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JL Cooper PPS1 | |
Tape-to-MIDI SynchroniserArticle from Music Technology, December 1987 |
An American cost-effective alternative to SMPTE synchronisation; Rick Davies clocks an innocent-looking box designed with the budget studio in mind.
The need for a cost-effective yet versatile tape sync device has grown - the PPS1 meets the need with a cheap alternative to SMPTE.
OPERATING THE PPS1 is simplicity itself. Record some music into a drum machine or sequencer, and set up the desired tempo. Set the PPS1 switch to the To Tape position, then run the sequencer's MIDI output into the PPS1's MIDI input, and the PPS1's Tape Out to one track of the tape recorder. Put the tape into record, and start the sequencer a few seconds later.
"It only took two to three seconds for the sequencer to lock to tape, and even followed when I started messing with the tape speed control."
When the sequence or song has finished playing, the tape is striped with the PPS1's timecode. From this point on, the tape sync track drives the PPS1, which in turn provides the MIDI timing messages needed to control the sequencer.
When the tape plays back, the PPS1 switch is set to one of the two From Tape positions (Fast or Slow), the Lock LED lights, and the sequencer follows the tape. If you're working with a four- or eight-track recorder, the track you sacrifice for the sync track essentially buys you extra "MIDI tracks" which do not need to be started and stopped independently of the tape recorder - both the tape and sequences can be fast forwarded or rewound with the tape transport controls. Now you're free to overdub vocals, guitar, or whatever on remaining tape tracks, or overdub more synth parts on the sequencer.
Since the PPS1 doesn't require an input from the sequencer once the sync track is recorded, there is a MIDI merge function which allows you to play a keyboard through the PPS1 while it locks up to tape. This allows you to sync the sequencer to tape over MIDI and record new parts into it at the same time. This feature does make it necessary to disconnect the sequencer output from the PPS1's MIDI input, not only to free up the MIDI input for the keyboard, but also to avoid MIDI loops which could occur (otherwise the sequencer could play back into itself via the PPS1, and cause mayhem). JL Cooper get extra points for including a second MIDI output, which makes the PPS1 a MIDI splitter as well.
Of the two From Tape switch positions, Fast is the preferred position, and is suitable for most sequencers and drum machines. Slow is there for sequencers and drum machines that are slow in handling MIDI Song Position Pointer messages and the timing clocks that follow. (The Korg DDD1 is notorious for this, but works fine in Slow mode.) The first version of the PPS1 did not feature this three-position switch, but JL Cooper provided one of two different software versions depending on the sequencer or drum machine owned by the user.
There is one small point that can be easily overlooked here: not all drum machines and sequencers can handle MIDI Song Position Pointers. This is well worth investigating before getting a PPS1 or before buying an inexpensive or secondhand MIDI drum machine or sequencer. MIDI Timing Clock, Start, Stop, and Continue commands are pretty common, but Song Position Pointers didn't really catch on until the last year or two, so be aware.
"JL Cooper have included a MIDI merge function which allows you to play a keyboard through the PPS1 while it locks up to tape."
ALTHOUGH THE PPS1 is not intended as a SMPTE synchroniser, it can generate SMPTE timecode for striping tape with the real McCoy. And though it cannot convert SMPTE timecode into MIDI Song Position Pointer messages (due to the absence of any tempo controls whatsoever), it can generate MIDI Time Code (MTC), which, though not yet common on MIDI sequencers and drum machines, can be used as a timing reference by some sequencers and drum machines with more advanced features. As JL Cooper point out in the PPS1 manual, there are only a few systems that currently take advantage of MTC - including Digidesign's Q-Sheet - but the SMPTE and MTC features were extras that basically are thrown into the PPS1 for free. Certainly no cause for complaint.
Access to the SMPTE and MTC features requires opening up the PPS1, repositioning a jumper and then powering up with the switch in the To Tape/MTC Enable position. This is a smart move because it prevents the unwary first-time user from accidentally selecting SMPTE mode. Anyone who has gone to the trouble of opening up the PPS1 will know better.
In my tests, I tried striping track 4 of my four-track cassette with different signal levels (-10, -7, -5, and -3 volts), and all of them did the job just fine. It only took two to three seconds for the sequencer to lock to the tape, and even followed when I started messing with the tape speed control. (This yielded some interesting pitch shifts when both the sequencer and tape sped up, but only the tape changed in pitch.) Although the PPS1 performed admirably in all tests, I did find that unless the sequencer was already "rewound" when the tape started from the beginning, the sequencer missed the first beat, though it did not play out of sync once it got going. Nothing to lose sleep over, but it's worth remembering that the "chase" can be noticeable.
IF YOU'RE WONDERING how the PPS1 compares to standard SMPTE/MIDI synchronisers, the main difference is that once you've striped the PPS1 sync signal on tape, the sequencer tempo is fixed. The only way to run it faster is to change the tape speed, so it's a good thing that the PPS1 locks well to sped-up sync tracks. SMPTE synchronisers, on the other hand, offer facilities for altering the output MIDI clock rate with "tempo maps", something that falls well outside the scope of this review but is worth being aware of.
Once you've tried recording and sequencing with the PPS1, it becomes obvious why a low-cost device like this is long overdue; it makes it easier for the home studio owner to get sequencers to cooperate with tape recorders and provide "extra" tracks. It's a trustworthy device that offers extras that other budget synchronisers miss. At £500, the pros and cons of sophisticated tape sync must be weighed up carefully; at £229, the balance is definitely tilted in the PPS1's favour.
Price £229 including VAT
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