Banana Frac: The Definitive Guide

[parasitk]

So I woke up this morning considering selling my Frac to fund a Modcan and Serge system. After getting properly scolded by panda30y and Muff on Twitter, I realized that I really wanted to convert it to banana jacks and be rid of 1/8" cables and multiples forever.

There are a lot of posts about bananafying Frac modules around here, but honestly they're a bit scattered and I thought that perhaps a more focused thread might be handy for noobs like myself.

Searching turned up several threads with some bananafying teasers:

Banana Plugs on Blacet? http://muffwiggler.com/forum/viewtopic.php?t=840
Blacet modifications viewtopic.php?p=3273#3273
converting 1/8th to banana? http://muffwiggler.com/forum/viewtopic.php?t=2822

I'm not so much worried about switching jacks (add a switch), or normalization (not a fan of it to begin with). I am a little more concerned about panel mounted jacks and things of that nature.

Any tricks and tips for bananafying your Frac modules (any manufacturer - I have Wiard, Blacet, STG, Flight of Harmony, and Bananalogue) would be most welcome.

Banana is the future of Frac!



//Chris

[panda30y]

Well... i wouldn't say scolded...

I'm sure most of this information you already know, but it may be relevant to others.

via the BananaPlug man, you will want a reamer, as the jacks on the blacet modules are too small to fit the banana jacks. You can buy it at mouser along with your banana jacks of course.

Emerson/Johnson banana jacks are probably the preferred brand in the US, but I understand they are harder to get overseas. I know bugbrand recommended a brand that he uses that you can buy from rapidonline in the UK.

Banana cables can be bought at Testpath. Pomona are the preferred brand that Buchla and Serge will sell. You could make your own as well, as I know emerson/johnson sell the plugs, and I believe pomona does as well. Tom from Bugbrand seems to make his own as well and recommend the rapid connectors.

Aside from that, it seems that floating the ground is fine for the most part, as the banana jack only has one lug for the hot signal. Switched jacks you can install a toggle switch to retain function.

For panels that have board mounted jacks, I imagine you would have to deal with remounting the boards, or in some cases they have separate boards for the jacks and ribbon cables ran to them. You should be able to splice the ribbon cable for some panels and just run them straight to the jacks. I'm unsure about this, as I just stick to modules that seem easy to modify. So taking everything I say with a grain of salt. Hopefully BananaPlug will jump in to save the day, but there are many posts in the threads parasitk posted that should help.

[parasitk]

Aside from that, it seems that floating the ground is fine for the most part, as the banana jack only has one lug for the hot signal. Switched jacks you can install a toggle switch to retain function.

For panels that have board mounted jacks, I imagine you would have to deal with remounting the boards, or in some cases they have separate boards for the jacks and ribbon cables ran to them. You should be able to splice the ribbon cable for some panels and just run them straight to the jacks. I'm unsure about this, as I just stick to modules that seem easy to modify. So taking everything I say with a grain of salt. Hopefully BananaPlug will jump in to save the day, but there are many posts in the threads parasitk posted that should help.

Yeah I'm going to order a reamer, and I have some jacks already for my DIY stuff but thanks for adding that info here – I want this thread to be complete for the Frac user totally new to converting to banana (like myself!).

What to do with the ground cables on the old jacks is something I'm unclear about.

That bit in the other thread about the pullup resister also has me scratching my head a little. I asked about it there, and hope BananaPlug answers!

[panda30y]

I think it's to buffer the input a bit so the signal doesn't get too hot. That's my guess...?

[the bad producer]

When deciding upon formats to build my DIY stuff in a while ago, I decided upon Banana Frac, I found 5U too big, and Euro too fiddly, and wanted to save myself from Cliff Jacks and grey.

I have no Blacet modules myself, but have started to convert Doepfer and Plan B to Bananafrac (this probably seems like a silly idea!). On the most part it is fairly easy, though I have had to drill new holes in some PCB's to fix them to the panel, which is a little scary at times!

