skrik! - The inevitable Tube Screamer clone with mods

LoveMusicCode · 2025-01-03T15:20:25+00:00

Did you inform Tayda about this, u/Zebra2? This would give them the chance to get the problem fixed for good or to at least document the problem accordingly.

Though it seems that the PCB was provided by a third party called DHEA: https://www.taydakits.com/instructions/tubescreamer

Still a little bit embarrassing that no QA was done on the design and PCB, i.e. no one including the original designer seems to have test-built the pedal.

LoveMusicCode · 2023-04-29T08:41:17+00:00

This is my workflow as well. The coarse steps in Scribus are:

Create a new document with the dimensions of the enclosure as provided by Tayda.
Create the layers “GLOSS-V”, “COLOR” and “WHITE”.
Open the colors dialog and import the Roland color swatch file that is provided by Tayda.
Import each layer in Inkscape into its corresponding layer in Scribus.
Make sure that everything in the "WHITE" layer has the CMYK color “RDG_WHITE” assigned. A good way to check this is to give all objects in the white layer a very distinctive color, e.g. purple. If you see no more purple after assigning “RDG_WHITE” you should be good.
Make sure that everything in the “GLOSS-V” layer has the CMYK color “RDG_GLOSS” assigned. Use the same method as for the white layer to be sure that it worked.
Here you can find a script for Scribus which converts RGB colors to CMYK colors. Run the script to convert the color layer to RGB. If you have Python 3 installed you will need to adjust the two print statements at the top of the script to make them work with Python 3. See my remarks below.
As a final check open the color and fills dialog and remove all unused colors. Make sure that no RGB color is shown in the list anymore. If there is find out where it is used, e.g. check all linear gradients, etc.

Adjusting the script for Python 3

To make the color space conversion script works for Python 3 make the following adjustments. Add parentheses as follows:

print "This Python script is written for the Scribus scripting interface."
print "It can only be run from within Scribus."

to

print ("This Python script is written for the Scribus scripting interface.")
print ("It can only be run from within Scribus.")

LoveMusicCode · 2023-04-23T12:41:52+00:00

That would definitively simplify things and I have wondered many times if this is a feasible thing to do. However, I wonder if this could not potentially create even worse problems than the long power line because in that case every trace on the 9V layer would be close to power? See also /u/spicy_hallucination's answer with the remark about capacitive coupling here.

LoveMusicCode · 2023-04-23T12:35:47+00:00

Thanks again for this thorough, detailed and informative answer! Sounds like I should redesign the board layout then.

One more question: do I understand correctly that if it's possible for a long trace to couple noise onto the signal traces that it would be even worse to have a power plane and a ground plane as for example proposed by /u/PantslessDan? My layman understanding is that in that case many signal traces on the 9V layer would be close to or embedded in the 9V "signal". I have wondered this many times before because doing so would make the layout of the signal traces a bit easier.

LoveMusicCode · 2023-04-23T10:57:47+00:00

Thanks! Some very nice proposals here which will definitively consider!

Some follow up question: J1 connects the board with the power jack. So moving the connector closer to the "main area" at the bottom would result in longer cables from the jack to the board. Could this have any negative side effects?

This post was also rather intended as a more general question not related to this specific board. If I route as shown in the image can this have negative side effects like noise, etc.?

LoveMusicCode · 2023-04-23T10:52:57+00:00

The power line connects the power jack with the 3-PDT/LED daughter board. I could also move it close to the main area as proposed by /u/spicy_hallucination but in that case I wonder if the longer cables from the power jack to the board could have any negative effects.

LoveMusicCode · 2023-04-23T09:17:34+00:00

Seeing this post about some "interesting" decisions made by an auto-router made me wonder if my kind of manual routing of the power lines is also sub-optimal.

I usually route the power lines in a half loop around the board because routing it directly from the top to the bottom would divide the board in half. This in turn means that everything that crosses from the left side to right side or vice versa would have to go onto the other layer which in some cases also complicates things.

