SP12

Overview

The Drumulator II Roger Linn's company continued to set the pace for drum machine development in the early 1980's, and after the roaring sucess of the Drumulator, E-mu Systems moved into the upper end of the market in 1984. The Drumulator II was a complete revision of the original. It was designed with user sampling, MIDI and SMPTE, far better controls and a LCD. It takes its looks straight from the Emulator II, as well as using the same buttons and sliders ! The original PCB's even have Drumulator II on them, as well as "Paul is the Walrus" in mirror reversed writing. Those crazy guys at Santa Cruz!

Why the name change ? Umm don't know , but SP-12 stands for Sampling Percussion at 12 bits.

12-bit Heaven The SP-12 comes supplied with 24 drum samples stored in ROM. They are bass, snare, electronic snare, rim, 4 toms , 4 electronic toms, hi hats, crash, ride, claps, cowbell. An additional 8 user sample positions are available in battery backed up RAM for sampling into, but all 32 positions can use sampled sounds provided they fit in RAM memory . The samples are 12-bit linear at 27,500Hz, and there is a full set of sound editing controls on board for manipulating the samples. The machine is highly regarded in Dance and Hip Hop circles, for both its sound and beats.

Sample Time The base model maximum sampling time is 1.19 seconds (refered to as 1.2 seconds in the documentation). The Turbo model has quadruple this memory providing 4.76 seconds of sample time across 2 separate banks (a sample cannot span a bank). The documentation incorrectly refers to this being 5.0 seconds of sample time, although most factory sample diskettes only use up to around 4.2 seconds of sample time. The SP1200 uses a lower sampling rate of 26,040Hz.

Additional Features The SP-12 can store up to 100 patterns, 100 songs and has a 5000 note memory (4 times this with the TURBO model). It also has a mono mix output and eight individual outputs, MIDI in/out/thru, SMPTE sync, cassette/floppy disk storage and a metronome output.

Tips & Technqiues #1 I use the dynamic filter feature on my SP -12. Here's an easy way to play with it. Sample a breakbeat, or something that has several jumps in amplitude (i.e. not just a kick or other single percussive sound). Go into the output assign menu and tap the user key that holds the sample while you press "1," "2," etc. for output. The effect the dynamic filter has is dramatic. I think only the 1 and 2 outputs have dynamic filtering, 2 less than one. There are two SSM2044's in there.

In the stock configuration, the toms get the dynamic filtering on output one (which makes them sound so smooth I guess), and... shoot. Now I can't remember - - I think the snares are on output 2 by default. That would make sense. Anyway, try it, play with it. A lot of people don't seem to know about it. The multi pitch function on the SP-12 is pretty remarkable too! And don't forget that Prairie Prince (The Tubes) did the samples!

Many Thanks to David Bivins for this Tip

Technical Description

Architecture Two years after the original Drumulator E-mu Systems released the SP-12. This new drum machine was based very closely on the Drumulator but added 12-bit samples, user sampling and sound storage to diskette. The technical architecture is very similar, being based on a custom design micro-controller, Z80 processor and multiplexed audio.

The 8-bit Z80A processor runs at 3.3MHz, it reads the controls, writes to the display, and communicates to the outside world via an Serial I/O chip. It also runs the sequencing software. A CTC (counter timer circuit) is used for generating timing interrupts for scanning the controls every 1.2mS and keeping the sequencer accurate and sync'd to MIDI or SMPTE.

The micro-controller is the E-mu magic which enables the sample memory to be read for each drum sample. The eight voice channels are internally mixed into one, along with the click channel. A TL084 is used.

Sample Memory The SP-12 has a combination of EPROM and RAM memory for storing samples. The standard samples are stored in the 24kbytes of EPROM's and any user sampled sounds reside in the 48kbytes of RAM (SP-12) or 192kbytes of RAM (SP-12 TURBO). The sample RAM is powered by a Lithium battery when the power is off, so you don't lose your samples. The sample memory is actually 16-bits wide, and therefore has some de-muxing to fit the various 12-bit samples across all the chips.

