Tag Archives: clipping

TS Overdrive – new enclosure & sound samples

Old enclosure ready for tear-down

Old enclosure ready for tear-down, next to the new one.

Why?

When I built my first Tubescreamer clone (built with a great circuit board from DIY Effects) I was very pleased but left with a few issues that at the time I could not be bothered to fix.

Firstly, the paint finish I used on the enclosure did not turn out very well. I used Rustoleum, and sprayed it on way too thick (because I was impatient…lesson learned). It looked cool, but it didn’t wear well.

Secondly, the DC power connector I originally bought for it turned out to be the wrong size. I only discovered this when I got hold of a power supply, and it didn’t fit. In fact, it was at this point that I tried to use what I thought was an adapter for a smaller power connector. Little did I know that although the adapter fit, it was actually a polarity inverter too; so I blew up 3 JC4558 chips in the process.

So I decided to try an enclosure from Mammoth Electronics, who can provide a painted an drilled enclosure for around $10. Ridiculously cheap.

Wires for the LED "off-board"

Wires for the LED "off-board"

Getting on with it

The rehousing process was very easy; mostly a case of taking the old one apart and carefully assembling it all back into the new enclosure. I did have to redo the LED as the DIY Effects PCB allows you to solder it directly to the board, and let it just stick through the enclosure. I couldn’t do that with the new enclosure and still have it line up with the hole, so I attached wires to the LED and then soldered those to the board. Nice and easy.

The shiny copper on the MOSFET clippers

The shiny copper on the MOSFET clippers

Clipping with MOSFETs

Months ago, after I built my OD2 which uses plain diodes for clipping, I decided to change this OD to use MOSFET clipping. SLW had mentioned it in the excellent PDF file that lays out instructions for building the pedal, and he rated it highly. I was able to purchase the parts easily, and after doing the necessary physical modification (i.e. cutting off most of the mounting lug) the mod was trivial. But what a result in terms of sound! You’ll hopefully hear in the MP3 file below that it has a wonderfully soft clip. It’s as if it has rounded edges. Like an overdriven Marshall, but without the harshness. It does definitely get harsh if you turn the tone all the way up, and responds very well to tone adjustments on the guitar itself. In the clip you’ll hear a variety of pickups and guitar tone control settings (and sadly a lot of repetitive playing).

The setup was:

  • My own build of an AX84 P1 Extreme, with a 6V6 for the output section.
  • Tokai Les Paul with a 1961 Gibson PAF in the neck, and a modern Seymour Duncan JB in the bridge.
  • 2×12 cab with Celestion G12T-75
  • SM57 microphone
  • Recorded in Logic on a Mac. And a touch of reverb in the master output channel.

Click here for the MP3

Almost done

Almost done

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OD2 – final assembly

The Clay Jones circuit, plus layout

The Clay Jones circuit, plus layout. Click to see the big version.

In my previous post I was discussing a new project. Another distortion pedal based on a clone of a Landgraff Dynamic Overdrive. The circuit was drawn out (possibly from looking at the Landgraff device) a few years ago by someone called Clay Jones. See the picture on the right here. This circuit was made available to me, as a beautiful pre-built PCB, by the guys over at DIY Effects. They have a great OD circuit (currently at revision 2, I believe) that I had used previously, but this one is using their “revision one” board.

The clipping switch

The clipping switch. 3 diodes on the left, 2 LEDs on the right.

Clipping

The major difference between the revisions has to do with the clipping section of the circuit. Rev 2 has ample space for all kinds of options whereas Rev 1 is limited in terms of on board space. In this context that didn’t matter. I knew I wanted to mess around with clipping options and that meant it was easier to do that with a switch off the main board. I chose to try 3 diodes in one position and 2 LEDs in the other. The middle ‘off’ position is just the raw clipping of the circuit alone.

OD1 and OD2

OD1 refuses to make eye contact with the conspicuously naked OD2

Initial tests

I was able to wire up the board with power, pots and jacks very quickly, due to the great instructions, and had it plugged into my amp in no time at all. The goal here was to compare the clipping options and just make sure I wasn’t going down the wrong path. And I was not disappointed at all. The 3 diodes position has tons of gain, but in the lower positions sounds much like a cranked Marshall, but with a slightly softer attack. It doesn’t have the harsh bite of the typical Angus Young tone, which isn’t a bad thing. Then I switched it to the middle ‘off’ position, and it immediately got much louder, presumably because there aren’t any diodes clipping anything. Also for the same ‘drive’ position, the middle position had way less drive. Position 3, the 2 LED’s wasn’t a huge change from the middle position, but it softened the attack a little. Either way, I completely love this pedal!. So now to get it into a usable enclosure.

The enclosure

Measuring and drilling the enclosure holes

Measuring and drilling the enclosure holes

Based on a recommendation from DIY Effects I bought a box from Pedal Enclosures, specifically the YY type, in red hammer finish. All that remained was to drill some holes and start the assembly. This meant I had to think about how I wanted to lay things out inside the box as well as outside. But the basic dimensions of the box decided a lot of this for me. Here’s the basics:

  • The circuit requires Drive, Tone and Level pots.
  • I wanted to eventually add a switchable boost, so I need 2 foot switches. This will be like the “more” switch on Joe Satriani’s Vox distortion pedal.
  • I need a hole for my clipping switch.
  • LEDs for both the switches so I know where I am.
  • The usual 1/4′ jacks and power.
Making sure the parts fit as I go

Making sure the parts fit as I go

I covered the box with masking tape and found my old vernier calipers and a pen. With the box of components at hand, for dimensions, I was able to mark out the locations for the holes and punch them quite quickly. Then it was time for the drill press. After starting with an 1/8th ” bit for pilot holes, I layed into it with my El Cheapo “unibit” that I got from Harbor Freight Tools.

Assembly

Belly up, with new parts

Belly up, with new parts

Now for the fun part! As I had done most of the assembly work with parts I had laying around, I did have to replace the pots with smaller ones (16mm rather than 24mm), and also I had to wire up the full bypass switch (and the LED). But all of that was just busy work. This time, I purchased extra components from Small Bear Electronics.

I was lucky enough to have wired it correctly first time (as with the original OD pedal) so within the hour I had it plugged into my amp and was jamming away.

I am very, very satisfied with this pedal. I can get a wide variety of usable tones from it very quickly. I do need to replace the drive pot with something else as the range of “no drive” to “loads of drive” all happens in the first few degrees. Not sure if this is simply the difference between linear and logarithmic taper. Anyway, here’s another photo.

(Almost) finished in it's shiny red box

(Almost) finished in it's shiny red box. The toggle switch is for the clipping options. Forward is the 3 diodes, backwards is the 2 LEDs.

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