Mad Professor - Stone Grey Distortion  [traced]

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pollyn
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Post by pollyn »

Aight!
I got a tl071 ic today and with this chip the distortion is working :)
So don't use the CA3130, it won't work.

Thx everybody

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roseblood11
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Post by roseblood11 »

Nonsense! Any dual opamp will work here, it's a simple clipping arrangement, as in any tube screamer etc
I'm pretty sure that the CA3130 is used in the BJF version of the stone grey, and it was one of the IC's that I tested in my clone.

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Seiche
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Post by Seiche »

roseblood11 wrote:Nonsense! Any dual opamp will work here, it's a simple clipping arrangement, as in any tube screamer etc
I'm pretty sure that the CA3130 is used in the BJF version of the stone grey, and it was one of the IC's that I tested in my clone.
you mean single opamp, right?

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roseblood11
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Post by roseblood11 »

Seiche wrote:
roseblood11 wrote:Nonsense! Any dual opamp will work here, it's a simple clipping arrangement, as in any tube screamer etc
I'm pretty sure that the CA3130 is used in the BJF version of the stone grey, and it was one of the IC's that I tested in my clone.
you mean single opamp, right?
Sure! I was just working on another circuit that uses a ca3240 dual opamp...

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suicidemachine
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Post by suicidemachine »

again.This Op Amp in my test - CA3130ez ,TL071 ,TL081 and LF351.The CA3130ez still not work for me ,I get that ...clean sound.I know TL071 and TL081 nice work but I like LF351 any more. :D

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roseblood11
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Post by roseblood11 »

Maybe your ca3130 is flawed...

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TheLemon
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Post by TheLemon »

If you use a Ca3130ez make sure to lower the first resistor from 470k to 360k and use a bigger input cap from 2n2 to 22n. I personally like the use of 3mm diffused red.leds in the feedback loop for clipping instead of transistors in this type of high gain circuit but that's just me .

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Victor Nery
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Post by Victor Nery »

Greetings,

I went TL071 and CD4049UBE and by mistake I put 4k7 in place of R2. I got very low output even lower than bypassed. What do you say? Is any of the original components essential? Can it be R2?

Thanks

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Post by TheLemon »

Victor Nery wrote:Greetings,

I went TL071 and CD4049UBE and by mistake I put 4k7 in place of R2. I got very low output even lower than bypassed. What do you say? Is any of the original components essential? Can it be R2?

Thanks
No, R2 is originally 14k7 and just limits the amount of signal going into the op amp by a tiny bit. 4k7 is fine. Check all connections, and make sure the rest of the unused CD4049UBE is connected properly to V+

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Victor Nery
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Post by Victor Nery »

Greetings,

I debbuged the circuit and found the problem. Thanks for your support. 4k7 gives more signal going into the opamp right? So the problem wasn‘t there. I started checking the schematict and realized that I put a 470r in the first inversor instead of the 470k. I corrected this mistake and also took the oportunity to put a 15k resistor that measured 14,67k in place to the 4k7 and now the circuit is working properly. Great distortion unit. Now it‘s working, I just can‘t stop playing with it.

Thanks

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IvIark
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Post by IvIark »

Here's two vero layouts, depending whether you want to use JFETs or MOSFETs. The MOSFET one is verified:

Image

Image
"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

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Victor Nery
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Post by Victor Nery »

Greetings,

I started to think about the 15p capacitor connected from the inverting part of the opamp to the tone control and I'd like to know how it works. I could realize that the opamp stage is a mxr dist+ kinda circuit. Ok here's the point: How is it interactive with the tone control (frequencies, etc.) and would it work without the inverters of the cd4069 or they are what make this kinda arrangement possible? If you don't mind, please add the math.

By the way, I attached my layout. It's checked.

Stone Grey Distortion

Thanks in advance

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Post by phibes »

Victor Nery wrote:Greetings,

I started to think about the 15p capacitor connected from the inverting part of the opamp to the tone control and I'd like to know how it works. I could realize that the opamp stage is a mxr dist+ kinda circuit. Ok here's the point: How is it interactive with the tone control (frequencies, etc.) and would it work without the inverters of the cd4069 or they are what make this kinda arrangement possible? If you don't mind, please add the math.

By the way, I attached my layout. It's checked.

Stone Grey Distortion

Thanks in advance
You should use the attachment feature.
GuitarlCarl - "TGP = The Gear Polishers"

Image Ken

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Victor Nery
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Post by Victor Nery »

Greetings,

Sorry about that. If you click on the name in red "stone grey distortion" you'll be redirected to a page where you can download it. I didn't know how to say it in your language so I thought that "attach" had this meaning. Know I got it.

Cheers

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Bill_Mountain
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Post by Bill_Mountain »

Victor Nery wrote:Greetings,

I started to think about the 15p capacitor connected from the inverting part of the opamp to the tone control and I'd like to know how it works. I could realize that the opamp stage is a mxr dist+ kinda circuit. Ok here's the point: How is it interactive with the tone control (frequencies, etc.) and would it work without the inverters of the cd4069 or they are what make this kinda arrangement possible? If you don't mind, please add the math.

By the way, I attached my layout. It's checked.

Stone Grey Distortion

Thanks in advance
It looks like a very subtle high cut. I imagine that if you went with a higher value it would be more noticeable. Some pedals employ global feedback resistors that are supposed to affect the responsiveness of the distortion. Maybe this will have a similar effect on high frequencies.

I simulated a simplified version of the pedal and the highs shifted slightly but I couldn’t honestly tell you what frequencies if any were affected.

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Victor Nery
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Post by Victor Nery »

Greetings,

I spent more time analysing the circuit and I realized that it's slightly similar to the feedback connections of the rat and so many others but one of the RC filters connect to the tone control instead of ground. So I may suppose that this cap (15p) act like an RC filter in the feedback of the opamp and at the same time like a simple low-pass filter? So both things get in action as we turn the control pot? It seems this kind of arrangements are very common to b j t's desings. It's imressive how good they sound. May try it in other circuits to see what I get. My confusion is that the math is as follows: frequency = 1/(Resistor*Capacitor*6,28) but I don't know how to apply it in this circuit and how these components interact between them.

Cheers

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commondenominator
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Post by commondenominator »

roseblood11 wrote:schematic and veroboard layout.

UNVERIFIED!
Hi I like these. I look at victor nery schematic and this not the same and I like to know what is correct. CD4069UBE is different in both schematic and I no like want to build wrong one.

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roseblood11
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Post by roseblood11 »

I retraced the original pedal and compared my finished built with it, so I can say that my version is 100% correct. I never looked at Victors layout, because you can't download it without registering...

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Victor Nery
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Post by Victor Nery »

Greetings,

I actually based my layout on the schematic posted in this topic:

Image

The only differences are the CD4049UBE instead of the CD4069UBE, TL071 in place of a TL051 and the clippers. All of them are very easy to substitute the right components except for the CD4049UBE. However, there is a project at ROF that explains how to put this IC in place of the one I've used.

I'm still thinking about the way the tone control acts.

By the way I didn't attach the file because I was not sure if this was really necessary (considering that all of us have access to f*o*u*r s*h*a*r*e*d ) and/or allowed. If you guys prefer this way, I can post it as an attachment.

Cheers

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phibes
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Post by phibes »

I don't sign up at any of the free share sites, hence why I suggested attaching. No need for those really since we got a bitchin' attachment feature.
GuitarlCarl - "TGP = The Gear Polishers"

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