Sequence Memory The SP-12 has RAM memory for storing sequences. The base model has 8kbytes, whilst the TURBO has 32kbytes. The sequence RAM is powered by the same Lithium battery that is used for sample and program memory.

Program Memory The SP-12 has an Operating System of just 32kbytes held in ROM, with an additional small amount of RAM.

Digital Sampling A single 12-bit linear Digital Analog Converter (DAC) chip replays the samples (an AD7541), and is also used for sampling sounds via successive approximation. This saves the cost of an ADC chip. The sample input goes via an anti-aliasing filter to remove unwanted frequencies that are above half the sample frequency, the cutoff is brick walled at 42dB.

Micro controller This is made from discrete logic, although in the future this circuitry was encapsulated into one custom chip by E-mu Systems for the samplers made after the mid-1980's. The micro controller gets the sample out of memory, to the DAC and to the subsequent sample and hold circuits which are needed as the output channel is multiplexed.

OS Versions The SP-12 has 24kbytes of EPROM based OS, which was upgraded a few times during its product life. You can determine the OS version by watching the LCD display at power on. Version 2.1 was current in 1985 - the last version was 2.6. It can also be found by looking at the two OS EPROM's.

Eight Voices There are a total of eight voice channels, through which the 24 drum samples are played.

Analog Filters Yes, the SP-12 has analog filters ! Two of the channels the ride/crash and hit hats are unfiltered. Four others (snare/rim, bass, claps. cowbell) are each filtered with a static five pole 1dB Chebyshev filter, set at frequencies to optimise the sounds. The remaining two channels (the toms) each use a dynamic VCF. They use the SSM2044 with a simple AR enevelope generated by the Z80. They create a 5ms sloping attack, followed by a decay. The frequencies can be internally adjusted.

Diskettes The SP-12 uses DS/DD soft sectored 5.25" diskettes, which are becoming hard to locate. High quality diskettes are recommended (Imation and Maxell). Do not try and use HD diskettes, or DD diskettes that are hard sectored or IBM formatted. They will not work. We recommend Imation DS/DD.

Debug EPROM There is a debug EPROM to enable the SP-12 operating system to be replaced by a program that will run some diagnostics. Provided the basics of the SP-12 are working then this EPROM can be used to check out the following:

• Buttons
• Sliders
• Display
• LED's
• CTC and SIO chips
• Sound Memory
• Metronome
• Cassette
• SMPTE
• DAC
• Non Volatile Memory
• DAC Trim
• Dynamic Button Trim
• Disk

Repairs

Overview The SP-12 is on the whole a reliable drum machine, with few mechanical parts and a robust electronic design. The main problem areas are the PSU, the LCD and sliders and buttons.

Warning Please only attempt a repair yourself if you are competent at servicing electronics, use a service centre if in doubt. The SP-12 is easily damaged or melted by amateur attempts at repair.

LCD Overview The SP1200 uses the same 16x2 character LCD as the Emulator II. This is an Optrex unit with an EL backlight. When new the display is bright blue with grey/black characters. The LCD does fade dramatically over time, and the backlight can fail or the inverter that drives it can fail too.

LCD Age After around 2000 hours use the LCD will need replacement, and its a good idea to replace the LCD whilst parts are still available. You can check when the LCD was manufactured by looking at the code stamped on the back of the LCD in black. The first 2 characters are the year, and the third character is the month. 85 or 86 is a typical build year.

LCD Viewing Angle The LCD viewing angle can be controlled by varying the voltage on pin 3. The SP-12 has a preset viewing angle controlled by resistors R1 and R2 on the panel PCB. You will not need to change this.

LCD Part Number The original part number is an Optrex DMC16207-AE. This is a 16x2 LCD with EL backlight. The physical size is 84x44mm and it uses a standard single row of 14 data connections. E-mu Systems no longer have any spares, and this is a good job as its expensive from them! The current Optrex part number is DMC16207N-EB, and this LCD is widely available for under $25/£15. Try www.digikey.com.

LCD Inverter The LCD backlight (the blue colour) is driven by a small inverter that generates 100VAC at 400Hz from a 5V supply. The inverter is a NEC (NEL-D32-46), and its a small black plastic box that sits on the front panel PCB to the right of the LCD. The inverter can fail in which case it will need replacing.

