I was amazed to see a reference (MMD 030615) to the Wayne Stahnke
cassette system for the Ampico. I first heard of this system in the
1970s, after I had developed a similar system, also for the Ampico.
As I recall, the IMI system sold for around US$2000. I used to market
mine for A$600, with each system hand-built in my garage. I sold
around 15 systems, with most of them still in operation and now much
Although I supplied music cassettes, I found these to be unreliable and
went on to computerise the whole thing using an Apple II. Most owners
of my system updated to the computer, as it had so many advantages, in
particular a better performance. It also allowed me to increase the
sampling rate of my roll scans.
I never found out much about the IMI system, such as how the rolls were
recorded, the nature of the interface between a cassette player and the
Ampico, the design of the valves and so on. I guess Wayne and I used
similar technology, although I was never successful in gaining contact
with Wayne. The tyranny of distance!
However, there's an interesting legacy. Although I now use a higher
scan rate, my data format still allows my roll scans to be recorded as
audio files onto a conventional (audio) CD. The result is that quite
a few people here now play their Ampico from a CD player.
Pundits might say the results can't be successful, but not so, as
virtually most Ampico owners here will attest. My data format (my own
development, as MIDI had yet to be invented) is extremely efficient and
allows a resolution well within that of an Ampico roll. The result is
a performance identical to, sometimes surpassing that of a roll.
It's here I'd like to pose a question that has been on my mind for some
time. Just what is the level of interest in a system for the Ampico
where the input is from a CD player? At the moment, the only system
I'm aware of is the MIDI valve units from Spencer Chase, apart from the
now redundant PowerRoll. Both these systems require a computer, which
is an anathema to many Ampico owners.
I am seriously considering developing a unit that would fit into a
spool box, and operating it from CDs containing over 1500 files (Ampico
only at this stage). The system would be based on my existing design,
which is simplicity itself (read reliable and small). At this stage
the collection can be put onto around 90 CDs, although I have plans
to record more rolls. I hope eventually to cover the complete Ampico
It might be possible to include a MIDI interface, but there'd be little
point if I eventually record all Ampico rolls. It would also be possible
to supply the files in Windows PCM format, requiring around 14 CD-ROMs,
allowing the Ampico to played from a computer. But it's the audio CD
format that makes it all so easy.
While there is considerable interest here, to make such as concept
viable requires a few more customers, such as US collectors. Most of
the work has been done, and if there is enough interest from others
around the world, I would be happy to divert myself away from other
projects and concentrate on my proposed CD system. It truly works
well, as US visitors to my home will attest.
[ Data files for the IMI Cassette Converter were transcribed by Wayne
[ Stahnke using an Ampico B spool box fitted with precision vacuum
[ pouch switches. The Ampico music roll was played at normal tempo
[ and the switch data was sampled asynchronously at 100 samples per
[ second. The data was encoded in a serial bit stream using Harvard
[ Biphase (Manchester) encoding with sync words, total 128 bits per
[ frame, or 12,800 bits per second. The serial data stream was stored
[ on reel-to-reel master tapes; production media was Philips C-90
[ music cassette at standard 1.875 inches per second speed.
[ The valve box, mounted under the grand piano nearby the Ampico
[ action stack, contained all the electronics plus the magnet valves
[ that featured a compression spring to quickly return the tiny steel
[ armature disc to the valve seat.
[ Please tell us more about your system, Peter. -- Robbie