MOTM

(yawn, I've been messing with this thing for 6 hours, and I have to get up at 6AM)

Overall, the mechanical construction/pcb/component selection is better than a Moog from the same
period. Don was/is an aerospace engineer by trade, so all the IC's are military surplus
(ceramic/metal cans). There are a few LM741s in sockets (selected!) but most are old Teradyne
LM341H, which was a LM741 in a can with better temp. performance. There are also a few Motorola
MC1456CGs (can), and the later modules (1977) use RC4156 quad op amps or a Fairchild uA749 dual.
Most modules appear to be made in mid-1974.

What is really disappointing is Don used the same Moog 'trick' of using the front panel as a
ground. This was to "save labor" but really all it does is make for a noisy system. There is
already lots and lots of point-to-point panel wiring, why adding 1 buss wire and a solid ground
caused concern is beyond me.

I fired up the 294 Comb Filter. This, and the 10-ch 295, are really like the Moogs: low pass,
bandpasses, and a high-pass all in parallel. I'll run AP plots tomorrow, and compare it to the
Moog and the MOTM-450 :)

A handful of TL071s, new jacks and grounding should fix the old gal right up! Slide pots are
pretty icky, though. The rotary pots used are sealed CTS, not shabby.

Double sided pcbs, no solder mask, no silkscreen. Not much bypassing, if any.

Paul S.

Mr. Buchla was (still is, really...)a real hot-rodder.  He used the
best parts, techniques and ideas of that period.  The 60's surplus
scene in California was a bonanza due to the war and the economy. 
These same ingredients fueled the Fender plant in the 50's.

Good engineering is important, but there comes a time when you just
have to push something until it get hot and starts to crackle.  When
in doubt-BORE IT OUT!!!

I LOVE electricity...

Chub-hot rod engineer with the facial scars to prove it!


--- In motm@yahoogroups.com, "Paul Schreiber" <synth1@a...> wrote:
> (yawn, I've been messing with this thing for 6 hours, and I have to
get up at 6AM)
> 
> Overall, the mechanical construction/pcb/component selection is
better than a Moog from the same
> period. Don was/is an aerospace engineer by trade, so all the IC's
are military surplus
> (ceramic/metal cans). There are a few LM741s in sockets (selected!)
but most are old Teradyne
> LM341H, which was a LM741 in a can with better temp. performance.
There are also a few Motorola
> MC1456CGs (can), and the later modules (1977) use RC4156 quad op
amps or a Fairchild uA749 dual.
> Most modules appear to be made in mid-1974.
> 
> What is really disappointing is Don used the same Moog 'trick' of
using the front panel as a
> ground. This was to "save labor" but really all it does is make for
a noisy system. There is
> already lots and lots of point-to-point panel wiring, why adding 1
buss wire and a solid ground
> caused concern is beyond me.
> 
> I fired up the 294 Comb Filter. This, and the 10-ch 295, are really
like the Moogs: low pass,
> bandpasses, and a high-pass all in parallel. I'll run AP plots
tomorrow, and compare it to the
> Moog and the MOTM-450 :)
> 
> A handful of TL071s, new jacks and grounding should fix the old gal
right up! Slide pots are
> pretty icky, though. The rotary pots used are sealed CTS, not shabby.
> 
> Double sided pcbs, no solder mask, no silkscreen. Not much
bypassing, if any.
> 
> Paul S.

> Mr. Buchla was (still is, really...)a real hot-rodder.  He used the
> best parts, techniques and ideas of that period.  The 60's surplus
> scene in California was a bonanza due to the war and the economy.
> These same ingredients fueled the Fender plant in the 50's.


This has 'military surplus' written ALL over it. Even the power connectors are some non-standard
European DIN version of the bladed Cinch-Jones ones in the ARPs and Moogs.

I'm sure in 1974, even at surplus, these LM341H can op amps were $2-$3 ea. But, inside they are
STILL 741s. Eck. Later schematics have pencilled in notes like "use NE5556 here?" so at least he
was thinking of using 'better' parts down the road.

