Mad Professor Sky Blue Overdrive [traced]
- analogguru
- Old Solderhand
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I would think so.ibodog2 wrote:Anyone able to decipher the value from the markings? Would it be a 1K linear?
Try acetone (or the finger-nail remover from your girlfriend or mother).Any tips for removing the neoprene/glue left over on the bottom?
Heat it with a soldering iron an remove it with a pick or little flat screwdriver.How about the hard black gunk at the top?
And when you take another pictures please don´t forget to make one (or more) where the wiring between the pcb and the potis can be seen.... yes and one with the tracks between the FET´s.
analogguru
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.
- TheLemon
- Breadboard Brother
Cool stuff! From some of Bjorn's recent designs, I am guessing that the transistors are used as clippers shunted to ground while the red LEDs are used as clippers in the opamp feedback loop. Although, the OP275 is a dual op amp chip.. hmm.
- culturejam
- Old Solderhand
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analogguru wrote: finger-nail remover
Reminds me of that awful torture scene in Syriana where Clooney gets his fingernails pulled out with pliers. Ouch.
I have a few carbon film resistors that are aqua-green and have four color bands. At first I thought they were inductors. But those inductors are usually in the low micro-henry range at that size. Not sure how useful they would be in this context.ibodog2 wrote: Actually, are some of them inductors?
- analogguru
- Old Solderhand
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Ooops.... somewhere the word color got lost....culturejam wrote:analogguru wrote: finger-nail remover
Reminds me of that awful torture scene in Syriana where Clooney gets his fingernails pulled out with pliers. Ouch.
should read finger-nail color remover.
analogguru
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.
- IvIark
- Tube Twister
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COD V1.0 on the PCB?
Dano Coolcat Overdrive clone!
Dano Coolcat Overdrive clone!
"If anyone is a 'genius' for putting jacks in such a pedal in the only spot where they could physically fit, then I assume I too am a genius for correctly inserting my legs into my pants this morning." - candletears7 - TGP
- mictester
- Old Solderhand
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Perhaps. More likely "Crap Over Drive V1.0"! I was very disappointed when I tried one of these recently.IvIark wrote:COD V1.0 on the PCB?
Dano Coolcat Overdrive clone!
"Why is it humming?" "Because it doesn't know the words!"
- Greg
- Old Solderhand
The plastic parts will melt before the goop is destroyed.. you need to use localised heat.ibodog2 wrote:I was looking on this site for some degooping techniques (in addition to the soldering iron AG mentioned). What do you think would happen if I rigged this board up in a toaster oven component side down over a small pan to try to melt the goop off? How hot do you think it would need to be to melt the goop and not damage the board or components?
culturejam wrote: We are equal opportunity exposure artists.
- mictester
- Old Solderhand
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I was expecting something rather different - these have been hyped so much, I was expecting something special. The "Z" control just loads down the pickups, and just loses some level with modern humbuckers - it's a wasted control. The "Texture" control is a tone control that they got wrong, and decided that because it sounds a bit weird, they can leave it like that. It also hisses more than a modern pedal should. I was not impressed.ibodog2 wrote:Not that I disagree with you, but what were you expecting versus what you heard when you played it?mictester wrote:Perhaps. More likely "Crap Over Drive V1.0"! I was very disappointed when I tried one of these recently.
"Why is it humming?" "Because it doesn't know the words!"
- Greg
- Old Solderhand
These are 2 things that BJ seems to like to do with his circuits, and I agree that they're often not terribly effective.mictester wrote: I was expecting something rather different - these have been hyped so much, I was expecting something special. The "Z" control just loads down the pickups, and just loses some level with modern humbuckers - it's a wasted control. The "Texture" control is a tone control that they got wrong, and decided that because it sounds a bit weird, they can leave it like that. It also hisses more than a modern pedal should. I was not impressed.
A pot to lower Input Impedance and a non-straight forward Tone Control that only allows limited tones.
culturejam wrote: We are equal opportunity exposure artists.
- Greg
- Old Solderhand
That's a pretty good description I think.. and the problem is that you can't just add or cut Treble or Bass individually.. which is often needed to suit your other equipment.ibodog2 wrote: On one side the tone is more mid rangey and the other side the highs and lows are hyped. Like a car stereo graphic eq going between smiley face and slight frowny face settings.
culturejam wrote: We are equal opportunity exposure artists.
- soulsonic
- Old Solderhand
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Looks like you probably need to swap the Noninverting and Inverting inputs on the opamp symbols, but other than that, it looks like you're probably more than 80% there. The part with the FETs connected to half the tone control looks strange, but I guess it sorta makes sense....
Actually, looking at this makes me not even care what the actual values are.
Actually, looking at this makes me not even care what the actual values are.
"Analog electronics in music is dead. Analog effects pedal design is a dead art." - Fran
- Greg
- Old Solderhand
Yeah I think we've pretty much seen it before.. except it's using the 2nd stage of the opamp for a bit of tone shaping instead of the usual JFet buffer.soulsonic wrote:
Actually, looking at this makes me not even care what the actual values are.
And a control on how much clipping the (transistor) diodes to ground do.
culturejam wrote: We are equal opportunity exposure artists.
- soulsonic
- Old Solderhand
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First thing I thought was, "oh, another one of those... nevermind, then."
"Analog electronics in music is dead. Analog effects pedal design is a dead art." - Fran
- Greg
- Old Solderhand
Probably not.. it looks like it just has the RAT style filters.ibodog2 wrote:Sorry for the messy schematic. But yeah I was thinking still it would be good to get the filters on this one. I kept probing around trying to find a feedback loop back to the 1st op amp. But I'm pretty sure there's not one here. If anyone sees evidence of something different from the photos let me know.
BTW - not knocking the work you've done in saying it's nothing much new.. it's appreciated..
Do you like the sound of it ?
culturejam wrote: We are equal opportunity exposure artists.
- analogguru
- Old Solderhand
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The FET-configuration is nothing surprisingly new. It can be found in the Boss MG-80 from 1989.
analogguru
analogguru
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.
- RnFR
- Old Solderhand
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just a heads up- i think you have to careful when measuring resistors in circuit. you can get some off readings.
"You've converted me to Cubic thinking. Where do I sign up for the newsletter? I need to learn more about how I can break free from ONEism Death Math." - Soulsonic
Blog-APOCALYPSE AUDIO
Blog-APOCALYPSE AUDIO
- Greg
- Old Solderhand
Yes.. always good to confirm with colours if possible..RnFR wrote:just a heads up- i think you have to careful when measuring resistors in circuit. you can get some off readings.
also, I would suspect the voltage divider resistors are more likely in the 30 to 50 K range.
culturejam wrote: We are equal opportunity exposure artists.
- analogguru
- Old Solderhand
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470k is correct. You forget, that the bias divider is connected directly to the non-inverting input, resulting in a total max. input impedance of only 150k. (47k would give a max. input impedance of < 20k). BTW, I think R2 should be 2M7.Greg_G wrote:Yes.. always good to confirm with colours if possible..RnFR wrote:just a heads up- i think you have to careful when measuring resistors in circuit. you can get some off readings.
also, I would suspect the voltage divider resistors are more likely in the 30 to 50 K range.
analogguru
There´s a sucker born every minute - and too many of them end up in the bootweak pedal biz.