MiniDisc: Sony MD Walkman MZ-R30

In April 1988, I purchased this portable unit as much needed company on a boring daily commute into central London.

As it was my very first Minidisc device, I chose to purchase a recorder. Comparatively at the time, most personal stereo cassette units were playback only, with the exception of the most desirable Walkman WM-D6C.

The MZ-R30 supported both analogue and digital S/PDIF recording – the latter input via an optical Toslink connection through the ‘line-in’ socket. Analogue input signals could either be from a plug-in power stereo microphone or via ‘line-in’. Audio output was analogue only – either at the fixed ‘line-out’ level socket or though attached headphones on a different 3.5mm connector.

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In Playback …

The supplied in-ear headphones unfortunately weren’t up to much (bass non-existent), but Sony made them nicely removable from the supplied in-line remote control (weird plug) so that a better model of theirs could be bought.

I instead ditched the remote and went for Sennheiser’s HD25 SPII – a closed back design much better suited to my daily train journey. Unfortunately these were a bit hard to drive, so I had to run the player at maximum volume – which thankfully worked without distortion.

The supplied Li-ion cell life was quite decent in this situation, and a charge would generally last me a couple of days. It would normally charge inside the unit when powered from the mains adaptor, but at a couple of electronic shows I found an external twin-cell charger and an additional Li-ion cell for longer playtime enjoyment.

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Adventures in Analogue Recording

This was one of Sony’s first MD recorders and a few ergonomic issues were evident. Mainly, to start a new analogue recording with manual recording level, the following two-handed finger gymnastics were required.

• Press ‘End search’ to position to the end of the disc (or have the new recording trample over elsewhere on the disc),
• Simultaneously hold in the pause button, press the centre of the record button and slide it over to the left. Keep the two like that until the LCD shows ‘ManualREC’. Release both.
• Adjust the recording level using the track skip forward/reverse buttons.
• Press the pause button to start recording.

Looks pretty easy written up like that. But fiddly and damn easy to do incorrectly and have to go through again.

The ‘End search’ action upset many concert tapers and it was only after a large number of MD recorders were made and sold, did Sony finally get it right.

The quality of analogue recordings made was very good and largely noise free. I bought a small Panasonic RP-VC200 lapel mount stereo microphone – It was excellent for recording live performances.

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Digital Recording and DAC usage

On the whole Digital recording was easier – no manual record level setting required. The recorder supported S/PDIF streams of 32, 44.1 and 48 kHz – using the built-in sample rate converter, and when recording from CD the ‘Synchro Rec’ function would detect and create new track marks as necessary.

Protected SCMS streams were blocked from recording with the stern LCD warning – ‘NoCopy’.

At the time my optically connected MP3 jukebox PC had a huge internet sourced collection of music tracks stored at both 44.1 (CD) and 48 kHZ (DAT) sample rates. Digitally transferring to MD these tracks, that had previously been Winamp decompressed from their MP3’d storage and then recompressed by Sony’s ATRAC processing, impressively didn’t show up too much deterioration when played back.

But even more impressive was the performance of the unit as a high quality DAC for live playout of my computer audio.

Placed into record-pause mode as described above (with a blank Minidisc), the recorder converted the digital input (from a cheap and S/PDIF hacked C-Media CMI8330 soundcard) to a very good line-out analogue rendition. In fact, this was a whole different world than that available from PC soundcards at the time, including the more expensve Soundblaster Live series.

I found the MZ-R30 a well built unit of quality materials and the weight indicated as such. I’ve just dragged it out to write this review, so am clearly on a nostalgia trip. Better stop now 😉

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Speakers: TDL Studio 1M

A little while ago, TDL Electronics Limited used to be the British speaker manufacturer that championed the consumer advantages of transmission line principles in bass reflex ported speaker cabinet design. Making mostly floor-standers, their speakers gained some attention of export markets and there were some multiple drive unit monsters headed for the USA in the late nineties.

With a complex folded cavity inside the speaker to delay the reverse phase acoustic wave generated at the rear of the bass driver (but allowing it to supplement the wave generated in front without cancellation), transmission line speakers are efficient to drive and are capable of very low and distinct bass.

