SKU: 55289900912

Esx Quantum Digital 4Ch Amp Qe900.4

$173.25 $192.50
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Ships within 48 hours · Estimated delivery Aug 5 - Aug 10

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Description

Esx Quantum Digital 4Ch Amp Qe900.4High Performance 4 Channel Class D Amplifier with Bridgeable Option Power Output: 4 x 150 Watts RMS @ 4 Ohms 4 x 225 Watts RMS @ 2 Ohms 2 x 450 Watts RMS @ 4 Ohms (Bridged) Amplifier Type: Class D Features: Highpass Filter CH1 2: 50 5000 Hz Highpass Filter CH3 4: 10 500 Hz Lowpass Filter CH3 4: 50 5000 Hz Bandpass Mode Bass Boost: 12 dB @ 40 Hz Copy Mode (CH3 4 > CH1 2) Line Outputs 2 4 CH Input Mode Included Bass Remote Start Stop Ready High Level

High-Performance 4-Channel Class-D Amplifier with Bridgeable Option

Power Output:

  • 4 x 150 Watts RMS @ 4 Ohms
  • 4 x 225 Watts RMS @ 2 Ohms
  • 2 x 450 Watts RMS @ 4 Ohms (Bridged)

Amplifier Type: Class-D

Features:

  • Highpass Filter CH1/2: 50 - 5000 Hz
  • Highpass Filter CH3/4: 10 - 500 Hz
  • Lowpass Filter CH3/4: 50 - 5000 Hz
  • Bandpass-Mode
  • Bass-Boost: 12 dB @ 40 Hz
  • Copy-Mode (CH3/4 > CH1/2)
  • Line-Outputs
  • 2/4 CH Input Mode
  • Included Bass-Remote
  • Start/Stop Ready
  • High Level Inputs with EPS
  • Auto-Turn-On
  • Efficiency: 84%

Elevate your car audio experience with our high-performance 4-channel Class-D amplifier. This powerhouse delivers 150 Watts RMS at 4 Ohms and 225 Watts RMS at 2 Ohms for each channel, providing exceptional sound quality. When bridged, it produces an impressive 450 Watts RMS at 4 Ohms, making it perfect for those seeking even more power.

The amplifier offers versatile filtering options with highpass filters for CH1/2 ranging from 50 to 5000 Hz, and for CH3/4 from 10 to 500 Hz. Additionally, there is a lowpass filter for CH3/4 with a frequency range of 50 to 5000 Hz, and a bandpass-mode for precise sound customization.

You can enhance the bass performance with the 12 dB boost at 40 Hz, and with the copy-mode functionality, the audio signals from CH3/4 can be copied and routed to CH1/2, expanding the configuration possibilities.

Featuring line-outputs and 2/4 CH input mode, the amplifier allows you to connect various audio components seamlessly. The included bass-remote provides convenient control over the bass levels, while the Start/Stop ready feature adds to the user-friendly experience.

The amplifier is equipped with high level inputs with EPS (Easy Power Supply) and Auto-Turn-On functionality, ensuring hassle-free integration into your car audio setup. With an efficiency rating of 84%, this Class-D amplifier maximizes power utilization while delivering exceptional performance.

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 55289900912

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4.6 ★★★★★
Based on 29 reviews
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Product Reviews
K
Verified Purchase
Kindle Customer
Pawtucket, US
★★★★★ 4
keyboard and case is phenomenal, trackpad is borderline unfunctional
Color: Black
I bought this case, because of the keyboard and trackpad, i wanted to use my ipad more like a laptop. the keyboard is phenomenal and certaintly better than other cheap ipad keyboards i have tried, I can actually use this one without having to repeatedly slam or hard press certain keys and can actually have a flow of typing. additionally, everything else regarding the case itself is amazing. it isnt cumbersome or bulky and it is very easy to swap between ipad and laptop mode on the fly. the trackpad however is genuinely unusable. the sensitivity on the trackpad is horrid and I cannot figure out how to change it, and additionally, clicking using the trackpad is outright impossible. you try to left click, it registers as a right click, or you try to click and it instead snaps your cursor to the bottom of the screen instead. it is also impossible to use any gesture functions with the trackpad, even something as simple as scrolling up and down or left to right is impossible. it is outright impossible to have any kind of workflow using the trackpad. it is unfortunately just a lot easier to use the keyboard and touch screen! its a shame that the keyboard and case itself is very nice too, so I will now have to spend more money on a separate mouse, which is additionally ANOTHER item i will have to carry around, just to make what I already bought work the way I expected.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on June 4, 2026
J
Verified Purchase
Jessie A.
Omaha, US
★★★★★ 5
Great quality at a great price range!
Color: Navy Blue
Works very well for the day to day. Great quality at a great price range. Would definitely buy again if needed.
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Reviewed in the United States on May 14, 2026
A
Verified Purchase
Allana W
Bozeman, US
★★★★★ 5
Solid case.
Color: Sky-Blue
Love this case. Fits great and the color is great! The keyboard is nice and it even has a little spot for a stylist.
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Reviewed in the United States on June 3, 2026
N
Verified Purchase
Nosiest
San Leandro, US
★★★★★ 4
Cheap and good
Color: Black, Color: Black
I chose the color black and it gives a really nice look, especially with the multicolor led lights around the keys. It is very easy to clean and you can shut off the keyboard to prevent any mess with the iPad. The magnet is very nice and keeps the keyboard in place. The keyboard doesn’t easily slip or anything so it holds the iPad very well. Only bad thing is that over time the iPad begins to scrape off the pain and it leaves your keyboard with some white spots all over :/ but if looks isn’t something that you care about, this is the keyboard for you. Don’t use it for gaming because there is a delay in functionality when you press a key and then try to use the pad. Also, you have to press the keys a bit harder than the usual keyboard. But for the price? This is a great item! Definitely worth my money
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Reviewed in the United States on January 18, 2026
G
Verified Purchase
Grant In Austin
Houston, US
★★★★★ 5
Great quality at a remarkable price
Color: Navy Blue
I got an iPad and was looking for a cover to protect it. I came across this case that has a Bluetooth keyboard. It seems to be working great. It was less than $30 and had 4.5 stars with over 4k reviews. The keyboard is magnetic and detachable, so I’ve got lots of configuration options. The keyboard pairs easily and allows you to use the iPad like a laptop. The point of an iPad a lot in one shot is kind of the touchscreen, but when I’m typing a lot of text as once (like now), it’s really nice to have a physical keyboard and touchpad. The keys are comfortably spaced and I’m comfortable typing on it. There is no additional setup for the keyboard besides pairing it to the iPad. At that point, all the cursor and keyboard features are immediately available. The case is well built and has nice features like a slot to hold a stylus and multiple grooves to set your viewing angle. It’s configured to be used in landscape mode, but if for some reason you wanted to use it in portrait mode, you can pop the keyboard off to lay it flat. Especially for the price, this is an exceptionally nice iPad cover.
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Reviewed in the United States on May 8, 2026

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