Thursday, 11 March 2021

MXR El Grande Bass Fuzz

 Per request. Note that there is an option to choose between internal trim pot (as in original) or external potoentiometer for the Freq control. Freq switch is external and the MPQ3904 transistor array is replaced with ordinary 2N3904s.

Schematic is avaiable HERE




 

 


 



14 comments:

  1. Awesome. You have taught me well Obi-Wan

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  2. got it built tonight . fired right up first time. It doest seem to have much bass. the sub switch acts more like aon off switch for the freq pot. When you turn the freq pot up all the way you get a very high pitched deafening squeal.It doesnt seem to add any bass or low end. the freq switch doesnt seem to do alot . I can hear it change the frequency of the background hiss. I did triple chech my build for mistakes. all looks good. Any suggestions? Its late , off to bed.

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    1. I'll take a look but I'm not back home until monday so I can't upload anything new until then if there is any mistakes.

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  3. No worrie, Thanks for everything. Have a great weekend

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  4. Update. I got the lack or lowend sorted. One of the solder pads on my cheapo stripboard lifted at one of the tone pot wires. It was very hard to spot. Overall, it doesn’t sound to bad. I think it’s nature of the beast for the freq switch to not do much, it does something but very subtly. The only issue really is the sqealing with the freq pot maxed out. Work around, don’t max it out. I would like to find a way to boost the overall volume just a pinch. I really like the sounds you can get with the freq pot turned down just a little but the freq pot actually works as a boost /cut. I believe that’s the way it is intended to work as well. If you turn down the freq pot just a little ( it brings in some thump) and turn up the tone pot just a little , it sounds killer. I’m not sure you will find any issues with the layout, I will be surprised if you do.
    Thanks
    Matt

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    1. Thanks Matt!
      Great work, since the Freq switch and pot s internal in stock units, I don't know if they are simply "set and forget" controls and I have not found any useful info online how thay work and should react. So I guess it is plausible that your build works as it should?

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  5. I would say, yes. It’s definitely plausible that it works as should. It has been recommended to maybe try a W100k pot for the freq. I will order some the next time I stock up and post the results. Unless someone can prove me wrong I would say this is Verified.

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    1. Ok, I'll tag this one, then.
      Thanks for tackling this one Matt!

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