MOTM

Hi all,
I want to make a Mult Panel. Is the correct way of doing it connecting the Jack's Tip & Ground 
to one another in a chain? Is this how the MOTM Mult is built?

Is it true that I lose a certain amount of dB with each connection? (like 3dB?) is there a way 
around this?

I'll appreciate any insights on this.

Thanks,
Ithai B.

Wire all the tips together, wire all the grounds together. You can
also do all sorts of fancy switching things using the switched jack if
you're so inclined, like the motm mult panel.

I use the bottom 8 jacks in my blacet-motm conversion panels, and make
2 sets of 4 multis. You can never have enough...

I've never noticed any signal loss. No more so than any other
connection in the system.

On 7/17/06, ithaib <ithaib@...> wrote:
>
> Hi all,
>  I want to make a Mult Panel. Is the correct way of doing it connecting the
> Jack's Tip & Ground
>  to one another in a chain? Is this how the MOTM Mult is built?
>
>  Is it true that I lose a certain amount of dB with each connection? (like
> 3dB?) is there a way
>  around this?
>
>  I'll appreciate any insights on this.
>
>  Thanks,
>  Ithai B.
>
-- 
------------------------------------------------------------------
Stephen Drake
sduck409@...
makeme1witheverything@...

The multiple itself will not introduce signal loss.  However, if you 
distribute a signal that uses the typical 1K series resistor on its 
output and patch that to a lot of other inputs, there will be a small 
signal attenuation, due to the voltage divider formed between that 1K 
and the other input impedances.  Examples:

1K output to a single 100K input.  The signal is 100/101 or about 99% of 
what's on the op amp output pin.

1K output to 4 100K inputs, which is equivalent to 25K.  The signal is 
25/26 or 96%.  This is still a small attenuation, that you might not 
notice unless you were driving 1V/oct VCO inputs, where the pitch 
difference would be apparent.  Many controllers that drive 1V/oct for 
pitch have something around 100 ohm output impedance in order to 
minimize this problem when driving multiple VCOs.

In short, signal loss isn't much of a problem with using multiples.  If 
you know the output and input impedances in your patch, you can do the math.

I never fully understood the choice of 1K as a standard output series 
resistor.  Electronotes (Bernie Hutchins) used 1K.  I think one reason 
is that you can hard patch 1K outputs together in a multiple and not 
draw excessive current.  Most MOTM modules use 1K.  Serge uses 330 ohm 
resistors here.  I've seen 100 ohms used on Blacet module outputs.

Richard Brewster
http://www.pugix.com

Stephen Drake wrote:

> Wire all the tips together, wire all the grounds together. You can
> also do all sorts of fancy switching things using the switched jack if
> you're so inclined, like the motm mult panel.
>
> I use the bottom 8 jacks in my blacet-motm conversion panels, and make
> 2 sets of 4 multis. You can never have enough...
>
> I've never noticed any signal loss. No more so than any other
> connection in the system.
>
> On 7/17/06, ithaib <ithaib@...> wrote:
>   
>> Hi all,
>>  I want to make a Mult Panel. Is the correct way of doing it connecting the
>> Jack's Tip & Ground
>>  to one another in a chain? Is this how the MOTM Mult is built?
>>
>>  Is it true that I lose a certain amount of dB with each connection? (like
>> 3dB?) is there a way
>>  around this?
>>
>>  I'll appreciate any insights on this.
>>
>>  Thanks,
>>  Ithai B.
>>
>>