I bought this pair of new Studio 1M’s just after the original company closed down and was sold. Indeed I was quite lucky to get £500 shaved off the original £999 selling price, after dragging my existing equipment down to a listening room in my local Hi-Fi shop and listening to a few alternatives which came nowhere close for the bass!

They are 1 metre in height hence the 1M in the model name, and came wandering into the house in two rather large cardboard boxes – which initially caused a few domestic concerns around here.

TDL’s speakers then characteristically had a mostly flat neutral ‘transparent’ response over the normal audio bandwidth due to their usage of innovative materials and custom manufactured drivers. My Studio 1M speakers feature stiff aluminium diaphragm drivers for both the tweeter and the bass driver, a design choice taken to reduce the crossover response mismatch found with usage of different materials.

The benefits are particularly telling with brass instruments, percussion and female vocals which really project themselves into my listening room. I have a small collection of demo CD recordings distributed by equipment manufacturers themselves (Naim, B&W, Dali) that impresses me in a way that music commercially designed ‘loud’ for the radio sadly doesn’t. Oh well.

So, moving on to the bass and holding on to the roof tiles…

My Mission Cyrus ‘Straight Line’ amplifier does not feature a bass control (or allow any other tonal modifications) but with these speakers it does manage to generate quite a weighty soundstage for recordings that have a naturally deep content like church organs, stringed bass and the occasional thumpin’ dance track.

The heritage of TDL grew from an earlier 70’s company called IMF whose history is told here. Looking forward there are professional transmission line products by PMC that are used in recording and broadcast studios including those of the BBC.

The TDL company website of today includes some history and descriptions of the internals of these speakers, but the current range produced are quite different products made abroad using traditional components and designs. They are now owned by The Audio Partnership – Julian Richer’s ghostly collection of former great British Hi-Fi companies. eBay is probably the best place to find an original TDL Transmission Line model.

Interestingly, Bose seem to have taken some of the transmission line delay principles and built them into their over-hyped clock radio, which does sound impressive for bass (I’ve played with one!) but loses it tonally in comparison to a proper Hi-Fi system (and a few midi-systems as well …)

Compact Disc: Rotel RCD-971 (HDCD)

This Rotel RCD-971 is a fine performer for a CD player, incorporating a few late nineties features to get just a bit more out of the format including solid bass and the extended volume dynamics of HDCD.

The latter goodie relies on specially mastered CD discs encoded with the Pacific Microsonics (now Microsoft) High Definition Compatible Digital system.

I have a few of these discs from various artists that do seem to give my system a bit of a work out. At the same time they reveal a bit of detail in dry unprocessed instruments and human voices because of the included HDCD decoder.

However, as the most heavily used mechanical thing in my audio system, the RCD-971 has a few moments of misbehaviour.

I’ve found on accidentally placing a blank computer CD in the deck that the poor thing gets confused checking it out and won’t release it on eject. Also if the tray is open a slight tap will very quickly close it, which is reminiscent of the famous cash register scene on Ronnie Barker’s ‘Open all Hours’. Then finally, and I haven’t figured out quite why it’s doing this, track 10 is sometimes the first track to play rather than track 1!

Because the Rotel’s strengths seem to be the 18-bit Burr-Brown DAC and the HDCD decoder, when the time comes that the Sony mechanism used eventually loses its marbles, I may check out using the remains as an outboard digital converter to another deck – possibly a self modded DVD player or even a PC CDROM drive.

Cassette Decks: Marantz SD-460

I purchased this autoreverse cassette deck at a secondhand shop in London’s Notting Hill District for something like 40 quid. It looked hardly used but someone had removed the cassette load door. Happily my local HiFi shop managed to order one for me, and it fitted nicely.

The autoreverse feature of these decks are typically scorned at by some cassette users for having a detrimental effect to the sound. There are two possible choices for tape head configuration – either use a 4-track head and switch pairs in-use depending on the direction of the tape, or use a 2-track head and spin it around on a little platform to again match the tape direction. There is also the complication of driving the correct reels, providing twin capstan rollers, sensing tape type and overwrite protection, adding an erase head (or two!) and ultimately maintaining good speed stability and audio fidelity

I’m happy to say my SD-460 performs well in this respect, and is reliable to this day. This is even more remarkable given that the great Dutch Royal firm of Philips was in ownership of Marantz when this deck was built – and their traditional cost cutting which fails other Phillips products hasn’t taken it’s toll with this one 🙂

MiniDisc: Sony MDS-JB920 Minidisc Deck

currently live editing article…

After the purchase of a portable MiniDisc recorder (Sony’s MZ-R30), I became interested in purchasing an accompanying MiniDisc recording deck for the Hi-Fi stack.