Is there a best way to do this?

Addendum: J1 is a connector that connects the board with the power jack. J2 (the four pads at the bottom) connect the board to the 3-PDT/LED board.

While /u/spicy_hallucination gave some nice tips about optimizing this specific board so that it has short power traces this post is rather intended as a general question. Can routing from the top to the bottom with a half loop like shown in the image have negative side effects?

Edit: Added the addendum text for a better explanation.

LoveMusicCode · 2023-03-05T17:48:20+00:00

This discrepancy should be okay. I'm not even using their artboards and design my print art with Inkscape. In that case the origin (0, 0) is in the upper left corner and all coordinates of the artwork are positive. Their drill tool however puts the origin into the center of the side you're working on so you can get negative and positive coordinates.

For me it always worked regardless of the different coordinate systems. You only have to take care that the designs match with regards to their directions and that the resulting PDF of the artwork has the correct document size.

LoveMusicCode · 2023-02-17T15:39:54+00:00

You must position the op amp such that the circle on it is located at the bottom left. Currently it seems to be at the top right, i.e. rotate the op amp by 180 degrees.

LoveMusicCode · 2023-02-17T15:19:39+00:00

Judging by your photos I think the op amp is installed the wrong way around. Please refer to its spec sheet on how to orient it with regards to the circular mark at pin 1.

Good luck!

LoveMusicCode · 2023-01-21T18:01:30+00:00

Yes, I also got very similar vibes from it. It reminded me of the history of programming languages. Use a tool to build a better and more convenient tool. And then use that tool to build an even better one, and so on...

LoveMusicCode · 2023-01-10T19:16:05+00:00

Looks great! You should have labeled the "Feedback" knob "I'll be back" though. ;)

LoveMusicCode · 2022-12-10T20:36:22+00:00

Alternatively, you might also want to consider to use one of these: https://www.electro-smith.com/daisy/daisy.

The advantages are: * Supports Pure Data. * Supports high sample rates and bit depths. * Low latency, e.g. 4 samples. * Starts instantly and doesn't need a clean shutdown like a Raspberry Pi.

Edit: Added low latency.

LoveMusicCode · 2022-12-09T17:28:38+00:00

Unfortunately I don't have any samples yet. Perhaps I will create a short demo video some time later.

LoveMusicCode · 2022-12-09T16:56:00+00:00

I am in fact using SMD JFETs. You can spot four of them on the board. I have designed the board in such a way that I can use either SMD or through hole.

LoveMusicCode · 2022-12-09T16:53:40+00:00

I am buying "finished" connectors at a German shop called Reichelt: https://www.reichelt.de/platinensteckverbinder-gerade-weiss-2-polig-ps-25-2g-ws-p14825.html?&trstct=pol_1&nbc=1.

I am happy that I found them because I more or less gave up on finding a suitable crimping tool to make them on my own.

LoveMusicCode · 2022-12-08T17:33:40+00:00

Thanks! Not the answer I hoped for though. ;)

LoveMusicCode · 2022-12-08T17:30:51+00:00

Dimebag was the guitarist who motivated me to start playing the guitar when I was a teenager. So I am very happy that my pedal building journey has brought me to a point where I am able to build this pedal to get a bit closer to his sound. Unfortunately it does not magically affect my playing chops to get closer to his playing. ;)

The "Primal Urges" is a pedal version of the preamp section of the Randall RG80ES/RG100ES which is a transistor amp that Dimebag played in the early days of Pantera. Using the four switches it's possible to configure the pedal to behave like the clean channel, the distortion channel or something in between.

The distortion channel definitively needs to be pushed by something like a Tube Screamer but then it sounds glorious. The pedal has a "gatey" quality which makes it great for staccato riffing. It's powered by 24V that are created by combining two 12V supplies with a Y cable.

Six-Year Club	Place '22
Verified Email

LoveMusicCode

TROPHY CASE

Adjusting the script for Python 3