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Clíodhna My Designs Overdrive

Design Our Own Super Screamer Like Pedal

After covering a lot of ground around Tube Screamer like pedals, I think it’s right time to try our hand at doing some super mod heavy design of our own pedal. In several steps I’ll try to design some DIY overdrive pedal that will have all the character of a Tube Screamer but with much more versatility.

What are we doing?

This post is a kick-off post for this project. It builds upon my previous posts that cover TS808 and derivatives: breadboarding TS808 pedal, how does it shapes the tone, I did an alternative version and I also covered SD-1 and MXR Zakk Wylde versions.

I’ll try being brief. In this post I’ll do some important things – like the most important thing there is when you are doing a new creation: giving it name!!! Then I’ll go through the vision what I plan on doing. For the reminder of this post I’ll go through the first part of that vision – doing a custom clipping stage.

As usual, if you can’t be bothered to read, just skip to the video. You can always come back for more detail.

The Name

As we all know – the most important thing to do when making something is giving it a name. The name should represent the essence of the thing – the essence of our pedal. And with that I dub thee “Clíodhna”.

Clíodhna (pronounced as Cleena) is a queen of the banshees, at least here in Cork. She is said to have three brightly coloured birds who eat apples from an otherworldly tree and whose sweet song heals the sick people. Exactly what we’re trying to do here! Heal people with the sweet sound coming out of our pedal and our guitars!!! And god knows, this world needs healing … more and more with every passing day by the looks of it.

The Vision

Based on all of the schematics I’ve been through – and not just Tube Screamer related, I thought I’d do the following 4 parts/phases:

  • Clipping Stage – Gain Filter
    • I’ll cover this in the remainder of this post
  • Clipping Stage – Clipping Options
    • Asymmetric, symmetric clipping, something to that extent, I’ll most likely give some ideas as well what to try out
  • Tone Stage
    • I still don’t know, let’s keep it vague 😅. I’m thinking two knob tone control (bass and treble) at the moment, but we’ll see
  • Miscellaneous bits
    • As vague as it gets 🤣 but there is a plan in place I assure you. Depends on what I do with the tone stage, I’m thinking of adding extra gain boost, maybe bass cut, again, a few weeks away no need to overthink it. This is all based on differences between different TS like pedals and what might be useful to add

I’m just hopeful by the end of the project all of this comes together nicely. If all comes along nicely, I’ll design a PCB for this as well so stick around … that’s like 5th phase?

Finally – something that doesn’t really have anything to do with sound but might be even more important than the sound itself – the looks!!! I’ll design some nice graphics for the pedal (or at least I’ll try to get some help for this since that’s not my strong suit). Anyway, let’s get going.

Clipping Stage – Phase 1

I had no idea how to name this, but hopefully the schematic makes it clear what I’m trying to do:

Schematic of the first part of the Clíodhna project a Tube Screamer like pedal.
Clíodhna – Phase 1 Schematic (click for full diagram)

I stripped down the clipping section of the TS, removed the tone section for now and added 3 different options for controlling which frequencies are amplified and by how much.

Option one is standard TS808 like arrangement – formed by R5 & C3 on the diagram. In this position we have a Tube Screamer clone essentially.

Option two is RAT like arrangement, I did a post on RAT distortion before. Obviously, RAT is very much different from Tube Screamer – different clipping, way more gain, etc. I thought to try out this arrangement since RAT is one of the most popular distortion pedals out there after all. R6, C4, R7 & C5 are components used for this.

And finally, option three is “transparent” arrangement formed by C6 and R8. Filtering out very little of the audio spectrum, leaving as much of the low end in the signal as possible.

Breadboard

I’ll do a breadboarded version of this as per the diagram below and we’ll see if there’s any difference in the sound and if this avenue is worth taking.

Breadboard diagram of the first part of the Clíodhna project a Tube Screamer like pedal.
Clíodhna – Phase 1 Breadboard (click for full diagram)

Note though, I’m not married to any of these options. If something does not work out, I’ll just toss it away or replace it.

Bill of Material

Below is the BOM used for this demonstration. In one of the earlier posts I used 10K linear pots for controls, in this one I chose 100K linear pots. It is just one of the decisions we have to make when designing our pedal. With 100K pots it was easier for me to do scaling of the components.

DesignatorsComponentNotes
BreadboardAny breadboard will do, I used full size breadboard. You probably don’t want anything smaller than that.
Jumpers and wiresAs many as you need. I got some online, but 24 AWG solid core wire will do just fine.
9V batteryI used 9V battery snap with Dupont wire.
INSwitchcraft 12BIn – stereo jack (mono will do too)
OUTSwitchcraft J111Out mono Jack
RV1, RV2Alpha 16mm 100K linear potAny 100K linear pot will do, I used 16mm with PCB pins
C110n (0.01uF) Metal film PET cap
C2220pFCeramic C0G cap
C3, C4, C7220n (0.22uF) Metal film PET cap
C5470n (0.47uF)Metal film PET cap
C64.7uF Electrolytic cap 25V
C847uF Electrolytic cap 25V
C10100uF Electrolytic cap 25V
C9100n (0.1uF)Ceramic X7R
D1, D21N4148Small signal diode for clipping
R1, R32.2M1% 250mW metal film
R2, R5, R81K
R4, R10, R1110K
R6470 ohm
R75.6K
R9100 ohm
U1TL072op-amp
List of components for Clíodhna – phase 1 breadboarding

The Video

Here’s the video with me trying out all the options covered in this post.

Trying it out

I hope you liked the video. There is definitely difference in sound between the three options, and I think it’s worth going forward with this and trying to expand on this. As I mentioned – this is not the final sound, there was no tone section used so the final result might and most certainly will sound different. Stay tuned for the next part!

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