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SR-18 Home Theatre Receiver Over the last decade or so it could be said that audio equipment has not really developed or improved much. But the increasing emphasis on DVD and home theatre products has changed all that. There have been some big strides made recently, as demonstrated in the Marantz flagship, the SR-18 Home Theatre Receiver. M arantz is back! Or rather, the Marantz styling and cham pagne finish is back. In the long decade or so of the dominance of black as the accepted finish on high fidelity equipment, owners of older Marantz “champagne finish” gear have languished. They loved their older gear and they were loath to change over to black. Now the “dark ages” could be said to be over and a number of manufacturers are offering equipment in champagne or gold finish. So Marantz should find that this model SR-18 will sell in big numbers. Not only does it have the trademark gold finish but it also has other Marantz styling cues: two big knobs, one at each end, for input selection and a large flywheel knob in the centre of the panel, the so-called Gyro-Touch, for tuning. About the only thing missing is the little blue scope screen for signal strength and multipath indication. Maybe Marantz will bring that back in a future state-of-the-art FM/AM tuner? Actually, I have to say that while the various knobs look impressive, they really are a bit superfluous these days now that everything is remote-controlled. Apart from initially turning the unit on, you don’t ever have to touch the SR-18 in normal day-to-day use, any more than you need to touch your TV set to use it – you just point the remote control at it and press a button. And while some people may hanker for the old-style flywheel tuning for FM and AM stations, it really is a bit pointless once you have all your normal stations programmed in. Where it is good is when you are occasionally tuning across the dial looking for all those other stations. In fact, if you live within about 200km of Sydney or Melbourne and you have a sensitive tuner, it really is surprising just how many stations are dotted along the FM band. It is at those times when you want to listen to radio but you don’t like the current fare from any of your usual stations that the Marantz flywheel tuning knob comes into its own. You can creep along (in 50kHz steps – it is still full digital tuning) or whirl from one end to the other in a flash, something you can’t do in conventional FM tuners with synthesised tuning. And it makes the process of tuning and storing stations simpler. Marantz has kept the front panel clean and uncluttered but has a large drop-down door which reveals no less than 22 push-buttons, the stereo headphone socket and auxiliary inputs for a video camera or camcorder. We don’t have the space to mention all 22 buttons or indeed the endless features of this complex receiver but we’ll touch on some of them as we proceed. The SR-18 front panel also has the obligatory vacuum fluorescent dot matrix display to indicate all the operating modes but for a variety of reasons it is less effective than it otherwise could be. For example, it apparently does not have enough characters accessible, so that, when indicating CD Direct mode, it displays “CD-DIRCT” and yet it can also display “THX CINEMA” which requires more characters (ten, including spaces). In a large room, when you are sitting quite some distance away, the display is not all that readable but again, that is not really that important because the remote control handpiece, which we’ll come to in a moment, is very comprehensive and has its own LCD panel. In any case, you can always resort to the on-screen display which works in the same way as for DVD players and late-model VCRs. While there is little clutter on the front panel there is plenty on the rear panel. This is inevitable on any large receiver and more so on a home thea- Review by LEO SIMPSON 4  Silicon Chip The big Marantz SR-18 has virtually all features controllable via its equally large remote control. All those button light up each time one is pressed. The drop down door on the front panel (inset right) reveals the headphone socket and the 22 buttons for a range of functions including the tone controls. Note the Aux inputs (and S-video socket) for easy connection of a camcorder. Long-time Marantz fans will love the flywheel tuning knob. tre receiver which caters for so many operating modes: Dolby surround, Dolby Digital (AC-3),THX Cinema and DTS (Digital Theatre Systems). Hence, there is a large array of RCA sockets for all the program sources, including the video inputs from DVD, VCRs, TV (presumably cable or Pay-TV decoder boxes) and laser disc players. These are accompanied by S-video and optical fibre sockets where applicable. There are also quite a few audio and video outputs and there is no getting away from the fact that any home theatre receiver or amplifier must do a lot of video switching. How they manage it without any sign of video or sync buzz breakthrough must be a story in itself but it is routinely achieved in all of these products. We really did like the large binding post terminals for the five power amplifier outputs (did we mention that it was a fully Dolby surround receiver with the usual 5.1 output channels: front left & right, centre, two rear