MOTM

I am designing a larger power jumper pc board with:

2ea 3-position screw terminal blocks (INcoming and OUTgoing)
some number of MTA-156 connectors

So the question is, how many MTAs? 16? 20? These are for "big ass cases". I
am
thinking maybe 18 is a good number.

You can always add another one in the case. That's the reason for the
OUTgoing terminal. You
use 3 wires and connect to the second pcb's INcoming terminal.

Paul S.

i'll be buildin' a modular desk with stackable cabs in a couple of 
months.  it's lookin' like it'll be 20U across.   so 20 gets my vote, 
though 18'd work for me as well...
peace,
doc

--- In motm@egroups.com, "Paul Schreiber" <synth1@a...> wrote:
> I am designing a larger power jumper pc board with:
> 
> 2ea 3-position screw terminal blocks (INcoming and OUTgoing)
> some number of MTA-156 connectors
> 
> So the question is, how many MTAs? 16? 20? These are for "big ass 
cases". I
> am
> thinking maybe 18 is a good number.
> 
> You can always add another one in the case. That's the reason for 
the

> OUTgoing terminal. You
> use 3 wires and connect to the second pcb's INcoming terminal.
> 
> Paul S.

From: Paul Schreiber <synth1@...>
> I am designing a larger power jumper pc board with:
> 2ea 3-position screw terminal blocks (INcoming and OUTgoing)
> some number of MTA-156 connectors
> So the question is, how many MTAs? 16? 20? These are for "big ass cases".
I am
> thinking maybe 18 is a good number.
> You can always add another one in the case. That's the reason for the
> OUTgoing terminal. You
> use 3 wires and connect to the second pcb's INcoming terminal.

hello all,

i think there's an optimum number which is the theoretical maximum number of
modules which can be powered, less a couple to allow for things like 181
keyboards. i designed each of my cabinets with this in mind - each cabinet
can be powered by one supply (unless it's full of 800s), with a little left
over for my 181
if possible, the MTA connectors could be given a little more space though...

on a personal note paul - could you email me that fed number when you have
it

cheers
paul b
(eagerly awaiting either a voltage or bovine controlled xmas)

Paul,

I would think that using 16, 18, or 20 with the ability to serial chain the 
boards, would extend the 900 past it's capacity, or would give you a single 
board that does not allow the use of the available capacity.  Of course one 
could buy a larger Power-One supply.

I would like to see either a 22 or 24 connector board, with wider 
spacing.  Or keep the current 12 connector type, but add the screw terminal 
blocks.  This would allow mounting two boards in a "big ass case" which 
would reduce the length of the individual cables going to each module.

-dave-

At 09:34 PM 12/16/00 -0600, you wrote:

>I am designing a larger power jumper pc board with:
>
>2ea 3-position screw terminal blocks (INcoming and OUTgoing)
>some number of MTA-156 connectors
>
>So the question is, how many MTAs? 16? 20? These are for "big ass cases". I
>am
>thinking maybe 18 is a good number.
>
>You can always add another one in the case. That's the reason for the
>OUTgoing terminal. You
>use 3 wires and connect to the second pcb's INcoming terminal.

> So the question is, how many MTAs? 16? 20? These are for "big ass cases". I
> am
> thinking maybe 18 is a good number.
> 
I suppose it depends on how big the ass of your case is.  I doing some
sketching out of modules in cases using the current line and the proposed
line of motm modules (with at least one of each module in a case, except
just 2 filters & at least 2 osc's and 2 adsr's, + 1 900) [***yes, very
subjective***], some (gu)estimates:
3 rows, 10U wide rack case: about 18 per case
4 rows, 10U wide rack case: about 25 per case
3 rows, 14U wide case: about 27 per case

These (albeit limited) (gu)estimates indicate a minimum of 18 mta's up to
maybe 28 (the latter seems a bit high).  24 would probably cover many of
the top 2 examples.

BTW I believe someone mentioned having 2 900's to power separate cases.
Would this cause problems in connecting modules from different cases?

[back for more coffee] Jeff

I haven't had any problems with 2 900's powering separate cases.

-dave-

At 10:20 AM 12/17/00 -0600, you wrote:
>BTW I believe someone mentioned having 2 900's to power separate cases.
>Would this cause problems in connecting modules from different cases?

In a message dated 12/17/2000 5:56:24 AM, weather@... writes:

>i think there's an optimum number which is the theoretical maximum number
>of
>modules which can be powered, less a couple to allow for things like 181
>keyboards. i designed each of my cabinets with this in mind 

>if possible, the MTA connectors could be given a little more space though...


In a message dated 12/17/2000 8:22:01 AM, jpont@... writes:

>> So the question is, how many MTAs? 16? 20? These are for "big ass cases".
>I
>> am
>> thinking maybe 18 is a good number.
>> 
>I suppose it depends on how big the ass of your case is.  I doing some
>sketching out of modules in cases using the current line and the proposed
>line of motm modules, some (gu)estimates:
>3 rows, 10U wide rack case: about 18 per case
>4 rows, 10U wide rack case: about 25 per case
>3 rows, 14U wide case: about 27 per case
>
>These (albeit limited) (gu)estimates indicate a minimum of 18 mta's up
>to
>maybe 28 (the latter seems a bit high).  24 would probably cover many of
>the top 2 examples.


I think Paul B has the right idea, base the number on the PSU current 
capabilities and the average module consumption. I also agree that it might 
be nice to have a little more space for the connectors themselves though I 
rarely unplug them at the PSU side once they are plugged in.

And being a big ass, I can add to Jeff's points too. My plan is to build a 
cabinet of three rows by 24U wide which will probably have about 40 modules 
requiring power when it's finished (I will be using two of the legendary 12U 
flat cabinet rails). I am using a 1.5A supply, and I think that will be more 
than enough for the 40 modules (didn't Paul say that the 900's 0.8A supply 
would be enough for 40 modules?). So I'd imagine 20 output connectors per 
block would be enough since the larger cabinets could just use two of these.

JB

I think it's more like 26 if you use the average module requirement of 20 
ma and Paul's safety factor of not using more than 65% to keep power supply 
heat down.  Those of us who have installed Dave Bradley's mod for LED's for 
the 800's have to tag on another 5 to 10 ma per LED I believe.  I'm using 
22 as max on my setup (lots of extra LED's:)

-dave-

At 01:22 PM 12/17/00 -0500, you wrote:

>And being a big ass, I can add to Jeff's points too. My plan is to build a
>cabinet of three rows by 24U wide which will probably have about 40 modules
>requiring power when it's finished (I will be using two of the legendary 12U
>flat cabinet rails). I am using a 1.5A supply, and I think that will be more
>than enough for the 40 modules (didn't Paul say that the 900's 0.8A supply
>would be enough for 40 modules?). So I'd imagine 20 output connectors per
>block would be enough since the larger cabinets could just use two of these.