[sdiy] to banana or not to banana

[Cynthia Webster]

Hi Derek!

Many of your concerns are simply not an issue, for example, Summing is 
exactly the same as with any other jack;
The circuit behind the front panel has no idea what type of jack the 
wire feeding it is soldered to.

Once the ground is stripped (cut) from an external input  you simply 
re-ground the signal on the way out.
Even an "all banana" system has a few typical audio output jacks for the 
final output to your board or amplifier.

More info on banana system grounding can be found here:

http://www.cyndustries.com/modules_powerdist-FAQ.cfm

It's a simple connection required if you want to patch between different 
synths and once made - no other grounding
is necessary on all of the cables, (remember that synth signal levels 
are strong and far less susceptible to noise.
(some phd in electronics may argue this tooth and nail until blue, but) 
it just ain't necessary to use shielded cables with bananas). 

It is true that bananas are not a switching type jack, however a simple 
workaround is to substitute a switching potentiometer or "pull-pot" if 
you need to add another switch, (and frankly this gives more options 
than a switching
jack, (unless you were to add yet another front panel switch to tell the 
switching jack, "not to switch this particular time").  There is 
actually a switching circuit for bananas possible, but I'd rather not 
dedicate any pc board space to
the circuity required.

How might one "loose the possibility of individual input attenuation" ?  
Unless you are specifically talking about
making little quarter-inch phone plug attenuator assemblies, which are 
rarely practical and often either broken or lost.

The early Buchlas utilized several power supplies of different voltages, 
there were no LEDs at the time so
incandescent lamps were used all over the front panels and these had 
their own power requirements.  Also the
control voltage were a mighty ten or even more volts in the system, 
while the outside world was using the standard
one volt peak to peak audio line level and Don adapted his audio chain 
to those levels. The simplest way to keep
all of that isolated was to use separate connectors.  It was probably 
this necessary isolation between control and
audio that lead to exploration with opto-isolators and the rest is Low 
Pass Gate history.

While Don Buchla was working with Morton Subotnick and Cal Arts, Serge 
Tcherepnin arrived on the scene
and made three changes/improvements to what Don had started firstly by 
making sub circuits into modules so
that a user might manipulate the cores of certain circuits to their own 
uses, rather than accepting whatever fixed function the front panel 
proclaimed.  Secondly, Serge wanted to lower the entry level price of 
getting a synth in
the first place and he did this by standardizing the panels by drilling 
the same size hole everywhere, and using
xeroxed paper for the front panel legends so they could be re-arranged 
to each customer's liking.  Serge also
eliminated the mini-phone jacks and went with banana jacks only for the 
sake of the size of the holes in his panels,
the savings of ordering one part in greater quantity, standardization of 
the same voltage levels for audio and CV, and here it is...  for the 
sake of complexity.

Instead of wasting front panel space with a few pitiful mults, the use 
of stacking banana jacks allowed the most  flexibility as the multiple 
jacks were no longer necessary, allowing you to mult anything to 
anything anytime and
give your patch cords the versatility of a queen on a chessboard - being 
able to go in any direction - any way that
you like with impunity!  That is mightily empowered patching indeed, and 
your sounds created can or will reflect this difference.

I've read of supposed limitations of things that you should or shouldn't 
do with bananas as they might tax the power supply, but this is 
apparently due to the use of cheap or marginally rated power supplies as 
I completely ignore this
and never ever have problems, (of course my own brand of power supplies 
are quite beefy, intentionally), just use
a decent power supply and not a cheapie.

STS Systems has carried the Serge torch on to new heights for years 
using banana jacks.
Bruce Duncan at Modcan was inspired by Serge and others and chose to 
build his system with bananas
I liked what Bruce had done, that I started making banana modules too.  
There were other systems in Europe that
also used bananas.  Once you start using them you really get addicted, 
and frankly it's a bit of a drag when you find
yourself back in front of an audio-jack-only system because you're 
stymied and unable to do so many of the favorite  patching tricks that 
you've learned because the damn jacks just won't let you, and there 
aren't enough mults, and
you must simplify everything and give up all the wonderful feedback 
loops that you like to do and well, it all  just gets more vanilla, or 
more "east coast", or just not what the patch might have been if it had 
had a lovely panel full of banana jacks in the first place.  I think Mr. 
Therepnin got it right.

Go Banana!


Cynthia

http://www.cyndustries.com/




Derek Holzer wrote:
> My latest monstular synth is underway, with a nod towards the Buchla 
> and Serge classics. Which has led me to the question of whether or not 
> to banana it.
>
> So I wanted to ask people's opinions, pro vs con.
>
> I like the stackability of banana inputs, but you lose the possibility 
> of individual input attenuation.
>
> Also, how do people handle the signal summing with bananas?
>
> Does that mean an extra buffer on the output side of the modules in 
> the system rather than a summing buffer on the input side?
>
> And, do people still keep grounded, ac-coupled inputs on the same 
> modules for external audio signals? Or could an incoming audio signal 
> get "stripped" of it's ground via some converter panel, and run via 
> banana to the module? I see that the old and new Buchla stuff in 
> particular still uses grounded minijacks for some stuff like audio 
> inputs.
>
> What are people's compelling reasons to go banana over balanced minijack?
>
> In the end, will I have panels with both anyways?
>
> Best!
> Derek
>