Hertz CP 5.1K vs Alpine S2-A36F: 5-Channel or 4-Channel Amp?
By Car Audio and Tint | Car Toys | Washington, Texas, Colorado ... | Published: 2026-11-02
Category: Comparisons
Hertz CP 5.1K vs Alpine S2-A36F: compare a 5-channel and a 4-channel amp on power, size, and cost to pick the right one for your system.
Quick answer
Choose the Hertz CP 5.1K if you want one compact amplifier to run front speakers, rear speakers, and a subwoofer with Hi-Res Audio certification. Choose the Alpine S2-A36F if you need only four channels, want Alpine’s Class D circuit, and prefer a lower-cost entry point.
Channel count: one box or two?
The Hertz CP 5.1K is a five-channel amplifier, so it can power a full system—front left, front right, rear left, rear right, and a subwoofer—from a single chassis. The Alpine S2-A36F is a four-channel amplifier, which covers front and rear speakers but leaves the subwoofer without a dedicated channel. If you plan to add a subwoofer later, the Hertz saves you from buying and mounting a second amp, but it costs more upfront.
Power and efficiency: what the specs tell you
The Hertz CP 5.1K is rated at greater than 85% efficiency and is fully bridgeable, which means you can combine channels to deliver more power to specific speakers if your system design calls for it. The Alpine S2-A36F uses Alpine’s Class D amplifier circuit and is Hi-Res Audio certified up to 40kHz. Neither catalog listing provides exact wattage figures, so match either amp to your speakers’ RMS power handling before buying.
Size and installation
The Hertz CP 5.1K uses a compact aluminum diecast casing, which helps with heat dissipation and fits into tighter install locations. The Alpine S2-A36F has a two-sided terminal layout that can simplify wiring in tight spaces. Both are Class D designs, so they run cooler than older amplifier classes, but the five-channel Hertz still needs planning for five sets of speaker outputs plus power and ground.
Trade-offs to weigh
- Upfront cost vs future expansion: The Hertz CP 5.1K costs more than the Alpine S2-A36F, but it includes a subwoofer channel. If you will add a subwoofer within a year, buying the five-channel now avoids a second amplifier purchase and extra wiring later. Decide whether you want to pay once for a full-system amp or start with four channels and add a sub amp later.
- Installation space: The Hertz’s compact aluminum diecast chassis may fit where a larger five-channel amp would not. The Alpine’s two-sided terminal layout can ease wiring in tight spots, but you still need room for a separate subwoofer amplifier if you go that route. Measure your planned mounting location before choosing; a five-channel amp saves space only if it physically fits.
- Audio certification: Both amps are Hi-Res Audio certified, but the Alpine specifies up to 40kHz while the Hertz specifies 10Hz to 41kHz. If you play high-resolution files, either can reproduce ultrasonic frequencies, but speaker capability and source quality matter more than the amp’s upper limit. Match the amplifier’s frequency range to your speakers and source files—not just the certification badge.
Product facts
- Alpine S2-A36F S-Series Hi-Res 4-Channel Amplifier: Alpine S2-A36F is a 4-channel amplifier with Alpine’s Class D amplifier circuit and Hi-Res Audio certification up to 40kHz. It suits a four-speaker system where you do not need a dedicated subwoofer channel, and Hi-Res certification supports high-resolution audio sources.
Alpine S2-A36F S-Series Hi-Res 4-Channel Amplifier - Hertz CP 5.1K Cento Series 5-Channel Amplifier: Hertz CP 5.1K is a 5-channel amplifier with greater than 85% efficiency and a compact aluminum diecast casing. It can power an entire system from one chassis while taking up less space and wasting less power as heat.
Hertz CP 5.1K Cento Series 5-Channel Amplifier
Which amp fits your build?
Best for
- Drivers who want one compact amplifier to power four speakers plus a subwoofer.
- Systems where a compact aluminum chassis and high efficiency are priorities.
Not for
- Budget-focused builds that only need four channels and no subwoofer.
- Installations where the lower upfront cost of a four-channel amp is the deciding factor.
