Catalinbread - Formula No. 5  [traced]

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Ice-9
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Post by Ice-9 »

Ok, I have for now just hand drawn the schematic as i dont have access to my own pc with schematic program. Right click and download the pic to get full size version , it's a little bit of a bad picture but its readable.

Image

I havent breadboarded the effect but the schematic is correct. There no real suprises in there.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

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Post by MicMicMan »

The biasing of that first mu-amp stage looks very weird to me, are you sure of that one ?

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coldcraft
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Post by coldcraft »

the biasing is probably correct. i haven't seen it before, but I can believe it.

nice, I was only off by two resisters! woot!
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Post by Ice-9 »

MicMicMan wrote:The biasing of that first mu-amp stage looks very weird to me, are you sure of that one ?
Yeah it looked strange to me too, the 2m2 resistor between the gate and drain of Q2

I will double check now to make sure.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

Ice-9
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Post by Ice-9 »

MicMicMan wrote:The biasing of that first mu-amp stage looks very weird to me, are you sure of that one ?
I have just checked and that is correct.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

Ice-9
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Post by Ice-9 »

Here are the values of the caps in case you cant read them in the schematic, I will post a better schematic when I get time, in the meantime if anyone else wants to make a more readable schematic please feel free to do so.
Formula 5

Q1- 4 2N5457

C1 – 2u2 50v electro
C2 – 4u7 50v electro

C4 – 1n
C5 – 0.1uf electro
C6 – 4n7
C8 – 100n
C9 – 100n
C10 – 47n
C11 – 1n
C12 – 1n
C? styrene cap 47p

D1 – 1N400x
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

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Post by coldcraft »

coldcraft wrote:the biasing is probably correct. i haven't seen it before, but I can believe it.

nice, I was only off by two resisters! woot!
and a cap... :oops:

Here's the eagle-ized version. I added a front end pull down and left in Vref from my eagle template, so that's if you were going to switch to noiseless biasing.
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Post by MicMicMan »

Okay, thanks then. Thanks a lot anyway :applause:
Yes it makes sense, but that's quite unusual for a mu-amp.
So, the first transistor gate should be biased at something like 1/6 Vcc. Maybe there's some asymetrical clipping going on within that first gain stage.

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Post by Ice-9 »

coldcraft wrote:
coldcraft wrote:the biasing is probably correct. i haven't seen it before, but I can believe it.

nice, I was only off by two resisters! woot!
and a cap... :oops:

Here's the eagle-ized version. I added a front end pull down and left in Vref from my eagle template, so that's if you were going to switch to noiseless biasing.
Thats great Coldcraft, you might want to update the component values, there are a few that are not correct.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

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Post by coldcraft »

I was initially thinking it was just negative feedback, but it probably affects the bias of the input gate as well. However, I'm not sure how that affects the clipping. My understanding was that the bias of the output of the gain stage affected the clipping.

My train of thought was, without the 2M2, the Gate is biased to Ground, so the addition of the 2M2 might be to raise it a fixed amount over that.

Ice-9 wrote:Thats great Coldcraft, you might want to update the component values, there are a few that are not correct.
I see we have a different styrene cap (47p vs 470p) Did you measure that with a DMM? I'm only asking because the 5E3 schematic had a 470p/500p there.

where do you see the other errors? I thought I updated everything based on your posting.

MODS, it would be really nice if I could edit my own posts. pretty please!
Black Dynamite wrote:you need to shut the fuck up when grown folks is talkin.

Ice-9
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Post by Ice-9 »

The cap is marked 470j which is 47p 5% tolerance . i beleive if it was 470p it should be marked 471
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Post by Ice-9 »

I have just checked over your eagle schematic Coldcraft and the only values to change are (as labled on your schemo)

C7- is a polarized electro cap (value is correct)
R13 -should be 47k instead of 10k
Gain pot is a 1MA instead of 1MB
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

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Post by coldcraft »

I'm not sure why they would use a polarized .1uF. 100n is much more common value, especially since they have a handful of other 100n caps in the circuit.

Anyway, here are the corrections. I will take down the incorrect ones once I can edit my posts.
Most Recent Corrections
Most Recent Corrections
Formula No 5 Fixed.png (8.39 KiB) Viewed 692 times
Black Dynamite wrote:you need to shut the fuck up when grown folks is talkin.

