Home Forums GuitarPCB Build Support BMPOA Wilkie mod (answered)

This topic contains 8 replies, has 4 voices, and was last updated by  Matt 3 months ago.

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  • #2292

    Matt
    Participant

    Good evening. I just fired up my BMPOA completely stock and it rocks. Cheers. But now I’m thinking about going back in and doing the @wilkie1 mod mentioned in the build doc to jump in at pin 7 and put in the Tone TwEQ. I have one standing by and I think this build would do nicely but I just can’t quite wrap my head around the mod. Is there a link anywhere showing that in greater detail? Or a picture perhaps? I’ve certainly jumped my share of TTs into circuits but I don’t quite get how this one is supposed to roll. Thanks!

    #2293

    Barry
    Keymaster

    Hi Matt,

    Pin 7 is the same as doing the following per the guide below using Pad A in the diagram section.

    https://guitarpcb.com/wp-content/uploads/2018/07/BD_Tone-TwEQ.pdf

    Looking at the BMPOA Build Document schematic you will see that by placing the Tone TwEQ in Pad A you are now bypassing everything downstream from Pad A which is the Tone section and Volume Pot for which the Tone TwEQ will now take over for both.

    The Tone TwEQ is now a Plug & Play Active Tone Control & Volume for your BMPOA. Very clever IMHO.

    Incidentally several other boards include A/B pads for experimentation as well.

    #2295

    wilkie1
    Moderator

    That’s right, Barry.  By using the connection at Pad A and eliminating all of the other components downstream, you also remove the Tone and Volume pots from the original circuit.  This helps reduce the total number of pots on the enclosure since you are adding the four pots of the Tone TwEQ.

    #2301

    Matt
    Participant

    Doh! Totally forgot it’s in the build doc for the TT. And my confusion lay in the wording of the mod description. By suggesting it picks up at pin 7 I was imagining hotwiring ito the IC connection somehow and that seemed dubious at best. This is a much better idea and will be used at once. Cheers all.

    Btw I love the AB pads. I think it was the Dr. Rock that I did some evil surgery and grafted on a pair of Roto-Tones a while back. That thing smokes!!

    #3340

    Matt
    Participant

    Sorry to revive a dead thread. This pedal is absolutely killer with the TT inserted. I removed the Tone a and Vol from the BMP and just left the Sustain. It smokes.

    But now I’ve suddenly drawn my boss for our work gift exchange. He’s a bass player and once loaned me his early 70s Big Muff, one if the best things I’ve ever heard. I’d like to gift him this pedal but was curious if there are any recommendations for mods for bass? I don’t have a bass to test with, so I’ll be winging it. Cheers!

    #3343

    wilkie1
    Moderator

    The Tone TwEQ circuit is designed to handle bass frequencies since the bass filter is a shelving type that filters well below bass frequencies..  The BMPOA looks like it will do a good job for bass as well.  The only mod that I see that may help for bass is to increase the value of C1 from 100n to 220n.  You may not notice a difference except with a 5 string bass.

     

    #3345

    Matt
    Participant

    Copy. So this one may be good to go as is. Most of his pedals are standard guitar pedals anyhow, so I’m not sure he’d specifically hear a difference- just looking to make this one special. Just need to finish it up (and take some pics for the forum here!) Thanks Wilkie!

    I’ll be sad to see this one go. So I’ll be duplicating it for sure.

    #3481

    pinkjimiphoton
    Participant

    haha

    my “stiffler’s mom” pedal is the bmp driving the tonetweq.

     

    holy cow. mucho intestinal fortitude. stupid sustain, too. may oscillate and howl at extreme settings. the loudest muff on the planet. seriously. yummmm

    #3485

    Matt
    Participant

    Right on! I posted my final product in the Show Em thread. It ended up as a gift to my bass player boss and he’s blown away by it. Now I have to get through the holidays and put in my order for another BMPOA. I think I have a couple of TTs in stock. But I need to have this one back in my life!

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