VCO 12V build

Warung · Joined: Jun 28, 2017 Posts: 5 Location: Europe

Hello Im just a very beginner trying to build my first VCO. Can someone explain me what are these connections shown in the picture of pcb components? As i guess the upper one is just connector for supply line (socket type?) and what is the bottom one?

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translucent · Joined: Sep 29, 2006 Posts: 8 Location: the Netherlands

When building it for 12 Volt, you can fit a connector in order to connect the board to a Eurorack standard power bus (see also https://www.sdiy.info/w/Eurorack)

gdavis · Posted: Wed Jun 28, 2017 6:39 pm Post subject:

There are three different types of power connectors commonly used in modular synths (MOTM, DOTCOM and Eurorack IIRC?). The PCB includes pads for all three so you have the option of choosing which ever one you want. Your top box actually surrounds the pads for two different connectors. The lower box is a Eurorack style power connector which is normally +/-12V as Translucent mentioned. I think the other two are usually +/-15V, but there's nothing stopping you from using them for +/-12V other than you'd be defying convention which may lead to some confusion down the line.

Warung · Joined: Jun 28, 2017 Posts: 5 Location: Europe

Found the connection. Can someone tell me what wattage resistors i should use?

translucent · Joined: Sep 29, 2006 Posts: 8 Location: the Netherlands

Looking at the schematics I would say it doesn't matter, except for R1 and R2 that will have somewhat higher current flowing through them, so you may choose .5 or .6 watt resistors there to be on the safe side.

Warung · Joined: Jun 28, 2017 Posts: 5 Location: Europe

Does polyester and mylar film capacitors are the same?

wackelpeter · Posted: Tue Jul 11, 2017 12:46 am Post subject:

Yes.

An interesting summary from Harry Bissel for most of the different cap types and their use can be found here.

http://analogrules.com/capacitors.html

Warung · Joined: Jun 28, 2017 Posts: 5 Location: Europe

wackelpeter · Posted: Tue Jul 11, 2017 2:41 pm Post subject:

For most applications Wima MKP2 or FKP2 caps are good Options, apart from decoupling at the IC's which can be done with simple ceramic caps.
Those MKP and FKP are polypropylene and as per the list and the manufacturers advice best suited for timing caps, S&H, oscillators, etc.

Also have to admit that i had and still have some circuits with non proper caps inside... maybe soon i'll change some of them to see if i can observe any improvement.

translucent · Joined: Sep 29, 2006 Posts: 8 Location: the Netherlands