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expiredvid1900 posted Jul 3, 2026 7:49 PM

Monoprice Monolith M2100X 2x90 W/Ch Home Theater Power Amplifier

$200

$400

50% off
+ Free S&Hat Monoprice
32 Comments
15.8K Views
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Deal Details
Monoprice has Monoprice Monolith M2100X 2x90 Watts Per Channel Stereo Home Theater Power Amplifier (43863) on sale for $399.99 - 50% off w/ promo code MOVE50 in cart = $199.99. Shipping is free.

Thanks to Community Member vid1900 for finding this deal.

Features:
  • 2 Channels of Amplification
  • 90 Watts Per Channel into 8 ohms
  • Unbalanced RCA Inputs
  • XLR Inputs
  • 3RU Height
  • Class AB Amplification
  • 3 Year Replacement Warranty
Expired:
  • SHOP50

Editor's Notes

Written by SubZero5 | Staff
  • About this deal:
    • This price is $100 less than the previous FP deal.
  • About this product:
    • Rating of 4.7/5 from Monoprice customer reviews.
  • About this store:
    • Details of Monoprice's return policy (here)

Original Post

Written by vid1900
Community Notes
About the Poster
Deal Details
Community Notes
About the Poster
Monoprice has Monoprice Monolith M2100X 2x90 Watts Per Channel Stereo Home Theater Power Amplifier (43863) on sale for $399.99 - 50% off w/ promo code MOVE50 in cart = $199.99. Shipping is free.

Thanks to Community Member vid1900 for finding this deal.

Features:
  • 2 Channels of Amplification
  • 90 Watts Per Channel into 8 ohms
  • Unbalanced RCA Inputs
  • XLR Inputs
  • 3RU Height
  • Class AB Amplification
  • 3 Year Replacement Warranty
Expired:
  • SHOP50

Editor's Notes

Written by SubZero5 | Staff
  • About this deal:
    • This price is $100 less than the previous FP deal.
  • About this product:
    • Rating of 4.7/5 from Monoprice customer reviews.
  • About this store:
    • Details of Monoprice's return policy (here)

Original Post

Written by vid1900

Community Voting

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+49
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Top Comments

vid1900
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The Fosi v3 only puts out 34wpc into 8 ohms with the stock power supply...so you need to buy the 48v supply to get the 89 watts.

The Fosi lacks the XLR inputs

The Fosi lacks the 12v turn on circuit

The Fosi is a great little amp, but not in the same league as the Monolith.
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32 Comments

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Original Poster
Pro
Jul 3, 2026 8:00 PM
3.3K Comments
Joined Sep 2016
vid1900
Original Poster
Pro
Jul 3, 2026 8:00 PM
3.3K Comments

Our community has rated this post as helpful. If you agree, why not thank vid1900

Just in case the original post gets edited:

The perfect amp to power your Streamer Box, add 2 more channels to your 7 channel amp, or to give some serious power to a dedicated Stereo system.

90wpc into 8 ohm speakers, 135wpc into 4 ohm speakers
3
Jul 3, 2026 8:28 PM
171 Comments
Joined Sep 2018
MaroonLeopard1601Jul 3, 2026 8:28 PM
171 Comments
What would be the difference between getting a fosi v3 / Douk a5 and this?
Jul 3, 2026 8:54 PM
458 Comments
Joined Nov 2018
madsci1016Jul 3, 2026 8:54 PM
458 Comments
Dang need the 3 channel
Original Poster
Pro
Jul 3, 2026 9:52 PM
3.3K Comments
Joined Sep 2016
vid1900
Original Poster
Pro
Jul 3, 2026 9:52 PM
3.3K Comments

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Quote from MaroonLeopard1601 :
What would be the difference between getting a fosi v3 / Douk a5 and this?
The Fosi v3 only puts out 34wpc into 8 ohms with the stock power supply...so you need to buy the 48v supply to get the 89 watts.

The Fosi lacks the XLR inputs

The Fosi lacks the 12v turn on circuit

The Fosi is a great little amp, but not in the same league as the Monolith.
4
Jul 3, 2026 10:06 PM
405 Comments
Joined May 2016
VolumnusJul 3, 2026 10:06 PM
405 Comments
Quote from vid1900 :
The Fosi v3 only puts out 34wpc into 8 ohms with the stock power supply...so you need to buy the 48v supply to get the 89 watts.

