Dunlop - Octavio

All about modern commercial stompbox circuits from Electro Harmonix over MXR, Boss and Ibanez into the nineties.
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azrael
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Post by azrael »

Fwiw, I fixed it. Not sure what was wrong, but it sounds great now.

Anyone know what the diff cap values do? I didn't really notice much of a difference going from 33uF to 22uF.

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Dr Jones
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Post by Dr Jones »

Alex,

Did you ever make your "body mod" by attaching the 0.047 uf caps at the input of the effect and transformer? If so, can you explain what you did?

Thanks.

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Alex Frias
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Post by Alex Frias »

I've found .047uF a very high value, so I used .022uF instead. A DPDT toggle to switch in and out that and the other cap, as shown at GGG. But to be honest, I rarely use it anyway, the original sound is much better IMHO.

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Dr Jones
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Post by Dr Jones »

Alex,

I got a question for you about the gain/boost engine. I've etched and drilled the tonepad pcb, but the Dunlop gain/boost enigne doesn't exactly work with it because there is the additional 22 uF cap and 5k1 resistor. That isn't really a big deal, I guess, because you can wire them off-board and solder onto the leads of the pot or resistors and then to ground, which is what I assume you did. But then there is the issue of the boost pot and the 22 uf cap connected to it. The tonepad schematic puts the boost pot between ground and the cap (100 uF on tonepad schematic, 22 uF on Dunlop spec schematic), but the Dunlop spec schematic puts the 22 uF cap between ground and the boost pot. Does the order of the cap and pot matter? Can the tonepad pcb be used as is by simply replacing the 100 uF cap with a 22 uF cap and the appropriate boost pot?

Thanks,

Dr Jones

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Alex Frias
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Post by Alex Frias »

I think it works properly as I kept the Tonepad order regarding the pot + cap positions. The Boost control has a very effective action along all the pot's course.

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Dr Jones
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Post by Dr Jones »

I got this circuit working yesterday morning and I have to say that it is bad ass! The effect is amazing. The octave is more apparent on the top notes, but the bottom notes have the broken synth-like quality that I really like. My thanks to all who have contributed to this thread.

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Waynerd
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Post by Waynerd »

Can anyone tell me if the black lead from the board at TP3 connects to the footswitch? You can see pictures of it at my post on BYOC.

http://www.buildyourownclone.com/board/ ... =9&t=26622

Thanks for any input.

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Bernardduur
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Post by Bernardduur »

I've read the discussion

Must say the unit strikes resembles to the original unit Tyco made it from:

http://wc6w.50webs.com/wc6wvint/pops.html?fr411g.gif
More on it!

Great to see! Great sounding unit!
'No more....... loud music.......'
Follow my love for pedals and amps on https://bernardduur.blogspot.com and https://www.instagram.com/bernardduur1

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Jaicen
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Post by Jaicen »

Any chance of some samples back to back with the stock Tycho unit?

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Volume11
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Post by Volume11 »

sinner wrote:Here is my funky version
If I want to take a crack at using this.... what should the size be when I go to print it? I have both photoshop and illustrator, with minimal knowledge. I've only etched a couple boards, so I am still new to it, but I want to build this pedal really bad. I usually use veroboard, but I want to get more familiar with PCB.
Thanks

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Volume11
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Post by Volume11 »

Volume11 wrote:
sinner wrote:Here is my funky version
If I want to take a crack at using this.... what should the size be when I go to print it? I have both photoshop and illustrator, with minimal knowledge. I've only etched a couple boards, so I am still new to it, but I want to build this pedal really bad. I usually use veroboard, but I want to get more familiar with PCB.
Thanks
This is the image I was trying to show in the previous post...
Image

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ddr
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Post by ddr »

Hi Folks,
Can you tell me the orientation of the transformer? In the analogguru and fuzzcentral schematics the side of the transformer marked primary is toward the diodes and output. Is this correct?

Thanks,
Dan

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sinner
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Post by sinner »

Volume11 wrote:
Volume11 wrote:
sinner wrote:Here is my funky version
If I want to take a crack at using this.... what should the size be when I go to print it? I have both photoshop and illustrator, with minimal knowledge. I've only etched a couple boards, so I am still new to it, but I want to build this pedal really bad. I usually use veroboard, but I want to get more familiar with PCB.
Thanks
This is the image I was trying to show in the previous post...
Image

Can't help mate, I lost all my data after OS crash :(

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dai h.
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Post by dai h. »

it's a good idea to have back ups(even multiple). Today even big 1.5-2TB drives are pretty affordable, and (probably?) you won't need anything that big for effects stuff. I try to back up regularly after losing a couple HDs simultaneously. (That was definitely not a good feeling.)

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ddr
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Post by ddr »

Volume11 wrote:
sinner wrote:Here is my funky version
If I want to take a crack at using this.... what should the size be when I go to print it? I have both photoshop and illustrator, with minimal knowledge. I've only etched a couple boards, so I am still new to it, but I want to build this pedal really bad. I usually use veroboard, but I want to get more familiar with PCB.
Thanks
I would print it, then place the transformer on the paper where it goes and see if it needs to be shrunk or expanded.

By the way, I don't think that is the most recent layout. Look at the next post down from where you got that one.

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ddr
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Post by ddr »

ddr wrote:Hi Folks,
Can you tell me the orientation of the transformer? In the analogguru and fuzzcentral schematics the side of the transformer marked primary is toward the diodes and output. Is this correct?

Thanks,
Dan
An update, I spoke to someone from Tycobrahe Sound and he told me the transformer is:
The primary was 1.2K, the secondary 600 CT -- 2:1 impedance ratio, 1.4:1 turns ratio with the low impedance side connected to the diodes.

The frequency response was fairly flat 40-20K at around 10 dBm.

The adjustment of the Boost knob is fairly touchy. And then it needs to be "played". The input level is also quite important. Properly tweaked it should just be on the threshold of sustaining.
So, I reversed the transformer I am using so that the secondary is toward the diodes. I think it sounds better now, but that just may be because I no longer need to have the intensity at zero (which was the case when I had the transformer the other way around).

Regarding the Dunlop, it already has the transformer facing properly, so if you are using the schematic posted in this thread you are fine.

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sinner
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Post by sinner »

:secret:

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Post by sinner »

Alex Frias wrote:No, I think our friend RnFR is just a bit confused by so many Octavias, as Dunlop promotes it as a Mr Hendrix original.

I made the cap exchange and some mid bass emerged, but nothing that big...

The only thing I really can't understand is the gain pot wiring. And to be honest, although I realy liked the resulting sound, I found the project using the standard Tycho scheme (with 22uF, not 100uF) it has lots of gain even with the pot on its minimun position. So I think Dunlop used a little trick to put it down a bit more...

Let's try to figure out:

Image
does the values are correct? R3 looks more like 1k8 to me...

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sinner
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Post by sinner »

vero on the way. Can't promised to be added today

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Post by sinner »

Radial caps are gay!

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