulaic, “Big, heavy, and able to drive just about any speaker on the planet. Yeah, don’t make them like they used to.”

Well, if you’re nostalgic for those “good old days” of massive amps pumping out gobs of clean power then the time has come for deja vu all over again. I’m not talking about an amp costing upwards of $10K or $20K from a legendary audio company.  I’m talking about an upstart—a punk, for lack of a better word—that made its name selling HDMI cables (of all things) at a bargain basement price. That’s Monoprice.

Yes, Monoprice. Over the past year, Monoprice has made an immediate and aggressive move into the world of audiophile-grade equipment. In other words, audio that you’d use as part of a reference system.

Monoprice Monolith Amplifier YouTube Review

Designed & Engineered in the USA

I don’t know about you but I never would have thought about buying reference gear from Monoprice. It was exactly that notion that prompted this strategic focus.

Monoprice’s foray into high-end audio started as an idea towards the beginning of 2015. It was the brainchild of Hobie Sechrest, Monoprice’s Sr. Product Manager who convinced Monoprice’s then President Bernard Luthi, to bless the endeavor.

Monoprice Monolith-7 Front

Front view of the Monolith 7. When the Monolith 7 reaches full power, the front power button glows blue. 

There is no way to turn off the blue LED while the amp is activated.

It could have been easy for Monoprice to source its amplifiers from an overseas outfit, slap on their logo, and call it a day. However, Monoprice smartly realized that they needed some street cred for their amps if the were going to be taken seriously. To do so, they made (in my opinion) a brilliant move: they worked with US-based ATI.

ATI may not be a household name, but chances are you’ve either seen or heard an amplifier built by ATI.  Some of the most well-known companies (ie. Lexicon, Outlaw Audio, etc) in audio have either used ATI-designed amplifiers or had ATI build amplifiers to their specs.  Now you can add Monoprice to that list. According to Monoprice, ALL Monolith amplifiers are built in the same Montebello California based facility that ATI builds their other amplifiers too.

With ATI behind the scenes, it should come as no surprise that the Monolith is an absolute beast of an amplifier in size, weight, and power specs. In fact that’s what I nicknamed it shortly into my review period, “the beast.”

All Monolith amplifiers are Class AB topologies and share the same overall chassis, with the difference being the number of amplifier channels under the hood.  In my seven-channel review model there are two massive toroidal transformers capable of delivering 200 wpc with all channels driven into 8 ohms and 300 wpc with all channels driven into 4 ohms at full bandwidth.

What’s remarkable to me about all Monolith amplifiers (not just my seven-channel review unit) is the readiness and openness with which Monoprice provides specs.  With some companies you’re searching for certain measurements and they don’t provide them or you’ll find that they fudge some numbers by only driving the amp with two channels and measuring it at 1kHz. That’s not a completely accurate way to rate amp’s performance—regardless of what the so-called industry standard measurements are.

Monoprice Monolith 7 front LED light

The Monolith 7 front power button has a blue LED that illuminates once the amp is fully powered up. 

The light does not light up for the first 25 or so seconds while the amp is powering up, which can lead users to conclude incorrectly that the amp has malfunctioned.

Monoprice’s specs, on the other hand, are how we like to see them: with all channels driven and across the entire frequency band. Want to know the EIA 1kHz output power at 8 Ohms? 250 watts. How about 4 Ohms? 375 watts. Want to know the THD, intermodulation distortion, damping factor, crosstalk, capacitance, slew rate, phase response, signal-to-noise ratio, or the input sensitivity for full rated power? Monoprice gives you all that and more on their spec sheet. In other words, Monoprice hasn’t tried to hide a single number or measurement. Whether or not a manufacturer’s measurements can be corroborated is another discussion.

I was not privy to the results of our Audioholics measurements during my review period. Nevertheless, if my first-hand experience is any indication, I expect the Monolith to sail through all our tests in textbook style with flying colors and come right in line with their published specs. You can see Gene DellaSala’s notes and bench measurements, which he’ll be including later on in this review, for more info.

