Class AB car amplifiers across monoblock, 2-channel, 4-channel, and 6-channel configurations from $159 to $39,999.99. The working topology for SQ-focused builds.
Class AB is the default topology for SQ-focused car audio. A bias current holds both output stages partly conducting, which eliminates the crossover distortion of a pure Class B design, without the continuous heat, efficiency penalty, and chassis size of full Class A. For a buyer who wants linear amplification without redesigning the electrical system around it, Class AB is the architecturally correct answer.
This is a deep collection, spanning $159.99 to $39,999.99 across monoblock, 2-channel, 4-channel, and 6-channel. The brands: Audio Wave at the reference tier, Tru Technology for US-built audiophile mid-tier, Crescendo for the SQ-focused practical tier, and US Acoustics for accessible Class AB across every channel count.
Need help picking the right Class AB amp? Send us your speakers and your build goals and we will match the amplifier at the right channel count and impedance before you buy.
Authorized Dealer
Every amplifier is brand new with the full manufacturer warranty.
Power Matching
Send us your subwoofer or speaker specs. We'll recommend the right amplifier at the right impedance before you buy.
Hands-On Expertise
Direct support from staff who designs, builds, and competes with these systems. Honest recommendations, not upsells.
Fast Shipping from TN
In-stock orders ship within 1-2 business days from our Tullahoma, Tennessee warehouse.
Class AB runs two output stages that hand off between the positive and negative halves of the waveform, with a bias current holding both partially conducting at all times. That bias is the whole point: it removes the crossover distortion a pure Class B design produces at the handoff, without paying Class A's price of conducting continuously whether there is signal or not.
What it costs is efficiency. Class AB runs at roughly 50% to 65%, so a third to a half of what it draws leaves as heat. That means a bigger chassis, real ventilation, and more current from the alternator than a Class D amp of the same rated power. What it buys is the linearity that sound-quality builders keep coming back to on a front stage.
Class AB or Class D
This is not a good-versus-bad question, and anyone telling you Class D is a compromise has not listened to a modern one. They are different trades.
Reference builds where Class A is impractical. Class A conducts continuously, which is why it measures the cleanest and why it needs a high-output alternator, battery capacity and dedicated cooling to live in a car. Class AB gets you linear amplification without redesigning the electrical system around it. The Audio Wave Aspire Pro USA and CR 401 Dual Mono sit at that ceiling.
Matched topology across a multi-amp system. Running one topology from front stage to sub keeps the character consistent end to end. Tru Technology is the line that makes this easy: Tungsten and Tungsten Grande both come as monoblock, 2-channel and 4-channel, so the whole rack can match.
Full-range speaker duty. A subwoofer works a narrow band. A front stage works 80Hz to 20kHz, through the midrange and treble where the ear is least forgiving. That is where topology choice actually shows up, and it is why the common SQ layout is Class AB on the components and Class D on the sub.
Competition. We judge IASCA and MECA and we compete in our own truck. The front stages that score at the top run Class AB or Class A.
Catalog by Tier
Entry Tier, $159 to $399
US Acoustics Lisa, 4-channel at 4 x 50W ($159.99). The accessible way into 4-channel Class AB, and the right answer for putting proper power on factory speakers. Wendy, 2-channel at 2 x 75W ($159.99), does the same job for a dedicated front stage. Andrea, 2-channel at 2 x 150W ($289.99), steps the per-channel power up for higher-output components. Barbara Ann, 4-channel at 4 x 100W ($399.99), handles most aftermarket component sets cleanly. See the full US Acoustics lineup.
SQ Mid-Tier, $499 to $799
Crescendo Revolution 3A4, 4-channel ($499.00) and 5A4, 4-channel ($779.99). US Acoustics Lanna, 6-channel at 6 x 150W ($695.00), is the practical entry to an active three-way, which normally costs a lot more to get into. Crescendo Revolution 5A1 ($749.99) is the odd one and the interesting one: a Class AB full-range monoblock holding 450W at 4, 2 or 1 ohm, where nearly every other monoblock on the market is Class D. See Crescendo amplifiers and 6-channel amps.
