Forums > MaxMSP

RCA MK II

October 18, 2006 | 12:11 pm

I just came across some sites about the first synthesizer, the RCA. I
found that nice block diagram, and thought why not build a Max patch
resembling the old RCA MK II. Problem, there is not much more
information than that diagram, but it seems Brad Garton has the original
in his room and could eventually pull out some additional infos?

After looking on a picture of a punchcard, it seems all values are coded
in 4-bit, which would be a snap in Max, What I am curious about
especially are the blocks called "Frequency Source", "Frequency Glider"
and "Resonator Chains".

If there is more info available, it would be a fun project to rebuild it
in Max/MSP…

here the link to the diagram:

http://uv201.com/Misc_Pages/Misc_Images/rcasynth_block_large.jpg

Stefan


Stefan Tiedje————x——-
–_____———–|————–
–(_|_ —-|—–|—–()——-
– _|_)—-|—–()————–
———-()——–www.ccmix.com


October 18, 2006 | 1:26 pm


October 18, 2006 | 2:33 pm

On Oct 18, 2006, at 8:11 AM, Stefan Tiedje wrote:

> it would be a fun project to rebuild it in Max/MSP…

sounds great stefan. it will have a nice home next to my reaktor
emulation of the ems synthi AKS…
cheers
bruce

bruce tovsky
http://www.skeletonhome.com

"Reality is that which, when you stop believing in it, doesn’t go away."
Philip K. Dick


October 18, 2006 | 4:00 pm

Hey Stefan and max-list –

Wow, you read our minds! :-)

As some of you may realize, this coming year (depending on how you count
it) is the 50th anniversary of the Columbia/Princeton Electronic Music
Center (now the CMC). We’re talking with the NIME organizers and our
Princeton compatriots about appending a big "CMC day" at the end of the
conference with a bunch of installations, performances, etc. at our
studios. The culmination of the day will be THE RCA SPEAKS when we’ll
crank it up again and (hopefully) get some sound to happen. This is all
very recent and not completely formed yet, but your post prompted a
response. :-) Stay tuned!

Also, we’re organizing our spring seminars around a theme of ‘RCA-ness’;
not so much to build an exact emulation of the device but instead to think
about the needs it met and the function it served back when it was built
(1957!). We’ll be using this as a jumping-off point for designing some
new hardware and software, not sure where it will all lead.

And one more thing — we’re planning to put a lot more information about
the RCA and the Center in general on-line, including schematics and
technical docs about the various devices we have.

Couple of fun facts:

– The RCA Mark II does indeed sit in our main office in Prentis Hall.
Various institutions (like the Smithsonian) have been after it for years,
but we want to keep it and be sure it remains relatively
publicly-accessible (I have visions of an Indiana Jones-like warehouse
with the RCA locked up in an anonymous crate…). Columbia is planning a
large (*very* large) campus expansion that involves our current building,
and most of the architects who have visited would like to feature the RCA in a
prominent place in the final design.

– The last piece – so far – done on the RCA was by Cycling’s own Luke
DuBois, featured on the Freight Elevator Quartet CD release "Jungle Album".

– We have a number of other historic pieces of hardware at the CMC,
including one of the first synths that Don Buchla built and a some custom
ring-mod/frequency-shifter units made by Harald Bode.

brad

http://music.columbia.edu/~brad

On Wed, 18 Oct 2006, Stefan Tiedje wrote:

> I just came across some sites about the first synthesizer, the RCA. I found
> that nice block diagram, and thought why not build a Max patch resembling the
> old RCA MK II. Problem, there is not much more information than that diagram,
> but it seems Brad Garton has the original in his room and could eventually
> pull out some additional infos?
>
> After looking on a picture of a punchcard, it seems all values are coded in
> 4-bit, which would be a snap in Max, What I am curious about especially are
> the blocks called "Frequency Source", "Frequency Glider" and "Resonator
> Chains".
>
> If there is more info available, it would be a fun project to rebuild it in
> Max/MSP…
>
> here the link to the diagram:
>
> http://uv201.com/Misc_Pages/Misc_Images/rcasynth_block_large.jpg
>
> Stefan
>
> —
> Stefan Tiedje————x——-
> –_____———–|————–
> –(_|_ —-|—–|—–()——-
> — _|_)—-|—–()————–
> ———-()——–www.ccmix.com
>
>


