The tubescreamer bad bob mod questions.

Discussion in 'The Stomp Box' started by markfresh, May 6, 2021.

  1. markfresh

    markfresh TDPRI Member

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    Hi,
    I was watching "that Pedal Show" the other night and the were using a tube screamer with the bad bob mod installed in the pedal, i liked the sound/idea.

    Heres the same idea i found online .
    https://reverb.com/item/28338241-analogman-maxon-od-9-with-silver-mod-bad-bob-boost

    Ok so moving forward, prior to seeing this, i was looking at the cheap Behringer tube screamers and thinking i might buy one and put it a metal housing.

    Then i thought how hard would it be to build a dual pedal with 1 side tube screamer and the other side bad bob mod?

    The tubescreamer part would just be re-housing a behringer vintage tube overdrive, but im not sure on exactly what the bad bob mod is (i dont need the whole Bad Bob pedal just the mod part people are putting in the tubescreamer)

    I found a post on here saying it could be based on the "Jack Orman AMZ Mini-booster"
    http://www.muzique.com/amz/mini.htm


    So could anyone tell me how i would go about this, ive only ever made 2 simple pedals and not the best at working out complicated diagrams.

    I also found a pre built mini-booster and would this be easier to add this to the Behringer guts.
    http://www.muzique.com/tech/module1.htm

    Also i cant find whether these TS/Bad Bob moded pedals use the whole Bad Bob circuit or just parts of it etc

    Thanks Mark
     
  2. markfresh

    markfresh TDPRI Member

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    I also just read this :"The OD-9 board has many parts removed in preparation for the SILVER mod, so there is less circuitry in your signal path for a clearer, purer tone"
    So im not sure what was taken out of a OD-9 and if this is possible with a behringer.
    https://www.ebay.com.au/itm/2547805...m3b521b5f18:g:9iUAAOSwDHtfs0dK&frcectupt=true


    Also more info "The Bad Bob pedal is a booster based on the famous and much copied mini-booster "JFET mu-amp" design of Jack Orman. This design was also used as the basis for most other boutique boost pedals"
     
  3. 11 Gauge

    11 Gauge Doctor of Teleocity

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    Yeah, it's not a 'Bad Bob mod' - it's a specific mod for a TS (analogman's 'Silver mod'), that includes an entire non-related (to a TS) booster circuit.

    IOW, there's nothing under the hood of any TS that contains anything like a Bad Bob/Orman Minibooster.

    Analogman offers the Bad Bob separately as a standalone boost, so they must have figured out that there was a way to completely retrofit it inside a TS9/OD9, specifically.

    Personally, I'd just get or build a Bad Bob or Minibooster, and use it in conjunction with whatever TS variation I might prefer. I think something like the Bad Bob is just really good on its own, and might even be better when stacked with a non-TS type of OD.
     
  4. markfresh

    markfresh TDPRI Member

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    OH ok that makes sence , as i read that the maxon size case is the only one they do the mod in due to room in the housing,
    so they must just be able to fit the bad bob pcb inside there .

    Ok so maybe i will make a dual pedal , one side TS and the other boost, then i can use them seperatly or together , but would have to put a before/after switch in it,
    or just make two separate housings .

    Thanks for the info :p
     
  5. markfresh

    markfresh TDPRI Member

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    Just thinking about this again,
    I just received a Behringer overdrive pedal and have found a tiny boost pedal circuit.
    http://www.diyguitarpedals.com.au/shop/index.php?main_page=product_info&cPath=1&products_id=35

    If i did want to add this boost to the pedal how would i connect the 2 together if i wanted to have the boost after the overdrive?
    Is it a matter of wiring the boost to the output lug of the overdrive etc?
    I guess it would be similar to making a dual overdrive/boost pedal?