LCD Replacement The LCD can be replaced relatively easily but you will have to remove the front panel PCB and desolder/resolder the 14 way data cable and 2 way backlight cable that connect it to the front panel. You may also need to file down the PCB to get the LCD to fit as new LCD's don't have sloping corners. Ensure the new LCD face and the LCD transparent cover in the front casing are both protected whilst your desolder/solder. You may also need to replace the 14 way cable between PCB and LCD, as this is difficult to desolder.

EL Backlight Replacement An easier solution to replacing the whole LCD is to replace just the EL backlight itself. This works well if you know the characters are working okay but you just cannot read them properly. An added plus is that the black on blue lettering remains, which is easier to read. Visit Backlights for more details.

The EL backlight is easily removed by unsoldering the two connections on the LCD and then pushing the backlight out using a credit card. The new backlight can then be slotted in and the connections soldered in place.

Battery The Lithium battery in the SP-12 will last around 5 years. It is bright yellow and located at the rear of the main PCB. When it fails your songs and the RAM based samples will not be stored after power off. To replace it you need a Panasonic Lithium 2/3 A 3V battery with tags - part number BR-2/3AT-2SP. DigiKey in the USA stock them , the Part # is P201-ND

DAC Chip The SP-12 uses an AD7541 12-bit DAC, which is still widely available. mo

Filter Chips The Emulator SP-12 uses SSM2044 analog filter chips, which occasionally fail and take a voice down. These are hard to locate.

Slider Knobs Looking for replacement Slider Knobs? They are available from Farnell at Farnell (part number 766756).

Small Push Buttons The SP-12 uses a small momentary push button for most of the controls. After 15 years use they are beginning to wear out and even with cleaning still don't work immediately. They are easily replaced with new buttons made by E-switch and are available from Digikey in the USA (blue: EG2556-ND, red: EG1325-ND, black: EG1321-ND). A full set of buttons will cost around $60, and you can choose from a range of cap colours. You will need to desolder the old buttons carefully.

Large "Pad" Buttons Replacements can be bought for US$11 from EPR Electronics in the USA. If you find the pads stick, carefully lever the top off and lubricate the pins with a silicon lubricant.

Fuseholder Not quite the same colours! The SP12 uses a square black external fuse holder, with an internal red lid and fuse. These were made by Littelfuse and are: Low Profile Snap Mount 15A 250V Part Number 348871

Rotary Pots The SP-12 uses three front panel potentiometers which tend to grind a bit after 15 years use. They can either be cleaned or better still replaced by a higher quality 10k Log potentiometer. We use nice Bourns Conductive Plastic models with new knobs.

Power Supply The power supply is getting old by now and failure is not uncommon. One of the rails may go out of specification. Replacement PSU's are not available, so the best option is a service centre repair. It is very easy to service as it is made of discrete parts and its not a linear power supply.

Upgrades & Add Ons

Factory Upgrades The E-mu Systems factory have long since stopped providing upgrades or spares for the SP-12. Users are on their own, and there are no third party suppliers either.

Sample Memory The standard SP-12 can be upgraded to TURBO with a full 5 seconds of sample memory - the longest single sample is 2.5 seconds, by adding 18 additional memory chips into the vacant sockets on the motherboard, and by replacing the existing memory addressing PAL chip with a new one. The upgrade is for both sample and sequencer memory.

OS Upgrades The SP-12 operating software resides in two EPROM's at IC location 114 and 115 on the motherboard, underneath the mains transformer. OS versions 1.6, 1.8, 2.1, 2.4 (31 January 1986) and 2.6 exist. The latest OS we are aware of is Version 2.6, current in Spring 1988. An OS version (8.7) for Phil Collins SP-12 has been reported . If you wish to upgrade to OS 2.6 please contact us. OS 2.4 implemented SPECIAL #20 which provides TUNE/DECAY RANGE SELECT.