and the sub-woofer line output?). These binding post terminals are fully shrouded and are reasonably spaced so that connecting up thick speaker cables is easier than it is on a lot of other surround sound systems – on some, it can be a real chore. Inside the SR-18 is a labyrinth of PC boards which you would expect from its operational complexity but even so, it does appear as though it would be relatively straightforward to disassemble and service. All the PC boards are single-sided, with lots of wire links, which is the usual approach for consumer products designed and made in Japan. That approach also makes for much easier servicing when the time comes! Another good point is that a great deal of the circuitry appears to rely on discrete semiconductors and there is not so much in the way of surface-mount components – another plus. The power supply features a very large toroidal transformer which must be rated at well over 1kVA. It is accompanied by two large filter capacitors which feed all five power amplifiers. The filter capacitors are 56000µF at 71V which seems like an odd voltage rating but that’s what it is. Obviously the main DC supply rails must be in the vicinity of ±70V which would be necessary for power amplifiers of this rating. As with a number of other high power surround sound amplifiers we have seen, the SR-18 has the five power amplifiers around a tunnel heatsink assembly with a thermostatically-controlled fan at one end. This fan would also cool some of the power supply components such as the bridge rectifier which has its own heatsink. Each power amplifier has just two very large bipolar transistors in plastic encapsulation. We have remarked on the size of these power transistors in a previous review but they never fail to impress. In the Marantz receiver they have also managed to work some technical magic because the overall distortion level is very low, as we shall see. Perhaps part of this is due to a circuit feature of the Marantz SR-18, their so-called HD-AM PC board. This stands for “high definition amplifier module” and there are two visible in FEBRUARY 2000  5 Inside the Marantz SR-18. The toroidal transformer is a whopper. The HD-AM PC board with their copper shields can be seen in the centre of the picture. the internal photo. We have not been able to find out anything about them apart from the fact they are discrete preamplifier stages used instead of op amp ICs. Remote control handpiece There are remote controls and there are remote controls! This one must be one of the largest we have come across and it is also one of the most impressive. While it does have quite a few buttons there are not so many that you would shrink from 6  Silicon Chip it as being too complex. They are also legibly marked which makes a nice change and to top it off, they are all illuminated for a few seconds, each time a button is pressed. You can vary the time of illumination, by the way. Button illumination is highly desirable in a home theatre’s remote control because it is a fair assumption that it will often be used in a darkened room. Mind you, it should be possible to temporarily turn the illumination off and save the batteries as it will also often be used in normally lit rooms. Note that it is possible to turn off the illumination entirely but then you presumably have to go through the routine to turn it on again. By the way, under normal usage, the four AA cells can be expected to last about four months but that really does depend on how long you have the illumination set for. A major feature of the remote control is the LCD panel which is backlit every time the buttons are illuminated. Our photo shows the CD source selected and there are a bunch of buttons down both sides of the screen which can select various features. In This side view of the chassis shows the heatsink tunnel for the five power amplifiers. The fan is at the other end and also provides cooling for the power supply components. fact, with each program source there are normally four screens (or menus) of commands which can be accessed. Furthermore, it is a “learning” remote so it can take the place of the remote controls of all your audio and video program sources and as can be seen there are buttons for controlling CD players, VCRs, DVDs, TV tuners, FM/AM tuners and you name it. The SR-18’s remote can also use “macros” which let it store and carry out a series of control functions. This is a desirable feature, say, if you want to turn on all the equipment and make settings to watch a DVD movie or cable television program. In fact, as you learn about the features of the remote control and read about it in the owner’s manual you start to realise just how complex and how capable the Marantz SR-18 is. In reality we think that there are not a lot of owners who will fully comprehend all the features and thought that has gone into this top-of-the-line home theatre receiver. One point that could be improved is the range of the remote. This is stated as five metres and within an angle of 60° and in a fairly large room it is not enough, particularly since other ordinary remotes have no problem and can even work by bouncing off the walls. OK, so the remote does virtually everything except bring you chips and a drink (Toohey’s Red thanks, in a glass) but I still had some difficulties getting the machine