Rocktave divider stereo output mod

[wcampagner]

Hello,

I'm building the Rocktave divider using the borad layout from GGG.

It has a lot of mods already in the board.

I'm planing to do the sereo output mod... i've already have the stereo closed jack and the two capacitors.

What i want to know is how to wire the stereo closed jack... i didn't understand the schematic.

On the board there are the points labeled "X" where the wires from the jack come from.

I've already figured out the tip and the ring wire... but the third one i don't know what to do.

Does anybody can help me?

Thanks in advance,
Wagner.

[Mark Hammer]

The final output mixer, IC1c, is set up as a unity-gain buffer.  As it happens, it needs to be inverting for the clean signal and noninverting for the other three signals, so that they can all be in phase at the mono output.  You will note that R17=22k=R18.

The stereo "break" jack in the article, essentially allows C8 to be connected to R17 when nothing is inserted in it, but breaks the connection when a plug is inserted.  IC1c doesn't particularly care that R17 is just left hanging there under those circumstances, and will remain unity gain for the other three signal sources (fuzz, F/2, F/4).  Unfortunately, there is no terminating resistor for the clean sound using this switchover scheme.  You will also note that the way Craig has drawn it, the assumption is that a single stereo plug will carry out two signals: clean on one line, and effect on the other.  You could actually just use a mono closed circuit jack to interrupt the C8/R17 path and it would work just as well.  The 3 processed signals would still come out J2 as before.

Does that make sense?

I have one of the GGG/Hazelwanter boards sitting populated, but I've never been able to figure out how to integrate the extra 4017 for alternate intervals, so it just sits there.

[Dean Hazelwanter]

Since Mark has answered the first question, the least I can do is answer his question. To get the additional intervals...

- Make sure Ux (4017), the 1K and 10K resistors at the bottom of the board are populated, as well as the diagonal jumper from U3 pin 11.
- Disconnect the top (terminal 3) connection from the 'divide by 4' pot.
- Connect the pad immediately to the left of the bottom 1K resistor labeled with what looks like a mangled 'R', to the top (terminal 3) of the 'divide by 4' pot.
- Connect the pad 'SW-C' to any one of pads '2, 3, 4, 5, 6, 7, 8 or 9' to select the interval. If you only find 2 of these intervals to be musically useful, use an SPDT switch to connect SW-C to the 2 useful interval's pads. Or use a rotary switch to connect SW-C to whichever interval pads you like.