Welcome to the Revolution

Hi there, welcome to my blog - La Revolution Deux. It's an odd name - but I like it! Here you will find all the info on my various DIY Guitar effects builds, amplifiers and guitars. Everything from a humble Ibanez tubescreamer to the holiest KLON Overdrive.

You may also find a few effects builds that I am looking to move on - usually in exchange for other effects/gear/cash. You can always check my ebay account to see what I've got up for grabs.

Have fun, enjoy the blog - Fred Briggs :-)

CONTACT ME



Feel free to get in contact with me about anything you see on this blog or with any general questions about guitars, amplifiers and effects, I'll be happy to answer! Just click the button above to email me directly or alternately my email address is fredbriggs2007 [at] googlemail [dot] com

Search This Blog

Tuesday, 28 February 2012

Fred Briggs - Super OCD

Fred Briggs - Super OCD Schematic
The Fulltone OCD has been an overdrive favourite for many years now. It's got a really nice tone when your amp is set right (I prefer it with Marshalls I must say). Well, I've always thought about modifiying the basic circuit (which itself is based around the old Voodoo Labs Overdrive) to give it a little more variety and use over a wider spectrum of tones.

As you can see the "Super OCD" has a few extra controls:

- Firstly the "Bass" control - it's nicked from Paul C's Timmy pedal and works very well to add in pregain bass for more low end response.

- Secondly the "Saturation" control, this allows you to increase the clipping headroom of the circuit and have an overall "cleaner" tone while dialling in just the required amount of diode clipping.

- Thirdly the "Boost" control, I've configured the second opamp to allow a range of clean boosts to be selected to really allow you to push the front end of your amp into overdrive.

- The final control I've added is a switch to go between 9 volt and 18 volt operation. The 18 volt operation adds extra headroom to the circuit to stop the opamp clipping from fogging up the tone. The 9 volt operation retains the original headroom seen in the OCD.

- Other changes include alterations to the Tone control and a swap of opamp from the TL082 in the original OCD to the Burr Brown OPA2134. These changes all add up to create a really nice overdrive/distortion box. It's got all the original Fulltone OCD tones in there and loads more. If you like the original OCD you'll love the Super OCD :-)

Here's a vero layout by beedotman, it's unverified at the moment, if you build it report back please :-)


Here's the discussion topic on freestompboxes.org: http://freestompboxes.org/viewtopic.php?f=13&p=183753

10 comments:

  1. I just built the vero layout posted, and it sounds fine to me. Sounds close to the OCD clone I built previously. Definitely more tweakable and versatile.

    ReplyDelete
    Replies
    1. Cheers for the feedback. Which is your favourite new control?

      Delete
  2. I've not had much time with it yet, plus I'm using it with bass. If I had to pick one, I would say the Boost, with the Saturation a close second.

    ReplyDelete
  3. Hi Fred.
    I just built the Vero Version you have posted and although it works, I`m getting a Feddback that`s Squealing like crazy whenever I turn up the gain and/or the boost controls.
    Any ideia on what could be happening? I`ve checked the connections and cuts and everything.
    Also I`ve used Tant. Capacitors on the 10mf and 1mf .
    Appreciate your help and expertise.

    ReplyDelete
    Replies
    1. Hi Oscar. I've same problem too. How are you fix it?

      Delete
  4. Are you going to make a PCB or do i have to add it myself to the previous pcb for the other clone?

    ReplyDelete
  5. Hello Fred!

    I also built the pedal without the added voltage doubler, but the circuit is oscillating like Oscar Jr.'s (my power supply is clean, filtered).
    I built it with 1uF film capacitors. In the schematic there are polarized caps. Oscar built it with tantal-s, and the problem is the same. I don't know, what's wrong with it. Have you any idea?

    Thank you for your answer!
    Marcel

    ReplyDelete
    Replies
    1. Don't make your wiring too long. It will introduce noise to the circuit. Unless you use shielded cable.

      Delete
  6. eu contrui esse pedal e soa muito bem o melhor pedal de overdrive que ja contrui usei o ci 4558 original e ficou muito bom!!!!!

    ReplyDelete
  7. Hi guys, do you think that switching the voltage (back and forth from 9 to 18 volts), could cause any damage to the active components of the circuit (transistor and IC) in the long run?

    ReplyDelete

Comments are welcome on Revolution Deux. However, please do not spam links to unrelated sites - these comments will be removed! Thanks - Briggs.