October 18, 2006 | 4:39 pm

On Wed, 18 Oct 2006, Stefan Tiedje wrote:

> I just came across some sites about the first synthesizer, the RCA. I found
> that nice block diagram, and thought why not build a Max patch resembling the
> old RCA MK II. Problem, there is not much more information than that diagram,
> but it seems Brad Garton has the original in his room and could eventually
> pull out some additional infos?

i’ve got the schematics and the operating manual (ditto-printed in 1957)
in my apartment. it’s not the first synthesizer by any means, but it’s
probably the earliest example of a programmable sequencer/synth unit.
last time we turned it on it caught on fire, but we’ve got enough spares
to build two more of them, so we might give it a shot at some point.

eric chasalow made a ‘virtual rca’ at some point to realize the piece
babbitt was working on when the machine was vandalized. a good chunk of
the machine works fine, though it’s not much of a synth to begin with
(4-note polyphony combined + little continuous parameter control + 472
vacuum tubes, half of which are blown = kind of limited). we’ve got
buchla and serge modular units that are way more powerful in terms of
synthesis… it’s the operational logic of the thing that’s kind of
amazing.

> After looking on a picture of a punchcard,

the machine uses paper tape, not punchcards (actually two synchronized
tape drives, each controlling two ‘voices’ of the synth). it synchronizes
to a shellac record lathe for recording of your output.

> it seems all values are coded in 4-bit, which would be a snap in Max,

it’s a 4-bit system, though a lot of the parameters only paid attention to
0-11, with the top four values unused. remember that the system was
designed for dodecaphonic music, so most of these guys could only count to
12.

> What I am curious about especially are
> the blocks called "Frequency Source", "Frequency Glider" and "Resonator
> Chains".

the first two are how the RCA codes pitch and portamento time,
respectively. the synthesizer works by heterodyning a bunch of
high-frequency oscillator pairs: a set of fixed tones (still in tune last
i checked) and a voltage-controlled one for each voice… what you hear
from the synth are the difference tones, which you can combine through
this really messy octaver thing to get different timbres for each pitch.
the frequency glider is just a way to do portamento by switching between
different oscillator pairs instead of actually gliding the source
oscillator; i never figured out why the hell you would do this (it’s
broken anyway), but my guess is that since the paper tape has no way to
represent a continous function you would use this to ‘step’ between
different in-between states. the ‘resonator chains’ are just a bunch of
analog comb filters (short delay banks… very similar to those found on
the buchla 200 series). they also had a big EMT plate reverb wired in
later along with some other gear.

> If there is more info available, it would be a fun project to rebuild it in
> Max/MSP…

go for it.

> here the link to the diagram:
>
> http://uv201.com/Misc_Pages/Misc_Images/rcasynth_block_large.jpg

here’s a few other articles:

http://en.wikipedia.org/wiki/RCA_Mark_II_Synthesizer
http://machines.hyperreal.org/manufacturers/RCA/rca_ems.txt

http://www.obsolete.com/120_years/machines/rca/

best.

/luke


October 18, 2006 | 5:43 pm

On Oct 18, 2006, at 12:39 PM, luke wrote:

> go for it.

hey luke
great background info, man it really brings to mind how far we have
come in 50 years. even in my 30+ years of electronic music labor
it’s mind-boggling what i had to do then (lots of tape and razor cuts)
and now (lots of pulled hair and yelling at the lcd.)
cheers
bruce

bruce tovsky
http://www.skeletonhome.com

"Sometimes the appropriate response to reality is to go insane."
Philip K. Dick


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