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Boss Dr Sample SP202

DJ Looping Sampler By Chris Carter
Published January 1998

Boss Dr Sample SP202

Boss's popular 'Doctor' range of inexpensive and useful studio gear is now over 15 years old, but remains very much alive, and the Dr Sample SP202 is the latest newcomer, offering quick and easy sampling for DJs or beginners in the field. Chris Carter gives it a full physical...

First, let me ask you a question: hands up anyone who can tell me the criteria for deciding whether a product is released under the Roland or the Boss moniker? After all, both ranges are made at the same factory, are probably designed by the same R&D team, and are both produced for musicians. Maybe Roland products are perceived as more pro while Boss are more hip? Answers on a £50 note please...

The Boss 'Doctor' range started way back in 1980 with the original Dr Rhythm drum machine, the funky DR55 (sadly, my own is long deceased and gone to silicon heaven), and although the SP202 is the latest product in the long‑lived range, it isn't the first portable sampler from Boss. The DSD2 Sampler, produced in 1986, was a 12‑bit, single‑sample footpedal which could drain a PP3 battery in about 15 minutes (believe me — I used to have one!). Happily, things have improved a lot since then; the SP202 will happily run on six AA‑sized Duracells for up to eight hours of continuous use.

Trust Me, I'M A Doctor

Before I get I get down to the nitty‑gritty, let me just give you a quick run down of the vitals. The Dr Sample is a 4‑voice, 16‑bit stereo sampler, with a bpm calculator, a 3‑digit LED display, built‑in effects, a built‑in microphone, stereo audio line in and line out, and MIDI (in a very basic form). It's designed primarily as a portable DJ looping sampler, and with this in mind, Boss have not only made it quick and easy to sample and loop with the Dr Sample, but have also endowed it with options for mains or battery power, and given it the capacity to retain samples even without main batteries installed or external power. Very useful indeed, particularly if your batteries have run flat and you can't get replacements in a hurry. On the rear panel, connections to and from the outside world are via four phono sockets, a MIDI In socket, a power input socket (9V) and an on/off switch. Round the front, there's a stereo mini‑jack headphone socket, a standard mono quarter‑inch jack socket for an external microphone, a mic/line selector, a Source Mix on/off switch and a small slot for Smart Media memory cards.

All The Style Of... A Tricorder?

Straight out of the box, the stylish Dr Sample catches your eye immediately, with its minimalist black casing, oversized orange lettering and generous complement of buttons. This feeling is enhanced when you switch on the power; 18 of the 30 rubberised buttons and pads glow bright red when pressed, and there are plenty of flashing LEDs. Also, I'm apparently not the first person to point out that the SP202 bears an uncanny resemblance to Dr McCoy's Medical Tricorder in Star Trek (the original series, of course, not The Next Generation). Perhaps the Boss design team are Trekkies...?

Even though it's slightly larger than a house brick, the Dr Sample weighs only 850g (with batteries) and could, at a push, be described as hand‑held (if you have big hands). The build quality is up to Boss's usual high standard, and the main control surface is fairly busy, but even so, everything is logically laid out with all the controls clearly labelled, and because of the contrasting colour scheme, nobody should have any trouble using it on a dim stage.

What's Up, Doc?

Up to 16 mono or eight stereo samples can be recorded into the two internal banks, and samples can be recorded at four sampling frequencies: Hi‑Fi (31.25kHz), Standard (15.63kHz), Lo‑Fi 1 (7.81kHz) and Lo‑Fi 2 (3.91kHz). Using Hi‑Fi mode, the maximum sample time in mono is 32 seconds, and this jumps to an amazing (but distinctly grungy) 4 minutes 27 seconds mono in Lo‑Fi 2 mode. This is quite impressive, because by my reckoning the internal memory is only about 500K, which means there must be some serious data compression going on inside this Doctor. Sampling times and the number of samples available can be increased dramatically by plugging Smart Media cards into the memory slot on the front panel (more on this in the 'Get Smart' box elsewhere in this article).

It's A Sampler, Jim...

Starting at the front edge of the top control panel and working our way back, we first encounter eight reasonably‑sized sample pads which are used for recording and playing back samples, though sadly they're not velocity sensitive. As I mentioned earlier, these pads glow bright red when hit andstay lit for as long as the sample is playing, which makes it very easy to see what's going on, even from across a studio. Next to the sample pads is a Hold key for temporarily sustaining samples that haven't been programmed to loop indefinitely, and a Source button which directs any signal connected to either the line or mic inputs through the effects section.

Above these pads is a row of smaller buttons for recording, deleting and setting the start and end points of a sample, plus a Cancel button and a Remain button for checking how much sample time is available. Two Bank Select buttons, A/B and C/D, let you choose which pads are active from two internal sample banks or, if a memory card is inserted, two external banks.