Sample and Song Librarian Software Two companies produced Mac software for the SP-12. Blank Software produced Drum File 1.2 which provided sample and song transfer to a Mac, and librarian and sample import facilities. It cost $295 and was available between 1986 and 1989. Then Blank Software was taken over by Passport and the software appears to have been killed off. It is not available new. A second company called Water's Edge produced a similar Mac application but without the sample import facility.

MIDI Sample Dump The SP-12 (OS 2.4+) does support MIDI sample dump and a user who has the SP-12 used by Phil Collins, reports a new OS version and MIDI sample dump lsited on the front panel.

1541Floppy Drive E-mu Systems introduced removable storage for the SP-12 by using an external Commodore computer diskette drive. This is a 5.25" self contained unit with its own power supply and a serial interface. It was the best choice in 1985, when 3.5" drives had yet to appear, and an internal 5.25" would have taken up too much room. The diskettes are used to stored samples and sequences.

1541 Operation Notes First, make sure that you've removed all diskettes from the disk drives before powering on. Power the 1541 on before the SP-12 The 1541 disk drive will have its green light on, and then the red drive/error light will blink. Once the red drive/error light has stopped flashing on the drive, it is safe to begin working with it. To open the door on the drive, simply press the door catch lightly, and the door will pop open. If there is a diskette in the drive, it is ejected by a small spring. Take the diskette to be inserted, and place it in the drive face-up with the large opening going in first and write-protect notch to the left . Press it in gently, and when the diskette is in all the way, you will feel a click and the diskette will not spring out. Close the drive door by pulling downward until the latch clicks into place. Now you are ready to begin working with the diskette. Remember to always remove the diskette before the drive is turned off or on. Never remove the diskette when the red drive light in on! Data can be destroyed by the drive at this time!

1541 Technical Description The 1541 has circuitry for both a disk controller and a complete disk operating system, a total of 16K of ROM and 2K of RAM memory. This circuitry makes the 1541 disk drive an "intelligent" device. This means it does its own processing using a "pipeline" software system. The 1541 disk drive contains a dual "serial bus" interface. This bus was specially created by Commodore. The two ports at the rear of the drive allows more than one device to share the serial bus at the same time. This is accomplished by "daisy-chaining" the devices together, each plugged into the next. Up to five disk drives can share the bus simultaneously, but the SP-12 can only read one.

Which Floppy Drive? The original drive used was the Commodore 1541, which was more usually used with the C64 computer. It stores 170 Kbytes on a DS/SD diskette, but works at cassette tape speed, and is therefore rather slow! 5.25" DS/DD diskettes can be used today, although the storage space remains the same. If you have a SP-12 TURBO, samples may take two diskettes to save, as there is more sample and sequence storage to save.

Proven Drives: Commodore 1541 (1984), Commodore 1541-C (1986)

Recommended: Commodore 1541-II (1988)

Unsupported: Commodore 1581 3.5" diskettes

Finding a Drive You will be able to find a second hand one on eBay, alternatively you could buy a new/recon one at Creative Micro Designs web site. The only problem with the 1541 is the very slow data transfer rate of 400 bytes/sec. This means samples load very very slowly. You are much better off using Mac software to hold your samples.

1541-II Setup The advantage of the 1541-II is improved reliability thanks to an external power supply and better PCB design, however you need to set its device ID to 8 via DIP switches to work with the SP-12.

Left	Right	Device#
UP	UP	8
DOWN	UP	9
UP	DOWN	10
DOWN	DOWN	11

Cabling The SP-12 connects to the Commodore floppy drive by means of a standard serial cable with 6 pin DIN plugs at both ends.

Commodore Serial Cable

1541 Pin Out	Description	SP-12 PinOut
1	Serial Service Request In	1
2	Ground	2
3	Attention	3
4	Clock	4
5	Data	5
6	Reset	6

Sample Diskettes

E-mu Systems Factory Library E-mu created a 5.25" diskette library of 21 sample banks for the SP-12 and SP-12 TURBO. Each diskette came with a coloured insert card which explained the samples.

Northstar Samples have a 63 sample Diskette Library for the SP-12 ($20 each), it is still available (just).

