Denon fans are a dime a dozen, but most of them seem to be fixated on powerful amplifiers. On the other hand, people looking for a good amplifier with low or medium power are more likely to choose a Rotel, NAD, one of the many British amps, or something from the 70s. Lower power Denons (20-40 W per channel) are not very popular and it appears that at some point Denon stopped making those and offered mini systems instead. But in the 80s there were several such models, including one particularly worthy of attention due to availability and low price: the PMA-250.
The amplifier has a very simple design in and out, which is an obvious advantage. The only solutions that are not quite standard are the CD Direct button that cuts off the input selector and passes the signal from the CD input directly, and the volume control potentiometer that has separate adjustments for left and right channel (rather than common volume adjustment for both channels and a separate balance pot). Interestingly, CD Direct does not bypass tone control, only the input selector and tape monitor switches – but it shortens the signal path, audibly improving the sound quality. Apart from that, the amplifier is as simple as possible, while maintaining the standard features. PMA-250 doesn’t even have low, high and loudness filters, and there are connectors for only one pair of speakers. The amplifier is clearly designed for a small, simple system. It was available in black and silver, black fading to dark gold, much like on Protons. The effect actually can look good, unless the previous owner put stickers on the amp – then the surface under the stickers remains black. In any case, silver face version looks better to begin with and does not have the fading color problem.
The PMA-250 is as clean inside as it is on the outside. Wires are few, power supply section and power transformer are separated from the audio sections with a decent heatsink, phono stage and volume control are far from the transformer. The design is mosty discreet (1 IC in the phono stage, 2 in the power amplifier section). With decent PS and cooling, the amplifier handles low impedance speakers very well (within the limits of its power).
Sonically – we liked the amplifier from the first note. It had very good clarity, dynamics, and the presentation was very pleasant. We immediately decided to compare it with a few other amplifiers that can be purchased for a similar price and that we had at hand at the time: Kenwood KA-31B, Fisher CA-2221, and Russian Vega 10U-120S. The A/B comparison showed how good this amp really is. Kenwood and Fisher did not stand a chance: Denon sounded a little brighter, but much more dynamic, created way better soundstage, with greater depth, and it was smoother, more musical. Vocals sounded great – presented with class, without any grain or sibilance. Denon exposed the details, which in the case of the other two Japanese amplifiers were buried somewhere in the background, or inaudible at all. Bass was less generous than from the Kenwood, but present in adequate amounts and very well delivered. Surprisingly, the only amplifier that did not fail miserably in this comparison was the Soviet Vega, which sounded different, but not clearly worse (bass was lower, but shorter, highs and mids a bit softer). In any case, Denon showed class we would not expect from a budget Japanese amp from any period, not just the 80s or 90s. Its sound was actually quite… British. Incidentally, this Denon was highly praised by British reviewers and compared with NADs.
A small hint: it is worth hunting for units with intermittent / disappearing sound in one or both channels. A very common source of problems in this model are solder joints under the volume potentiometer. 5 minutes with a soldering iron and problem solved.
Note that this review is written for the first version of PMA-250. There are also two later incarnations: PMA-250 SE and PMA-250 III. We have not heard those and don’t know if they are as good as the first version, or any good at all (although user reports for PMA-250SE are good). The first version of PMA-250 was manufactured in Japan (more common) and Taiwan (less common). Both units that we had were made in Japan, but the units assembled in Taiwan are based on the same design, If there are any differences, they should be minor. According to user reports, the units made in Taiwan sound great.
Denon PMA-250 is a perfect choice for a system with small and medium-sized speakers in a 10-25 m2 room, and a great alternative for NADs (including the 3020), Creeks and Cyruses. It is extremely hard to find something that good for the price it usually sells for (around 50 euros, less with luck or if the amp needs minor repairs), or twice that price. On top of that, the amp is quite common, so it appears often on auction sites. We liked this amplifier so much that a year later we I bought another one (in silver) to refresh our memory of its sound – the second unit did not disappoint either.
Denon TU-450 is the matching tuner; it is decent. There are units with station memory problems, dry capacitor is usually the culprit.
Country: Japan and Taiwan
Manufacturer: Denon (Nippon Columbia C.O.)
Continuous power: 2x25W into 8 ohms and THD 0.05%, 2x40W into 4 ohms
Music power: 2x60W into 8 ohms, 2x90W into 4 ohms
Speakers: 4-16 ohms
CD, Tuner, Aux, Tape: 150 mV, 47 kOhm
Phono (MM): 2.5 mV, 47 kOhm
Frequency response: 5 Hz – 150 kHz (+0/-3 dB, 1W),
Power bandwidth: 10 Hz – 40 kHz (THD 0.1%)
10 Hz – 40 kHz (thought w pełnym zakresie mocy)
Treble: +/- 10 dB at 10 kHz
Bass: +/- 10 dB at 100 Hz
S/N ratio: >72 dB (phono input), >96 dB (line inputs)
Power consumption: 80W
Dimensions: 434 x 257 x 85 mm
Weight: 4,9 kg