I expect that distinctive ring modulator effect to start appearing at a lot of clubs real soon.

A Little Cut Here,
A Little Cut There

Directly above these controls is another row of even smaller Edit buttons and LEDs to control the sample editing and playback options. The sample editing functions are minimalist in the extreme; they just about do the job, but only by a cat's whisker. There are options for forward or reverse, looping or one‑shot playback modes, gate or trigger and sample start and end point adjustment. That's yer lot! No sound‑shaping, no velocity and no sample level adjustment options. The start and end points are set with a single button labelled Mark (nice lad, but a bit dim) and any trimming is done entirely by ear and finger coordination, with no displays or digits; so don't try this if you've been partying all night! Editing involves pushing Mark once where you want the sample (looping or not) to begin and then tapping it again where you want the sample to end. Er, that's it. I know this sounds pretty fast and intuitive, but actually it isn't. If you are trying to edit a short loop it's almost impossible to get decent results; I found it quicker to sample the loop again from scratch. The moral of this is: get it right in the sampling stage. To make the most of the available memory, you can delete any unwanted portions of the edited sample by pressing the Del button.

While we are on the subject of sampling, another option available is the Source Mix on/off switch on the front of the unit. This allows you to feed the audio input signal (mic or line) straight through to the Dr Sample line outputs and is handy if you need to monitor the input source before sampling. Otherwise you will only hear the input signal if you go into record mode or if you press the Source button next to the sample pads.

Tap Tap Tap

Above the sample editing controls, there is the bpm/Tap section, which comprises the 3‑digit display, Up/Down buttons and a large Tap pad. Though this may seem basic, the section does perform a couple of nifty tricks, even if it isn't always entirely successful. The Tap function works just like any other bpm calculator; you just tap in a regular beat and the Dr Sample displays what it thinks the bpm is, and quickly too. Sometimes, it's almost too quick; unless you are spot‑on with your timing, the bpm figures constantly shift up and down while you're tapping, which can be pretty distracting.

If you set a bpm figure before you sample a phrase or loop, (with the bpm Up/Down button or by using the Tap function), the Dr Sample will try and assist you by quantising the record stop point to the nearest bpm beat figure. This sounds fine in theory, but you still have to be fairly accurate with your own timing, otherwise the Dr Sample will move the bpm amount a couple of digits higher or lower than you expected it to be. If you are having trouble getting a loop to play back at the correct bpm, you can, as an alternative, use the Pitch or Time effects button (or both) to move the bpm (which is always displayed for the most recent sample selected) to a new figure. This works surprisingly well, but has a major drawback of robbing any other samples of any effects they may have been using.

The Effects

Above the Tap section, you find the controls relating to the Dr Sample's effects section. I must admit to being surprised at finding one of these on a budget sampler, but before you get too excited, let me warn you that this is a bit of a mixed bag, not to mention a downright misnomer in one case. What we have here are six buttons labelled Pitch, Time, Delay, Filter 1, Filter 2 and Ring Mod, plus the Record Level knob, which doubles as an audio input level adjustment and an effect value controller. Unfortunately, the effects section does have a few frustrating restrictions. One is that, with the exception of the Pitch effect, only one sample can use an effect at any one time. This means that if two or more samples are programmed to use an effect and an effected sample is already playing, then playback of the second sample cuts off the other sample, resulting in some unexpected hiccups, if you're not prepared. Other limitations are that the Time and Delay effects won't work with stereo samples. Also, once an effect is selected, voice polyphony is reduced by one for Standard and Lo‑Fi grade samples and by two for Hi‑Fi grade samples. However, it's not all bad, as a nice feature is that each sample pad remembers any effect and corresponding controller amount assigned to it. Another feature sure to find a lot of friends is the option of feeding external sounds (in stereo or mono) through the filters and ring modulator section of the effects bank, which does offer some exciting possibilities.

Looking at the effects in more detail, Pitch, which is also referred to as the tempo change control, is the only effect that can be used in conjunction with all the other effects. To my mind, this isn't really an effect at all, but a function, and certainly shouldn't rob you of samples when in use. What it does here is change the pitch globally (and hence the tempo) between ‑20% and +10% for any and all samples that are playing, and it changes them all by the same amount. Usefully, when the Pitch button is active, the bpm display changes to show the new pitch‑shifted bpm.

The Time 'effect' is for time‑stretching in real time over a range of ‑50% to +25%, relative to the original bpm. And it works too, although it gets very flammy past ‑20%, but for fine‑tuning bpms without altering the pitch, it works OK. It's a shame that it won't work with stereo samples, though.

Delay adds a single slapback delay, at the same audio level as the selected sample. The delay time is adjustable in 13 quantised steps (relative to the original bpm) from 64th note through to whole note using the controller knob. This also works well enough for what it does, but a proper set of DDL parameters would have been preferable.

