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The Klipsch THX Ultra2 KA-1000-THX is a Class D amplifier.
The KA-1000-THX delivers 1000 watts of power into a 4-ohm load.
Yes, the KA-1000-THX can support two high-performance subwoofers.
The amplifier uses professional NL2 SpeakOn outputs for high current power transfer.
The KA-1000-THX features a built-in, defeatable low-pass crossover, level control, boundary-gain compensation switch, and completely variable phase control for enhanced audio customization.
Review Summary
2026-03-13T20:00:00
I don't review most Klipsch products I own, but feel compelled to correct misinformation in a negative review that would mislead others. First I will address the error, then I will give a review of the amplifier itself. 1) A review condemns Klipsch customer service for telling him he could replace a fuse, but "there was no place to install the fuse" and "certainly did not want to disassemble the amplifier to install the fuse!" In fact there is a common, drawer-style fuse holder that is part of the socket where the power cord attaches. Parts Express even sells a lighter-duty version, #090-412. The fuse is accessible from outside; no disassembly required, yet the reviewer and his neighbor set out to correct Klipsch. No wonder customer service did not know how to fix a problem that did not exist. They got blamed for a customer's mistakes, and other potential buyers are steered away by a negative review. 2) This amplifier shows that its power supply is up to delivering acoustic power cleanly. So few amplifiers will produce a genuine doubling of wattage when speaker impedance is halved, but this one does! 500 watts in to 8 ohms and 1000 watts into 4 ohms is excellent. Decades ago Rockford Fosgate produced some mobile amplifiers that did the same, but nearly all audio manufacturers cut corners in the expensive power supply. Klipsch did not with this amplifier. Klipsch also paid attention to haptic design. The knobs are solid aluminum for a weighted feel that also reflects quality and provides tactile satisfaction.
StPete

2025-11-22T19:00:00
This amp drives both subs with power to spare I had been using a crown amp with higher specs but this amp is better in my opinion
Cooperdog

2025-04-09T20:00:00
I am the owner of a Klipsch THX home theater speaker system. The system consists of five speakers, and two passive subwoofers. The five speakers are driven by a Marantz receiver, and the two subs are driven by a dedicated Klipsch subwoofer, being model number KA-1000. Approximately six weeks ago the subwoofer stopped working. I contacted the Klipsch customer service and was informed that I should try installing a 15 amp slow-blow 5x20 mm fuse to see if that would resolve the problem. The customer service representative that I spoke to at Klipsch, whose name I shall not provide (to protect the guilty), told me the fuse was readily available and I ordered from Amazon a pack of eight fuses for approximately $8.00. When I attempted to install the fuse on the back of the amplifier, per the instructions of the customer representative, there was no place to install the fuse. My neighbor did a little research, which took about two minutes, and determined that the fuse was inside the cavity of the amplifier. I certainly did not want to disassemble the amplifier to install the fuse! After this took place, I made a second call to customer service and advised them of the above. I was informed that I needed to provide customer service with my proof of purchase, my full name, shipping address, and the fifteen digit serial number on the back of the amplifier. I took to this task the following day, and the information/documentation was provided to Klipsch, via email. Approximately a week later I called back and the Klipsch representative I spoke to informed me that my email had been forwarded to the Design Team for review, and I should await further instructions. Approximately two weeks later I called back again, and was told it was still with the Design Team, and they were waiting for a response. I called back a third time, explained my extreme frustration why this matter was not being resolved in a timely fashion, and the customer representative told me there were only two people working in the Design Team department, and they would get back to me once they had a chance to review the documents/information I previously provided in my earlier email. The following day I received a response informing me what I already knew, that the amplifier was out of warranty (it carried a two year warranty, and my phone call took place approximately three years after the date of purchase), and they provided me with a name of a Klipsch authorized service center for the repair. The authorized service center is located in Clackamas, Oregon. I certainly do not want to ship off my amplifier to the West coast (when I reside in Ohio) only to encounter similar frustrations as noted above in the repair and return of my product to my residence. This entire process took approximately six weeks. If any of the readers out there own a home theater system with subwoofers, they know how important it is to have the subwoofers/base compliment the rest of the speakers to truly enjoy this system. Watching a movie without subs is like listening to am radio! If anybody who reads this critique of my experience with my experience with Klipsch service is considering Klipsch as a source for the purchase of their speakers or accessories, I would urge you to consider my experience and the poor quality of customer service that I experienced. I am not going to take my amplifier to a Kilpsch authorized service center, but instead I will deal with a reliable local source. Shame on you Kilpsch for treating your customers like you do, especially when one considers I purchased fifteen thousand three hundred fourteen dollars and 95/100 ($15,314.95) for your speaker products! Sincerely, Mike T.
Miket54

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20Hz-1kHz +0/-3dB
Use only with KW-120-THX subwoofer enclosures (either one or two)
High-Efficiency Class D
FTC Rated Power: 500W into 8Ohms, 1000W into 4Ohms, 20Hz-1kHz at <1.5% THD
Dynamic Power: 2050W into 8Ohms, 3025W into 4Ohms at 5% THD
2 second ON delay, 15 minute OFF delay
Continuously variable from 40-120Hz, 24dB/octave slope above 120Hz (non-THX mode)
2 Gold-plated RCA phono jacks
2 Gold-plated RCA phono jacks (unfiltered) / 2 SpeakOn NL2 jacks
Continuously variable from 0 to 180 deg.
Black anodized aluminum
110/120VAC, 60Hz
230VAC, 50/60Hz
THX On/Off, Boundary Gain, Compensation On/Off
4.75 x 17.5 x 12.25" / 120.65 x 444.50 x 311.15mm
27lbs / 12.25kg
743878026122