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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 :-)

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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

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Friday 10 February 2012

Fred Briggs - '64 - Vintage Vox Tones Galore!


Here's another (nearly) new one from me. It's a tricked out super mod of the old Electro Harmonix LPB-1 circuit that produces some lovely singing overdrive tones reminiscent of an old VOX from their 1960's heyday. I took the Lovepedal Englishman (A supposed Vox AC30 / AC15 emulator) as a base and went from there - Firstly I wanted a little more gain, hence the 4k7 collector resistor. Along with more gain I wanted more emphasis and clipping on the higher mids to replicate that treble laden Vox overdrive hence the 82nF bypass cap and the 47k/22nF mids filter at the end of the circuit. These changes make the circuit sound livelier and give it more character. The use of the *super* low forward voltage SB340 diode in combo with the BAT46 diode produces harmonically rick asymmetrical clipping, the levels of which can be controlled using the "Headroom" control. The headroom control also allows a nice rich low end to be retained while allowing the top end to be clipped, as you roll back the clipping a nice tube like "note attack sag" effect becomes prominent - it's quite pleasing and cool to play with. The use of the 2N3565 transistor is due to some tests carried out a while ago where it was found that the 2N3565 sounded best in these sort of applications, you can replace it with a 2N5088 or BC108 or, in fact, any decent gain NPN transistor.

Here's the schematic for you:


Here's the freestompboxes.org forum thread where there's some discussion on the design: http://freestompboxes.org/viewtopic.php?f=13&t=16153

Here's some images of the finished pedal:



Classic vintage Vox tones. You'll notice this version has a diode switch installed which is basically the same as the Lovepedal Englishman's set up (But instead of the dual BAT 46, there's the BAT 46/SB340 combo) that lets you alter the diode settings between BAT 46, 1N4148 and nothing. The switch is used in series with the "Headroom" control to add an extra dimension of tones..

4 comments:

  1. Hey Fred,

    Thank you so much for posting all this information. I enjoy it a lot just reading about different pedals and artist etc.

    For now I'm looking for a new project to build and I'm considering your '64 Vox pedal. I'm used to those diy kits, so I wonder if you could help me with some (noob)questions?

    1. which type of capacitors do you use in different applications for this project?
    2. what would be the easiest way to make a vero layout from the schematic you have provided?
    3. I can't find the SB340 at my webshop, but they do have the SB360. Does it make any difference?
    4. Are all potentiometers linear in the '64 vox pedal schematic?

    Thanks a lot for reading this. Looking forward to your reply.

    Leon

    ReplyDelete
    Replies
    1. Cheers Leon, all pot are linear. You can just use 2 BAT46 diodes if you like. You're going to need an electrolytic capacitor for the 10uF, for the smaller caps any film type will be fine. Doing vero layouts is all about practice, download DIY layout creator and start playing around with it, it won't take you long to knock up a vero layout for this pedal.

      Good luck, hope it goes well..

      Delete
  2. Hi fred already have send you and email,but maybe someone knows wath kind of fuzz was used in the guitar intro of "everyones a winner" by hot chocolate guitarist.caburron@yahoo.com

    ReplyDelete
  3. Built it using 1N914/BAT 46 - sounds awesome! You can get from Vox to Marshall type tones setting volume and master the right way. Thanks Fred Briggs for making it available here for us. :)

    ReplyDelete

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