Tuesday, 12 July 2016

Mesa/Boogie Throttle Box

Another circuit by Mesa Boogie.
This one uses an Inductor, a dual LED and a different Bypass Switch wiring.
There's already an unverified layout (multiple boards) by Savvas in the Contributions section of the forum but I wanted to add one on a single board.
You can find the original thread and schematic here.


46 comments:

  1. Alex you must have read my mind. I was just looking at Savvas's layout 20 minutes ago pondering wether i should tackle it. Now you've made it a so much easier decision. Thanks.

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  2. This is .... AWESOME!! Thank you guys so much. Going to try to tackle it this week sometime,

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  3. thank god you did this!that's great news! i didn't like my boards at all..this and rust bucket..ahhh! ..in some point i was about to re-design a BIG vero for the rust bucket cause i've tried my 13700 layout and couldn't make it work and debugging was a nightmare..imagine how boxing would have gone...no more multiple boards! cheers Alex!

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  4. Only place i can find that value inductor is Mouser but at £12 delivery charge seems a bit of a rip off. Anybody found any other sources?

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    1. 250mH seems to be a common value. Check eBay!

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    2. Should it actually be 250 microhenries which would be written as 250 uh not 250 mh.

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    3. Not quite sure about the "common". With search for "250mH inductor" ebay gives me 3 hits. Search for "250uH inductor" gives out 8 results. So no. I would not call that a common value.

      All datasheets for iunductors list values 220µH and 270µH - as well as 220mH and 270mH.

      Also, the schematic does say 250mH, not µH.
      +m

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    4. Oops I had mistaken the 250uH inductors on eBay for 250mH.

      I know Vox grey wah is supposed to have a 250mH inductor, so I'm thinking out best bet is mouser or a wah geek like Gagan or Castledine

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  5. Is there a way to make a gyrator(daughter board) to work in place of the 250mH inductor?

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  6. Hey mirosol, can you post those links you found because i can't find any links except to Mouser. Thanks.

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    1. These'll be the cheapest ones on ebay.
      http://www.ebay.com/itm/222001383276
      +m

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  7. If you can't find one I would just ask any of the wah guys like Joe Gagan or Stu Castledine.

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  8. I'd just use a 270mH, it would set the cutoff at 653Hz instead of the 678Hz set by the 250mH, I know I for one would struggle to hear the 25Hz... What's more, 270mH is inside the ±10% tolerance of most of the parts you'd actually get hold of anyway...

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  9. that ebay link is for nuts and bolts.

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  11. Wow cool circuit I like how it uses the Inductor for the mid cuts kind of how a wah does it . Where can you get these inductors the other link was for bolts. Its a really high gain pedal . Thanks Guys I might have to solder one of these up.

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  13. Alex, thank you. This is a must build for me. Anyone finish this one yet?

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  15. Just waiting the stuff to arrive for the build! I'll try 2 x 500mH in parallel, thank you for this!!

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  16. Got the wrong parts... Gonna try again lol.. Will keep you updated

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  17. So i built this but am getting no signal at all. Also no bypass signal. All connections good board and completeley debugged. Any ideas?

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    1. Sorry "All connections good and board completeley debugged. Any ideas?

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    2. Hi Gavin!
      Did you follow the footswitch wiring on the layout?
      It's different from the usual wiring.
      If you did you should at least have bypass signal.
      The switch lugs are numbered as usual:
      1 4 7
      2 5 8
      3 6 9

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    3. Look at the 47p. Output of pin 1 is going through that to ground. Should be between pins 1 and 2.

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    4. Thanks Ciaran and Leon. Mistakes are easier on large layouts. Sorry about that. It has now been modified to correct the cap mistake, Tone and Gain orientations (schematic mistake).

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  18. Hi Alex,
    Yes, i followed the wiring layout. I will check again that i haven't done something stupid when i get back from work but i am sure its correct.

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  20. Gain and Tone work in reverse.Layout is O.k

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    1. Hey Leon, you got yours working? I still get no signal even in bypass. Did you wire your footswitch differently? This ones got me stumped.

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    3. I figure i must have dodgy footswitch. I'll change it out now and see. First dodgy 3PDT out of about 200.

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  21. Eventually got mine working. Would you believe a dodgy jack. Sounds f*^"$£ng amazing. Thanks Alex.

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    1. Would you believe today I was debugging my Wriple Treck clone (just in case someone gets angry for naming it) and after a bunch of days scratching my head I remembered about you and your dodgy 3PDT. I ended up opening the 3PDT and repairing it ;)

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  22. Finished this one, I got some kind of "Hiss noise" behind the distortion only when playing. The basses are weird... Gain and tone are reverse.

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  23. Hi guyssss thnx for awesome vero again
    I have an issue with old layout 3 parts.... i have too low output and no significant gain

    Ξεναγος νεκροπολης can u send me an email to contact yoy??.
    Thnx in advance

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    1. And my main led stays always open....
      Also mu inductor is 100mh but i think that isnt the oroblem with low output

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    2. Update... i checked with audio prob and fount out that 4558 boost signal-> 1k5!low signal-> dual opamp boost-> low again from restistora and at the end ouput is very low........ i check 3rd ic and it boost but same problem at the end :( too low output
      Wvrything checked from vero and no bridges at alla double checked

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  24. Can i connect 3x 3.7v parallel 18650 accumulators its ~ 11.1v? Or need some modifications? Sorry for my english.

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  25. Hi! I'm about to start building this one and already have all the parts except for the... yeah, 250mH INDUCTOR.
    I have a 220uH inductor available, and can get them up to 1000uH (I guess that's 1mH) but I don't see myself connecting 250 units of 1mH in series...

    I read something about replacing the inductor with a gyrator. It looks like it would be two resistors and two capacitors connected in some way that would replace the inductor, but I have absolutely no idea on how to calculate them. I actually read somebody here mention 678hz but no Q bandwidth was mentioned, and that's as far as I got. I don't even know where should I connect whatever it replaces the inductor.

    Anyway, any to solve this?

    This was my first wanna-do project but pedals and projects are growing around and this one is still a wish...

    Thx in advance!

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    1. BTW, I'm in Argentina so getting it from overseas (Tayda, Mouser, whatever) is a no-no. :(

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    2. Well, I cannot sleep without trying sort this out.

      I'm working with the 33x22 layout and the schematic from
      http://www.freestompboxes.org/download/file.php?id=22610&mode=view

      It looks like IC3D is unused so I thought I could use it to build the Bandpass EQ gyrator design from muzique.com .
      For abreviation I will use "MTB" to refer to the schematic from the link, and "BPEQ" to refer to BandPassEQ from Muzique.
      If I replace C10 @ 220nf of "MTB" to be C1 of "BPEQ" @ 100nf, then replace the 250mH inductor with the C1, C2, R2 (all of them connected to IC3D as the "BPEQ" schematic suggest), and finally output that to lug 1 of POT3 (MID CUT), and then keep R17 of "MTB" to ground...

      Would that work???

      Values assuming 4.5v before R1 should be:
      R1 10k
      R2 1k2
      C1 100nf
      C2 47nf
      This would give me 670.5Hz @ 1.98Q

      Please let me know if this is correct and if it would sound "close enough" to the original design.

      Or maybe you're all laughing your a$$ off to what I wrote.

      :/

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    3. Yes, you can replace the inductor and the capacitor with the gyrator, and te 10K pot should be placed betwen C1 and C2, to allow you to change te value of Q of the equalization, because the boost/cut level is already set in te MTB by R15 and R16 (almost full cutted), you only control te value of Q in the MTB schematic. I did tis in my pedal and work as the same as the original.

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