On sale $199.00
Part Number:Q4-90

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Bundle Options help
QX-652 6.5" Coaxial Set [+$49.00]
QC-HF Component Set [+$89.00]
QX-693 6x9" Triaxial Set [+$59.00]
QP-TH25 "SuperTweeter" Set [+$29.00]
QP-MR6.5 6.5" Pro Mid Set [+$39.00]
QP-MR6.5 Grilles (set) [+$5.00]
The Q4-90 is the most versatile amplifier in our lineup. With its feature rich design you're able to power a complete system, including the mid/highs and the sub off one amp. It features a high power 4 channel class A/B output section that delivers superb sound quality and ample power to drive multiple arrays of speakers. The Q4-90 features variable high and low pass filters that can also be used in a band pass configuration. The Q4-90 also has variable bass boost, remote gain control w/ clipping indicator, and RCA pass through jacks to optimize the amplifier for multiple types of installs. 
  • Stable down to 2ohm Stereo or 4ohm Mono
  • Stereo Audio Outputs for Daisy Chaining multiple amplifiers 
  • Four way protection circuits: Speaker shorts, DC offset, High/Low voltage, Thermal protection
  • Double sided boards with high current MOSFET switching devices
  • 24db/oct slope crossovers, Fully adjustable High Pass, Low Pass Filter and Band Pass Filters
  • Includes Remote Gain Knob (for use in BP/LP mode on channels 3/4)

Model Q4-90
Mounting Foot Length
2 5/8"
Input Sensitivity8V~0.2V
Low Pass Filter50Hz ~ 5kHz
High Pass Filter20Hz ~ 5kHz
Crossover HPF/FULL/LP-BP
Remote Gain Control Included
Clipping Display LedYes
Signal to Noise Ratio105dB
Damping Factor200 <
Bass Boost @45Hz 0~18dB
External Fuse Rating40A x 2 pcs
4 ohm power @ 14V 90Wx4
2 ohm power @ 14V 130Wx4
4 ohm mono power @ 14V 260Wx2
Power and Ground Inputs 4ga
4 Stars
Very Nice Amp
Upgraded from the alpine ktp447 powerpack. This amp is far more powerful. Had a hard time dialing in the amp and a quick call to soundqubed got me on the right track. Customer service was top notch!
Did you find this helpful?  16 of 16 Found Helpful
Reviewed by:  from Edmond. on 1/19/2016
5 Stars
SQ Q4-90
This amp is a blessing in disguise. The reasons for this are that for the price you get superior build quality, excellent sound quality and a incredibly great price. This amp does rated power and then some. Also with the right speakers, crossover and gain settings this four channel puts out an amazingly clean signal. As a class AB amp this amp does not get too hot. It gets warm but not hot. If you want a heavy, clean old school looking four channel, then buy this SQ Q4-90. You will not be sorry.
Did you find this helpful?  12 of 12 Found Helpful
Reviewed by:  from Fullerton, CA. on 12/28/2014
5 Stars
Very clean amp. I turned the amp all the way up and the clipping light never flashed on the DD1. Plenty of power for my components. Don't second guess yourself, get it.
Did you find this helpful?  10 of 10 Found Helpful
Reviewed by: (Verified Buyer)  from Olive Branch. on 5/7/2015
5 Stars
Very Clean 4 channel
Got this amp to replace my Rockford Fosgate P400x4 with clean setup and was very surprised that it sounded way cleaner at the higher volume and was half the price. Great amp for a SQ build or even a Spl mids and highs
Did you find this helpful?  8 of 8 Found Helpful
Reviewed by:  from Vancouver WA. on 6/1/2015
5 Stars
Little Beast!
best 4 chan for the price! Does its power and the sound quality is amazing! If you havent gone soundqubed yet you my friend are missing out!
Did you find this helpful?  8 of 8 Found Helpful
Reviewed by:  from San Diego, CA. on 12/7/2014
5 Stars
Helped bring out lows
I went from a head unit to this amp and it did wonders for my sound quality. Obviously it can get loud but it really brought out the mid bass in my 6.5" components. Well worth the install and money.
Did you find this helpful?  7 of 7 Found Helpful
Reviewed by:  from California. on 7/29/2016
5 Stars
Awesome 4ch Amplifier
I hooked up the power and ground backwards on accident (referencing my AQ 2200 which the connections are apparently opposite) and the fuses went but the amp lived on. For that alone this amp is 5/5.
Did you find this helpful?  5 of 5 Found Helpful
Reviewed by:  from MSP, MN. on 10/3/2016
5 Stars
Great amp Great price
Awesome 4 channel amp for a great price!! I have it wired to 4 Mclaren Neo 8s and they love it! Great product!
Did you find this helpful?  5 of 5 Found Helpful
Reviewed by:  from ORMOND BEACH. on 7/30/2016
5 Stars
Picked this up for my front component and rear coaxial, this thing put out clear sound. I've always been a fan of SQ products so without a doubt this would be my choice for a 4 channel amp. Plenty of power for what I need, and the price is awesome : )
Did you find this helpful?  4 of 4 Found Helpful
Reviewed by: (Verified Buyer)  from SOCAL. on 11/4/2016

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