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expiredvid1900 posted Jul 3, 2026 1:53 AM

Monolith by Monoprice M7100X 7x 90W/ch Home Theater Power Amplifier

$325

$650

50% off
+ Free S&Hat Monoprice
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Deal Details
Monoprice has Monolith by Monoprice M7100X 7x90 Watts Per Channel Multi-Channel Home Theater Power Amplifier with RCA & XLR Inputs (43866) on sale for $649.99 - 50% with promo code SHOP50 in cart = $324.99. Shipping is free.

Thanks to Community Member vid1900 for sharing this deal.

Details:
  • 7-channel Class AB power amplifier
  • 90W per channel into 8 ohms, all channels driven
  • THD < 0.02% with SNR > -100 dB
  • Unbalanced RCA and XLR inputs
  • 3RU height

Editor's Notes

Written by SaltyOne | Staff
  • Rated 4.9 out of 5 stars from customer reviews.
  • At the time of this posting, our research indicates that this is $195 lower than the next best comparable online prices starting from $519.99.

Original Post

Written by vid1900
Community Notes
About the Poster
Deal Details
Community Notes
About the Poster
Monoprice has Monolith by Monoprice M7100X 7x90 Watts Per Channel Multi-Channel Home Theater Power Amplifier with RCA & XLR Inputs (43866) on sale for $649.99 - 50% with promo code SHOP50 in cart = $324.99. Shipping is free.

Thanks to Community Member vid1900 for sharing this deal.

Details:
  • 7-channel Class AB power amplifier
  • 90W per channel into 8 ohms, all channels driven
  • THD < 0.02% with SNR > -100 dB
  • Unbalanced RCA and XLR inputs
  • 3RU height

Editor's Notes

Written by SaltyOne | Staff
  • Rated 4.9 out of 5 stars from customer reviews.
  • At the time of this posting, our research indicates that this is $195 lower than the next best comparable online prices starting from $519.99.

Original Post

Written by vid1900

Community Voting

Deal Score
+76
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Model: Monolith by Monoprice M7100X 7x90 Watts Per Channel Multi-Channel Home Theater Power Amplifier with RCA & XLR Inputs

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187 Comments

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Original Poster
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Jul 3, 2026 2:11 AM
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vid1900
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Jul 3, 2026 2:11 AM
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Our community has rated this post as helpful. If you agree, why not thank vid1900

https://www.audiosciencereview.co...st-2605699

If you want to see how a bunch of the new receivers only put out ~30 watts when they go into a secret 'limp mode' with no indication that you are not getting the 135wpc you paid for......
Last edited by vid1900 July 2, 2026 at 07:13 PM.
6
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Jul 3, 2026 2:31 AM
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Joined Nov 2008
faja92Jul 3, 2026 2:31 AM
98 Comments
Very interesting... thank you for sharing! I literally just bought an rz30 an hour ago. So place this after the preouts and you're good to go.

I didn't quite see the rating on the audioscience link about when exactly limp mode occurs, but it seems to be when the system is 'pushed' - I'd imagine when trying to blast your socks off
Last edited by faja92 July 2, 2026 at 07:34 PM.
Original Poster
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Jul 3, 2026 3:02 AM
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vid1900
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Jul 3, 2026 3:02 AM
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Quote from faja92 :
Very interesting... thank you for sharing! I literally just bought an rz30 an hour ago. So place this after the preouts and you're good to go.

I didn't quite see the rating on the audioscience link about when exactly limp mode occurs, but it seems to be when the system is 'pushed' - I'd imagine when trying to blast your socks off
If the amp puts out more than 30wpc into 4Ω, it locks into limp mode (unless unplugged for more than 10mins).

If you have old 8Ω speakers, they might never go into limp....but 8Ω speakers are pretty rare nowadays.

The odd part is that there is no indication on the unit that you are in limp mode. The receiver just keeps working at the greatly reduced wattage.
2
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Jul 3, 2026 4:39 AM
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CharlieC9067Jul 3, 2026 4:39 AM
1.6K Comments
im seeing $650

nevermind, didnt see coupon
Jul 3, 2026 4:50 AM
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Joined Jul 2010
supermanrobJul 3, 2026 4:50 AM
13K Comments
Quote from faja92 :
Very interesting... thank you for sharing! I literally just bought an rz30 an hour ago. So place this after the preouts and you're good to go. I didn't quite see the rating on the audioscience link about when exactly limp mode occurs, but it seems to be when the system is 'pushed' - I'd imagine when trying to blast your socks off
As someone pointed out approximate point is 30wpc.
In real world use, 30 is quite loud!
Unless you have very inefficient speakers & listen at higher than normal levels, you're probably not gonna come too close to that.

This supposedly issue has plagued those PAC units since 2021.
There has not been very many owners claiming they heard/had an issue in that time.
Quite the opposite, most have been happy with their units.

FYI the RZ30 doesn't offer preamp mode, so internal amps will continue to draw power.
The RZ30 is THX Select certified so you may not hear much of a difference.
4
Original Poster
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Jul 3, 2026 5:00 AM
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vid1900
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Jul 3, 2026 5:00 AM
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Our community has rated this post as helpful. If you agree, why not thank vid1900

You can enable "Pre-amp Mode" on most of these receivers, and then the unit does not power the internal amps.