Which brings up my favorite topic: do you leave the circuitry alone or put say TL071s in there?
If Don *had access* to a TL071 in 1974, would he have used it?

Paul S.

If Don did a lot of aerospace design, he may have grounded things to the 
front panel as a natural continuation of one of the standard aerospace 
grounding architectures.  A common architecture is to have a single point 
ground on the aircraft structure somewhere, with every avionics unit's 
primary power return wire tied to this single point ground.  Then each unit 
has its chassis tied to structure, but only its secondary grounds tied to 
its own chassis.  This way there is isolation between "primary" and 
"secondary" power returns, and any noise created in the units does not get 
carried back to the power supply and propagated to other units.  On the 
other hand, he may have had no clue about grounding architectures and 
followed the other extreme which was to tie ALL grounds together in hopes 
something good will happen.

At 01:14 AM 6/7/2003, Paul Schreiber wrote:

>...What is really disappointing is Don used the same Moog 'trick' of using 
>the front panel as a
>ground. This was to "save labor" but really all it does is make for a 
>noisy system. There is
>already lots and lots of point-to-point panel wiring, why adding 1 buss 
>wire and a solid ground
>caused concern is beyond me....

I guess that depends on what you want out of the instrument.  One 
side of the argument says "If he didn't have the parts then and 
built this instrument that everyone loves, then don't mess with it, 
it will change the character."  It's like putting DiMarzio pickups 
on a 59 Les Paul.

On the other hand, if what you want is a modern version of a Buchla 
then go for it.  You may sacrifice some 'character' but then again, 
hiss is not the kind of character that everyone can deal with!

I *really* wish I had this particular problem!  Though if push came 
to shove, I would not give up my MOTM rig for it.

Mike

--- In motm@yahoogroups.com, "Paul Schreiber" <synth1@a...> wrote:
.
.
.

> Which brings up my favorite topic: do you leave the circuitry 
alone or put say TL071s in there?

> If Don *had access* to a TL071 in 1974, would he have used it?
> 
> Paul S.

>
>Which brings up my favorite topic: do you leave the circuitry alone or put 
>say TL071s in there?
>If Don *had access* to a TL071 in 1974, would he have used it?

I'd say that if it lowers the noise floor without changing the character, 
swap it.  Buchla's are noisy but they have a great deal of character and an 
interesting UI.  I'm very jealous Paul!

         Eric

> If Don *had access* to a TL071 in 1974, would he have used it?

Probably, particularly if scribblings on schematics suggest that he later
considered upgrades to certain components.

Why just drop him a note and ask?

One of the more surreal experiences of my life happened at a trade show,
when I ended up doing a demo of the audio software I'd been working on for
Don Buchla. If you've seen "Wayne's World", recall the scene in which they
meet Alice Cooper, and prostrate themselves in front of him yelling "NOT
WORTHY!" That's sort of what I felt like doing.

--Adam

This seems to be pretty typical of the period.  Wavemakers did this too.


John Loffink
jloffink@... 

The Microtonal Synthesis Web Site
http://www.microtonal-synthesis.com/

The Wavemakers Modular and Integrated Synthesizer Web Site
http://www.wavemakers-synth.com/

> What is really disappointing is Don used the same Moog 'trick' of
using
> the front panel as a
> ground. This was to "save labor" but really all it does is make for a
> noisy system. There is
> already lots and lots of point-to-point panel wiring, why adding 1
buss
> wire and a solid ground
> caused concern is beyond me.

This is a very good question.  IMHO the value of an old Buchla or Moog
is in the history of the instrument.  After all, one can buy a modern
modular synthesizer with much better audio characteristics (Signal to
Noise ratio, CV rejection, etc.). :-)  I would tend to favor replacement
only when repair is necessary, and then with the closest modern
equivalent.  One can always clean up the noise later with outboard or
computer processing.  This way one can keep the historic accuracy of the
instrument and still use it for recording. 