You've probably seen this thread on e-m, which may be of some interest;

http://electro-music.com/forum/viewtopic.php?t=32779

there are quite a few others about banana systems and ground in general, such as;

http://electro-music.com/forum/viewtopic.php?t=35507

I tend to put two sockets in place of switching jacks, which I can then link together with a patch cable or shorting bar to normalise.



Charlie

[DGTom]

awesome thread parasitk. I've been thinking we need this thread, maybe keep it rolling with all out trials & tribulations as we all go along.

I have started... slowly but surely! I can add a couple of modules to the piss easy, don't think twice about it, even your drunk uncle could do it despite constantally stopping to get you to pull his finger...

Oakley Little Lag (my bet is all the oakleys would be similar, they use the larger minijacks & the 5U under & over layout)

Banalogue 3P - despite the fact I feel kinda guilty pulling a nice little daughterboard jack mounting thing out, real easy!



(sorry, bit sketchy, its early)

BananaPlug will be able to answer this better than me, but, pull up resistors can be used where a connection needs to be high in its nominal state, like the Gate(rst) In on the Binary Zone, this is really easy, its just a resistor & there will already be a pad on the PCB where the normalled socket was hooked up, basically what happens is when you have no banana in the Gate(Rst) is pulled high keeping everything ticking along, when a jack is inserted the output impedance of the sending module overcomes the pull up resistor & you can jam your signal in.

Modules I am worried about; VCS... this has boardmounted jacks.. but there are transistors / resistors on those board, unlike the 3P, so you need to keep the little boards & remove the jacks. Little bit more de-soldering & will need some tricky way to re-mount the little boards I'm going to do some others before I tackle that one!

The only other annoyance I have is most of my metalbox modules have panel mount LEDs which are epoxied in place, this just means I'll have de-solder the wires from the board in order to remove the electronics prior to hole expanding. Still pretty easy converts because of the way the panels are laid out & all flying wires.

With the grounds I'm just tucking them away so they don't accidentally short to anything. The Lag is a wire which I just trimmed right back & stuffed inside the heatshrink that already shielded the wire. Too easy. With the 3P I just soldered my wires into the holes on the main board, these where linked to the jack board via jumpers which I removed, all very nice in the end.

At the moment I have 4 Frac'nana modules loving every minute of it!

but have started to convert Doepfer and Plan B to Bananafrac (this probably seems like a silly idea!)

This makes so much sense it hurts

I tend to put two sockets in place of switching jacks, which I can then link together with a patch cable or shorting bar to normalise.

Very cool! This has just changed the way I've been thinking about the Blacet micro LFO which normals a pulse into the CV in in order to bend the waveshape when no CV is used, gonna check the schem to see if I can get away with bringing it out to the front panel, I think the most I'd need to do is stick a 1K resisitor inbtween the pad & the banana!

[tragedybysyntax]

Thing is tho... if you can't banana every module in your system... you still have to use minijacks to use the modules that couldent complete the convert. DAMNIT. I have to check tonight but i'm pretty sure between the euro and frac modules I have.... alot of pcb mounted.

[Cat-A-Tonic]

There are, of course, ways of working around the PCB mount jack issue as others have noted.
I reckon if you're committed to having an all-banana system then you can find a way to bulldoze thru such obstacles.

...or there are also solutions like Ken Stone's 3.5mm to banana converter plugs.

This banana-frac movement is cool as hell,
but that doesn't mean you need to hop on the banana boat.

Personally, I'm too lazy to conduct such an enormous modification to my entire system and any other bits that I might acquire...
for now at least.

Though I must admit bananas do look, and I imagine feel, quite nice... but
I honestly don't have any problems using 3.5mm.
I don't have any of those accursed Cliff jacks that people tend to have issues with though.
Mono-splitters make 3.5mm just about as 'stackable' as bananas.
I don't find too much of a need for huge multiple jack panels.
Only occasionally do I mult beyond 4-6 points.

I must applaud those who undertake this bananafication though.
Your systems all look delightful.