    Thanks Mark
     
  6. 11 Gauge

    11 Gauge Doctor of Teleocity

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    I'm assuming the Behringer pedal uses buffered, non-mechanical bypass switching. If so, it will probably not be as easy as trying to insert it just prior to the output jack. It would also have to be before the output buffer circuitry if you wanted both the OD and boost to shut off when actuating the footswitch.

    I'm also assuming the Behringer pedal probably won't accommodate a big additional mechanical footswitch either, to allow the boost only to be turned on and off, separate from the OD. So this means you'd have to resort to a toggle for the boost, and that assumes a toggle would fit, which it may not, either. And it will probably be the same issue for trying to find somewhere to add a boost pot.

    Lastly, even if you could figure out a way to get everything inside the enclosure and get it all to fit, you may end up with switch pops and/or hum, or other similar issues.

    IMO, using something like a Behringer pedal as your host/starting point is probably simply the wrong way to go. If you insist on adding it to an existing pedal, I'd suggest that it have some or all of the following:
    • a metal enclosure
    • room to add switches, wires, add'l circuitboard, and a pot for the boost
    • 'through hole' construction (not SMD)
    • actual mechanical switching (with true bypass probably being the most preferable)
    ...Looking at that list above, I don't think the Behringer pedal is going to check any of those boxes.
     
  7. markfresh

    markfresh TDPRI Member

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    Thanks for the reply and the info.

    I dont want both the OD and boost to shut off at the same time i want them to act independently, does this fix the buffered problem?

    So i imagine then that wiring a another pedal from a existing pedals output wire to the in of another pedal circuit then to a output jack is not the same as what a patch cable does between 2 separate pedals?

    I took the Behringer apart and i think i can make it fit by removing the spring for the battery cover and drilling a hole, will have to look at the boost pot.

    But yes i see what your saying and i may just build a seperate boost pedal which would be easier.
    Also the reason i dont want to make a dual pedal is that i think mounting the Behringer internals to a metal case would be a major hassle especially as the Behringer on/off switch is tiny etc.
     
  8. 11 Gauge

    11 Gauge Doctor of Teleocity

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    The Behringer pedal has the in and out jacks mounted right to the PCB, right? So how or where are you going to 'insert' your boost circuit? Your boost circuit requires 9VDC, so you'll have to figure out a way to get that from the Behringer PCB to the boost PCB - again, if the DC jack is PCB mounted, it will probably be a real pain to run a wire from it. And, you'll need to run a ground wire, too.

    You still have to think about both the switch and pot for the boost, too. Where and how will you mount them? Is there room? Will the plastic enclosure properly support them?

    Just because you can find somewhere inside the pedal to put the boost PCB itself doesn't mean that there's room for everything else, and it doesn't mean that it's going to be easily possible to wire the boost 'into' the existing pedal's circuitry. It's not just a simple add-on.

    Basically, to 'tap in' the boost circuit will require cutting PCB traces of the Behringer pedal, and then figuring out the right spots to connect the boost in and out wires to, which typically means trying to solder right to a component itself. Maybe you might be able to drill tiny holes into the PCB to do this, but that might not be feasible. And even if you can get the wires attached, they're probably not going to be sturdy. You'll probably also burn and lift some PCB traces in the process, creating even more headaches.

    ...It's honestly just hundreds of times harder to try and add add'l circuitry to a mass-produced pedal such as this, than it would be to get a DIY TS kit, and an enclosure big enough to house everything, which would also have room for a 2nd footswitch, and the boost pot. Such a kit would have simple true bypass wiring and off-board in and out jacks, and DC jack, so you could properly connect everything together.

    The way you're trying to do it is like trying to run a race backwards, IMO. You might be able to do it, but you probably won't be pleased with the results.
     
  9. markfresh

    markfresh TDPRI Member

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    Thankyou and ur correct, it sounds like a lost cause, i was going to say ill just build the boost in its own seperate box, but now i might look at as u mentioned a TS circuit kit and the boost in a dual pedal.
    Im basically looking for a project for my enjoyment and you have defiantly made me go the simpler way.

    Cheers Mark
     
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