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“is this the best DAB+ tuner available?” Marantz NA7004 Network Audio Player Review by Leo Simpson This Marantz hifi tuner may have a prosaic name but it is one of the few units that will provide the best audio reproduction from such diverse sources as DAB+, AM, FM, USB, iPod and the internet. It will also function as a high quality DAC and can handle Toslink and coax digital signals. Y ears ago if you wanted to listen to AM or FM radio, there was a host of hifi AM/FM stereo tuners available. These days that has been whittled down to just a few and even then they don’t receive DAB+ broadcasts. And what if you want a DAB+ radio but you also want to receive AM broadcasts on the same unit? You will find there is very limited choice. And what if you want internet radio as well? The only solution that we know of is the Marantz NA7004. It is odd, isn’t it, that DAB+ is supposedly a high quality broadcast medium but few DAB+ radios available in Australia have any pretensions to high sound quality. Even fewer still will let you listen to AM as well. Of course, DAB+ 62  Silicon Chip is only available in the major cities and even then its reception is patchy. So if you do purchase a DAB+/FM radio, it may work in your present location but there is no guarantee that it will work OK if you move elsewhere. If it doesn’t work, not only will you not be able to listen to DAB+, you will also miss out on the AM stations which are now all available via DAB+. But why confine yourself to DAB+, FM and AM when there are thousands more stations available via the internet? And why stop there? Just as in your car, you will probably also want the ability to play music stored on flash drive in a variety of formats. Which is why we are reviewing the Marantz NA7004 Network Audio Player. This model has been available for over a year now and has the same styling and build quality as other audio equipment in the Marantz range. It is quite a large unit, measuring 441 x 106 x 354mm and it weighs 6.5kg which is quite a lot for what is basically a tuner. To be fair though, it is a lot more than just a basic tuner. Its appearance is very similar to other Marantz equipment, such as the model siliconchip.com.au CD6003 which we reviewed in June 2011. Let’s start with the rear panel, which is far busier than any old FM/AM tuner. Yes, there are antenna sockets for AM (via a supplied loop antenna) and FM (75Ω coax), as well as DAB+ (F61). But there are also sockets for ethernet (for internet radio), RS232, RCA in & out and flasher in (for remote control functions), analog (R & L) outputs, digital (SPDIF), M-X port (for Bluetooth), USB (for PC connection) as well as the 2-pin IEC power input. The front panel is quite simple by contrast. It has a USB socket for connection of an iPod or other player or a flash drive, and a 6.5mm jack socket for stereo headphones. There is a central dot matrix display and four playback buttons. To the right of the display is another group of buttons, including one marked “M-DAX”. What is M-DAX? It is Ma- The amount of circuitry inside is far in excess of what you would expect with any normal rantz’s Dynamic Audio eX- tuner. Not only is this a universal tune, it can function as a high-performance DAC. pander which calculates the amount of high frequency information discrete componentry. By contrast, the DAB+ section is typical file compression formats reWe were very impressed with this in clearly very good, although we don’t move and then restores it to improve the CD player and we remain that way. have the test equipment to verify it. the fidelity when playing back MP3 or So even if you never used this unit as Sensitivity is quoted as -90dBm (good) WMA music files. tuner (unlikely) you could use it as a and signal-to-noise ratio at -95dB. first class DAC for decoding any digital Even better, total harmonic distortion We take the lid off . . . audio source. It does that job extremely is quoted as .025% at 1kHz and chanInside the NA7004 is a revelation well. It will handle linear PCM signals nel separation is -70dB at 1kHz also. too, since this is such a complex unit. with a sampling frequency of 32kHz, So we have a particularly good DAB+ As well as tuner modules for FM/AM 44.1kHz, 48kHz, 64kHz, 88.2kHz, tuner here. and DAB+, there is an interface board 96kHz, 176.4kHz and 192kHz, ie, just It also works very well when confor the ethernet connection and a very about every audio sampling frequency nected to an iPod or MP3 player, eslarge board carrying a bunch of VLSI available. pecially with M-DAX enabled which SMD chips and the complex power Mind you, you cannot feed in other seems to give the sound quality an supply. The main power supply is PCM signals such as Dolby Digital, overall lift. It works well as an internet conventional (not switchmode) and DTS, AAC etc as they will only result radio too, giving you access to countless there is a tiny supply which provides in excessive noise from the analog stations around the world, although a the standby function. Power consump- outputs. WiFi connection would be nice. tion is stated as 30W and in standby it We have to say that the specifications Attemping to describe all the features pulls 400 milliwatts. for the AM and FM tuner modes are less of the NA7004 in detail would take far There are also three PCBs for the impressive: the AM is quite ordinary more space than we have available. Suffront panel display, headphone output and the FM is adequate but not up to fice to say that the Marantz NA7004 is and the on/off switch. But the most the very high standards for FM recep- a fine product with a range of features impressive board is that which houses tion that were available from Marantz that is simply not available from any the DAC (digital to analog converter) and other fine Japanese tuners in the other manufacturer. circuitry. This is very similar to that past. Sensitivity for 30dB quieting is Its recommended retail price is used in the above mentioned CD6003 only 9µV (IHF) and mono signal-to- $1499 including GST. For further inplayer and it carries Marantz’s proprie- noise ratio is quoted as 65dB. This is a formation and the rest of the Marantz tary HDAM (Hyper-Dynamic Amplifier far cry from the days of yore when you range of high fidelity equipment, conModule) circuits and Current Feedback could expect stereo S/N ratios of 65dB tact the Australian distributor, Qualifi topology. Apart from the Cirrus CS4398 and mono of up to 80dB from the very Pty Ltd. Phone (03) 8542 1111. Web: DAC chip itself, all the circuitry is best FM tuners. www.marantz.com.au SC siliconchip.com.au January 2013  63