MOTM

I recently got two pair of 21U rack rails as I plan to move my growing MOTM
in to a Moog 35 style cabinet. I'm not sure whether I'll go fine wood or
plywood/Tolex. This will probably take me several weeks to plan and build,
but I thought I'd ask for general comments from those who have already built
your own cabinets -- basic things you've learned now that you've done it, as
well as a few specific questions:

1) Did anything ever become of those plastic washers for 1/4" jacks?
2) I was thinking of having a couple of metal strips manufactured which could
be used as a buss/multiple system that would distribute the signal across the
length of the rack rails (similar to Larry's suggestion a month or so back)
-- has anyone tried this?
3) If I don't do the buss thing, I might like to mount the middle two rack
rails together so that there is no strip of wood separating the top row of
modules from the bottom. Has anyone else done this? I've thought about using
simple "L" brackets to mount the rails to the sides of the cabinet -- I'm
hoping it would be strong enough(?)
4) Anything else I should think about?????

We now return to our regularly scheduled 50 daily posts about MOAS,
John B.

> I recently got two pair of 21U rack rails as I plan to move my growing

MOTM

> in to a Moog 35 style cabinet. I'm not sure whether I'll go fine wood or
> plywood/Tolex. This will probably take me several weeks to plan and

build,

> but I thought I'd ask for general comments from those who have already

built

> your own cabinets -- basic things you've learned now that you've done it,

as

> well as a few specific questions:

Well, I have not built yet, BUT, I have been thinking about it quite a bit.
Since you have the rack rails, that is a great way to go. Paul mentioned
to me some small brass inserts that could be put directly into wood that
could be used too. However, the rack rails should be much easier.

> 1) Did anything ever become of those plastic washers for 1/4" jacks?

Not as far as I know. However, I think I know a decent way to make
something similar. One could take colored paper and run it through one of
those laminators (we have one at work). One sheet would give plenty of
material for several washers of that color. The trick would be cutting
them neatly. I was wondering if there might be some kind of punch.
However, I think a little care could produce good results with plain old
scissors.

> 2) I was thinking of having a couple of metal strips manufactured which

could

> be used as a buss/multiple system that would distribute the signal across

the

> length of the rack rails (similar to Larry's suggestion a month or so

back)

> -- has anyone tried this?

I'm still thinking about this. However, I am still JUST thinking.

> 3) If I don't do the buss thing, I might like to mount the middle two

rack

> rails together so that there is no strip of wood separating the top row

of

> modules from the bottom. Has anyone else done this? I've thought about

using

> simple "L" brackets to mount the rails to the sides of the cabinet -- I'm

> hoping it would be strong enough(?)

Once you bolt the two rack rails together (assuming they are "L" shaped)
you will have a "T" shape. That should be quite strong, and would get
stronger with the modules installed. However, here is an idea I was
planning to check out. At my local hardware store, they sell aluminum flat
bar and "L" shaped pieces 8 foot long. I used the flatbar to make my end
caps. I am almost certain that they make that stuff in channel too (you
know a square "U" shape). A one inch wide channel would be great. The two
rails (in the center) could be bolted to either side of the channel and
recessed so the front of the channel was flush with the front of the
modules. This one inch wide channel could be used for a variety of things
including the bus across feature we discussed some time ago. And, there
would be no question about strength with this arrangement. I'll see if I
can find the channel and report back.

My real concern is attaching the rails to the sides of the cabinet (I'm
leaning towards just bolting the rails together and using large "L" brackets
bolted through the wood cabinet sides).

In a message dated 9/11/99 5:33:28 PM, jlarryh@... writes:

>Sure. What are you going to do when your 42 space cabinet is no longer
>big
>enough for MOTM. HAHAHA...

DAMN! I better get another couple pair! Actually, I still have two pair of
the MOTM rack rails (which I plan to use for a guitar unit). So that should
hold me for a while.

>And, I plan on building
>mine to have a wood finish. I just HATE tolex on anything other than
>guitar amps.

I agree about the look of Tolex, but it would match the ARP, and I've already
got some plywood. Plus the learning curve is cheaper than walnut.


In a message dated 9/12/99 5:02:54 PM, jlarryh@... writes:

>> From: "Paul Schreiber" <synth1@...>
>> Watch AH/DIY for some news! (CEM related)

>Oh goodie. Maybe some valuable replacement parts.....

And of course MOTM users will get first crack at those $15 3340s and 3310s,
won't they?

> From: JWBarlow@...
>

> 2) I was thinking of having a couple of metal strips manufactured
> which could
> be used as a buss/multiple system that would distribute the
> signal across the
> length of the rack rails (similar to Larry's suggestion a month
> or so back)
> -- has anyone tried this?

Paul will tell you that distributing audio signals on a buss is asking for
noise and crosstalk. Control voltage signals would be less sensitive - you
might think of distributing kbd and gate information. You still might need
to drive the signals with a simple op amp unity gain buffer.