John Loffink
jloffink@... 

The Microtonal Synthesis Web Site
http://www.microtonal-synthesis.com/

The Wavemakers Modular and Integrated Synthesizer Web Site
http://www.wavemakers-synth.com/

> I guess that depends on what you want out of the instrument.  One
> side of the argument says "If he didn't have the parts then and
> built this instrument that everyone loves, then don't mess with it,
> it will change the character."  It's like putting DiMarzio pickups
> on a 59 Les Paul.
> 
> On the other hand, if what you want is a modern version of a Buchla
> then go for it.  You may sacrifice some 'character' but then again,
> hiss is not the kind of character that everyone can deal with!
> 
> I *really* wish I had this particular problem!  Though if push came
> to shove, I would not give up my MOTM rig for it.
> 
> Mike
> 
> --- In motm@yahoogroups.com, "Paul Schreiber" <synth1@a...> wrote:
> .
> .
> .
> 
> > Which brings up my favorite topic: do you leave the circuitry
> alone or put say TL071s in there?
> > If Don *had access* to a TL071 in 1974, would he have used it?
> >
> > Paul S.
>

> This is a very good question.  IMHO the value of an old Buchla or Moog
> is in the history of the instrument.  After all, one can buy a modern
> modular synthesizer with much better audio characteristics (Signal to
> Noise ratio, CV rejection, etc.). :-)  I would tend to favor replacement
> only when repair is necessary, and then with the closest modern
> equivalent.  One can always clean up the noise later with outboard or
> computer processing.  This way one can keep the historic accuracy of the
> instrument and still use it for recording.

I think perhaps I agree with you in principle but not in practice.  :-)

It is true that much of the value of an older synth is its history, and
perhaps the goal of restoring a synth is to return it to factory-new
condition. But it is not necessarily true that one can buy a modern
equivalent with better audio characteristics. Yes, I put the word
"equivalent" into your mouth, but my point is that modern synths don't
always have the same features as older synths. So substituting a modern one
for a vintage model may or may not be a viable substitution, depending on
what you're after.

Your last two points are the ones that I find most difficult to ratify with
practice. First, I've spent a number of hours over the past several weeks
attempting to clean up noise in some location and voice-over recordings with
computer processing. I have some pretty good tools at my disposal and I
still wasn't able to achieve completely satisfactory results. The
long-standing studio advice about getting as good a signal in the first
place still stands, despite new-fangled noise-reduction techniques.

Second, it's not always the case that a historically accurate synthesizer
can actually be used for recording. I've attended recording sessions in
which some "vintage" synth was brought in for the occasion, and its
oscillator drift (or some other aspect) was so bad that it couldn't be used
for the session. Was this because the synth was old and uncalibrated? Not
always. We all know that one of the things we love about MOTM oscillators is
that they don't drift like older designs. I don't think many of us wax
nostalgic for VCOs that drift so badly that the instrument won't stay in
tune for the duration of a recording session, or less.

IMHO it comes down to the goal of the restoration: is the goal to return the
instrument to factory-new condition, i.e., a museum-style restoration? Or is
the goal to put the instrument into as "musically useful" a condition as
possible? I know that "musically useful" is a subjective term, which is why
I put it in quotation marks. Some people may find oscillator drift useful; I
personally do not. If the Buchla's performance (e.g., frequency stability,
noise level) can be improved by substituting new op-amps, personally, I'd do
that.

In short, I'd say it's up to Paul, based on what he intends to do with the
thing. 

--Adam

One thing I can't help commenting on is the colors, particularly those
baby-blue knobs. Bleah! I guess I'm more attached to the black & white look
than I thought.

OTOH, I suppose, based on the information in "Analog Days", it makes perfect
sense that Buchla used a number of different colors on the panel controls.
It would help the machine fit in with the psychedelic scene...

--Adam