Thursday 23 February 2012

Xotic EP Booster

And the original version.  You can supply this with 18V if you want the extra headroom, but if you are likely to do that make sure you choose appropriately rated caps.  Xotic's info:

What do the tones of renowned guitarist such as Page, EVH and Johnson have in common? They all used the legendary echo machine EP-3 as a pre-amp.  We've captured that magic in a new Xotic Effects pedal, the EP Booster.

We've used the highest quality parts available with a discrete FET design and low impedance output, the EP Booster provides up to +20dB of unadulterated boost with multi-dimensional, shimmering highs and lows, and no ear fatigue. The internal DIP switches let you choose the boost frequencies, and EQ settings.


Update: I noticed I had a cut in between the JFET drain and the 8K2 resistor which shouldn't be there.  If you've already made this then make a solder bridge over that cut and it should work, or if you want to build it use the updated layout below


166 comments:

  1. hi IvIark,

    If I don't want the fat/bright mod, the layout is the same? or I have to include some modify?
    thanks so much! :)

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  2. or better, can I substitute the 2 switches with a on/off/on one?

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    1. If you want to omit the switches completely then still use all the other components, because then at least you have the option to add the switches easily at a later date if you want to.

      You could add a single on/off/on switch instead, although you obviously won't be able to have the fat and bright mod enabled simultaneously. To do this use a DPDT on/off/on with lugs laid out like this:

      1 - 4
      2 - 5
      3 - 6

      1 - Sw1a connection
      2 - Sw1b connection
      3 - No connection
      4 - No connection
      5 - Sw2a connection
      6 - Sw2b connection

      and that should do the trick.

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    2. Hey, I made this, love the boost it gives and it's always on at the end of my 12 pedal long chain, however the fat boost switch wired above makes almost an indectible shift in tone, even with my amp dimed.

      Are there any videos of what it is meant to do? Everything is as it should be in the diagram and all solders are good. I can't work out why it isn't doing anything.

      Cheers

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  3. This comment has been removed by the author.

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    1. The layout is correct for my 2SC1815s and I'm pretty sure they're Toshiba. I think the datasheet view where you see the pinouts is a bottom view looking at the pins rather than a top down view.

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    2. Oh, my bad, you're right.. sorry for that. I deleted my post

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  4. hi IvIark,

    I've built it and it's very cool booster! congratulations! :)

    but I don't notice any difference when I active the fat mode...how can increase this difference? can I increase the 10u value maybe?

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    1. It's the 100u cap that the switch brings in, and puts in parallel with the 10u. If you're happy with the non-fat sound it would be better to increase the 100u, to maybe 150u or 220u. I'm surprised that you can't hear any difference though because that's a big jump from 10u to 110u.

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    2. ...so I think I should try with high volume!!! :)

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  5. Just to add to future trouble-shooters' knowledge: When I first made this, the boost pot didn't do anything. It was basically on full blown boost all the time. I thought I saw a piece of copper strip bridging the cut on the third row from the bottom so I fixed that up, and now it works fine. So if anyone ever happens to have the same exact problem as me, you'll know how to fix it!

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    1. Hi! I have the same problem, but i don't understand when you you say "I saw a piece of copper strip bridging the cut on the third row from the bottom so I fixed that up". Can you explain to me how you did?
      Thanks

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  6. There's a substantial pop when I turn the effect on and off. I noticed the 1M resistor going from input to ground, which I assume is acting as a pulldown resistor on the input. So I added a 1M resistor from the output to ground as well, but it didn't make any difference. Any idea on how to fix this?

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    1. Are you using an LED? If so that can cause pops when switching on, have a look at this:

      http://www.muzique.com/lab/led.htm

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  7. I found the spst switches at smallbear but not sure if this are the ones :S


    http://www.smallbearelec.com/servlet/Detail?no=672

    A little help hear!

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    1. That's a momentary stomp switch, you need a toggle switch. SPST are available but more unusual, and so you can get a SPDT for less money despite it giving you more potential functionality. So just use something like this:

      http://www.smallbearelec.com/servlet/Detail?no=38

      And just use 2 of the lugs (middle and either of the outer lugs).

