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peng
Joined: Feb 23, 2006 Posts: 111 Location: Chicago
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Posted: Mon Mar 09, 2009 11:27 pm Post subject:
Frac rack Banana Jack...some spec guidlines |
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Let me start by stating who I am.
I am MegaOhm Audio and run these two websites:
www.megaohmaudio.com
www.fracanana.com
There's nothing on the fracanana site yet.
So, I started out doing small module runs a few years ago in MOTM format. This led to some custom modules done in Modcan A format. I fell in love with bananas!
Last Nov I made a pcb for a Delta VCF and did a batch of five MOTM format and a few Modcan A format. It turns out this was a no-no. One said No outright and the other gave me the impression that permission may be conditional. No problem. To each his own.
So I have abandoned both formats. If it's not FULLY open then I'm not interested.
For 1/4" format I have settled on Moog/Synthesizers.com format. There are many benefits to this form factor but that's for another post.
For banana jack format I settled on Frac Rack. Racks ard power supply are easy to get and are priced reasonably. Also, the smaller form lends itself to live rigs which is very much an interest of mine.
While waiting for my panels to arrive, I saw that BugBrand put out a line of cool modules in banana frac format. I was VERY happy. The more people doing this format the better. Also, Metalbox does versions of their CGS modules in banana jack. Very cool.
So, I'm not here to dictate the standards. I'm not that presumptuous. This topic is an effort to establish some rough guidelines for DIYers and/or companies that are interested in this format so that a variety of modules from a variety of places can play together happily.
Jack colors.
I think one of our members, Neandrewthal, is on the same page here (please chime in).
Green - audio input
Yellow - audio output
Blue - CV input
That's all I have for now. My first module was a Delta VCF and that is all it needed. I went with green for audio input because that seems the standard for old analog computers (and because I really like the color green!). Yellow, for some reason, seemed intuitive. Maybe it is from the Modcan A modules I made? Blue because Serge and Buchla use it and it seems like the standard.
I am a little biased here because I will be using colored knobs. The most populous jacks on most modules will be audio in and CV in. The jacks and knobs that I like the most on a black panel are blue and green. So...there's my logic!
If we can accept the above, then what about the remaining colors and functions?
Red - Logic? Input or output...or both?
Brown - System ground?
Any more functions that need colors? How about CV outputs?
For electrical standards I propose...actually going with the common standards:
audio signals - +/-5V or 10Vp-p
CV signal - 0-5V (for example: an envelope output)
Gate,Trigger, Pulses - I'm going with 0-5V but higher signal here shouldn't matter much. How about threshold voltage? Anything above 1V equals on/high?
Power: +/- 15V
I'm sure I am forgetting some things.
Give your opinions and suggestions. I think this format is really going to take off for a variety of reasons. My thought is it would be best to have some rough standards so that modules from a variety of different sources will patch and play well together. Looking forward to some feedback.
Thanks,
p.
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Fracanana / MegaOhm Audio Delta VCF |
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The Bad Producer
Joined: Mar 08, 2009 Posts: 282 Location: The Manhole
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Posted: Tue Mar 10, 2009 5:28 am Post subject:
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Hi Peng,
Very interesting, I have started making Banana Frac panels for myself, after starting on bananas with an enormous 16 sequencer project (I was led to bananas by cost, each sequencer had 64 sockets, and I could get non-ROHS bananas from Rapid here in the UK for next to nothing).
I have a Eurorack rig and was tempted to continue in the format but continually failing 3.5mm sockets kind of did my head in, and the cost of the racks is too much, and a bit fiddly somehow DIY fashion.
I have thought about colour coding, and done a bit of research, I found out that there are several Forum members who have also thought about this:
Rykaard:
Audio out = orange
Audio in = purple
CV out = yellow
CV in = blue
Digital / Clock in = black
Digital / Clock out = white
ADSR trig / gate = grey
multiples = green / white
Neandrewthal:
Logic In: Red
Logic Out: Orange
CV In: Blue
CV Out: Pink
Audio In: Green
Audio Out: Yellow
Bugbrand:
· Blue = Control Signal Input
· Red = Control Signal Output
· Yellow = Audio Signal Input
· Green = Audio Signal Output
It seems a good idea to set a rough kind of standard, but AFAIK I would not be able to get my hands on the more esoteric coloured bananas from the UK, Rapid seem to only sell Red, Green, Yellow, Blue, White and Black.