Ice-9
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Post by Ice-9 »

coldcraft wrote:I'm not sure why they would use a polarized .1uF. 100n is much more common value, especially since they have a handful of other 100n caps in the circuit.

Anyway, here are the corrections. I will take down the incorrect ones once I can edit my posts.
Formula No 5 Fixed.png
I totally agree about the polarized cap, and it should make zero difference if a normal 100n cap is used here. They have put in a electrolytic here so to keep the project 100% correct i have also stated the same.

We now have a 100% formula 5 done. :)
Happy building everyone.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

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Post by GuitarlCarl »

Sweet, nice work!
But Hey, OTHER ARENAS!!! not here.
I never meant catlin was misleading OR you guys...
OTHER ARENAS!!!

You can't tell me you've never been to ANOTHER site where you know the values are wrong, backwards, or just plain missing.
Even a nube like my old ass can tell it ain't accidental.

So peace, I never mean to offend, and don't assume I did... now if I just had some fets in my pocket....
I want it to sound like bees buzzing around in a 55 gallon drum...

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Post by coldcraft »

i don't think anyone took offense to your comments from the previous page, including myself.

my statements at the top of this page were just opinions I wanted to share, sparked by your post but not really aimed at rebuffing it or anything like that. To be honest, I'm not really sure what other sites would have contradicting or misleading information on schematic values.

Please let us know if you build this thing and how it sounds. I'm already thinking of some design refinements from a schematic point of view, but I won't be able to build this for some time.
Black Dynamite wrote:you need to shut the fuck up when grown folks is talkin.

Ice-9
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Post by Ice-9 »

Im off to look in my parts bin to see if i can breadboard this tonight. I will test it side by side with the original and report if all works the same.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

Ice-9
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Post by Ice-9 »

I have just breadboarded this and the results were good.

1st i would like to say that i didnt have all the correct values so had to sub a couple of values out, i will list them and refer the components numbers on coldcrafts latest schematic which he has modified to match my hand drawn schematic which is verified.


1. R14 should be 62K I only had a 56K (will make next to zero difference)
2. C3 should be a 47p styrene cap ( I tested with 150p ceramic and a 470p silver mica) This make a big difference.
3. C4 should be a 4n7 (i had to make up a 4n4 using 2 * 2n2 in parallel) Close so not much difference here
4. C9 should be a 47n (again i made a 44n from two 22n caps)

RESULTS

The clone, bearing in mind the subbed components sounds pretty perfect to the real formula 5. I tested the tone control using the 150p cap as C3 and with the gain at all settings and it performed the same as the original with only very slightly less top end at full tone . I then tried the 470p as C3 which made the tone control totally inefective (as suspected)

So if C3 is the correct value of 47p then i also suspect the full tonal range to return to exactly the same as the original pedal.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

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Post by HEAD »

I can confirm that. I modded the vero posted here to the new specs. The only thing I had to sub was the 2M2 for a 2M7 as this was the only value that I had at hand. Now it sounds as suspected. Buuuuuuuut, I got a strange issue - it only works for some seconds then the voltage seems to drop like a discharging/charging cap until I touche the solderside. I cannot say how much I hate vero - it always plays tricks on me! Damn! Double checked everything but still couldn't find the failure. :D Damn again!

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Post by Ice-9 »

HEAD wrote:I can confirm that. I modded the vero posted here to the new specs. The only thing I had to sub was the 2M2 for a 2M7 as this was the only value that I had at hand. Now it sounds as suspected. Buuuuuuuut, I got a strange issue - it only works for some seconds then the voltage seems to drop like a discharging/charging cap until I touche the solderside. I cannot say how much I hate vero - it always plays tricks on me! Damn! Double checked everything but still couldn't find the failure. :D Damn again!
Im not sure if the 2M7 would have this efect on the circuit, But the 2M2 is part of the FET biasing so it could make a difference. Although the problem you describe sounds more like a dry or bridged joint.
It's fairly straight forward, if you want to start it , press start. You can work out the rest of the controls for yourself !

No silicon heaven ? preposterous ! Where would all the calculators go ?

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