Even if you forget and leave the internal amps on, the heatsink fans will never come on because they are not actually under load.
5
Jul 3, 2026 5:38 AM
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Joined Feb 2004
armedmetallicaJul 3, 2026 5:38 AM
6.5K Comments
Quote from vid1900 :
If the amp puts out more than 30wpc into 4Ω, it locks into limp mode (unless unplugged for more than 10mins).

If you have old 8Ω speakers, they might never go into limp....but 8Ω speakers are pretty rare nowadays.

The odd part is that there is no indication on the unit that you are in limp mode. The receiver just keeps working at the greatly reduced wattage.
I didn't realize 8Ω isn't common anymore... when did that become a thing? Last speakers I got were Polk Monitor 75T about 15? Or so years ago

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Jul 3, 2026 6:00 AM
224 Comments
Joined Nov 2014
golf4djJul 3, 2026 6:00 AM
224 Comments
Just pulled the trigger - not sure I needed it but seems like a great price to pair with my denon 3800 driving a 7.4.2 speaker setup.
Jul 3, 2026 6:01 AM
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Joined May 2009
khalid7412002Jul 3, 2026 6:01 AM
1.9K Comments
I'm using kef R11 for LR, Kef R2C for center, kef R3 for surrounds.

Using an older marantz SR7007 avr waiting on a deal for next gen avr with full bandwidth hdmi 2.1 ports

Was thinking about buying a used marantz 5 channel amp for like $500-$600 but maybe this would work as well

I live an apartment so don't get too loud but wondering if an external amp might help me, which I'm guessing 99% I won't notice a difference at my mid-volume levels but wanted to ask the experts here
Original Poster
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Jul 3, 2026 6:16 AM
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vid1900
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Jul 3, 2026 6:16 AM
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Probably during the late 80s and 90s with the loudness wars.

The 4ohm speakers pull more watts so if you were A/B ing speakers at a store, the 4ohm would sound "louder" than 8 ohms.

Or think of car audio, where subwoofer drivers are often 1 ohms nowadays. Amps will deliver 4000 watts into 1 ohm, but only 1200 watts into 8 ohms.
1
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Original Poster
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Jul 3, 2026 6:22 AM
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vid1900
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Jul 3, 2026 6:22 AM
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Our community has rated this post as helpful. If you agree, why not thank vid1900

Quote from khalid7412002 :
I'm using kef R11 for LR, Kef R2C for center, kef R3 for surrounds.

Using an older marantz SR7007 avr waiting on a deal for next gen avr with full bandwidth hdmi 2.1 ports

Was thinking about buying a used marantz 5 channel amp for like $500-$600 but maybe this would work as well

I live an apartment so don't get too loud but wondering if an external amp might help me, which I'm guessing 99% I won't notice a difference at my mid-volume levels but wanted to ask the experts here
External amps will give you more dynamics and cleaner sound.
1
1
Jul 3, 2026 6:51 AM
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Joined Jul 2010
supermanrobJul 3, 2026 6:51 AM
13K Comments
Quote from vid1900 :
You can enable "Pre-amp Mode" on most of these receivers, and then the unit does not power the internal amps.Even if you forget and leave the internal amps on, the heatsink fans will never come on because they are not actually under load.
FYI this is similar to the RZ70.
It's either L/R front or all, not independent.

The 2021 models don't offer it.
2
Jul 3, 2026 6:58 AM
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Joined Jul 2010
supermanrobJul 3, 2026 6:58 AM
13K Comments
Quote from golf4dj :
Just pulled the trigger - not sure I needed it but seems like a great price to pair with my denon 3800 driving a 7.4.2 speaker setup.
FYI the 3800 does offer independent preamp mode for all channels.
The channels are all assignable also.
1
2
Jul 3, 2026 7:06 AM
13K Comments
Joined Jul 2010
supermanrobJul 3, 2026 7:06 AM
13K Comments
Quote from khalid7412002 :
I'm using kef R11 for LR, Kef R2C for center, kef R3 for surrounds.Using an older marantz SR7007 avr waiting on a deal for next gen avr with full bandwidth hdmi 2.1 ports Was thinking about buying a used marantz 5 channel amp for like $500-$600 but maybe this would work as wellI live an apartment so don't get too loud but wondering if an external amp might help me, which I'm guessing 99% I won't notice a difference at my mid-volume levels but wanted to ask the experts here
That 7007 can easily drive those speakers.
You very likely would not hear a difference. Better off saving the $325 for the new AVR.

I wouldn't upgrade until you were out of that apartment imo.
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Jul 3, 2026 7:06 AM
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ROOSKIEJul 3, 2026 7:06 AM
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Quote from armedmetallica :
I didn't realize 8Ω isn't common anymore... when did that become a thing? Last speakers I got were Polk Monitor 75T about 15? Or so years ago
It is because a lot of affordable amps have no problem driving the lower impedance loads now.

You don't need to know this...
The speakers impedance is a nominal rating, which means approximate.
The actual impedance varies with frequency, every single frequency has it's own impedance value.
You also have the speakers phase angle, this is also dynamic with frequency.
If have a low or even just lower impedance coupled with a strong phase angle it will draw high current levels from the amp and generate a lot of heat as the amp is very inefficient when the phase angle is high.
Because this often occurs in speakers in the midbass and upper midbass region there is often a lot or content there in media and often with a lot of high energy levels(SPL).
You can see how a robust amp will perform better. These days a robust amp does not need to be expensive at all, just well designed.
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