[panda30y]

Yeah, I would have to agree that it is unfortunate than a few modules seem a little difficult to convert. But I've heard that people have converted the Hex Zone, and I would have to imagine that as difficult as any other module. Luckily, I decided to go into frac in March or April with the mindset of a banana frac system. So I try to choose modules that are easy to convert as most blacet modules are, metalbox can build for you in banana, all FoH modules come in barebones kits, and unless you run a shallow case, all of the diy pcb kits I've found so far will fit. The only 2 things that I might bite the bullet which might be difficult to convert are the window comparator and STG Wave Folder. I love the wave folder, but I might rather have 2 plague bearers. But what about a bugbrand or FoH delay? oh but I want the blacet I/O!? Wait! I need more space!

[parasitk]

From what I can tell I think the Wave Folder would be pretty easy. Everything is mounted off board, and STG thoughtfully used headers for all the cabling.

I agree that the VCS may be a pain, and I'm scared of messing with the Wiard modules because, well, they're Wiard modules! Don't want to fuck those up!

edit to add: I'm also not sure about the Plague Bearer – not because it'll be difficult, but rather the panel might get really ugly with all those closely spaced holes. I wonder if there's enough room for one banana for every minijack hole?

Though I must admit bananas do look, and I imagine feel, quite nice... but
I honestly don't have any problems using 3.5mm.
I don't have any of those accursed Cliff jacks that people tend to have issues with though.
Mono-splitters make 3.5mm just about as 'stackable' as bananas.
I don't find too much of a need for huge multiple jack panels.
Only occasionally do I mult beyond 4-6 points.

I felt the same... until I spent some time on banana based systems. Then everything changed.

[DGTom]

edit to add: I'm also not sure about the Plague Bearer – not because it'll be difficult, but rather the panel might get really ugly with all those closely spaced holes. I wonder if there's enough room for one banana for every minijack hole?

Thats the main reason I flipped mine sideways;



thing is, with bananas you don't need all the mini-jacks, these are just multed / 'summed' to the same 4 points on the PCB anyway, I've just been stacking the inputs.

Though I must admit bananas do look, and I imagine feel, quite nice... but
I honestly don't have any problems using 3.5mm.
I don't have any of those accursed Cliff jacks that people tend to have issues with though.
Mono-splitters make 3.5mm just about as 'stackable' as bananas.
I don't find too much of a need for huge multiple jack panels.
Only occasionally do I mult beyond 4-6 points.

I felt the same... until I spent some time on banana based systems. Then everything changed.

Before using bananas I thought they were kinda cool, after I'd built my lunetta using them it totally changed the way I thought about patching! It makes whole sets off modules feel & act like single devices, going back to that 'instrument or collection of modules' discussion, minijacks just feel clunky.

The only module I'm really worried about now is the Cynthia Saw Animator... the main I/O will be easy enough, but the 6 LFO outs on the bottom are so close together... it may require a totally new panel.

[panda30y]

edit to add: I'm also not sure about the Plague Bearer – not because it'll be difficult, but rather the panel might get really ugly with all those closely spaced holes. I wonder if there's enough room for one banana for every minijack hole?

Thats the main reason I flipped mine sideways;



thing is, with bananas you don't need all the mini-jacks, these are just multed / 'summed' to the same 4 points on the PCB anyway, I've just been stacking the inputs.

Does it work the same? I alway thought that you weren't suppose to stack the inputs?

[parasitk]

thing is, with bananas you don't need all the mini-jacks, these are just multed / 'summed' to the same 4 points on the PCB

I know you don't need (at least) all of the outputs on a banana PB (I'd keep the multiple inputs), but I'm working with the original Frac panel, and I'd be trying to stuff the bananas in the minijack holes. You made a whole new panel! If I convert my Frac I'd like to keep the panels the modules came with

[DGTom]

Does it work the same? I alway thought that you weren't suppose to stack the inputs?

You can't stack just any inputs. On (some) Buchla systems (I understand) you could stack pulse inputs because all the pulse outputs had a diode & the inputs where set-up as summing nodes, I'm playing with this idea in my lunetta at the moment because it would save a tonne of space & make patch programming complex gate patterns alot of fun.