Walt Whitney This small company based in Overland MO produced a 7 bank set of samples on 5.25" diskette or as an Atari ST 3.5" diskette.

Other SP-12 sample libraries came from Sampleware and Mohawk.

K-Muse This California company based in Tarzana made a range of high quality sounds for the Emulator II and Emax as well as the SP-12. In mid 1986 they introduced seven sets of sample diskettes called the Sound Composers Series. Each boxed set cost $99 and consisted of four diskettes, three diskettes with a total of 24 samples and one sequencer diskette.

• Disk #1 - kick, three snares (centre hit, rim shot, sidestick
• Disk #2 - complimentary percussion in the low registers
• Disk #3 - complimentary percussion in the high registers
• Disk #4 - a group of sequences to demonstrate the sounds

The Sound Composer Series

• New York
• L.A.
• Techno
• Euro
• Electronic
• Island
• Sledgehammer

SP-12 Librarian

Overview In 1989 Water's Edge software in Canada launched an Apple Mac program called SP-12 Librarian. This amazing software provides both sound and song management, a sample bank catalogue facility and sample transfer over MIDI from the SP-12. However, unlike Blank Software Drum File, there are no facilities for sample editing or loading samples from external software.

Product Description " SP-12 Librarian" for E-mu System's SP-12 and SP-12 Turbo digital drum machine lets you save and load sounds and sequences in a fraction of the time by using your Apple Macintosh computer. Sounds, songs, and song segments can be named to help organize your work. Also, the SP-12 Librarian's Sound Catalog keeps track of your entire SP-12 sample library, so you don't have to. And of course, the Sound Catalog can be printed at any time to document your library. So can sound files and song files, too.

General Features The SP-12's data is saved on Macintosh disks - hard disks, floppies, optical, removable disks, just about anything.

• Saves and loads files a lot faster than the Commodore 1541 disk drive or cassettes.
• SP-12 Librarian files are compact. A single 800K floppy disk can store about 5 average sound files, or a few dozen huge sequence files.
• "Fail Safe" file management makes sure you don't lose an existing file if something goes wrong while you are updating it with new SP-12 data.
• Each SP-12 Librarian disk is inspected for computer viruses before leaving our facility.
• Compatible with System 6, MultiFinder System 7, and newer
• Memory efficient. Will run with as little as 180K.
• Comprehensive, illustrated User's Manual.
• Full support for monochrome, gray-scale and color monitors, as well as Macintoshes with multiple monitors.

Sound Files

• Each sound can be named. This includes ROM samples too!
• The names of all 32 sounds can be seen simultaneously. The sounds are organized into banks, just like your SP-12.
• Each sound indicates if it's a RAM or ROM sample.
• Each sound can be classified in a manner that suits you best (such as: Kick Drums, Toms, Electric Toms, Cymbals, Hi-Hats, etc.)
• The SP-12 Librarian can remember a list of sound categories. This list can be used to standardize and simplify the classification of sounds.
• Each sound's Name, Category, Channel Number, Mix Level, Tune/Decay Selection, Tune/Decay Value, Sample Time, and Loop can be viewed simultaneously.
• Each sound's Name, Category, Channel Number, Mix Level, Tune/Decay Selection, and Tune/Decay Value can be edited on the SP-12 Librarian.
• You can alter the tuning and decay of ROM sounds beyond the range which is normally possible when using the SP-12's control panel.

Sequence Files

• Each song and song segment can be named.
• Both songs and song segments are viewed simultaneously in the same window.

Sound Catalog

• The Sound Catalog is a comprehensive listing of your SP-12 sample library. It's like an index to your samples.
• The Sound Catalog can be sorted by sound file. This list is best suited for determining the contents of each sound file.
• The Sound Catalog can also be sorted by category. This list is best suited when looking for a particular type of sample. For example, all the "Snare" samples are grouped together, indicating the file in which each sample can be found.

Printing

• Sound files, sequence files and the Sound Catalog can all be printed.
• The SP-12 Librarian produces professional results, especially if you have a laser printer.
• Reports are printed in the font and font size of your choice.

