Denon is a 'badge' name, belonging to Nippon Columbia, originally a Japanese progeny of the US giant, Columbia; famous for its big role in records, films and broadcasting in the 40s. This 3-head model is typical of the present day domestic cassette machine genre.

This model lacks spectacular features, but its mechanism and styling are clearly refined. Is it, though, up to studio use? Cassette decks suffer a variety of punishments when they pass under the Big Red Light. Perils include incessant stop-start-stop actions, as editing or selection takes place, or hassles with dodgy cassettes, supplied by well meaning musos 'For an extra copy of our mix'. It was a pity he or she forgot to mention the fact that the tape was a 'bit sticky', having been drenched in a wine-bar upset a few weeks back, and has been picking up grit in their back pocket ever since.

Biasing and Memory Stop

The manual identifies 19 features (See table 1), only a handful of which are noteworthy. Firstly (No. 10), the machine senses the tape in use, and switches itself to Normal, CrO² (Chrome) or Metal accordingly. The machine's decision is alas, final: there is no manual override. Many types and makes of tapes were tried, and a couple were found to which the machine responded adversely.

The answer is to read the manual. Other than improving your French, the drawing in Figure 1 shows the vital detection holes (Inner for Metal, outer pair for Chrome) which the rogue tape had omitted. The reason for this was that it was old stock, before the idents were universally introduced by the gamut of Japanese and European tape manufacturers. Without idents, the M33 always switches over to the Normal setting. In the opposite direction, Metal prevails when there's no cassette in place, and a luminous label bearing the legend Metal lights up.

Next, there's a Memory Stop. We simply set the tape counter at 0000, then press Memory Stop, and the M33 will come to a halt here on rewind. You can also take it past this point if necessary by pressing Rewind a second time. It won't stop at 0000, however, when you fast forward. The one setback found was the lack of memory back-up power, meaning the readout and memory are both wiped when the machine is switched off. At switch on, the readout always resets to 0000, regardless of tape position. This is outright bad design; back up supplies are basic stuff, even on £70 hi-fi gear. The good news is the readouts' size, and with it being luminous silver, on a black backdrop, it's bold enough to be easily visible across a room.

The M33 has a bias tweaking knob that adjusts the bias current level, applied to the tape. Turned left of the central click-stop, the bias is attenuated. This increases HF output at the expense of distortion. Turned clockwise, bias is boosted, meaning we can opt for cleaner highs, but less of them. We use this facility to tweak the bias on each brand of tape to a fine balance, after some initial experimentation with the settings.

The souped-up version (M44) replaces this with an automatic box. Again, as with tape selection, auto bias tuning means the possibility of creative misuse is ruled out completely.

The upshot is that the M44 version is perhaps best ignored for studio use, unless the machine is allotted to a single, tweak-free task, or you're able to satisfy yourself that the machine's decision happens to agree with your own, with respect to the tape brands you use or expect to use.

It's also likely that individual machines will differ in this respect, so the machine you carry away should be the one you successfully auditioned, not one out the dealer's storeroom. Otherwise you could ask the dealer to corroborate the autobias calibration as a condition of sale. This applies to any cassette machine of course.

It should also go without saying that any new machine should be checked for azimuth and the like before you begin to use it. It's hard to believe that an air freight trip from Tokyo and distribution via Britain's decaying pot holed motorways should predispose any sort of mechanical setting to remain in cast iron alignment. In fact the M44 sounded pretty sick at first, but better after the maintenance man had re-established the horizontal plane.

The possibility of the cassette labelling and tape being at odds cannot be wholly discounted and the machine is no more likely to be at fault than the tape maker's description. They may just draw the line at a different point. Overall, auto-selection is not for those who are accustomed to switching down the tape category on replay if they need a bit of added sparkle. Against the possibility that the M33 may interpret rogue, or older types of tape incorrectly are those occasions when someone forgets to set the tape select buttons correctly and a naff recording results. Sticking to the tapes listed the M33 will save this sort of embarrassment.

"...the machine senses the tape in use, and switches itself to Normal, CrO² (Chrome) or Metal accordingly."

The M33's mechanical functions are servo (logic) controlled via soft touch buttons. The switch overrides these. Set to Record or Play, the machine will leap into the selected mode as soon as mains power is applied. The actual timing function is provided by any convenient mains timer, through which the machine is powered. One annoyance is that the selection switch is too easily knocked from Off to Record, being a light action slide switch, near the on/off button: a vulnerable position. As a result, two tapes were largely erased during tests when the rack's power was next turned off, then on again. A Super Nova LED would put a stop to this sort of accident.

Double Capstan and Full Strength Metering

The cassette carrier can't be removed outright, but the transparent cover slips off for cleaning the heads and capstan. Keen observers will notice two capstans. This is no hallucination: there's a second rubber wheel at the left hand end of the tape transport, for a smoother journey. This is invaluable if the machine is subject to heavy vibration or if the machine's used at an eccentric angle.

This second capstan further constrains the limited head space, thus the M33's record and replay heads are at only half the accustomed spacing, of around 1". This will spell a shorter than anticipated slapback, should you use the machine for sound-on-sound FX.

