Wednesday, 29 July 2009

Fred Briggs - Silver Orchid Overdrive

I've been away for a while. I'm back and here is a schematic for you! It's a great overdrive and boost, a development on from my standard overdrive. Add a switch to the diodes for extra fun :-)


4 comments:

  1. Hi Fred, Breadboarded this up last night and it sounds excellent. I am using it with P90s at the mo and i really like the sound. Didn't have any BAT46 so I have tried everything else. I really like Germs and silicon diodes in this so i think i will try a rotary switch. I also prefer the 18v to 9v.

    Really interesting circuit.

    I am having a little trouble with the bloom control - it has a really nice subtle effect when the gain is up full but with the gain below about 80% it has no discernible effect. I am going to check over it this morning maybe i hooked something up wrong. I am using linear pots. I also subbed a 68ohm as i didn't have a 62ohm so I will try 2x120 ohm in parallel and see if that helps. I noticed you had a 470nf cap in the standard version and 220nf in the Silver orchid so I will mess around with this also.

    This is the first time i have ever used a charge pump, I think I will leave it setup on the Breadboard and experiment with 18v on other designs.

    If I can tweak this bloom control i will definitely box this one up. One of the nicest sounding drives I have stumbled across.

    Cheers from Edinburgh.

    JJ

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  2. Hi Jacob, Thanks for the kind comments - I would certainly try using a 470n or 680n cap there, it'll make the effect of the control much more pronounced, infact, in the future I think I will update the scheme with a switch which will allow you to go between 220n/470n/680n - it's a nice addition. The 18V adds headroom to the drive, and dynamic response. On a rotary switch I'd put some 1N4001, BAT 46 and some BS170 mosfets configured as clippers. Those combinations should give you some great combinations. I keep meaning to draw up the scheme for a "Double Drive" version of this I designed, it allowed you to really crank the gain and get some great classic rock tones! I may try this with some even higher voltages in the future - possibly up to 35V, I imagine the double drive version would really start to rock then!

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  3. Tried the 470nf and it works much better. Also tried a few BS170s and found a much nicer sounding one.

    This thing is awesome. Will try and box it up in the next couple of weeks.

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  4. Dear Fred,
    I am about to breadboard this circuit after trying the Briggs Overdrive and the Brigg Clock of Tone. I am having trouble reading the values on the handwritten paper, is there a larger image for download?
    thanks a million. your blog is fantastic.

    Doron

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