Filter 1 and 2 are basic but usable low‑pass filters, possibly 12dB types by the sound of them, with the controller knob used to sweep the cutoff frequency (though it sounds distinctly stepped). The only difference between the filters is that Filter 2 has more resonance than 1. Both sound a bit bland unless the sample has a high harmonic content or, funnily enough, if the sample was recorded using Standard or Lo‑Fi grade, in which case the filters emphasise the digital grittiness of the sample.

Ring Mod is the truly redeeming effect, and makes up for the shortcomings in the rest of the effects section. Although it does sound a touch digital, it's great fun to use, and really does mangle a sample as a ring modulator should. Also, because you can feed external sounds through it, you can use the Dr Sample as a stand‑alone ring modulator, or basic VCF. It's splendid stuff, and ideal for those 'Dalek on heat' impersonations.

Sampling — The Final Frontier

OK, so that's the tour of the front panel complete — so how easy is it to sample? The answer is "very". If you stick to the default sample settings of mono, Hi‑Fi grade, loop on and no bpm set, the actual process of sampling is quick and easy. Select an input from the small recessed switch on the front (microphone or line), adjust the input level until the Peak LED just flickers slightly and hit the Rec button, which starts flashing. Now comes the smart bit, because the Dr Sample automatically chooses an empty sample pad and sets that flashing, to let you know which one it's going to be, so no worries about overwriting an existing sample (assuming all your pads aren't full). Hit the Rec button a second time, preferably on the beat, and it glows steadily; sampling has now commenced. Hit the Rec button once more, again on the beat, and sampling stops. The bpm display then instantly shows the calculated bpm of the sample loop. Like I said, quick and easy! When in record standby (Rec flashing) you can press Cancel at any time to drop out of sampling mode and if you're unhappy with a loop you can either press the Delete button to erase a sample or use some of the editing features to change it.

Determined to put the immediacy of the Dr Sample to the test, I timed how long it took to sample from a cold start using the built‑in mic at the default record settings. From switch on, through the initialisation routine where the LEDs do a little dance, to pressing the Rec button and screaming down the mic took just five seconds, pretty fast by any standards. Used in this way, the Dr Sample makes a great sampling notepad for quickly jotting down vocal melodies, phrases, riffs or even spoken instructions. If you set the sampling grade to Lo‑Fi 2 you could babble on for more than four minutes (or 35 minutes with a memory card). All this and on battery power too — it's great for anyone on the road. The external microphone input also works well with guitar, and if the level is pushed to distortion, and the filters or ring modulator are active, the Dr Sample produces a very strange‑sounding digital overload, which is almost a seventh effect!

Say Aahh...

Of course, you don't have to record just loops from vinyl and CD with the Dr Sample; there's no reason why you can't record keyboards, pads, effects, percussion or vocals. You can also use the built‑in microphone, which sounds surprisingly good, although it does pick up the sound of tapping the Rec button when you begin sampling, which puts a thump at the beginning of each sample recorded through it. Much better results are achieved by using an external mic plugged into the front‑mounted socket via an XLR to quarter‑inch jack adaptor.

Samples and loops recorded at Hi‑Fi grade (31.25kHz) can't really be faulted; sounds are full‑bodied and full‑ranging, with an impressive bottom end that could give some full‑priced samplers a run for their money. And there are no obvious artifacts from the data compression that must be going on to get such long sampling times into such a small amount of memory. Bright or toppy samples recorded at the Standard grade take on a noticeable digital, gritty edge and lose some bass definition, but dull or softer sounds usually emerge, while the two Lo‑Fi settings are best kept for special effects or sounds that you hate.

Loops, Not Tunes

Sadly, the Dr Sample's MIDI specification is pretty basic. Although the rather contradictory MIDI specification sheet says otherwise, the SP202 does not respond to MIDI velocity. Nor, for that matter, are volume, pitch‑bend or modulation data recognised, and although it does respond to MIDI note numbers 35‑67, there is no way to play individual samples chromatically across a MIDI keyboard. All the samples are fixed at the pitch at which they were recorded, and are assigned to two preset MIDI maps, one being a Roland GS map, for some reason. The main (and only) MIDI channel can be changed to any from 1‑16 and the sample pads glow red when any relevant MIDI notes are received, which is a nice touch, but that's about it as far as MIDI goes. Because of these limitations, you don't really gain much by playing the Dr Sample over MIDI, unless you use it hooked up to a sequencer, and personally I found it more natural to play using the sample pads while twiddling with the effects knob.

Cult Classic?

When I first heard about the Dr Sample, I wasn't quite sure what to expect, because although on paper the features look interesting, I wasn't convinced that a sampler in this price range could sound any good. Fortunately, my concerns were misplaced, because it sounds great, but the effects implementation and MIDI specification are a bit of a let‑down.