Build Quality Galore

If you have any doubts about the Monolith, cast them aside. Build quality is impeccable. The heat sinks on this amp are massive and integrated on the amplifier modules themselves inside the chassis.  There is no fan for cooling.

Even though the individual channels are on discrete amplifier modules, the Monolith models aren’t upgradable.  You cannot, for example, start with a two-channel model, and then ship it to Monoprice and add a few amplifier modules to upgrade to a five- or seven-channel version.

Top view of the Monoprice Monolith 7 Power Amplifier

Top view of the Monolith-7.  You can readily see each of the seven amplifier modules with their massive heat sinks.

To prevent tripping your breakers, the Monolith has a soft-start feature that gradually powers the amplifier up over a period of about 20-30 seconds. It’s a wonderful feature. My only complaint about this feature is that the Monolith’s front blue LED doesn’t light up immediately. When I first unpacked the amplifier and turned it on, I thought there was something wrong with it.  I don’t like the way this is implemented and I would suggest that Monoprice change the behavior of the LED from the factory so that it blinks when powering up and then turns solid when it reaches full operating power.

If Monoprice can’t make an adjustment to the LED, they would do well to include a tag on the amp or make a note in the user manual that the LED won’t light up until the amp has reached full power.  You can, however, play any source during that power up period without issue.

Editorial Note about Power LED

We didn't experience the delay in LED illumination for the Monolith-2 that we bench tested so this issue may only be limited to the 5 and 7 channel versions.

The Monolith has no current limiting circuitry so that if your speakers’ impedance drops, current won’t be limited like most AV receivers often do.  That’s not to imply that the amp will blow your speakers or get damaged if there’s a problem. There are monitoring circuits specially designed for this purpose. They are optically coupled and sit outside the circuit path. They’ll detect electrical shorts from your speaker wire or electrical outlet and disengage the amplifier’s output. The amp will then check the problem circuit every 10 seconds and restore power when things are clear.  Monoprice makes it a point to say that there’s no fuse or relay in the output, which can lower the damping factor and change the sound.

The five-way binding posts and RCA jacks aren’t fancy but they are incredibly rugged.  The RCA jacks are mounted directly to the chassis instead of a separate circuit board.  You can tell the difference immediately.  Plugging an RCA interconnect feels solid and stable. If you have stiff speaker cables, they also won’t start to bend the binding posts.

Monoprice Monolith 7x200 rear view

The Monolith 7 features unbalanced inputs and sturdy, high quality five way binding posts and a ground lug.  Channels are not bridgeable.

The only thing missing from this amp are unbalanced connections.


Oh, and legendary amps have heft, right? Well get ready for some serious exercise because the Monolith weighs in at a massive 93.2 pounds.  Yes, 93 pounds of solid, amplification muscle. To put that into perspective, the Monolith weighs more than my SVS Ultra Tower speakers. It weighs more than SVS’ SB13-Ultra subwoofer (by a hair).  So, if you have any intent of placing a Monolith amp in a rack or on an amp stand, double check to make sure they can hold this much weight.

Clarifying Compliance

The rear panel of the Monolith caused us some confusion that had to clarify directly with Monoprice. There are no compliance notices silk screened directly on the Monolith. The user manual (you can view a downloadable copy here) however, indicates that the Monolith 7 has FCC compliance. Moreover, the rear of the amp does not say it was built in the USA. It simply says designed and engineered in the USA. We confirmed with Monoprice that the amplifiers are made in Montebello, California. We can certainly understand cost savings and the like when building and branding a standard chassis.  However, in our opinion, we'd like to see Monoprice make both its FCC compliance and "Made in USA" silk screened onto the units themselves.

Set Up

The Monolith came impeccably packed. Due to its weight and especially its density, it’s very, very difficult to maneuver. Therefore, make sure you have help when you unpack it.

I tested the Monolith across a few different equipment configurations and it was an outstanding performer in each. I plugged the Monolith into a dedicated 20-amp circuit that is reserved solely for my home theater setup.

If you have dimmers in your house or the issue known as DC offset then the Monolith’s massive transformers may start to hum. They did in my case when the lights on my microwave were on and set to low.  To be clear, this isn’t a design problem with the Monolith. To fix the humming, I plugged the Monolith into Emotiva’s CM2 AC line restoration and common mode filter system. This two-outlet receptacle is specially designed to eliminate DC offset issues without limiting current or dynamics.

