The L-30 was the cheapest amplifier in Luxman's 1976 range. Not that it looked anything like a budget model – rather, it had an almost intangible feel of quality and superior finish that in terms of showroom appeal put it above all but the very best offerings from the Japanese big names at the time.

At around £180, the L-30 occupied a place in the market where amplifiers began to be considered of interest to the more serious listener. For the same money you could also have had a Sony TA-3650 or Sansui AU-5900, fine units both. For those who preferred British equipment a Cambridge P80 or a Sugden A48, both of which were well regarded at the time, cost about the same as the L-30. This, then, was the point of entry to the Luxman range, which went up to an eye-watering £11,000 for the M-4000 power amplifier – the most expensive standard production model on sale in the UK at the time.

Simple Minded
The L-30 was a simple, yet well executed, package. It was rated at 32W per channel into 8ohm, which again represented something of a dividing line between the run-of-the-mill amps and the more specialised fare. All the facilities one would require for a basic system were present, from a built-in phono stage that suited the bulk of MM cartridges in use at the time, through to switched outputs for two pairs of loudspeakers and a pair of headphones. Just as with every Japanese amplifier of the 1970s, a matching tuner was also available – the T-33. Both shared an unusually shallow cabinet, making them suitable for placement on the shelving units that were fashionable in homes of the period.

Building a system around the L-30 is straightforward thanks its two auxiliary inputs while the phono input suits most modern MMs

At a time when hi-fi technology was surging forward in leaps and bounds, the L-30 was a surprisingly conservative design. Key to the circuit was its simplicity at all stages – this when the number of components being used by the company's rivals were expanding greatly year by year. The amp was built around a DC-coupled output stage running under Class AB conditions. This method, where there are no coupling capacitors or transformers between the output transistors and the loudspeaker load, gave consistent performance and made speaker matching reasonably straightforward. The downside of DC coupling is that it renders the amp's power transistors vulnerable to common user mistakes, such as when the loudspeaker connections are inadvertently short circuited. It also places the woofers in loudspeakers directly across the amplifier's power supply should something go wrong, which would quickly damage them.

Feedback 'N' Fuses
By this stage, many of the large Japanese companies had evolved automatic circuits based around relays and electronic control systems that disconnected the amplifier from the loudspeakers should anything go wrong. They also isolated the speakers from the amplifier for a few seconds after switching on, eliminating the familiar 'thud', which was the hallmark of many of the early DC-coupled designs.

The L-30 did without all of this and instead used multiple fuses to protect all the system components. It was common practice in cheaper amplifiers to place a fuse in series with the loudspeaker outputs, but this also has undesirable effects. A fuse changes its resistance slightly as the power it dissipates alters, so with a complex music signal it can be shown to be a source of distortion. This would be a particular problem at high volume levels so Luxman included the fuses in the positive and negative supply rails to each output stage instead. Using this arrangement the circuit as a whole (including the four extra fuses) was linearised by the action of the amp's feedback loop – a useful refinement.

The separate left and right channel treble and bass controls can be frustrating to use, especially as they all lack a centre detent. Two pairs of speakers can be connected

Active Action
More careful design could be found in the preamplifier, which received its power from an active filter circuit which minimised the amount of hum introduced at this point. Passive high- and low-pass filters were included at the inputs of the preamp and when using the line-level inputs (tuner, tape, etc) the volume control preceded all the active stages, meaning that when normal sources were used it was impossible to overload the input of the amplifier.

The tone controls were active and described as being of the 'Lux type', although the circuit was largely conventional in its layout. The phono stage was also of a familiar design, but in line with the theme of simplicity in the signal path it used only two transistors per channel – compare this to the Gothically complex external phono stages of today!

The L-30 was only current in the range for a year. It was replaced in 1977 by the almost identical L-31 whose main improvement was a marginal increase in output power to around 40W per channel. This would have made almost no difference when it came to everyday listening, but was important for marketing reasons since in 1970s hi-fi culture the manufacturer's claimed power output was one of the key ways the status of an amp was determined.

