TubeScreamer+ Project - Part 2

I'm a few hours into the project. Below is the current progress. I discovered that I am short one diode so there will be some delay (no pun intended). Image below shows the components, and the stomp switch.

CLIPPING CIRCUITS

Here, I've highlighted the clipping circuits. Circled in red is the standard clipping circuit found in the original TS-808. It's basically just a set of diodes reversed. One mod to this is for asymmetric clipping, which is achieved by adding a third diode. I opted to keep this circuit the same as the original, so instead of adding the third diode, I just ran a jumper in its place. The section surrounded by blue is an option for clipping using two LEDs. Since the design supports only two clipping mods, I opted out of this one. In green is a third option, using two MOSFET transistors and two diodes.

CAPACITOR MOD

Looking closely on the lower right, there is a spot for a capacitor with nothing in it (C11, upside-down). There is another optional mod that allows for changing out this capacitor with others in order to boost the lower frequencies. DIY Effects offered three possible replacements for the stock capacitor. This will be my second mod, but before I decide which capacitor to put into place, I need to hear them. I can't play through the unit without the second missing diode, so this will have to wait.

Next up will be drilling the case so I can get the pots, jacks, and switches mounted.

PART 1 ~ PART 2 ~ PART 3 ~ PART 4 ~ PART 5

TubeScreamer+ Project - Part 1

PROCUREMENT

As I was jamming with my buddy Simon (Check out his blog for other cool guitar projects), He fired up his Tubescreamer clone from DIY Effects. It was one of those 'THAT'S IT! THAT'S THE SOUND!' moments. So, it's off to the electronics store (and DIY Effects for the circuitboard). So, this is part one of my journey to build my own TS clone. It's modeled after the Ibanez TS808 (the original), but I'm introducing two additional mods (hence the "+" in the name) that will provide additional tone and clipping options without sacrificing the original sound. Everything has arrived, so tonight we start assembly.

The original TS808 was green, so I opted for a green case as a sort of nod to Ibanez. That said, the layout of the enclosure and the mods will make this a very different pedal, while still keeping the sound close to the original.

Update: 5/7/2016

Since I ran into a defective part and had to re-order, I thought it might be useful to add some comments on ordering parts. DIY refers to a "project" available at Mouser where you can just type in the project name, and get a shopping cart filled with everything except the potentiometers, knobs, and case. Unfortunately, that project is a bit dated, and not everything is available any longer. Here are some notes that might help:

• Part numbers for the transistors, IC socket, and LEDs have changed, but replacements are available (I took the replacement diodes from Mouser, and went to DigiKey for the others.) Replacement part numbers from Digikey are:
• Transistors: MPSA18CS-ND
• IC socket: AE9986-ND
• Mouser no longer carries the 1N34A diodes. If you're not doing the diode/transistor clipping mod, this is no big deal (it's the only place they are used). If you do want that clipping mod, you can get the diodes from DigiKey.com (VERY expensive), or Pedal Parts Plus (much more reasonable).
• You can get the footswitch , potentiometers, knobs, etc. from Mammoth Electronics. They have a great site that makes finding exactly the part you need really easy.
• When you start going to multiple sites, you're going to find that you get soaked on shipping. Most places are around $8.00/order for USPS. Make sure you get everything you need from as few places as possible.
• You can also get a lot of the parts from Pedal Parts Plus. Their selection is not quite as good, but the prices are really reasonable, and turnaround is quick. You might have to do some research to cross-reference part numbers.

PART 1 ~ PART 2 ~ PART 3 ~ PART 4 ~ PART 5