Detail view of the Monoprice Monolith's thick metal chassis.

Detail view of the Monoprice Monoltih-7's thick, vented, metal, chassis. You can see each amplifier through the generous vent holes.

When the amp first arrived at the tail end of 2016, I paired it with the superb-sounding Anthem AVM 60 preamp processor, our pre-pro of the year, where it powered the main channels of an 11.1.4 setup anchored by SVS Ultra speakers.

In the second setup, I paired the Monolith and Anthem with the RSL CG3 5.1 system that I reviewed

In the third pairing, I connected the Monolith to my Denon X7200WA AV receiver to drive the seven primary channels of my 11.1.4 Atmos and DTS:X setup.  I left the height channels to the Denon’s internal Class A/B Amplifier.  The speakers for this setup consisted of SVS Ultra Towers and Ultra Center. Ultra Bookshelves rounded out the surround and rear channels and Beale Street in-ceiling speakers served as height channels. An SVS SB13-Ultra subwoofer anchored the bass.

I used the Denon’s unified 11.1.4 layout with front and rear height assignments so that I could play Dolby Atmos, DTS:X, and Auro-3D titles interchangeably.

I’ve implicitly noted the Monolith’s performance as part of the Anthem AVM 60 and RSL CG3 reviews. Therefore, my comments below pertain to the Monolith, Denon, and SVS Ultra setup.

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About the author:

Theo is a serious audiophile and home theater enthusiast—a passion he's enjoyed for over 20 years. He heads up many of our speaker system and receiver reviews as well as covering the latest in streaming technologies and Ultra HD video.

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Recent Forum Posts:

Jon AA posts on August 01, 2019 19:19
PENG, post: 1329584, member: 6097
All 3 factors have been dealt with to some extents with the introduction of XT32 and the Editor App, but I am not aware of any such re-match/review conducted by any credible/reputable group.
That's a very good point. These days any comments about Audyssey “sounding bad” “messing up” “sounding better without” etc, need to be taken with a large grain of salt if they're talking about XT32 and a device capable of using the App. With the addition of the App, the end result is basically infinitely variable. If it really sounds that bad, chances are very good whatever is wrong could be eliminated or a much better result achieved by a user with more effort and/or knowledge.
gene posts on July 30, 2019 21:36
PENG, post: 1329584, member: 6097
Whether XT32 is as good or not is mostly a matter of personal preference, and is subjective. There notable differences in their approach, for example, AARC apparently eq bass such that it would ramp up towards the low end whereas Audyssey would aim to flatten it the best it could but you can do a custom curve yourself using the Audyssey Editor App. Both can EQ without down sampling to 48 kHz, but when it is done on board the device, there may not be enough processing power to do it at higher sampling frequencies, so all D&M AVRs/AVPs, even the flag ship models do down sample to 48 kHz when running Audyssey. AARC, the AVM would down sample to 96 kHz for the digital inputs and 48 kHz if analog inputs are used. To a lot of people, 48 or 96 kHz is academic, makes no difference in sound quality.

There are probably more positive reviews on AARC than XT32, but I think that had a lot to do with hearsay started after Harman did a shoot out between 5 or 6 REQ systems including an earlier version of Audyssey, and in that shoot out, the main thing that caused MultEQ to score low was the fact that it tended to level/flatten the bass, forced a mid range compensation (aka BBC dip), and EQ all the way to 20 kHz. It turned out a lot of people just didn't like the resulting sound signature. Note that Harman ranked them according to their scores, but never identify them, though most guessed Audyssey was among the one(s) with the lowest score. All 3 factors have been dealt with to some extents with the introduction of XT32 and the Editor App, but I am not aware of any such re-match/review conducted by any credible/reputable group.

I don't know how Anthem defines “truly balance”, so no comment. We do know the Denon AVP-A1HDCI is truly balance but it was listed for $7,500. ADTG had one, that failed after 8 years. I wouldn't expect a $3,000 unit, AVP or power amp, to be fully/truly end to end balance, without sacrificing something else along the line, but that's just my opinion.