User manual with simple instructions and some system building ideas. The open-reel recorder looks ambitious, but monitoring facilities for three-head machines are included

Seeing the L-30 today is an intriguing experience. A few years ago it would have been obvious that it was a vintage model but with the recent trend for reissuing yesterday's favourites (albeit with modern insides) it is harder to tell. If someone had told me the L-30 was new I'd have been none the wiser, until I was close enough to smell the distinctive and delightful aroma of old Japanese electronics (they haven't managed to copy that yet!).

DIY Centre
The only obvious ergonomic drawback here is the use of separate treble and bass controls for each channel, something I can see no purpose or justification for, other than to reduce the (unlikely) possibility of crosstalk inside the controls themselves. Tone controls should not be necessary in any case, and they are all best left at their centre position. This would be easier to do if a centre click-stop had been provided, but it has not, and trying to line up the four knobs exactly will be a source of unending frustration! The controls do at least have a limited range of operation so they 'trim' rather than generate a needlessly large effect. Similar comments apply to the loudness switch, which works well enough but should always be out of circuit for critical listening.

It's easy to build a system around the L-30 as two auxiliary inputs means there's one for a CD player and one for an external phono stage or DAC, etc. The only flies in the ointment are the loudspeaker connections, which are small screw-in binding posts. They are fiddly to use, especially with modern cables, but it is easy to make up suitable adapters. All the controls work smoothly and gently; nothing is abrupt or coarse. The front panel legends are engraved and this, along with the nicely machined knobs and levers, gives a distinct impression of quality. Note that some L-31s have screen-printed fascias which feel far more 'ordinary'.

Tim Listens
Amplifier design was a mature technology in Japan in the late 1970s so the L-30 still meets the basic requirements of modern listening, even though it is over 45 years old. It is essentially noiseless, broad in its tonal coverage and (just) powerful enough to generate realistic musical experiences through most types of loudspeaker. My first impressions were of a smooth and refined sound with a plumpness to the bass and a slightly smoothed-off top end. This suggests the amp was voiced to give optimal results with mid-priced MM pick-ups of the era, the essentially flat response of CD highlighting these subtle tweaks.

Promotional photo reveals the relatively shallow depth of the L-30's wooden cabinet, suiting contemporary shelving units

Striking It Rich
The title track for Ryuichi Sakamoto's album Heartbeat [Virgin America CDVUS46] gives a good idea of what the L-30 is all about. The bassline is gloriously rich and there's plenty of detail in the midrange, the only failing being a lack of bite in the percussion that robs the performance as a whole of some impact. Nevertheless, at moderate listening levels the presentation is fluid and natural – the L-30 has the sound of an expensive unit. Raising the volume reveals the limitations of the simple circuitry – it's the bass that goes first, becoming bloated and unfocused, though the top end remains intact well beyond this point.

This need not be a serious limitation, for with a pair of reasonably sensitive loudspeakers there is still plenty of volume available without sound quality suffering. To my surprise, the bottom-end lift of the L-30 did not make its presence felt with all types of music. Anyone Listening to Brahms' Concerto For Violin, Cello & Orchestra In A Minor, Op.102 [Deutsche Grammophon 410 603-2] would surely deem this amplifier to be tonally neutral, which is another way of saying that it displays an even balance and doesn't get in the way of the music.

A neat and well ordered internal layout with a careful division of functions. The four fuses that protect the DC-coupled output stages can be seen on the vertical PCB at the rear

Fine Art
At normal listening levels it was the presentation of fine detail that stood out as this amp's main strength – no doubt a result of the straightforward signal path used. Being critical I've heard strings rendered with a better sense of physical depth via amplifiers which are otherwise livelier sounding, but as with so many things in hi-fi this is mostly a matter of taste. The ultimate in high fidelity? Not quite, but it's a nice old thing all the same.

The cheapest model from a company that normally makes expensive components is always going to be of interest. There's enough here to make the L-30 feel and sound like a 'real' Luxman; it's a bit like an Oriental Naim Nait (only with more power, a greater choice of input connectors, better knobs and a superior balance control).

Buying Secondhand
Like a lot of late 1970s Japanese audio equipment, the Luxman L-30 is very reliable provided it is used with care. My advice is therefore to choose an example with the best possible cabinet work and then deal with the faults that are present – if indeed there are any.