I will also be making lots of effects in Frac format (mainly Haible clones etc) and I'll probably put 1/4" ins and outs on these (alongside the bananas) for ease of patching to my samplers and mixer...
Charlie |
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peng
Joined: Feb 23, 2006 Posts: 111 Location: Chicago
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Posted: Tue Mar 10, 2009 7:53 am Post subject:
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Hmm... this might be harder than I thought it would be. I guess bananas lend themselves to a greater variety which is good and bad I suppose.
Everybody has Blue as CV inputs. It seems we came to a consensus naturally for that one.
Upon futher thought, I like red for Logic inputs. Logic being any On/Off or two state signals (i.e.: gate and trigger inputs, Boolean type functions, start stop, etc.)
I have no problem assigning the most populace jacks with the easily available colors that you listed.
What i have in mind so far:
Blue = CV in
???? = CV out
Green = Audio In
Yellow = audio out
Red = trigger/gate/logic,etc. input
I also have another agenda. I am trying to mate colored knobs with the relevant jacks. I don't really like how the grey knobs look, so I'm not looking to use grey jacks (unless it is some function that doesn't require an attenuator).
I don't know where to get pink jacks.
The blue jacks that BugBrand uses look a lot darker than the jacks I have. I like them darker (better matches the knob).
I suppose panel color would make a difference in what jack colors to use. For instance, black jacks on a black panel is not to my taste, but black jacks on a silver panel look great.
It could be that my idea for a standard (even a rough one) is not appealing to all. Hopefully others will jump in and tell us what they like and why.
p. |
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creatorlars
Joined: Nov 26, 2007 Posts: 524 Location: Denton, TX
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Posted: Tue Mar 10, 2009 8:24 am Post subject:
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This is a great thread -- I am also using banana jacks and matching colored knobs. Generally my standard is...
CV/Audio input = Colored jack w/Colored knob for attenuator
CV/Audio output = Black jack
Any digital/logic input or output = White jack
The "color" varies from module to module, which I preferred to settling on a color standard from the beginning. This way I can color-code types of modules, or use it as a dating system to remember when I made certain modules. I started with yellow, but moved to orange recently. I use input attenuators where ever possible, and they always use colored knobs connected via a line to the appropriate jack (like your panel.) I have used a couple white knobs for threshold-based controls such as trigger sensitivity.
I am very satisfied with this so far, the only thing that bugs me is that the black jacks and black knobs blend against the panel when viewing from afar, so the overall synth doesn't give the striking impression it could. The bad thing is that most of the jacks/knobs on the synth are black, and it would be very expensive to replace them all. If I did, maybe I'd use white knobs/jacks for all outputs, and pick something else for digital signals.
For my panels, I am using MOTM-sized panels. Typically layout is in a 0.875" x 1" grid, same spacing for jacks and knobs. For rack panels, it's a 1" x 0.75" grid, which varies a bit depending on the needs of the module.
For the video synthesizer modules I'm working on, I've decided on using frac panels, still with banana jacks. Since with modules like the color encoder, you have Red, Green and Blue inputs, there is of course no better excuse for using appropriately colored jacks and knobs for these. |
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fluxmonkey
Joined: Jun 24, 2005 Posts: 708 Location: cleve
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Posted: Tue Mar 10, 2009 9:18 am Post subject:
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not as a recommendation, but you might also think about Serge:
Red is used for trigger signals
Blue for DC coupled signals
Black for AC coupled signals
Purple is used for sync.
no distinction between in/out, afaik. i think this "standard" is more of a guideline than a Law, and there is variation especially in older panels.
herding cats is a old and noble undertaking... best of luck!
b _________________ www.fluxmonkey.com |
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peng
Joined: Feb 23, 2006 Posts: 111 Location: Chicago
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Posted: Tue Mar 10, 2009 9:22 am Post subject:
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bbob wrote: |
herding cats is a old and noble undertaking... best of luck!
b |
LOL!
