[sdiy] to banana or not to banana

Wed Jun 24 23:56:06 CEST 2009

If you were sitting underneath the local radio station transmitter or your local
high-voltage power lines then this would be a real problem and that woudll apply
to 1/8" and 1/4" jack systems as well as many of them don't have or use the
screen. After all, you only really need the screen connection when
interconnecting between different systems - your own system already has all the
signal commons in place. Not having a screen also helps to reduce the thickness
and cost of those patch leads and my 3.5mm system patch leads are made from the
test leads that are used in good quality multimeter probes (the thick skinned
flexible type).

One would also assume that your leads are reasonably short (ie not 5m long and
thus run, more or less, from one jack to the next with out trailing along the
floor and so the chances of pickup are reduced.

If you do get noise problems from RF or mains then I would be looking at the
overall installation first to find the cause of the problem rather than going
through exhaustive techniques to reduce it. Much better to prevent a headache
from occuring rather than taking aspirin after it has started!

Best regards
Laurie Biddulph
www.elby-designs.com

On Thu Jun 25  7:28 , Stewart Pye  sent:

>Hi,
>
>I've been considering building a "banana" modular too. The thing that 
>concerned me is interference from RF and 240V mains supply due to using 
>unshielded cables. Can this be an issue?
>
>Regards,
>Stewart.
>
>
>
>
>Cynthia Webster wrote:
>> 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
>>>
>>
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