> 3) If I don't do the buss thing, I might like to mount the middle
> two rack
> rails together so that there is no strip of wood separating the
> top row of
> modules from the bottom. Has anyone else done this? I've thought
> about using
> simple "L" brackets to mount the rails to the sides of the cabinet -- I'm
> hoping it would be strong enough(?)

Should work fine. I plan on having an angled front cabinet that is 26 units
wide and 10 units tall. The middle will be supported by 2 L shaped rails
fastened together either to form a T or a U (T is easier but I'm not sure if
the hole spacing between the 2 rows will allow for it). L brackets on the
end is what I was going to use, but not the flimsy ones you buy at the
hardware store. And avoid bolting them through from the outside - you don't
want a bolt head messing up that beautiful piece of hardwood you paid dearly
for, now do you?

BTW, folks should avoid aluminum for the rails - it's too soft to tap good
sharp threads into, and won't last if you move your modules around much. Use
iron or steel.

Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@...

> From: "Dave Bradley" <daveb@...>
> Paul will tell you that distributing audio signals on a buss is asking

for

> noise and crosstalk. Control voltage signals would be less sensitive -

you

> might think of distributing kbd and gate information. You still might

need

> to drive the signals with a simple op amp unity gain buffer.

To clarify a bit here, since John was talking about an idea that I
originally proposed, the bus idea was not so much bussing of any signals,
BUT rather a different format for multiples, so that they were spread
across a row below the modules instead of all on one 1U or 2U panel.
However, Dave, you bring up a good point to consider about noise. Do you
think the extra cable involved in spreading the multiple out some would
actually be a problem if shielded cable was used to make the connections.
Inquiring minds seek you opinion.

> Should work fine. I plan on having an angled front cabinet that is 26

units

> wide and 10 units tall.

I am curious what your decision process was that led you to decide 26 units
wide. Was it the available space you have for the cabinet, number of MOTM
modules you expect to have, or ?? Spill the beans Dave.

Like Dave, I was thinking about 21 units because that same width would also
accommodate 2 19" standard rack units side-by-side if one wanted to include
some of that in their system -- either in the same case by going say 12
units high, or in a separate case with the same width.

> The middle will be supported by 2 L shaped rails
> fastened together either to form a T or a U (T is easier but I'm not sure

if

> the hole spacing between the 2 rows will allow for it). L brackets on the
> end is what I was going to use, but not the flimsy ones you buy at the
> hardware store. And avoid bolting them through from the outside - you

don't

> want a bolt head messing up that beautiful piece of hardwood you paid

dearly

> for, now do you?

OK, if you us "L" brackets (commonly sold as "corner braces" I believe),
bolting from the outside is stronger than screws from the inside. How
about bolts with wood plugs? Or bolts, recessed and covered with nice
matching wood filler for appearance?

> BTW, folks should avoid aluminum for the rails - it's too soft to tap

good

> sharp threads into, and won't last if you move your modules around much.

Use

OK, I have questions for BOTH John and Terry:

John, If you use the standard 21U rails they have #10 sized threaded holes
(10/32 I think, right?). Paul has us using # 8 with MOTM now. I see # 10s
will fit through the MOTM holes, but the "design slop" is all but
eliminated. Does this work OK? Have you tried it yet?

Terry, I agree that tinnerman nuts are a great way to go (like the SKB
racks, right?) I have not been able to find good ones for both threads,
only the ones that just catch one thread. Tells us where and what you
found. And, PLEASE tell me where you found those black # 6 nylon washers.
I want them on ALL my MOTM now !

Larry H

--------------------------------------
From: JWBarlow@...

I recently got two pair of 21U rack rails as I plan to
move my growing MOTM in to a Moog 35 style cabinet.
-----------------------------------------
From: "T.J." <goku@...>

On the 1/2" surface I drilled holes where the modules
would go, then placed "tinnerman"(sp?) clips for 6-32
screws. (Saw these on the back panel of a Minimoog).
I purchased a 1 lb.bag of black 6-32 screws at a surplus
store for a buck. Then added black nylon #6 washers so
the screws wouldn't scratch the panels.

>
> From: "J. Larry Hendry" <jlarryh@...>
>

> To clarify a bit here, since John was talking about an idea that I
> originally proposed, the bus idea was not so much bussing of any signals,
> BUT rather a different format for multiples, so that they were spread
> across a row below the modules instead of all on one 1U or 2U panel.
> However, Dave, you bring up a good point to consider about noise. Do you
> think the extra cable involved in spreading the multiple out some would
> actually be a problem if shielded cable was used to make the connections.
> Inquiring minds seek you opinion.

If that's what you are talking about, it should probably be OK. You may run
into loading issues if you send a CV to a lot of places. Even though the
input impedance of the CV inputs is high, it's not infinite. For instance,
my Expressionist CV outs seem to need some buffering, because I can hear the
pitch change when I plug more VCOs in.