The Fosi lacks the XLR inputs

The Fosi lacks the 12v turn on circuit

The Fosi is a great little amp, but not in the same league as the Monolith.
I have the Fosi V3 with the 48V power supply. They are down to around $80 in open box condition on eBay. To get around the on/off issue, I use a master/slave power strip. It also turns my Aircom cooler on and off with the receiver. The Cyberpower power strip was only $15. If I were using the external amp to push my fronts, I'd go with the Monolith (for twice the cost of the Fosi and a master/slave power strip), but I'm just using it to push two wide speakers that are barely even utilized.
1
1
Jul 3, 2026 10:42 PM
171 Comments
Joined Sep 2018
MaroonLeopard1601Jul 3, 2026 10:42 PM
171 Comments
Quote from Volumnus :
I have the Fosi V3 with the 48V power supply. They are down to around $80 in open box condition on eBay. To get around the on/off issue, I use a master/slave power strip. It also turns my Aircom cooler on and off with the receiver. The Cyberpower power strip was only $15. If I were using the external amp to push my fronts, I'd go with the Monolith (for twice the cost of the Fosi and a master/slave power strip), but I'm just using it to push two wide speakers that are barely even utilized.
Would the monolith be better than the amps I mentioned if I'm looking to run a 2.1 setup with Elac Debut 3.0 / Emotiva XB2? (although still researching bookshelfs. I did try the KEF LSX II from costco, loved the dispersion and soundstage on it) will also be using the wiim ultra as a preamp. Sorry I'm still noob when it comes to ohms and watts. Will be in an apartment but I do like things loud sometimes.
Last edited by MaroonLeopard1601 July 3, 2026 at 03:46 PM.
Jul 3, 2026 11:07 PM
249 Comments
Joined Feb 2011
sbattosaiJul 3, 2026 11:07 PM
249 Comments
Good to add that it's a class AB amplifier (I thought it was a class D)
1

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Jul 4, 2026 12:28 AM
218 Comments
Joined Nov 2007
serniterJul 4, 2026 12:28 AM
218 Comments
Quote from madsci1016 :
Dang need the 3 channel
How about the 7100 that's also on sale?
Jul 4, 2026 1:36 AM
2 Comments
Joined Jul 2016
ykcorsseldnimJul 4, 2026 1:36 AM
2 Comments
I have a Sony STR-AZ5000ES driving a 5.1.4 setup. Fronts are Martin Logan electromotion ESL pair, center is Martin Logan ElectroMotion C2. Rear and height channels are monopolize in wall and in ceiling. Will getting this or other amplifier help?
4
Jul 4, 2026 1:40 AM
124 Comments
Joined Jan 2018
nathan.swigertJul 4, 2026 1:40 AM
124 Comments
https://www.monoprice.com/product?p_id=43866
Im a total newbie but for a more universal home theater set up? This is 50 percent off too. M700x 7x90 watt
Jul 4, 2026 2:16 AM
458 Comments
Joined Nov 2018
madsci1016Jul 4, 2026 2:16 AM
458 Comments
Quote from nathan.swigert :
https://www.monoprice.com/product?p_id=43866
Im a total newbie but for a more universal home theater set up? This is 50 percent off too. M700x 7x90 watt
All of the models of this series were independently tested and the 7 channel version had some issues. Lower channel counts were fine. Check avsforum for the whole story. But the gist was avoid the 7 channel till a new rev is out and tested.
2
Jul 4, 2026 2:19 AM
458 Comments
Joined Nov 2018
madsci1016Jul 4, 2026 2:19 AM
458 Comments

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Quote from serniter :
How about the 7100 that's also on sale?
All of the models of this series were independently tested and the 7 channel version had some issues. Lower channel counts were fine. Check avsforum for the whole story. But the gist was avoid the 7 channel till a new rev is out and tested.
2
Jul 4, 2026 2:53 AM
1.3K Comments
Joined Feb 2010
ROOSKIEJul 4, 2026 2:53 AM
1.3K Comments

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For those wondering 90watts/135watts is more than enough for most people most of the time.
The next tier up in power requirements would be best served by amps with 2-4times as much power.
That would be high spl playback in larger rooms and users with very low efficiency speakers(rare)
2
Jul 4, 2026 5:37 AM
392 Comments
Joined Feb 2007
zaksterJul 4, 2026 5:37 AM
392 Comments
I have 4 rooms with 2 ceiling speakers each. Do I need 4 of this amp to drive each of the rooms?

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Jul 4, 2026 6:26 AM
1.3K Comments
Joined Jun 2016
geezeefosheezeeJul 4, 2026 6:26 AM
1.3K Comments
Quote from zakster :
I have 4 rooms with 2 ceiling speakers each. Do I need 4 of this amp to drive each of the rooms?
This isn't the right fit for that application. Look into fosi or wiim amps.
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