System Requirements

• A Macintosh computer ((512KB or higher, excluding the Macintosh Portable, all PowerBooks and all Duos)
• Two floppy disk drives, or a hard disk
• Printer (optional)
• MIDI interface for the Macintosh (running from printer port or modem serial port), with 2 MIDI cables
• SP-12 or SP-12 Turbo drum machine

Test Comparison In actual tests, the SP-12 Librarian always out performed the Commodore 1541disk drive and cassettes. The results are conclusive. If you're not using the SP-12 Librarian, you're spending too much time waiting on your drum machine. Time is shown in minutes:seconds.

SP-12 Action	SP-12 Librarian	1541 Disk Drive	Cassette Interface
Save Sounds	1:42 (0.25 disks)	12:05 (2 disks)	12:15
Load Sounds	1:42	4:20	12:15
Save Sequences	0:22 (0.05 disks)	2:19 (1 disks)	2:19
Load Sequences	0:19	0:50	2:19

Test Conditions When testing the SP-12 Librarian, a standard Macintosh Plus was used with two 800K floppy disk drives. The SP-12 Librarian startup disk was in the internal drive, and a blank disk was in the external drive. If you use a hard disk, you will obtain slightly better results (about 10%). In all cases, an SP-12 Turbo (5 seconds of sampling time) with version 2.6 software was used. The sample or sequence memory was completely full, depending on the data being saved.

Timing was started when the SP-12 command was entered, and ended when the SP-12 displayed "Cassette/Disk Complete." In all cases, the required disk or tape was inserted and ready to be used prior to timing. In the event that a second disk was required (as with the Commodore 1541 disk drive), the time required to insert a new disk and restart the SP-12 was not included (actual time takes a little longer).

The SP-12 Librarian's disk requirements were based on an empty 800K disk which actually has 779K available for use. The sound file was 194K, and the sequence file was 37K. Both files do not include extra disk space consumed.

Drum File Software 1.12

Overview In 1985 Blank Software launched an Apple Mac program called Drum File. This innovative software provides both sound and song management, with sample transfer over MIDI.

Drum File provides quick access to hundreds of sampled sounds, with individual samples transferring in less than 10 seconds, which is 10 times faster than using a Commodore 1541 disk drive. All data is transmitted via MIDI, eliminating additional custom hardware expense. Your entire collection of SP-12 samples can be organised into Drum File libraries on the Apple Mac. Samples can be organised into named groups, such as "Orchestra Hits" or "Electronic Drums". Samples can be previewed via the Mac's digital audio port. Song files can also be named, catalogued and moved.

Sound Manager The Sound File Window displays the names of all 32 SP-12 samples simultaneously, both the ROM and RAM samples. Remote Play enables samples in the SP-12 to be played from the Mac either via mouse or the keyboard. The amount of memory in the SP-12 is displayed using bar graphs and numerics. Both bytes and seconds are displayed.

Song Manager The Song File Window displays the names of all 99 songs and segments in the S-12. Segments belonging to a particular Song are highlighted. The Memory Indicator shows much memory remains for the current Song.

Sound Libraries An unlimited number of sound libraries can be created for organizing samples into categories. Up to four libraries can be on the screen simultaneously. Up to one hundred samples can be stored in each library.

Global Features Individual sample, song and segment names can be up to 12 characters long and can be edited at any time. There are copy, paste and clear commands, plus audio preview. This enables samples that are in the Mac's memory or on the Mac's hard/floppy drive to be monitored via the Mac's audio port.

Data Transfer Samples or entire sound banks can be transferred to and from the SP-12 over MIDI. Song files and segments can also be transferred. Each sample typically takes 10 seconds to transfer and an entire TURBO SP-12 memory will transfer in 1.65 minutes (that all the samples and songs).

Other Features Samples can be imported from, and exported to, a range of 8 and 16 bit audio file formats such as Sound Designer, Sound Lab, and Switcher. The software can be installed to the hard drive of the Mac.

System Requirements An Apple Mac or Mac plus with 512k of memory, a Mac MIDI interface and a TURBO SP-12 with ROM 2.4 or higher.

Drum File Previews