The PB barebones board literally has 4 points to connect on the PCB (ignoreing the grounds on the signal in/out) As far as I know these are just hooked up to multiple minijacks on the PB modules, so stacking 2 bananas on the CV ins is doing exactally what the minijacks do, I asked flight about it in the FoH forum but I think he missed it, so i just tried it & it works fine.

The PB is a special case tho, as far as I understand it the design allows for this kind of missuse, I wouldn't do it with any other module.

@ parasitk, aaahhh that makes sense sorry, didn't realize, yeah, mine where barebones, not modules. You are in the same boat with the PB as I am with the Saw Animator... basically them holes is way too close

If I convert my Frac I'd like to keep the panels the modules came with

So would I ideally...

[DGTom]

.... maybe a whacky (or just whack) idea, but.

If its physically possible, I would be tempted to add bananas, if they fit in next to the pots like bugbrand layouts then just swap out 4 of the minijacks on the panel for switching jacks (maybe they are already) so every 2nd in/out on the bottom is normalled to the bananas.

[DonaldCrunk]

i've been CNCing front panels out of 'extruded PVC' for bananafrac stuff lately with the intention of starting my own system.

another forum member and i are going to be 'beta testing' the first run of these panels - mainly to find out how the fuck to attach PCBs to the panel and how they will hold up with use.

there's a little bit of flex in the middle, but given their other positive attributes (i.e. cheap, malleable, available) i'm still quite happy with them.

here's a run of blanks i did for fellow forumite mome rath:



sorry about the shitty pic.


anyway, all this to say, if any of you have any bananafrac stuff you want some front panels for, i'm happy to poop a few of them out for you. the blanks are very easy to work with with your basic hand tools and a drill if you don't already have a layout in mind, and i can also do a complete layout sans text if you want.

just send me a bit o cash to cover shipping and maybe buy me a beer while i cut your panels out.

i'm happy to do other formats as well in the future, but i'd really like to restrict this to frac for the moment as that's what seems to be working the best with this material.


i think it's a good time to start a bananafrac system

[Reese P. Dubin]

Once you go banana you never go back. Worth every minute of downtime IMO, of course I built my few Blacets with them right of the bat.

5 years from now, minijackers will be the minority.

[Randaleem]

Hi DC!

Nice looking layouts!

Did you mean exPANded PVC? (Your pic looks like that as opposed to extruded PVC.) I believe you'll find Sintra (popular trade name for expanded pvc) too flexible for successful ongoing panel use. Even exTRUded PVC is more flexible than the PCB material some have used successfully. For example it's more bendy than acrylic, which seems to work okay for some things and people, but many find to be also too flexible for reliable use.

The issue is that the flexing leads to component and potential solder joint failure for the panel mounted items. Depending upon how you do solve the PCB attachment issue, this flex can transfer to it, and lead to all kinds of sticky intermittent sorts of problems. FWIW, My first DIY synth in 1976 used black 1/8" acrylic for its panels. I haven't used that material for panels since...

There's also the static charge issue to deal with when you use plastic panels. One help here is use of aluminum HVAC tape on the rear and grounded.

To perhaps kill two (Or three) birds with one stone, you could rout a channel from the top to bottom panel mounting hole on the back face of the panel. To a depth and using a width accomodating an aluminum angle to which the PCB mounts. A sort of "stooge" bracket, to use a term common to MOTM. Only instead of using the pots only to mount(and protect) the PCB, this way the entire panel is stiffened from top rail to bottom.

I see you are already happy with your present efforts, so feel free to take or leave any portion. IOW, YMMV, and all that...

I agree it is a great time to start a BananaFrac system! And (shameless commercial plug) if you need rails, the FE's are pretty inexpensive and capable! synthcase.com, GeoMetrics heading. (FWIW, short lengths of FErail could act as stiffener/PCB mount too.)