Metering is of the bargraph type, with 12 LEDs, indicating between -20 and +8dB. Above 0dB, the scaling is insufficiently detailed to read peak levels accurately at the place where we need to most of all. Moreover, the peak-reading response develops an excessive release time whenever the meter deflects above +2dB. This means that any repetitive peaks in the music cause the meter to stick. Indeed, the readout scarcely moves if you adopt the +3dB or +5dB record level, given by Denon, for CrO² tapes respectively. The recommended levels (+1, +3 and +5) for the three types of tape are identified by a fluorescent marker below the relevant LED, according to the machine's selection, but with the meters sticking, under or over recording is likely, unless you're very careful.

The meter's zero level with input faders set at maximum is -20dBu (8mV). For a console with a -10dBu output, you'd set the M33's input again at around 6, or setting 3 for an 0dBu readout, with a +4Bu source. We also measured the metering frequency response, which was accurate to within ½dB between 30Hz and 12kHz. At 14kHz, there was a small rise in sensitivity, followed by a sharp fall above 20kHz: so a 14kHz line up tone would read 1dB high, but overall, the metering's response linearity comfortably exceeds that of the best tapes.

The Dolby and MPX (MultiPleX) switches below the meters had a neat, positive action. In common with modern machines, their status is indicated by a luminous legend, eg. Dolby C. The same applies to the record function, the memory stop, and the tape/source switching. Alas, the legend has no obvious spatial relationship with the buttons themselves. Added to this, the legend is way to small to be visible, unless you're seated next to the panel. As a result, the illuminations are not much help for remote operation, across the control room for instance. Neither is the record legend bright or red enough. In practice, this means missing a take if the machine jumps out of record, while it's been sitting around in the pause condition. A simple red LED would be far more effective.

The M33's output gain control is the same, dinky size as the bias knob. The latter is positive and easy to use, but the output knob isn't. The pot behind the panel has a stiffer travel, and the knob is recessed too far. This would prove irritating if you work a lot with cans, or you drive the machine directly into a power amp, so the knob ends up being used as a volume control. Driving a power amp direct is no problem; Denon have thankfully adopted 0dBu (776mV) as their zero output level, and with the input sensitivity being -20dBu, you can use the M33 as a 0 to +20dB line amp, by switching over the output to Source.

The headphone socket is a loose fit, with no panel fixing nut. Panel sockets without firm fixings are increasingly common in oriental products. The socket float will lead to metal fatigue if any amount of plugging and unplugging goes on. Also, with a chunky, muso-proof jack plug inserted, a sharp knock is likely to tear the jack socket asunder from the circuit board. Sound level on 400 ohm cans was amply loud, but never painfully so.

Input level control is attained in fader fashion. The left and right knobs are stacked concentrically, with friction coupling, so they can be offset relative to each other, and yet retain the stereo balance when adjusted. These knobs are large (2"), feel good, and work well. Suitable sources are line level only; there are no mic inputs. This is a sensible exception for the majority of users.

Round the back a 5 pin DIN socket is provided for the optional remote control kit. Inputs and outputs are on phono sockets alone. As usual, the outlets are cramped together, and the proximity of the recessing doesn't help matters, so a pair of pliers are needed to withdraw the plugs if they've been pushed in up to the hilt (as is necessary for a good connection).

"It's hard to be too enthusiastic about mid-price cassette machines, knowing that a little more loot can always buy big improvements in the sound quality department."

Constructional rigidity is an improvement over the preceding generation of cassette decks. The plastic parts are stronger than cardboard, and the M33's cover and front panel are of steel and rigid aluminium. Overall, it's fine for studios and occasional journeys, but for any heavy-duty road-work, a wholly metal structure would be preferable.

On test, we had a couple of interfacing problems. In the record mode, and with input and output cables routed past an AM tuner, tuned to night-time Radio 1, Janice Long was obliterated mid-sentence by the bias frequency whistle. We couldn't replicate this effect at a later stage, but it should underline the potential interaction between tuners, computers, tape machines, and digital equipment, all of which are active emitters (and receivers) of RF energy. Another problem was a hum, evident when the machine was paused and with the output level set hard over. Initially, it seemed like an interface problem, but after some experiments with balanced interfacing, I concluded that the power supply smoothing was responsible, and so the defect could well be specific to the machine we tested.

Summary

On the plus side, the aesthetic and tactile qualities are great, and every bit as good as the refined exterior would suggest. Leaving aside the snags discussed, the vital functions are well laid out.

Sound quality was judged marginally below par for a machine at this price, but the majority of the design snags could be rectified with some judicious production mods. It's hard to be too enthusiastic about mid-price cassette machines, knowing that a little more loot can always buy big improvements in the sound quality department. On a tight equipment budget, this machine will be a contender only if its particular mix of facilities, strengths and weaknesses align with your own requirements and sentiments.

The Denon DR-M33 costs £289.95 including VAT. Further information is available from: UK Distributors, Hayden Laboratories Ltd, (Contact Details).