But these are personal gripes, and I shouldn't lose sight of the intended use of the SP202; it's designed to be sitting next to a DJ's pair of record decks, after all. As a quick and easy looping sampler, it works well, and is eminently suitable for providing spot effects, jingles and ambience and effects loops. And for bands that just want access to a few sampled sounds to jazz up their set but don't want to get a fully featured (and full‑priced) sampler, this is the machine. In these sorts of situations, you don't need multi‑note polyphony, complex control via MIDI and multitimbral voices — just a machine that delivers decent‑sounding samples and a reliable and quick way to save and load them, for which the Smart Media cards are excellent. What the Dr Sample isn't suited for is complex MIDI control and integration into a desktop MIDI setup, or anything requiring what top‑end samplists would consider quite mundane sample editing and manipulation tasks. In this case, you need something like the Akai S20, which even with its recent price cut is still £200 more than the Dr Sample. As the SP202 is primarily seen as a live performance tool, I would like to have seen some sort of footswitch facility for triggering sample record or playback, and a way of prioritising important samples so they don't cut off in mid‑flow just because you have accidentally exceeded the sample polyphony. Also, with the cost of Smart Cards falling so fast, it would be nice if Boss included one in the price (it might be worth seeing if you can come to an arrangement with your dealer over this). Finally, not including a power supply is pretty stingy — come on guys!

You may think the £299 price tag a little high considering some of the Dr Sample's quirks and limitations, but there are a lot of positive features on offer here, including the quality of stereo sampling, ease of use and portability. Will this be another in a long line of Boss/Roland cult classics? Only time will tell, but I expect that distinctive ring modulator effect to start appearing at a lot of clubs real soon.

Get Smart

One of the most innovative, not to mention useful features of the Dr Sample is the way it handles sample storage and backup in the absence of a floppy disk drive, SCSI and MIDI SysEx facilities. Instead, there's a slot at the front that accepts small RAM memory cards called Smart Media. Looking at the total sampling time table elsewhere in this review chart (see the 'Hi‑Fi Or Lo‑Fi?' box) you will see that using these cards increases sampling times quite substantially. The Smart Media RAM cards have been adopted by most of the major electronics manufacturers for use with the new generation of digital cameras and personal organisers that are seemingly appearing on a weekly basis. The consequence of this fast take‑up is that Smart Media cards are quickly becoming something of an an industry standard, resulting in dramatic price reductions as production increases. There are two types of card available: the S2M5 with a 2Mb capacity, and the S4M5 with a 4Mb capacity. At my local Tecno camera store, the cards currently sell for £40 and £50 respectively, while Boss will also be selling their own, though their prices have yet to be confirmed. It pays to shop around, too — Dixons quoted me £249 for a single 2Mb card, which is pretty outrageous!

Hi‑Fi Or Lo‑Fi?

Here are the total sampling times offered by the Dr Sample (total time available for 16 samples across 2 banks).






Hi‑Fi31.25kHz0m 32s 2m 14s 4m 27s
Standard15.63kHz 1m 05s 4m 27s 8m 55s
Lo‑Fi 1 7.81kHz2m 10s8m 55s17m 51s
Lo‑Fi 3.91kHz4m 20s 17m 51s 35m 43s

The Doctor's Symptoms — Feature List

  • 4‑note polyphony
  • 16 samples using internal memory
  • 16 samples on Smart Media card
  • 16‑bit A/D and D/A converters
  • Time‑stretch, Filter and Ring Modulator
  • Various sample times

(see 'Hi‑fi Or Lo‑Fi?' box)

  • Stereo line out @ ‑10dBm
  • Stereo line in @ +4dBm
  • Mic Input @ ‑60dBm to 30dBm
  • MIDI In
  • 9V DC in
  • Eight hours continuous use on battery power
  • Size: 83mm x 145 x 221 (hwd)


  • Excellent sound (when using Hi‑Fi setting).
  • Fast and easy to use.
  • Impressive sampling times.
  • Uses affordable Smart Media cards for longer sampling times and backup.
  • Some useful and novel effects.
  • Built‑in microphone makes it easy to sample in a hurry.
  • Extremely portable and quite happily runs on batteries for hours.
  • Looks great, especially with the lights off!


  • Only 4‑note polyphony at maximum, and less with effects and stereo samples.
  • Minimalist sample editing.
  • Basic MIDI specification.
  • Annoying playback interruptions when using effects and/or stereo samples.
  • No footswitch facility.
  • Power supply not included.


With a great sound that can really kick, and a couple of interesting effects to boot, sampling loops has never been easier or quicker. With a little practice, and when used in the right situation, this can be a storming little machine. Just don't expect too much of it in the MIDI or sample editing departments.