Thanks! |
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peng
Joined: Feb 23, 2006 Posts: 111 Location: Chicago
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Posted: Tue Mar 10, 2009 9:38 am Post subject:
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creatorlars wrote: |
The "color" varies from module to module, which I preferred to settling on a color standard from the beginning. This way I can color-code types of modules, or use it as a dating system to remember when I made certain modules. I started with yellow, but moved to orange recently. I use input attenuators where ever possible, and they always use colored knobs connected via a line to the appropriate jack (like your panel.) I have used a couple white knobs for threshold-based controls such as trigger sensitivity.
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I can relate to your point of having different colors for different modules. At some point I will be building self contained instruments as opposed to separate modules and probably use a system like: red for VCF controls and jacks, blue for VCO A, Green for VCO B, etc.
A benefit to establishing a common color scheme is really to the end user in putting together modules from various makers and having them all work together intuitively. Another benefit is less reliance on text.
A third plus would be to the manufacturer/builder because we wouldn't need to change colors for each customer dependent on which brand of module they buy first.
For the DIYer building modules for him/herself all of this is a lessor issue.
It seems there may be as many color schemes as there are builders, so who knows.
It is very interesting to hear the perspective of others.
p.
p. |
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neandrewthal
Joined: May 11, 2007 Posts: 672 Location: Canada
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Posted: Tue Mar 10, 2009 10:06 am Post subject:
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If I could start over I would do a banana frac, but these 60 3.5 x 8.75" panels and 1300 1/4" jacks I have lying around or already in use are telling me otherwise. Maybe after I run out of those
peng wrote: |
Everybody has Blue as CV inputs. It seems we came to a consensus naturally for that one.
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I actually came up with my color scheme synthaesthetically, by closing my eyes and asking myself "If I were a CV input, what color would I be?" Maybe everyone else did the same
peng wrote: |
I also have another agenda. I am trying to mate colored knobs with the relevant jacks. I don't really like how the grey knobs look, so I'm not looking to use grey jacks (unless it is some function that doesn't require an attenuator).
I don't know where to get pink jacks.
The blue jacks that BugBrand uses look a lot darker than the jacks I have. I like them darker (better matches the knob).
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I'm trying to do the matching thing too, but I wasn't planning on it before I made my color scheme. Luckily the CV inputs and audio ins/outs are easy to match up with knobs, but I don't know what to do about pink knobs for pots that are associated with CV outputs. _________________ " I went through quite a few trannies til I found one I liked" - Wild Zebra |
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numbernone
Joined: Aug 16, 2006 Posts: 477 Location: new york city
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Posted: Tue Mar 10, 2009 6:18 pm Post subject:
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I feel like the bad guys in 1984 or something...
All inputs-GRAY
Out (primarily audio)-WHITE
Out (primarily control)- BLACK
DUUUUULL DULL DULL DULL
But they do look nice against solid colored unlabeled panels. |
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Luka
Joined: Jun 29, 2007 Posts: 1003 Location: Melb.
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oscilloclast
Joined: Sep 29, 2005 Posts: 49 Location: VA
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Posted: Tue Mar 10, 2009 8:05 pm Post subject:
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I've also been agonizing over this issue as I convert my 1/8 jack fracs to banana jacks. One of the big issues I have with separating audio and CV into different colors is that it seems like a false distinction. Except for signal that goes into a filter (which tends to be in the audio range) most other places that "traditionally" accept a CV signal can accept an audio signal and visa versa. In my mind the reason to go to banana plugs is to break out of the traditionally dictated rules about what types of signals should go where and really start exploring the full potential of a system. I'm leaning towards a separate color for:
AC signal in
AC signal out
DC signal in
DC signal out
Logic in
Logic out
sync
ground
etc.
In reality this kind of follows the Serge distinctions (separating AC and DC signals) (oops I seem to be getting back some traditionally dictated rules...._) which in my mind seems to be the only real concrete distinction you can make between signals (not including sync, triggers, gates etc). I think its worth giving some thought to the idea of forcing oneself to see the ways modules can interact in a different way then you are used too. For myself just going through the process of trying to figure out the banana jack color scheme has really opened my eyes to how I've pigeon holed myself into seeing module interaction in certain ways.
