MOTM

OK, there is one other thing to consider: NEVER run these Power One's "harder" than 80% of
current rating. This is to keep the transistor junction temperatures low enough so that they are
warm to the touch, but don't give you the infamous "Batwing Tatoo" (old timers will know what
this means).

As a rule: assume every modules will draw 40ma off each supply EXCEPT the EGs, use 10ma. Add up
the current (don't worry about + and - current). Then, divide by 0.8 and that is what the current
(1 side) of the supply needs to be AS A MINIMUM.

Example:

50 modules x 0.040A = 2.0A + 8EGs = 2.08A. Then 2.08A/0.8 = 2.6A, buy a 3A supply.

Going "backwards":

an 800ma supply will power about (800ma)(.8)/0.040) = 16 modules (actually about 20)

a 1.5A supply will power about 30 - 35 modules
a 3A supply will power about 65 - 70 modules
a 5A supply will power about 120 - 130 modules

This is on the 'conservative' side, but the #1 failure mechanism in the power supply will be
power transistor junction temperature, which is proportional to the current draw. Also, the
ripple current in the big rectifier caps will cause heat in the caps themselves.

Paul S.

> 
> As a rule: assume every modules will draw 40ma off each supply EXCEPT the EGs, use 10ma. Add up
> the current (don't worry about + and - current). Then, divide by 0.8 and that is what the current
> (1 side) of the supply needs to be AS A MINIMUM.
> 
Since I've been going through 'more power'  process over the last month
and computing amperage draw, be aware that some other modules have more
amperage draw than motm modules.  For example, Blacet Klangwerk and Time
Machines draw more than 40 mA (I think the TM is about 95 mA - John 
correct me if I am wrong); and the UEG draws 60 mA.
Blacet and Encore have these values listed on their module manuals.
Jeff

At 2:01 PM -0600 1/12/01, Jeffrey Pontius wrote:
>  >
>>  As a rule: assume every modules will draw 40ma off each supply 
>>EXCEPT the EGs, use 10ma. Add up
>>  the current (don't worry about + and - current). Then, divide by 
>>0.8 and that is what the current
>>  (1 side) of the supply needs to be AS A MINIMUM.
>>
>Since I've been going through 'more power'  process over the last month
>and computing amperage draw, be aware that some other modules have more
>amperage draw than motm modules.  For example, Blacet Klangwerk and Time
>Machines draw more than 40 mA (I think the TM is about 95 mA - John
>correct me if I am wrong); and the UEG draws 60 mA.
>Blacet and Encore have these values listed on their module manuals.
>Jeff

When designing my cabinets I used a spreadsheet that let me try out 
different configurations of modules so that I could estimate the 
power draw and the number of power supply connectors required. I used 
the published power draw spec for each module, if available. 
Otherwise, I used an average value of all the other modules. This let 
me take into account the more power hungry modules like the Time 
Machine and UEG. In the end I came up with results that were fairly 
close to "Schreiber's law".
-- 
------------------------------------------------------------------------
Scott Juskiw 
scott@...

Our modules might draw a little more current than the "average" of 40mA
that Paul threw out. This is mostly because of added features. We do try
to use the lowest power technology and techniques as appropriate for our
design goals.

You will find module current requirements on the order (store) page, in
a link in our power supply section, and in each manual. Since the + side
is typically a bit more than the - side, just add up the + mA.

Regards,
___________________
John Blacet
Blacet Research
http://www.blacet.com