Banana jacks and impedance

[Jim Johnson]

Thank you, Harry. What you say makes sense; my rusty EE knowledge could not
make sense of why input impedance would be relevant here, but I picked that
notion up up somewhere - probably on AH. 

Damn, why on earth isn't _everything_ +- 10v p-p?

Jim Johnson 
Metaphoric Software
-------------------
Makers of Techno Toys
Software for Electronic Music
http://www.technotoys.com
info at technotoys.com


*********** REPLY SEPARATOR  ***********

On 12/28/99 at 4:35 PM Harry Bissell wrote:

>(spoken in the voice of the Wizard of Oz...)
>
>Impedance.... you don't want impedance... Any fool can have impedance...
>No... What you want is
>
>Adequate signal levels.... If you are running +-10V signal levels
(oscillators
>etc...) you
>can forget about impedance. It won't matter. The signal will clobber the
>noise...
>
>If you are running low levels (like line level... 500mV or less) you have
a
>"problem here Houston..."  Even low impedance lines will pick up noise...
noise
>clobbers signal here...
>
>If you can wrap your hand around the unshielded cable (don't ground your
>body...) and you can't hear the hum pickup... then banannas are probably
OK.
>
>oh yeah... IMHO.
>
>ps. I don't use bannana for that reason...
>
>:^) Harry
>
>Jim Johnson wrote:
>
>> I'm in the process of wiring an effects and mixing rack to go with my
>> Fenix/Serge modular, and I keep flip-flopping on how to do it. First I
was
>> going to bring out all of the connections on the back of the mixer and
the
>> effects to banana jacks; then I realized that this would be a bitch, so
I
>> decided to go with standard 1/4" patch bays and lots of cables. Just
about
>> the time I realized what this would cost, I came across a pair of blank
>> Trompeter patch panels on Ebay for $10.. so now I'm thinking of going
with
>> banana again.
>>
>> The real question I have is, what sort of input impedances must my gear
>> have in order to work well with banana jacks? Maybe this is a bad
question,
>> since I don't have any of the manuals for my effects and mixer other
than
>> one, whose input impedance is about 47K. All of the effects units (Boss)
>> have -10dBm inputs; the mixer (Roland) has -20dBm inputs.
>>
>> I figure I can keep the banana cord lengths fairly short within the
effects
>> rack, though I may need to use my longer cables (3 feet) to bridge the
gap
>> between the two cabinets. Fortunately, I have never had any noise
problems
>> even when using the 3-footers withing the Fenix/Serge combo.
>>
>> Any thoughts on this mess?
>>
>> Happy new year!
>> Jim Johnson
>> Metaphoric Software
>> -------------------
>> Makers of Techno Toys
>> Software for Electronic Music
>> http://www.technotoys.com
>> info at technotoys.com