Simple Octave Up schematic

SirPoonga · December 30, 2004, 01:36:29 PM

Well, I think i am going to give up for a while on finding a pitch changer pedal and just stick with an octave up.

I've been looking through many octave pedals trying to decipher which ones are clean octaves and which ones are actually octave fuzzes (some of them just say octave up).

I was looking at the SImple Octave Up schematic
http://www.diystompboxes.com/pedals/SOU2.GIF

I have a couple of questions about it being that I am a beginner in electronics. Under the 50 to 100l Lin pot there is 'cw ->', what does that mean? What is Ge on the diodes? And in the top middle that's just a cap coming off the power to ground, right? Also he says any transformer? Would there be something in particular to look for, otherwise I have parted out small electronics that have transformers on them.

Hal · December 30, 2004, 02:04:22 PM

http://www.generalguitargadgets.com/diagrams/simple_oct_up_ez.jpg

I think that should answer most of your questions.

cw means nothing. ge means the diodes are germanium (important) not any transforment, and FET input op-amp. Use the trans. speced in the other link.

SirPoonga · December 30, 2004, 02:16:26 PM

Very nice, thanks.

cd · December 30, 2004, 02:32:02 PM

CW indicates the clockwise direction, otherwise you could wire the pot the wrong way.

Eric H · December 30, 2004, 02:33:59 PM

Quote from: Halhttp://www.generalguitargadgets.com/diagrams/simple_oct_up_ez.jpg

cw means nothing. g

It means "clockwise" --referring to the rotation of the pot.

-Eric

SirPoonga · December 30, 2004, 02:48:00 PM

would TL082/TL082CP Wide Bandwidth Dual JFET Input Op Amp - 8 Pin DIP Catalog # 276-1715 from RS work?

David · December 30, 2004, 03:21:24 PM

Quote from: SirPoongawould TL082/TL082CP Wide Bandwidth Dual JFET Input Op Amp - 8 Pin DIP Catalog # 276-1715 from RS work?

Since this is a dual, you would use only one of the op-amps. You would then ground the inputs of the unused op-amp.

SirPoonga · December 30, 2004, 03:33:01 PM

Ahhhhh, I didn't see a single opamp at RS, though I may have searched for the wrong thing. I see the quad...

Is this a single opamp that would work?

LM741CN Operational Amplifier - 8 Pin Dip
Catalog #: 276-007

It's also good to know about grounding the inputs on the dual. Need to keep my options open. It's hard to find parts in stock in the middle of nowhere Wisconsin

Samuel · December 30, 2004, 03:48:10 PM

yes that is a single, but if you're just getting one or the other, the TL082 is generally respected as a superior performer to the 741

SirPoonga · December 30, 2004, 03:56:10 PM

Cool, I will prioritize that over the other one then. I'm looking for a small project to try out right now. But with so few parts needed I might as well get local if I can instead of paying shipping costs.

SirPoonga · December 30, 2004, 05:24:34 PM

Quote from: Halhttp://www.generalguitargadgets.com/diagrams/simple_oct_up_ez.jpg

I think that should answer most of your questions.

cw means nothing. ge means the diodes are germanium (important) not any transforment, and FET input op-amp. Use the trans. speced in the other link.

radioshack doesn't have Ge, does it....

jmusser · December 31, 2004, 01:08:14 PM

If you scroll forward to page 6, you'll see a review I did on this circuit. The first part of the review is refering to the NECK pickup, and not the bridge pickup. The neck pick up gives you the sustain and weird ring mod stuff on the high strings, and the bridge pickup gives you the crunch. I like this circuit a lot, and it's simple. It is a fuzz though, so if you're looking for clean go to another circuit like Scott Swartz's Octave Screamer.

SirPoonga · December 31, 2004, 01:42:46 PM

I breadboarded it last night. Sounds like a good fuzz on bass. I was getting a huge hum, not sure how yet....

Oh yeah, I only had one ge diode (stolen from some other electronics). So I put some other diodes in it. That shouldn;t cause a hum though. hum is usually ground loop issues. Though I don;t know how that is happening yet.

SirPoonga · January 03, 2005, 10:43:26 PM

Interesting. Well, I was breadboarding a Ruby amp when my sister walked by. I half took apart the SOU since I spread it out all over the breadboard. She wanted to put it back together. So while I was putting the ruby together on my side she was putting the SOU together on the other. We testested it, it worked perfectly. I added a 100uF cap in parallel on input and output (right, caps you do parallel, resistors series to add them together?)

Anyway it sounds good, no hum. The higher notes on my bass seem to sound a little better.

I could record a sample if I had a location to put the sound file.

Ben N · January 04, 2005, 01:17:51 AM

That's a pretty cool sister. If I wasn't married... :lol:
Ben

SirPoonga · January 04, 2005, 01:20:34 PM

She just took an electronics class in college

I got the hum when I plugged it back into my computer (using as a makeshift amp for now). But when I used headphones I got no hum. Hmmmm, interesting......

buildafriend · January 02, 2013, 01:16:48 AM

Quote from: Hal on December 30, 2004, 02:04:22 PM
http://www.generalguitargadgets.com/diagrams/simple_oct_up_ez.jpg

I think that should answer most of your questions.

cw means nothing. ge means the diodes are germanium (important) not any transforment, and FET input op-amp. Use the trans. speced in the other link.

I have every part I need for this just waiting... Does the circuit work? is this a tested design? I need to whip one together fast.

buildafriend · January 02, 2013, 01:17:22 AM

except those germanium diodes. what the crap is that? why not just 1n4007s?

Jdansti · January 02, 2013, 02:25:24 AM

^ The crap is:

Short answer> Ge and Si diodes sound different when to clip the wave form.

Long answer> http://www.diystompboxes.com/smfforum/index.php?topic=57927.0

samhay · January 02, 2013, 02:33:28 AM

If you can't find Ge diodes, then you might want to try Schottky's. Radio shack has a few of these...

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Simple Octave Up schematic