Roland 130 VCA PCB Design

vcfool · Joined: Jun 19, 2008 Posts: 23 Location: Barcelona

Hi,

Here's a PCB I'd like to share with you. It's one cloned VCA from the 130 module from the Roland System-100M. Rare parts that you will need are one BA6110 and one SK30A N-Channel FET transistor. I had some spare ones because I am sourcing parts to build a x0x0b0x.

First, I just cloned Roland's circuit, part by part. I don't know enough electronics to change many things. Also, someone with better experience in PCB designing, eagle cad and general electronics should have to look at this PCB: I designed it using common sense and what I learned DIYing. Of course the PCB works. I first breadboarded and tested the circuit. Then I designed, etched and populated the PCB. The module is actually finished and running.

I will not post the original Roland schematic here unless some moderator gives permission to do it. I downloaded it from curetronic site. There is a dual version PCB in there too: http://www.curetronic.com/curetrbau/neubau/130m.htm

-I used 2N3904 and 2N3906 instead of the 2SC1815Y and 2SA1015Y. These are used for the CV Lin/Exp converters so I thought it was not critical and gave it a try on a breadboard. The Lin/Exp responses still seemed pretty good to me without changing any resistor value around the transistors. But the pinout is different so if you want to use the original ones you'll have to cross legs or something.

-Of course, I also replaced the dual OpAmp for a single one. I used a TL071.

-I used a SK30A-Y, not a GR.

-I used 10uF electrolytic bipolar caps for the AC coupling (C1,C3). I don't know which will be the right polarity for them if using polarized caps. So ignore the polarity on the PCB parts layout.

-Finally some resistors were changed to match input levels, or because I didn't have the actual values. I used all 1% resistors but for R23 8K2, where I used 5% carbon because I didn't have that value on 1%. I guess you could use 5% everywhere in this VCA.

-Parts names match the first VCA from the original schematics. Extra parts are named 100 and up: Power input resistors/ferrites and decoupling caps.

I could document all this better if there's enough interest.

Thanks for reading.
Enjoy!

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Roland 130 VCA Clone - PCB Design

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Roland 130 VCA Clone - Parts Layout

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Roland 130 VCA Clone - Populated PCB

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Sebo · Joined: Apr 27, 2007 Posts: 564 Location: Argentina

I have some spare BA6110, I will be building one of this in the future.
Thanks a lot vcfool!!!

Luka · Joined: Jun 29, 2007 Posts: 1003 Location: Melb.

how does it sound?
do you get signal or cv bleed?

i also have some spare ba6110s and looking for a tight vca for my quadraphonc mixer module. i was going to use 3080 core ones but i might change if the 6110 sounds good just to use up my final 6110 stock

what is with the buffer option next to the 6110?

bubblechamber · Posted: Sun Apr 12, 2009 7:27 am Post subject:

thanks for posting this. futurelec has 2sk30 trannies for $.20, if anyone's looking for them. the tend to have a lot of weird japanese trannies.
david

Junk Rhythm · Joined: Jan 07, 2008 Posts: 81 Location: San Francisco, CA

Thanks for posting. I have some BA6110 and 2SK30 so I'll breadboard it up in the next week to check it out.

vcfool · Joined: Jun 19, 2008 Posts: 23 Location: Barcelona

peng · Posted: Fri Apr 17, 2009 12:41 pm Post subject:

Luka · Joined: Jun 29, 2007 Posts: 1003 Location: Melb.

thanks for the info gents. peng ive picked up similar info from sites like bergfotron. unfortunately i have no 13600 otas just a huge pile of 3080s and a few 6110s. now the game is all about using what i got Smile

ill etch up one of these boards tomorrow and check it out
is it possible to get a pdf of the layout?

jbeuckm · Posted: Sat Dec 26, 2015 7:12 pm Post subject:

MPF102 seems to work fine, but you have to bend the legs for this layout.

Any chance I could get a copy of the Eagle files? I would like to bring the connectors over to an edge to minimize wiring.

Thanks!
Joe

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cslammy · Posted: Sat Mar 30, 2019 9:03 am Post subject: