NAD 3155

“Two products in one”, is how NAD described its new 3155 upon its launch in January 1985. “As a preamplifier it matches most separate audiophile preamps in sonic performance and surpasses them in operating flexibility. As a high-current high-headroom power amplifier it drives even difficult loudspeakers to surprisingly high volume levels with clean, solid, full-bodied musical sound that remains refreshingly free from distortion even in transient peaks.”

By the time of this integrated amplifier’s launch, the company had been manufacturing hi-fi separates for over thirteen years, and it had been quite a ride. Its very early products were unexceptional, following a generic look and giving a decent but not particularly special sound. What changed the company’s trajectory was the 3020, launched in 1979. Despite being heavily cost cut to reflect its very low £60 retail price (a figure that soon rose by £20, after a welter of rave reviews, coincidentally), it offered dynamite performance. Indeed it was so good that you’d have struggled to do better at twice the price.

When the 3155 appeared some six years later, it was both going up a price point – it cost £290 new rather than the 1984 3020B’s £139 – and also ushering in a new design language for NAD. Along with the 3130 – the 3020B’s replacement – it introduced a wider 420x108x380mm case and new smaller switchgear and graphics. Looked at thirty five years later, and I would say that its styling was an unalloyed success; this new generation of NADs could never be called pretty, but the look is crisp, functional and has dated less than some of the more ‘far out’ eighties designs.

The main criticism is that it was – and is – anonymous; the 3155 looks less illustrious than perhaps it should do, and belies the quality of the design apparent inside. If you whip the casing off the very similar looking and identically sized 3130, you’ll see a lot of empty space – but not so with this amplifier. Its large chassis is well stocked with circuitry, including a heftier frame-type power transformer than the 3130, large heatsinking bars running right across the case and even a plug-in MM/MC phono stage card.

The 3155 was nowhere near as successful in the sales stakes as its Mission Cyrus 2 rival, despite offering a welter of features and more power that its Huntingdon-based rival ever could. It was also far better built than you might think by looking at it – whereas NAD’s 3130, like most NADs from 1978 to 1985, was built in Taiwan, the 3155 was made in Japan. Construction and component quality was clearly better, and even the fascia – which is a dark grey plastic moulding on the 3130 – is actually painted aluminium in the 3155. At 9.8kg it’s a lot heavier than its cheaper 3130 sibling, but inexplicably looks very similar all the same.

The power amplifier section of the 3155, and its 2155 stereo power spin-off, was claimed to be conservatively rated at 55W RMS per channel, rising to 150W RMS in bridged mono mode. NAD said both maintained a full 3dB of IHF dynamic headroom (2.5 dB in bridged mode), meaning that into a continuous signal they could deliver twice their rated power in brief bursts (110W per channel in stereo and about 250W bridged). 3155 owners could add a 2155 and run them in bridged mode, giving 150W RMS per side, with 250W peak power. The manufacturer also claimed up to 40A of current delivery.

By the time that the 3155 was launched, NAD had a great reputation for preamplifiers; even the preamp section of the 3020 was excellent at its price, with the phono stage being a real highlight. The 3155 got a more sophisticated, updated version of this that was optimised for 2V line level outputs from CD players. The phono section was upgraded, with ten specially selected transistors per channel with a differential FET input circuit and a custom-wound input filter. A separate high gain moving coil stage used ultra-low noise transistors, and offered switchable impedance. The result was a claimed 107dB dynamic range, which NAD amusingly noted, “comfortably accommodates all digitally-mastered LP recordings with room to spare.”

The preamp section sported some eccentric features, such as Bass EQ which gives 6dB of boost at 32Hz, “to strengthen and extend the deep bass response of closed-box loudspeaker systems” This was of questionable value then and now, as is the Infra Defeat switch, which switches off the built-in infrasonic filter – included to remove record warps. Loudspeaker impedance matching was carried over from the 3020B series, and reconfigures the amp to deliver more output voltage into higher (8 ohm) loads. NAD’s Soft Clipping circuit also featured, and was as handy as ever, gently limiting the output signal waveform when it goes into clipping. This spares the life of your loudspeakers if you overdrive the amp, but as with all NADs from this era it’s best switched off when listening at more normal, non-party levels. This is because it softens the sound slightly when switched on.

The 3155 is far rarer than either the strong-selling 3130 or the mega-successful 3020 series of amplifiers. It ran from January 1985 to January 1987, whereupon it was replaced and quickly forgotten about. Yet it’s an interesting amplifier for the value it offers now; it’s effectively the equivalent of something now selling at the £1,500 point in terms of general quality. It offers fine build, good longevity and some handy features – especially the split preamp/power amp and excellent MM/MC phono stage, yet routinely sells secondhand for under £300. Add a 2155 power amp and you’re going to struggle to find anything near £2,000 to properly beat it.

Sonically it’s not beyond criticism, yet still the 3155 does a lot very well. Most obvious is its quintessentially ‘NAD sound’, which is big, spacious, musically engaging and tonally slight warm. It’s absolutely not an amplifier that makes music sound thin, crispy and analytical; rather you get a big hearted and emotional rendition of what you feed it. There’s a good thump to the bass, and a strong centre image that sees vocals hovering ethereally in space, although depth perspective isn’t especially good. Everything in the mix is nicely separated out and given lots of room to breathe from left to right. Rhythmically it’s quite beguiling; music flows nicely and you get a sense that instrumentalists are playing together well, and enjoying it. In some ways it’s quite a romantic sound, almost slightly valve-like – but it is emphatically not as euphonic as the early versions of the 3020, which were more valve sounding than some valve amps!

The downside is that in absolute terms, the 3155’s midband is slightly opaque; there’s a subtle haze and a lack of real incision that’s never noticed through cheap speakers but high end designs will soon signpost it. Also, the bass lacks real articulation and grip – even though it’s got plenty of wallop – and the treble isn’t quite and open and airy as it could be, even though it’s pleasingly sweet. Although the soundstage is commendably wide, there’s some vagueness to the location of instruments within the stereo mix. Finally, compared to more high end designs, the treble can sound a bit generic; it has a lovely silky feel but doesn’t really get right into the grain of hi-hat cymbal sounds, for example. All of this is not meant as criticism though; its Mission Cyrus 2 rival did little better on many of these counts and worse in others.

Overall though, this is a capable and really rather likeable integrated amplifier – one that retains a strong taste of that classic ‘1979 to 1984’ vintage NAD sound, but with more power, better facilities and superior build. The great thing about buying one secondhand is that because it was underrated and overlooked when new, used prices today aren’t that different to the now-trendy 3020s and 3130s, despite it being easily superior to both. Find a good one, get it serviced (the switch contacts are a notorious NAD bugbear here) and enjoy it – while you count all the money you’ve saved by not buying a more fashionable classic!

NAD 3155

2 comments

  1. andyrawlins

    I don’t remember that one. Any chance of going back to the clickable photos which link to higher res versions pretty please?

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