to do what I wanted. For example, I could not get it to work with my CD player until I realised that you had to select analog (instead of digital) mode with the A/D button behind that aforesaid door in the front panel. To give it its due, it did try to tell me by flashing “no data” on the front panel but I had to read the manual several times before realisation dawned. On the other hand, it did not take long for us to realise that the SR-18 gave its best sound quality when switched to “Source Direct” which bypasses the tone control stages and presumably other signal processing. Another interesting touch is that when you connect an audio source to the Aux input sockets on the front panel, the SR-18 applies a steep bass cut below 100Hz. We found this out during our measurements. It probably is a good feature to minimise hum when you are connecting a video camcorder but we could find no mention of it at all in the owner’s manual. In fact, let us have a moan about the manual. It is nowhere Fig.1: frequency response of the power amplifiers taken at 1 watt into 8Ω. This is taken in Direct mode which bypasses the tone controls. Fig.2: total harmonic distortion versus power at 1kHz with the two front channels driven. Maximum power is 185 watts at the onset of clipping. Fig.3: total harmonic distortion versus frequency at a power of 100 watts per channel into 8Ω (Measured with a bandwidth of 20Hz to 80kHz). Note that there is no rise in the figure at frequencies above 5kHz. This is an excellent result. FEBRUARY 2000  7 near comprehensive enough – a complaint that can probably be directed at the manuals for all home theatre products. In fact, while the manual is in English and Japanese, it only has 35 pages to describe all the features in English. Just how inadequate that is becomes clear when you compare it to the owner’s manual for a typical car. My new car’s manual has 350 pages and yet it does not make any attempt to describe functions which are as complex and varied as those possible with the Marantz SR-18. So far then, we have really only touched upon some of the features of the big Marantz. We have not mentioned how each program source can be set up, how the time delays for the speakers are set, how the FM and AM tuners are programmed, the multi-room/multi-source capability, the 96kHz/24-bit decoding for DVDs and so on. We can’t hope to devote enough space for the all features so let us just acknowledge that this is a necessarily brief review. So how did it perform? We first put it though a battery of audio tests and even here we were pretty selective, testing only the stereo performance of the front channels. All five channels are identical so it can be assumed that the stereo performance is repeated for all channels. The SR-18 is rated to deliver 140W per channel into 8Ω loads with all five channels driven simultaneously. Alternatively, it is rated for 200W into 6Ω loads under the same conditions. 4Ω loads are not specified and so we did not test for this condition. Rated harmonic distortion is .05% and signal to noise ratio is 105dB. Frequency response is rated as within 2dB from 10Hz to 50kHz. This rear view of the SR-18 shows the complexity of a typical large home theatre receiver catering for a very large range of inputs. Note the large well-paced speaker binding posts. They are fully shrouded to reduce the risk of stray wires causing shorts. 8  Silicon Chip A close-up view of the large remote control. Each program source has a number of screens with all sorts of functions which can be selected. Fig.1 shows the frequency response of the SR-18 and it is about 0.5dB down at 10Hz and 2dB down at about 58kHz, so it comfortably meets the specification (as it does on every other measurement we made). Fig.2 shows the distortion versus per output and as can be seen, the onset of clipping (where the graph suddenly takes a steep rise) is about 185W. This was taken with both front channels driven. Under these conditions the top of the cabinet became quite hot but as far as we could tell, the internal fan did not cut in. It was silent during all our testing and listening sessions. Fig.3 is the standout performance graph and it shows that Marantz have done something special with their amplifiers. It shows the distortion versus frequency for both front amplifiers and as can be seen, it is virtually constant right across the range from 20Hz to 20kHz. The reading is close to .01%. How do they avoid the usually unavoidable rise as the frequency goes above 5kHz? We would love to know. That is one of the best performances we have ever seen, for any amplifier or receiver. Signal to noise ratio measurements came in right on the button, at 105dB unweighted (from 20Hz to 22kHz). Listening tests confirm that the Marantz SR-18 is a very fine performer. It has bags of power, and dare we say it, far more than virtually anyone would ever need. It is very clean (particularly in Direct mode) and once you work out how to drive it, it is very satisfying. It is expensive but when you consider all the technology and power output housed within its covers, it is fairly priced at $4990. Oh, and you can buy it in black, if you really must. For further information, contact the Australian distributors for Marantz products, Jamo Australia Pty Ltd by phoning (03) 9543 1522; email info<at> SC marantz.com.au