Denon POA-5000

Name: Denon POA-5000
Brand: Denon

Six channels of Denon Class A, three independent power supplies, and a German owner's manual that tells you more than most brochures ever did.

Overview

Pick up a POA-5000 and the weight is the first thing you notice. It's 24.2 kg in a chassis 434 mm wide, 185 mm tall, and 415 mm deep. It looks like a conventional multichannel power amp. It isn't. Denon built it as a six-channel amplifier with three completely separate power supplies, one for each stereo pair. The company's own documentation is blunt about why: with high-power speakers, shared supplies let the amplifier sections interfere with each other, and Denon wasn't willing to accept that.

The architecture is simple once you see it. The POA-5000 has six discrete high-performance output stages arranged as three stereo pairs - front, center, and rear. In stereo mode, the front pair delivers 100 W + 100 W into 8 ohms, and the center and rear pairs each deliver 50 W + 50 W. Under DIN 1 kHz measurement at 0.5% distortion into 4 ohms, those figures rise to 150 W + 150 W up front and 75 W + 75 W for center and rear. Denon's German-language manual also lists a tighter rating: 100 W + 100 W front, 50 W + 50 W center and rear, from 20 Hz to 20 kHz at 0.02% distortion. That's the full-bandwidth spec, not the single-frequency figure, so it's the one to trust.

The bridging is the unusual part. Each of the three stereo pairs can be bridged independently into mono, doubling its output: 200 W to the front, 100 W to center, 100 W to rear. A single POA-5000 can be set up as a 200 W + 100 W + 100 W three-channel mono amplifier, or you can pair two units for a very high-power multichannel system. Because the three amplifier sections bridge independently, it can also be combined with existing amplifiers or used with unusual speaker arrangements. Denon designed it for Dolby Pro Logic and other analog and digital sources, routing left, right, center, and rear channels through a single chassis.

The circuit is where Denon's amplifier-building history shows. The POA-5000 uses what Denon calls Class A with optocoupler. The output stages run in Class A up to a certain level, with the bias controlled by an extremely fast base-current regulator that feeds the output transistors through optocouplers. Denon's documentation claims the switching speed is fast enough to eliminate switching and crossover distortion entirely. Conventional amplifiers, the manual notes, either accept sonic compromises or limit output power because they lack this kind of base-current regulation. Every channel is fully discrete, with no op-amps in the signal path.

Total harmonic distortion is quoted as 0.008% or lower at rated output minus 3 dB, with intermodulation distortion at 0.005% or lower at rated output level. Power bandwidth spans 5 Hz to 50 kHz into 8 ohms at 0.05% distortion, and frequency response extends from 1 Hz to 100 kHz. Signal-to-noise ratio is 118 dB in stereo mode (A-weighted) and 113 dB in mono. Input sensitivity is 1.0 Vrms in stereo and 0.7 Vrms in mono, with a 47 kOhm input impedance in both modes. Output impedance is a low 0.08 ohms in stereo and 0.16 ohms in mono, which keeps a tight grip on difficult speaker loads. Power consumption is rated at 550 W.

The protection circuitry is smarter than most. The high-speed protection circuits continuously monitor the speaker outputs and shut things down to protect both amplifier and speakers if a short circuit occurs. But the circuit tells genuine faults apart from the heavy current draw of low-impedance speakers at high volume. In the latter case, it doesn't trip.

There's also a remote on/off feature. When the POA-5000 is connected to the matching AVP-5000 preamplifier, the power amplifier switches on and off automatically in parallel with the preamp, provided the POA-5000 is put in standby. Inside, the control section, left amplifier section, right amplifier section, and power supply each get their own circuit board. The board layout is optimized to keep the signal path from input to output jacks as clean as possible and to minimize crosstalk between channels.

Period coverage of the POA-5000 is thin in the English-language press. Audio (October 1991, p.145) ran a power amplifier listing that includes the model, but the OCR is fragmentary and doesn't yield usable measurement data. HiFi-Stereo (February 1992, p.65) listed a Denon power amplifier rated at 150 W per channel into 8 ohms with a toroidal power transformer and gold-plated input and output connectors, which gives a sense of where the POA-5000 sat in Denon's lineup at the time. The POA-5000 itself was aimed at the multichannel and audio/video market rather than the two-channel purist segment, which likely explains why it never got the same review attention as Denon's stereo separates.

That positioning is also why the POA-5000 remains a niche item today. It's not a collector's trophy in the way a Marantz tube amp or a McIntosh solid-state piece is. It's a working tool for someone who wants genuine six-channel amplification with independent supplies and Denon's Class A-with-optocoupler circuit — and who understands that 24.2 kg of Japanese iron from this era is built to a standard that most modern multichannel receivers can't touch. The German manual, the 230 V / 50 Hz power specification, and the DIN ratings all point to a unit intended for the European market, which means North American examples may be less common. For anyone building a serious multichannel system around vintage amplification, the POA-5000 is one of the few period pieces that takes the job seriously rather than treating surround channels as an afterthought.