Buffer PCB to replace multiple jacks in the 191J

Repair or Modifications of the Roland System 100M
sjones
Posts: 118
Joined: Mon Sep 24, 2007 6:46 am

Buffer PCB to replace multiple jacks in the 191J

Postby sjones » Tue Aug 12, 2008 1:46 am

I've got a PCB design which will allow for the multiple array in a 191J to be replaced with a new set of jacks that will offer 3 cascading buffers. I'm going to convert all four of my 191Js as a proof of concept and will demonstrate buffer versus multiple. The more PCBs I build the cheaper the project will be.

Replacing the multiple jack PCB is fairly easy. There are 5 screws (3 on the front, two on the bottom) which remove the 191J face plate. You can then remove the the jack plate (the new PCB will mount onto that plate). The buffer requires voltage which can be pulled from the power supply and won't be a burden to it at all.

Not only would this enhance your ability to come up with extensive patching but it would also:

1. give you brand new switched jacks
2. buffer solves the voltage/signal degradation issue that multiples have
3. buffer solves voltage feedback issue that multiples have which can damage your modules

More to come ...

sjones
Posts: 118
Joined: Mon Sep 24, 2007 6:46 am

Postby sjones » Sat Aug 16, 2008 7:08 pm

I've worked out the cost and for getting all new switched jacks and a printed PCB so that basically you just have a drop in replacement for the 191j its going to cost about $135/ea. I can commit to four of these myself, so the more I do the better the chance of the cost being lowered. If there is no one else interested in replacing their multiple array with a buffered mixer I'll still do 4 for myself. It would be great to order all the parts/boards at once if there is interest though. Let me know, thanks!

frax
Posts: 8
Joined: Wed May 14, 2008 12:30 pm

Postby frax » Sun Aug 17, 2008 7:00 am

I'll take one.

/frax

sjones
Posts: 118
Joined: Mon Sep 24, 2007 6:46 am

Postby sjones » Sun Aug 17, 2008 6:43 pm

Great! I think its the sort of thing that needs to be built and demo'ed before people understand how terribly useful it is.

I wanted to clarify what I meant by dividing up the jacks into a group of 3 buffered mixers. As you know the current multiple setup is passive and consists of 4 jacks. Any of the four jacks can be an input and the remainder can be an output. Of course, you can also use passive multiples for crude mixing, but you don't necessarily have definite control over that.

So with 3 buffered (and cascading) mixers you can think of all the 'a' jacks as your input, and the b, c & d being your outputs. So if you plug into 1a then that signal is buffered and cascaded from 1b - 3b, 1c - 3c & 1d - 3d. In that case, its a 1:9. Now if you plug another input into 2a, then you interrupt the cascade and now you have two groups: 1a input with 3 outputs 1b, 1c and 1d : 2b input with 6 outputs 2b, 2c, 2d, 3b, 3c and 3d. So if you plug another input into 3a, then you interrupt the cascade again in the same way.

Adam-V
Posts: 52
Joined: Wed Dec 12, 2007 11:08 pm
Location: Melbourne, Australia
Contact:

Postby Adam-V » Mon Aug 18, 2008 2:08 am

Just thinking aloud here but would there be any use for making one or two of multiples simple 3 input mixers rather than 1 in 3 out buffers?

Cheers,
Adam-V

sjones
Posts: 118
Joined: Mon Sep 24, 2007 6:46 am

Postby sjones » Mon Aug 18, 2008 8:24 pm

I've thought that may be a good idea to have because even though I personally don't use the multiples as a mixer (well, not directly) some one else might have a real need for that. Can you give me some examples where you'd like to use the multiples as a mixer?

Adam-V
Posts: 52
Joined: Wed Dec 12, 2007 11:08 pm
Location: Melbourne, Australia
Contact:

Postby Adam-V » Mon Aug 18, 2008 11:18 pm

I don't particularly need these as I have other modules that perform these tasks but here's a couple of ideas:
    - Mixing of gates/triggers to allow multiple gate/trigger sources to trigger a single event
    - Precision addition of CV sources to create more complex modulation signals although the lack of input attenuation might be an issue if mixing of LFOs or envelopes is desired.


Cheers,
Adam-V

synth_ollie
Posts: 157
Joined: Tue Sep 25, 2007 7:52 am
Location: 100M City, Sweden

Postby synth_ollie » Fri Aug 29, 2008 3:19 pm

Im not sure if I would have any use of something like this myself, but Im really curious to see how it turns out anyway

and there are lots of simple stuff like this that could be placed in the multiples too.....

syncretism
Posts: 5
Joined: Sat Mar 28, 2009 6:55 pm
Location: US/Eire
Contact:

Postby syncretism » Sun Mar 29, 2009 5:19 am

This looks really interesting; will it be possible to revert to the old multiples, if necessary? What's the status of the project? Have I missed the boat?

Thanks!
Yours,
Niall.

reeja
Posts: 1
Joined: Wed Dec 24, 2014 9:29 am

Re: Buffer PCB to replace multiple jacks in the 191J

Postby reeja » Wed Dec 24, 2014 9:35 am

great stuff.

if only someone can tell me this in french since i mooved here...
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