Kind regards, Randal

i've been CNCing front panels out of 'extruded PVC' for bananafrac stuff lately with the intention of starting my own system.

another forum member and i are going to be 'beta testing' the first run of these panels - mainly to find out how the fuck to attach PCBs to the panel and how they will hold up with use.

there's a little bit of flex in the middle, but given their other positive attributes (i.e. cheap, malleable, available) i'm still quite happy with them.
<snip>
i think it's a good time to start a bananafrac system

[parasitk]

Okay I'll be converting next week, and I have some questions which are probably REALLY basic or obvious to any experienced DIYer (which I am not!), so I ask you all for patience!

1) On the Blacet modules, the ground wires tend to run back to the PCB. I've noticed that often a couple jacks are connected together, then a black wire goes back to COM on the board. When I desolder the mini-jacks, should I just snip or desolder those wires from the board?

2) When replacing a switching jack with an actual switch, what kind of switch works there and which lug of the switch gets connected? Switch terminology still confuses me.

3) I'm going to re-read what BananaPlug wrote about using a pullup resistor on the GATE(RST) jack on the Binary Zone. Are there any other modules need/can use that sort of trick?

Thanks!
//Chris

[BananaPlug]

1) On the Blacet modules, the ground wires tend to run back to the PCB. I've noticed that often a couple jacks are connected together, then a black wire goes back to COM on the board. When I desolder the mini-jacks, should I just snip or desolder those wires from the board?

Yes. You don't need them for bananas.

2) When replacing a switching jack with an actual switch, what kind of switch works there and which lug of the switch gets connected? Switch terminology still confuses me.

The jack incorporates the equivalent of a SPDT switch. The Blacet jacks I've seen are not in little plastic boxes so if you look carefully at the mechanics of the switch you can actually see what's going on. The extra wire for the switch usually goes to a pad marked with an S. If something is plugged in, the jack's tip connection is whatever was plugged in. Unplug that cable and the signal on the wire from the S pad is hooked up instead.

3) I'm going to re-read what BananaPlug wrote about using a pullup resistor on the GATE(RST) jack on the Binary Zone. Are there any other modules need/can use that sort of trick?

Maybe but usually it makes sense to add a switch.

Thanks!
//Chris

[parasitk]

Thank you!

The jack incorporates the equivalent of a SPDT switch. The Blacet jacks I've seen are not in little plastic boxes so if you look carefully at the mechanics of the switch you can actually see what's going on. The extra wire for the switch usually goes to a pad marked with an S. If something is plugged in, the jack's tip connection is whatever was plugged in. Unplug that cable and the signal on the wire from the S pad is hooked up instead.

So while that basically makes sense, I'm still not exactly clear on how you'd wire it up with a banana and SPDT switch. Sorry!

[BananaPlug]

You know how a switch works, right? Now look at the jack and see what the little bits of metal do when you plug something into it. Got it? Now ignore the ground wire. What's left is two wires and a switch. Bingo.

[DGTom]

Fellow banana fracers,

just wondering if anyone has converted Blacets Micro LFO to & would lend me the wisdom of yr experi-ances with regards to dealing with these pesky board mounted sockets

I have two ideas; first is expand the holes of the sockets towards the edge of the panel - drawback being an odd shaped hole & possibly a gap that will need a washer behind the banana.

2nd idea; (leaning in this direction at the moment) expand the size of the pot holes so that they & the board can be scooched over to the right, freeing up enough room on the left - drawback is misalignment between the knob & the ring of dots, but, this might make some room on the left for a switch to replace the normal in the Rate CV socket...

Plan to use a pull-up resistor on the Gate input, much like BananaPlug has described for the BZ Gate(Rst) input, hopefully that will work here.

Part of me is hoping that once I get the socket holes drilled out I'll get lucky & the bananas will just fit in... somehow I doubt it

[DGTom]

Well, after playing around & taking a closer look I realized the best way to do it will be to remove the pots & LED from the board & mount the PCB on stand-offs, little trickier, but will be alot neater than hacking the panel.

[DGTom]

They said it couldn't be done.... no wait, they said it probably shouldn't be done... wait, whose 'they' ... what?