Starting from 1998, Sony were churning out quite a few different domestic models for the home. I found the spec of the MDS-JB920 deck mainly appealing due to the feature of S/PDIF digital output from the Minidisc deck AND the same digital output active while monitoring analogue or digital input signals when set up in recording-pause mode. I’ll cover this later.

The deck is part of Sony’s QS range of quality components and is solidly built to show the promise. It has the following connectivity.

inputs
1 analogue ‘line in’
2 digital toslinks
1 digital coaxial

outputs
1 analogue ‘line out’
1 digital toslink
1 digital coaxial

The supplied remote control is a bit of a monster

Accessories: Pioneer DT-530 Audio Digital Timer

I bought this timer from a car boot sale for the princely sum of fifteen pounds. The purchase intention was to automate recordings from FM radio, as all my recording decks could be set to auto-start in record mode from power-on.

Perhaps unsurprisingly as a second-hand item it didn’t have promising reliability.

I found several dry solder joints in the filament connections for the electro-fluorescent display, they caused flicker.

Later some low resistance conductivity (approx 20Kohm) ‘appeared’ between contacts of the main rotary mode selection switch where they should have been isolated. That caused the all-in-one ‘clock’ IC, constructed around pulse sensitive high impedance CMOS circuitry, to randomly set the time to strange values rather than keeping it!

I’ve now fixed all that and until the next breakdown occurs the unit operates as a convenient main power switch to the various ‘wall-wart’ adaptors that power my turntable and it’s preamplifier, the Technics tuner, and the MiniDisc recorder. For nowadays timer recording from the radio is a thing of the past now that the same programmes are also available on the Internet.

BTW If you are trying to fix one of these, my scribbled notes and pinout details for the MN6076 are here.

Turntables: Rega P3-24 / Rega Bias 2

This is my current turntable doing fine justice to the vinyl I have collected over the years.

It has stacks of nice low down bass, clear vocals and good stereo channel separation. It’s paired with a matching Rega Bias 2 cartridge. The tracking is fine. Even records purchased from second-hand shops and car boot sales that look badly handled (finger marks and swept across scratches) don’t upset the stylus that much to be annoyed by it.

In comparison to my previous owned and disgraced Pro-Ject Debut II, this deck has a solid plate glass platter (that does not resonate like a bell when hit), a very stiff arm made from die-cast aluminium as a whole piece incorporating the headshell, and a vibration free synchronous motor. The only thing that vibrates is the tip of the stylus. That is exactly as it should be!

http://www.rega.co.uk/html/p3.htm

The P3-24 is a recent development of the Rega’s classic Planar 3 turntable. That design is now over thirty years old and little has changed except for the design of different tone arms – a business that Rega itself is famous for; they build tone arms (and decks) for a few other turntable manufacturers. The tone arm on the P3-24 is known as the RB301.

Maybe it was just my luck, but I found the Rega Bias 2 seemed to be a magnet for getting clogged with contaminants from dirty records. But over time this problem has receded, which is a bit of a relief as the (£50) cartridge and stylus are an inseparable unit – you have to return the cartridge to Rega to get the stylus tip replaced!

Tuner: Technics ST-G70L LW/MW/FM Stereo Tuner

This Technics ST-G70L tuner was bought (and the timer above it – for I would normally be somewhere else when recording) for the one occasion of the year where UK radio excels – namely the DJ party mix compilation played on New Years Eve – and no doubt recorded by quite a few archive tapers like me 🙂

It has a few nice features that set it apart from other non-digital Hi-Fi tuners, particularly when used in a reception area plagued with interfering FM radio stations broadcasting on frequencies close to each other.

Namely dual bandpass filters in the FM front end (for the RF and IF sections) can be set to normal (+/- 400 kHz) or “super narrow” (+/- 200 KHz) as necessary.

The selection of these filters can be done by an ‘auto RF’ button which does a nice little dance on the display when doing so. The above video clip (with sound) shows a short demonstration of this feature.