Its well stocked rear is marred only by the small screw-type speaker cable terminals. A cover over the AC outlets for other equipment can be seen below the mains transformer – the connectors don't meet the regulations of all export markets

Distortion or a lack of output from one channel or the other should lead firstly to an inspection of the fuses, which number eight in total. The ones that protect the output stages must be of the fast-acting (F) type in order to be effective, while the rest should have a time delay characteristic (T) or they will fail at random intervals. The usual cause of output stage fuse failure is excessive DC on one set of loudspeaker terminals. Fault finding on the power amplifier PCB is difficult due to the construction of the unit – for example, the heatsink for the power transistors completely blocks one side of the board.

Twice Removed
A good tip here is that the circuit will function with the heatsink and the output transistors removed (they simply plug in) and it will even drive a reasonably sensitive pair of headphones when working like this. This is the best way to deal with faults that result in DC being present on the outputs or if there is no output at all.

It is, of course, essential to set the power amplifier up carefully as part of any service work – the L-30 has pre-set adjustments for both offset and bias. An insulated screwdriver is essential for this task as the relevant parts are buried deep among the other components.

Hi-Fi News Verdict
Buying the most affordable amp in the Luxman range at the time turned out to be no bad thing after all. Yes, you could have purchased more power and facilities elsewhere, but this simple and tough unit has an appeal all of its own. If you are of the belief that all Japanese transistor amplifiers from the period sound hard and brittle then the Luxman L-30 will surely change your mind.

Luxman L-30 Amplifier Lab Report

Luxman rated this smart-looking amplifier at 2x32W/8ohm and 2x37W/4ohm but the L-30 is actually a little more load-tolerant than this might suggest, delivering closer to 2x40W/8ohm and 2x52W/4ohm while incorporating sufficient headroom to accommodate 55W, 78W and 74W into 8, 4 and 2ohm, respectively, under dynamic conditions. This falls slightly to 60W into 1ohm, equivalent to a maximum 7.8A current at <1% THD – still generous for the era [see Graph 1]. Its other specifications, like the '<0.05% THD at 32W' and '15Hz-50kHz at less than –1dB (response)' are a little vague but the L-30 stands up well enough in practice. Distortion, for example, increases steadily with power output from 0.0035%/1W to 0.018%/10W and 0.035% at the rated 32W (re. 1kHz/8ohm) and with frequency from a minimum of 0.002%/300Hz/1W increasing to 0.008% at 20Hz and 20kHz [see Graph 2, below]. By modern standards, the +39.2dB gain is high, but not excessively so, but the 80dB A-wtd S/N ratio (re. 0dBW) is about 5-6dB adrift.

The L-30's moderate 0.155-0.31ohm output impedance will cause some variation in response, especially at HF, but into a 'flat' 8ohm load it reaches out across a wide 11Hz-44kHz (–1dB), falling to –3.2dB/100kHz. The 'Low Cut' and 'High Cut' filters are specified at 70Hz and 7kHz, respectively, with first-order slopes. The former actually operates below 200Hz, falling to –3dB/100Hz, –6dB/58Hz and –30dB/5Hz and proving more than sufficient to manage the most vigorous of arm/cartridge resonances when partnered with big reflex-loaded speakers. By contrast the 'High Cut' is gentler but offers an effective roll-off of –3dB/6.5kHz, –6dB/11kHz and –10.5dB/20kHz. PM

• Power output (<1% THD, 8/4ohm) 40W / 52W
• Dynamic power (<1% THD, 8/4/2/1ohm) 55W / 78W / 74W / 60W
• Output imp. (20Hz–20kHz/100kHz) 0.155-0.31ohm / 1.34ohm
• Freq. resp. (20Hz–20kHz/100kHz, 0dBW) –0.35dB to –0.25dB/–3.2dB
• Input sensitivity (for 0dBW/32W) 31mV / 178mV
• A-wtd S/N ratio (re. 0dBW/32W) 80.4dB / 95.5dB
• Distortion (20Hz-20kHz, 10W/8ohm) 0.011-0.022%
• Power consumption (Idle/rated output) 11W / 125W
• Dimensions (WHD) / Weight 440x160x225mm / 7kg 

Review: Tim Jarman, Lab: Paul Miller 

Source: www.hifinews.com