On a side note I really can't explain why but don't want to buy the Pomona cords (cost probably but I also don't like not being able to adjust the length of on my cords) so I've been looking everywhere for good quality, rear stackable (side stackable seems like a nightmare on a frac panel) cheap banana plugs that come in different colors. The best I've been able to come up with so far is the "quality banana plugs" at futurlec (http://www.futurlec.com/Banana-BananaPlugs.shtml), they come in five different colors, use a set screw (not solder), are rock solid, gold plated, rear stackable and are only 95 cents a piece. I also tried out the "stackable type banana plugs" from futurlec and they are absolute junk. Anyone else come up with a good source for banana plugs? |
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BananaPlug
Joined: Jul 04, 2007 Posts: 307 Location: Philly
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frijitz
Joined: May 04, 2007 Posts: 1734 Location: NM USA
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oscilloclast
Joined: Sep 29, 2005 Posts: 49 Location: VA
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Posted: Thu Mar 12, 2009 8:37 am Post subject:
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Thanks for the lead on the colored test lead wire, looks like good stuff!
David |
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zthee
Joined: Feb 20, 2008 Posts: 414 Location: Stockholm
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Posted: Thu Mar 12, 2009 2:24 pm Post subject:
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bbob wrote: | Red is used for trigger signals
Blue for DC coupled signals
Black for AC coupled signals
Purple is used for sync.
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That's what I'm using. And by trying to be in the true nature of the Serge spirit - I'm breaking the rules as often as I can....
BananaPlug wrote: | FYI: Pomona's at less than $5 each here. |
Thank you!! |
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creatorlars
Joined: Nov 26, 2007 Posts: 524 Location: Denton, TX
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Posted: Thu Mar 12, 2009 2:51 pm Post subject:
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I can vouch for Testpath -- ordered over 30 cables from them and they always ship really fast, and all the cables come individually wrapped! |
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BananaPlug
Joined: Jul 04, 2007 Posts: 307 Location: Philly
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Posted: Thu Mar 12, 2009 2:57 pm Post subject:
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Quote: | Red is used for trigger signals
Blue for DC coupled signals
Black for AC coupled signals
Purple is used for sync. |
You can count on Red, Black, Blue. All the other colors are bit inconsistent over the years. My '80s stuff has grey sync jacks, a '90s panel has purple for the SSG coupler jacks and yellow for ADSR trigger inputs. Stuff I've converted or built uses Red, Black, Blue, Grey.
The Modcan A color code would be another established standard to look at. The logic stuff is red there too. I think this is all there is to it:
Red - Gates, Trigger, etc.
White - CV in
Grey - Signal in
Yellow - Any out that wouldn't be red
To me the white/grey distinction is vague and not as useful as the Serge blue/black. On the other hand the Modcan system ins and outs are never mistaken for each other, which is not true of the Serge.
The nice thing about standards is that there are so many to choose from. |
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peng
Joined: Feb 23, 2006 Posts: 111 Location: Chicago
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Posted: Sun Mar 15, 2009 10:47 am Post subject:
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[quote="BananaPlug"] Quote: |
The Modcan A color code would be another established standard to look at.
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My ladyfriend doesn't like the bright colors look (I do!). She thinks the Modcan A color scheme is more tasteful. Thing is, I want to build modules to sell (along with pcbs for SDIY). Modcan states that he doesn't want anybody else building in that format. I only want to build in 'open' formats (even for my own personal system). Plus, the color scheme looks bad with my colored knob plans. Grey Davies are not so nice.
p. |
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bugbrand
Joined: Nov 27, 2005 Posts: 846 Location: Bristol, UK
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Posted: Mon Mar 16, 2009 2:36 am Post subject:
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Heya Peng -- yeah, I saw your VCF design recently and it really caught my eye -- this is really fantastic to see more banana based Frac designs.
My choices (as written above) did come from semi-conscious-ways! Coupled with availability of parts -- sourcing of decent banana plugs & sockets really influenced the choice of colours as, as mentioned above, Rapid only do certain colours. Their ones are, in my experience, very good value and quality - the bum is that Rapid are not good for people outside UK. (though if you wanted some purchased and sent to you I'd be very happy to help)
I did think it important to highlight differences between inputs and outputs. Differentiating between audio & control signals, though, is quite a fuzzy line for sure - I think that as long as modules are well documented, people will quickly learn how things work. As noted, colours really do help give a quite instant recognition of function.