I’ve got the user manual as a PDF here for download, which includes specs. I’d quite like a copy of the service manual if anyone has that!

Cassette Decks: Yamaha KX-300

This is my preferred deck for recording cassettes – and was used mostly with TDK Chrome soundalike “SA90” series of tapes for best results recording either from vinyl, radio or CD. I never got into using ‘Metal’ formulation tapes – their price put me off!

The single directional tape transport of the KX-300 is soft touch controlled by switches and also an optional infra-red RS-K3 remote control (top right!) allowing easy use of the track search and phrase repeat features found more commonly on CD players. The motor drive is stable and mostly forgiving of slightly warped cassette bodies 🙂

Yamaha KX-300 Specs

Motor

Capstan – DC servo motor

Reel – Flat torque DC motor

Heads

Recording / Playback – Amorphous

Erase – Double Gap Ferrite

Wow and Flutter

WRMS – less than 0.05%

W.Peak – less than +/- 0.08%

Signal-to-Noise Ratio

(Dolby NR off) – better than 60 dB

(Dolby B NR on) – better than 68 dB

(Dolby C NR on) – better than 76 dB

Frequency Response

Normal tape (-20dB) – 30 to 17,000 Hz +/- 3dB

Chrome tape (-20dB) – 30 to 19,000 Hz +/- 3dB

Metal tape (-20dB) – 30 to 20,000 Hz +/- 3dB

Harmonic Distortion

(315 Hz, 3rd) – no more than 1%

Channel Separation

(3150 Hz) – 40 dB

Crosstalk

(125 Hz) – 55 dB

As well as Dolby B and C Noise Reduction, this deck features a headroom extension system called ‘Dolby HX Pro’. This is a worthwhile improvement that increases the upper limit of frequencies that can be recorded on most type of tape. The Dolby HX Pro circuit does this by dynamically reducing the level of bias signal added when recording high frequencies that are known to have a self-biasing effect.

So what is this bias stuff about then? Well, in analogue tape recording a bias signal (a single frequency of roughly 100 kHz) is added to ‘help’ the magnetic particles on the tape into behaving linearly to the audio signal excitation coming off the recording head.

For good recordings the level of bias applied is important.

With too little bias, or none – as it was before this high frequency recording technique was discovered by the Germans during WWII – the tape formulation’s magnetic particles don’t properly align to represent the original signal level resulting in playback distortion. With too much bias signal, the high frequency information in the original signal is slightly erased from the recording.

Tape manufacturers generally make tapes to match different industry standardised bias presets (Type I, III, IV), and these are normally automatically selected from the identification holes present on the top of the cassette shell.

Though above these industry standards most Hi-Fi manufacturers tended to align their cassette decks to a particular cassette brand and model – and make the matching tape purchasing recommendations in their manuals, though this also could be seen as a useful marketing strategy, particularly for deck/tape products from Sony.

The Yamaha KX-300 deck was one of the few sold in the low-to-mid price range to have a variable bias control for the user to adjust the bias signal further from industry presets to match his/her preferred tape use, and a play trim control (+/- 3 dB at 10 kHz) to slightly boost or cut treble on playback of poorly recorded tapes.

A MPX (for Multiplex) filter is normally found in-use with Dolby B (or C) recording circuitry to avoid the stereo pilot tone (19 kHz) of an FM broadcast from confusing the noise reduction circuit. This deck usefully allows that low pass filter to be switched out when recording from non-radio sources.

Overall, I am pleased with this deck – I’ve thrown loads of tapes at it over the years from when I bought it in 1989. It still works fine today.

Amplifier: Mission Cyrus Straight Line

This ‘Straight Line’ amplifier from Mission gets it’s name from the simplicity of the design. No phono preamp, balance or tone controls. If the music doesn’t contain enough treble, bass, stereo balance and vocal presence, it’s the music that is lacking – not this system – so the lack of controls is not a problem :-).

Currently this 50W/Channel amp is driving TDL Studio 1M speakers. These transmission line speakers are efficient and quite easy to drive to high undistorted volumes.

Unfortunately the Straight Line’s ‘precision matched channel’ rotary volume control is getting a bit noisy when moved, a habit not uncommon to older amplifiers in this series.