Audiophile Mid-Tier, $1,399 to $2,399
Tru Technology Tungsten in 2-channel and 4-channel (both $1,399.99), then Tungsten Grande as monoblock ($1,999.99), 4-channel ($2,399.99) and 2-channel ($2,399.99). US-built, and the reason to buy into the line is that it covers every channel count at one topology. Crescendo Revolution 7A4, 4-channel ($1,699.99), is the SQ pick of the Revolution line. See Tru Technology.
Audio Wave Reference Tier, $2,499 and Up
Active 250, full-range monoblock ($2,499.99). Excel, 2-channel ($2,600), and Excel Monoblock, full-range ($3,099.99). Aspire Pro USA, 2-channel ($7,999.99, marked down from $8,999.99), and the Aspire Pro USA Monoblock ($8,999.99) for a matched pair. The Aspire Pro 6 Channel is a previous demo at $21,999.99 against $29,999.99, and it is the last one. At the top, the CR 401 Dual Mono ($39,999.99). See Audio Wave amplifiers.
If you are running an active front stage, the DSP lineup does the crossover work these amps would otherwise be guessing at. And whatever you buy, gain is what protects it: how we set amplifier gain.
Frequently Asked Class AB Amplifier Questions
What is the difference between Class AB and Class D?
Class AB is linear amplification with a bias current that eliminates crossover distortion, and it runs at roughly 50% to 65% efficiency. Class D uses a switching output stage to reach roughly 80% to 90%, which means less heat, a smaller chassis and less draw on the alternator. Modern Class D from a good manufacturer is transparent and appropriate for any application, including critical listening. The practical split most SQ builds land on is Class AB on the front stage and Class D on the subwoofer, where the narrow band and the current demand favor it.
What is the difference between Class AB and Class A?
Class A conducts continuously across the whole waveform, which produces the lowest distortion available and roughly 20% to 25% efficiency. In a car that means serious heat, serious current draw, and usually an alternator and battery to match. Class AB uses bias current to get linear behavior through the handoff while letting the idle stage draw far less, which is what makes it livable in a vehicle. If your install cannot support Class A, Class AB is the architecturally correct choice.
How much power do I need from a Class AB amp?
Match the amplifier's RMS per channel to your speakers' RMS rating, ideally 75% to 150% of it. Components rated 75W to 100W RMS are well matched by 75 to 150 watts per channel. Audiophile-tier drivers with higher ratings want 150 to 250 watts per channel. Underpowering causes clipping at volume, and clipping is what damages speakers.
Does Class AB run hot?
More than Class D, less than Class A. At 50% to 65% efficiency, roughly a third to a half of what the amp draws leaves as heat, which is why Class AB chassis are larger than Class D equivalents at the same rated power. Normal install practice with real ventilation handles it. Unlike Class A, it does not usually force an electrical system rebuild, though anything over about 500W RMS total still wants the Big 3 done.
Can I bridge a Class AB amplifier for a subwoofer?
Yes, most 2-channel and 4-channel Class AB amps bridge. For a permanent subwoofer a purpose-built Class AB monoblock does it better, because the circuit is built for the high-current low-impedance load a sub presents. The Tru Technology Tungsten Grande Monoblock, Audio Wave Excel Monoblock and Crescendo Revolution 5A1 are the Class AB monoblocks here.
Are these new with manufacturer warranty?
Yes, with one exception. The Audio Wave Aspire Pro 6 Channel is a previous demo unit at closeout pricing and is labeled as such on its product page. Every other amplifier in this collection is brand new, sold by an authorized dealer, and carries the full manufacturer warranty. We handle warranty claims directly with the brand.
Do you offer power-matching consultation before purchase?
Yes. Send us your speaker specs (RMS power, impedance) and your build layout and we will recommend the right Class AB amp for it. Pre-purchase consultation is free. We would rather spend 15 minutes confirming the match than have you return a mismatched amplifier.
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