Roctave Divider Questions

[fogwolf]

Hi,

I did my best to search the forum but couldn't find answers to a few things I'm not clear about, so I apologize if these have already been covered. I'm looking at building the Dean Hazelwanter Roctave Divider and had a few questions. Primarily regarding the components layout at http://www.generalguitargadgets.com/diagrams/rcktavpl.gif I've been able to work out most of what's what by cross-referencing with Anderton's schematic and his original BoM, but there are a few things on the GGG layout that I'm unclear about.

1) I found a posting addressing this, but just to make sure I understand correctly, if I don't want the stereo mod, ignore the pads labeled with Xs and don't add the 2 5uf capacitors but I would solder in the jumper there. Is that right?

2) For the tone pot (R7), are both terminals 2 and 1 connected to pad "L" - do you just wire terminal 2 to terminal 1 and then wire terminal 1 to pad L? Sorry, this one seems obvious, but just checking, since I've so far only built project with full off-board wiring diagrams.

3) It looks as though the pad at SW-C is connected to the rotary switch for the additional frequency divisions mod, right? I've never used a rotary switch before - which terminal goes to SW-C? Also the pad directly beneath SW-C, the one that looks like it's labeled with an "F" (but I see where pad "F" is elsewhere on the diagram) connects to pin 2 of the 4017. In Anderton's schematic that pin should be connected to terminal 3 of the divide by 4 pot (R6) - so is terminal 3 of R6 just connected to this pad? If so, is the R6 pot's terminal 3 still also connected to the other "F" on the circuit (to pin 1 of U3 (the 4013 dual flip-flop))?

4) Speaking of the rotary switch, does anyone have a Mouser part # for one they'd suggest for using with this project?

5) Also does anyone have a diagram (or could someone explain) how the terminals on a rotary switch are laid out as far as knowing which terminal to connect to which pad on the circuit?

6) I saw someone say something in another posting about "rewiring the divide by 4 pot for the 4017 mod, which isn't mentioned on the GGG site" - I haven't been able to find this information on the forum - what needs to be done for this exactly - does this have to do with my question 4 above?

7) Finally (sorry for all the questions) I saw someone mention that Dean made a substitution for one of the ICs or something, but there's no BoM on the GGG site - does anyone have Dean's updated BoM?

Thanks, as always!

[Dean Hazelwanter]

Hi,

Sorry for the delay - I haven't been around much. I thought I had addressed a bunch of these questions before but wasn't able to find those replies either.

1) Right.
2) Right again.
3) I'll try to get back to you on this one in the next day or so.
4) Sorry, I don't have a Mouser number handy, but any SP2T (if you want to only choose from 2 of the extra intervals) or SP3T (if you want to only choose from 3 of the extra intervals)... up to SP8T (if you want to be able to choose from all 8 of the extra intervals - and not all 8 are really that useful) switch will work.
5) If you have a multimeter, use it to figure out the pinout of a switch if you already have it. What you will notice is that (assuming you have an SPXT switch - only one 'pole') one pin will connect to each of the other pins as the switch is turned. Read up in the FAQs about switch operation to give a better understanding of how they work.
6) Yup, all part of the same discussion.
7) The original Craig Anderton design used 4136 quad opamps, which are harder to find. My layout uses TL074 quad opamps which are easier to find.

Hope that helps a little.

[fogwolf]

Hi Dean,

This helps a lot, thanks! If you could get back to me whenever you have a chance about my 3rd question I think I should be set.

Hi,

Sorry for the delay - I haven't been around much. I thought I had addressed a bunch of these questions before but wasn't able to find those replies either.

1) Right.
2) Right again.
3) I'll try to get back to you on this one in the next day or so.
4) Sorry, I don't have a Mouser number handy, but any SP2T (if you want to only choose from 2 of the extra intervals) or SP3T (if you want to only choose from 3 of the extra intervals)... up to SP8T (if you want to be able to choose from all 8 of the extra intervals - and not all 8 are really that useful) switch will work.
5) If you have a multimeter, use it to figure out the pinout of a switch if you already have it. What you will notice is that (assuming you have an SPXT switch - only one 'pole') one pin will connect to each of the other pins as the switch is turned. Read up in the FAQs about switch operation to give a better understanding of how they work.
6) Yup, all part of the same discussion.
7) The original Craig Anderton design used 4136 quad opamps, which are harder to find. My layout uses TL074 quad opamps which are easier to find.

Hope that helps a little.

[Dean Hazelwanter]

3) It looks as though the pad at SW-C is connected to the rotary switch for the additional frequency divisions mod, right?

Yes

I've never used a rotary switch before - which terminal goes to SW-C?

SW-C goes to the 'common' or 'wiper' connection of the rotary switch. This is the terminal that connects to one of each of the other terminals, depending on the switches position.

Also the pad directly beneath SW-C, the one that looks like it's labeled with an "F" (but I see where pad "F" is elsewhere on the diagram) connects to pin 2 of the 4017. In Anderton's schematic that pin should be connected to terminal 3 of the divide by 4 pot (R6) - so is terminal 3 of R6 just connected to this pad? If so, is the R6 pot's terminal 3 still also connected to the other "F" on the circuit (to pin 1 of U3 (the 4013 dual flip-flop))?

Actually, the pad under SW-C is F' (F prime), but it's pretty hard to read. If you don't do the mod using the 4017, connect pin3 of R6 to F. If you do use the mod, connect pin3 of R6 to F'.

Make sense?

[fogwolf]

Ah, ok. Makes sense. Thanks again!

3) It looks as though the pad at SW-C is connected to the rotary switch for the additional frequency divisions mod, right?

Yes

I've never used a rotary switch before - which terminal goes to SW-C?

SW-C goes to the 'common' or 'wiper' connection of the rotary switch. This is the terminal that connects to one of each of the other terminals, depending on the switches position.

Also the pad directly beneath SW-C, the one that looks like it's labeled with an "F" (but I see where pad "F" is elsewhere on the diagram) connects to pin 2 of the 4017. In Anderton's schematic that pin should be connected to terminal 3 of the divide by 4 pot (R6) - so is terminal 3 of R6 just connected to this pad? If so, is the R6 pot's terminal 3 still also connected to the other "F" on the circuit (to pin 1 of U3 (the 4013 dual flip-flop))?

Actually, the pad under SW-C is F' (F prime), but it's pretty hard to read. If you don't do the mod using the 4017, connect pin3 of R6 to F. If you do use the mod, connect pin3 of R6 to F'.

Make sense?

[the recluse]

Actually, the pad under SW-C is F' (F prime), but it's pretty hard to read. If you don't do the mod using the 4017, connect pin3 of R6 to F. If you do use the mod, connect pin3 of R6 to F'.

Make sense?

NUTS!!

The Rocktave to date has been the only project I have never been able to make work, and this may be why.  I have to wait for a parts order to come in, and then this is going back in the test rig!

[Dean Hazelwanter]

I have to wait for a parts order to come in, and then this is going back in the test rig!
When you take another shot at it, and if you still have problems, I'll try to help.