>
> > Should work fine. I plan on having an angled front cabinet that is 26
> units
> > wide and 10 units tall.
>
> I am curious what your decision process was that led you to
> decide 26 units
> wide. Was it the available space you have for the cabinet, number of MOTM
> modules you expect to have, or ?? Spill the beans Dave.
>

Heh heh. I chose 26 units for a few mundane practical reasons:

1. I vacated a synth cabinet that I had previously built that contained 8
9x9 panels and 1 6x18 panel. That worked out to 26 U long and slightly more
than 10 U high. It's just a temp plywood cabinet using wooden rails, that I
will replace with an angled front solid walnut version when I fill it up (6
2U wide modules to go).

2. 26 units fits on my Chroma (which is the controller) just about right.

3. It's within an inch of the actual width of the Moog cabinet. An obscure
esoteric reason to be sure.

4. I can get the basics of a 4 Voice poly system in a cabinet this size.
That leaves a top cabinet 5 U high for sequencing, formant filters (I
haven't forgotten, Paul!), lots of other filters and esoterica, and I can
add a second 5U high top cabinet if I don't run out of money first. Then
I'll have my monster IIIC looking MOTM!

> OK, if you us "L" brackets (commonly sold as "corner braces" I believe),
> bolting from the outside is stronger than screws from the inside. How
> about bolts with wood plugs? Or bolts, recessed and covered with nice
> matching wood filler for appearance?
>

Hey, do whatever works for you! Plugs would be much less visible than
filler. Obviously, the top and bottom rails are not an issue - just screw
the L directly into the cabinet. If you go 10 units or more high, the issue
is attaching the 'floating' rails at the end. Instead of an L bracket I'll
probably fabricate something that spreads out to a flat plate where it
contacts the wood so that I can secure it with 4 or 6 fat screws. Also, in a
cabinet as wide as mine I think I'll need to run a vertical brace at the
center of the cabinet, set back far enough to avoid the module circuit
boards, then run a small short horizontal brace forward to the rail at a
point where two modules would meet to avoid jacks, etc. This will brace the
very center of the panel effectively.

Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@...

> From: "Dave Bradley" <daveb@...>
> If that's what you are talking about, it should probably be OK. You may

run

> into loading issues if you send a CV to a lot of places. Even though the
> input impedance of the CV inputs is high, it's not infinite. For

instance,

> my Expressionist CV outs seem to need some buffering, because I can hear

the

> pitch change when I plug more VCOs in.

Yep. That's what "I" was talking about. Just a different format for
multiples that somewhat reduces the number of across-the-whole-mess cables.

> Heh heh. I chose 26 units for a few mundane practical reasons:
>
> 1. I vacated a synth cabinet that I had previously built that contained 8
> 9x9 panels and 1 6x18 panel. That worked out to 26 U long and slightly

more

> than 10 U high. It's just a temp plywood cabinet using wooden rails, that

I

> will replace with an angled front solid walnut version when I fill it up

(6

> 2U wide modules to go).
>
> 2. 26 units fits on my Chroma (which is the controller) just about right.
>
> 3. It's within an inch of the actual width of the Moog cabinet. An

obscure

J. Larry Hendry wrote:

> Terry, I agree that tinnerman nuts are a great way to go (like the SKB
> racks, right?) I have not been able to find good ones for both threads,
> only the ones that just catch one thread. Tells us where and what you
> found. And, PLEASE tell me where you found those black # 6 nylon washers.
> I want them on ALL my MOTM now !
>
> Larry H
>

Ok Larry, here's the scoop. Both the tinnermans and the washers
were found at a Sears Hardware store. They had an isle with
assorted hardware in gray plastic pull-out drawers. All kinds of
fasteners. I cleaned out my local store, then proceeded to the next
town a few miles and cleaned them out also. The washers were
expensive $.07 each. Cost about $4.00 for around 60 of them.
They had them in #6, #8, #10, and in black and natural (white).
The washers are 1/16" thick. Asked an employee about ordering
more, and got the RS response, that's all we have. They also had
fiber ones that looked similar, but they were $0.25 each.(ouch!).
Same story with the tinnerman clips. They had these in "U" and
"J" shapes. I purchased all of the 6-32 "U" type I could find, about
70 of them, but I never found these again anywhere. The bin I found
them in didn't even have them listed. Hope I can find another source!
Not sure if these are "good ones" so I scanned them so you can have a
look.
The screws I used were actually 6-32 by 1-1/2" black finish with small
pan heads, single slot. I cut them down to about 1/2". Almost invisible.
With the small washers, they work great holding the MOTM's in place.

Here's the pic:
http://www.geocities.com/SunsetStrip/Frontrow/4877/hardware.jpg

On top is the 6-32 hardware- washer,screw(cut-down),screw (long),
tinnerman front, and back.
Below is the standard 8-32 MOTM style hardware- washer, MOTM
8-32 screw, tinnerman front, and back.

Hope this helps. (There must be a better source for these. Some one is
manufacturing them.)
Terry

> Ok Larry, here's the scoop. Both the tinnermans and
> the washers were found at a Sears Hardware store.
> They had an isle with assorted hardware in gray plastic
> pull-out drawers. All kinds of fasteners.

OK. Thanks TJ. I will check out Sears here for the black washers. Thanks
for the complete description and photo.