Its funny you went for green as audio input! Opposite to me.. Oh well.. (this comes, I guess in part, from my long standing use of coloured hookup wires - I always went for yellow on inputs and orange on outputs, so when it came to choosing banana colours..)
I had wondered about other colours for clocking / etc signals, but feel that they can fit very happily into the normal control signal family -- I think its a good design practice to have clock inputs with a low threshold level (say 1v) and polarity protected so you don't have to be too careful about the type of clocking signals used.
I haven't used black other than for system ground (between PSUs) and white is not in any use so far..
Oh - one thing - I've gone for keeping all my modules very shallow (max 3.5") to fit into custom 4" deep cases - I always thought Fracs were wasting a load of space.
Great stuff! _________________ http://www.bugbrand.co.uk
http://www.bugbrand.blogspot.com |
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peng
Joined: Feb 23, 2006 Posts: 111 Location: Chicago
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Posted: Sun Mar 22, 2009 6:23 pm Post subject:
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bugbrand wrote: | I think that as long as modules are well documented, people will quickly learn how things work. |
Good point. Umm...gotta go write out that Delta VCF doc!
bugbrand wrote: | I think its a good design practice to have clock inputs with a low threshold level (say 1v) and polarity protected so you don't have to be too careful about the type of clocking signals used. |
Agreed.
bugbrand wrote: | Oh - one thing - I've gone for keeping all my modules very shallow (max 3.5") to fit into custom 4" deep cases - I always thought Fracs were wasting a load of space. |
Ohh! My Delta VCF pcb is 5" x 3.5". Frac needs to be mounted the long way so I actually use up all the space in a 6" depth!
This is because I use the same pcb for my Fracanana modules and my large 1/4" jack format. This may change in the future so I will definitely keep the 3.5" depth in mind if I decide to do different pcbs for frac and large format.
Thanks for getting in on this conversation and best of luck with the modules. I hope they are selling well.
P. |
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creatorlars
Joined: Nov 26, 2007 Posts: 524 Location: Denton, TX
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Posted: Tue Mar 24, 2009 8:08 am Post subject:
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While we're on the topic of specs for Banana jack SDIY, what about tackling the issue of modules designed to use switched jacks, and converting them for bananas?
I run into this quite often -- I generally add a toggle switch, extra jack, a push/pull pot, etc. as works with the module, but I wonder if any of you have any other ideas or suggestions? For example, does a simple signal detecting circuit exist that could trigger an electronic switch for this kind of purpose? |
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peng
Joined: Feb 23, 2006 Posts: 111 Location: Chicago
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Posted: Tue Mar 24, 2009 9:48 am Post subject:
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creatorlars wrote: | While we're on the topic of specs for Banana jack SDIY, what about tackling the issue of modules designed to use switched jacks, and converting them for bananas? |
I've used shorting double plugs on a lot of modules. The frac version of the Delta VCF can also use a shorting plug between the VCF out jack and the VCA in jack. The jacks have to be spaced 0.750" apart. I have always thought these would be great in stand alone type instruments and the Buchla Music Easel uses them to great effect.
The other way I've done it is with toggle switches but, for me, a switch is the most expensive panel component so I try to be conservative with how many I use (!). On the other hand, a switch is playable and can be used to good effect.
As far as a special circuit goes...I'm not having any great ideas. Maybe a comparator(s) to sense if the input signal deviates from 0V which turn on the jack input and turn off the 'normalled' input?
p.
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peng
Joined: Feb 23, 2006 Posts: 111 Location: Chicago
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Posted: Tue Mar 24, 2009 9:51 am Post subject:
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peng wrote: |
Maybe a comparator(s) to sense if the input signal deviates from 0V which turn on the jack input and turn off the 'normalled' input? |
I should have added: Turn on and off an analog IC switch. |
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loss1234
Joined: Jul 24, 2007 Posts: 1536 Location: nyc
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creatorlars
Joined: Nov 26, 2007 Posts: 524 Location: Denton, TX
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