I doubt the AVM60 is a fully differential design from input to output especially since their STR is NOT. The Anthem engineer I spoke to prefers converting to single ended between stages as you can see in my review:
https://www.audioholics.com/av-preamp-processor-reviews/anthem-str-preamp-power-amplifier
gene posts on July 30, 2019 21:34
PENG, post: 1329553, member: 6097
Gene, he's currently using an AVR, the SR7005 that was launched almost 10 years ago, not the 2018 prepro AV7705. I would think that the AVM60 is an upgrade compared to the SR7005 even just in terms of analog preamp, at least on paper, if no audible difference. I am just wondering if you thought he's comparing it to the AV7005.
Ah I misunderstood and yes agreed.
RichB posts on July 30, 2019 19:25
PENG, post: 1329584, member: 6097
I don't know how Anthem defines “truly balance”, so no comment. We do know the Denon AVP-A1HDCI is truly balance but it was listed for $7,500. ADTG had one, that failed after 8 years. I wouldn't expect a $3,000 unit, AVP or power amp, to be fully/truly end to end balance, without sacrificing something else along the line, but that's just my opinion.

A Monoprice HTP-1 post stated that it was fully balanced. The $4000 RMC-1L is fully balanced. The $3000 XMC-2 is fully balanced with DACs in mono-mode for the front three channels. Emotiva posts indicate the XMC-1 other channels DACs are stereo but use balanced outputs.

I think it may be easier to keep the noise in check with balanced hardware than not when you have 16 channels.

- Rich
PENG posts on July 30, 2019 18:12
Daniel Steixner, post: 1329572, member: 81561
Yes, it's the 9+ year old SR7005. So, this conversation has opened me up to considering the AV7705, which retails for $800 less than the AVM60. I was dead set on the AVM60 mostly because of ARC, but if folks are suggesting MultEqX32 is just as good, well then… Not to mention 2 independent sub outs.

Anthem makes mention of being truly balanced implying perhaps a lower noise floor? Not sure if that really means differentially balanced throughout all 11.1 channels with separate circuits for pos and neg parts of the signal? Can't imagine they could do that at the given price point. May just be marketing lingo? I would believe the AVM60 and AV7705 have very similar SQ. The lower price and dual subwoofers are real things - budget and functionality.

Whether XT32 is as good or not is mostly a matter of personal preference, and is subjective. There notable differences in their approach, for example, AARC apparently eq bass such that it would ramp up towards the low end whereas Audyssey would aim to flatten it the best it could but you can do a custom curve yourself using the Audyssey Editor App. Both can EQ without down sampling to 48 kHz, but when it is done on board the device, there may not be enough processing power to do it at higher sampling frequencies, so all D&M AVRs/AVPs, even the flag ship models do down sample to 48 kHz when running Audyssey. AARC, the AVM would down sample to 96 kHz for the digital inputs and 48 kHz if analog inputs are used. To a lot of people, 48 or 96 kHz is academic, makes no difference in sound quality.

There are probably more positive reviews on AARC than XT32, but I think that had a lot to do with hearsay started after Harman did a shoot out between 5 or 6 REQ systems including an earlier version of Audyssey, and in that shoot out, the main thing that caused MultEQ to score low was the fact that it tended to level/flatten the bass, forced a mid range compensation (aka BBC dip), and EQ all the way to 20 kHz. It turned out a lot of people just didn't like the resulting sound signature. Note that Harman ranked them according to their scores, but never identify them, though most guessed Audyssey was among the one(s) with the lowest score. All 3 factors have been dealt with to some extents with the introduction of XT32 and the Editor App, but I am not aware of any such re-match/review conducted by any credible/reputable group.

I don't know how Anthem defines “truly balance”, so no comment. We do know the Denon AVP-A1HDCI is truly balance but it was listed for $7,500. ADTG had one, that failed after 8 years. I wouldn't expect a $3,000 unit, AVP or power amp, to be fully/truly end to end balance, without sacrificing something else along the line, but that's just my opinion.
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