      Just so you understand what that means, the SPST is single pole single throw switch and so there are only 2 lugs, in one position a contact is made between both lugs, in the other position the contact is broken. Simple as that. SPDT is single pole double throw and with that there are 3 lugs (as you can see in the pic on the smallbear site). In one position a contact is made between lugs 1 and 2, in the other position a contact is made between lugs 2 and 3. So the middle lug is the common which is always used, and which outer lug makes contact with the middle lug is determined by the position of the switch.

      This is based on the toggle being 2 position, you can also get 3 position toggles where the centre position is "off" and so neither of the contacts are made.

      Because of the extra functionality you get from a SPDT it means they are made in greater quantities, which in turn means that you're probably not going to save money looking specifically for a SPST switch. But I will always mention it in my layouts as requiring a SPST switch simply because that is all you actually need, and I don't think it is helpful in a layout when you're trying to make it as simple to follow as possible, to tell people to buy something else and then add caveats about ignoring one of the lugs.

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    2. Great!!! Thanks a lot mate, already put the order for the parts and finaly Im begining to understand this whole switch buissines! and again sorry for all the rookie questions!

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  8. I used a dip switch with 2 on/off switches for fat and bright.
    The bright is very obvious as it adds high end, as mentioned by someone else the Fat switch doesn't seem to give a very noticable change. It's more like you feel there´s more low end. What are your experiences with the fat switch?

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    Replies
    1. I haven't built this yet so maybe someone who has can chip in?

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  9. I've a strange question, but is it important to connect the 2 ground wire mentionned on the vero to a AC jack, or just one of it (and for the second, for exemple connect the 1&2 lug of the potentiometer).
    Thanks

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    Replies
    1. All the grounds including the offboard grounds need connecting together, so the board, pots, DC adapter, input and output sleeves and ground lug on the switch all need connecting. Either by daisy chaining from one to the next, or by connecting them all to a central point in a star formation (the input or output sleeve or maybe even the spare holes on the bottom row of the board would be a good central ground point.

      You're probably better NOT connecting anything extra to the DC adapter because they're quite flimsy and the last time I tried to solder a couple of extra things on one it melted and the contact fell off! :o)

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    2. Okay thank so the 2 grounds wire to the vero need to be connected to a ground point

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  11. Replies
    1. Has this been figured out? If you put it sideways with the 10 rows can it fit into a 1590A?

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    2. Well you can certainly fit a layout which is 10 rows high in a 1590A with room to spare if you have it sideways. But that 17 columns is going to make it tight. I'd say it could be done, the box is 92.5mm high and 17 columns would be around 45mm so it's going to be taking up approximately half the box. That means the board will have to be mounted upside down and one of the sockets is going to be under the board to some extent. But if you use tantalum caps to keep the height down, and mount it with the left hand side of the layout as shown at the top of the box (so the taller components are mainly at the top and so have more room) then I think it should be ok. The one electro (tant) and transistor on the right hand side will have to be laid down flat in some way so that they don't interfere with the socket. Then of course you have the switch placement to think about if you're including them both.

      At the end of the day I've seen a Klon in a 1590A, so if you're careful with your measurements then you would expect this to be a doddle in comparison.

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    3. Confirmed that it fits in a 1590A enclosure. I used a DIP Switch on a small daughter board instead of SPST. I also had to wrap the thing in electric tape and flip it upside down, so solder side is facing out. Done deal.

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  12. What a great boost this is.. Probably the best I've tried. It doesn't suck anything out, very transparent. The switches are VERY subtle though and more noticeable when it's boosting an already dirty amp. Really nice though, glad I made one.

    Cheers matey

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  13. This comment has been removed by the author.

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  14. I've just read that the original has internal dip switches for boost level and eq, Do you know if there is any info on that being added?

    Cheers

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    Replies
    1. I'll have a look mate to see if I can find an updated scheme

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    2. yes, the original doesn't have the fat switch and the boost level DIP, on the original, allows the CCW volume to be unity or boosted 3db - as it is with this layout currently.

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  15. Hello and thanks for your great layouts. I built the lovepedal deluxe sixty last week which worked first time but I'm having trouble with this one. For the moment I'm having trouble getting any voltage readings on the board. Could you tell me what voltage readings I should be getting at the transistors or anywhere else. Thanks a lot and keep up the great work.

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    1. If you're not getting any voltage at the transistors then you've got a problem with the supply which could be a problem with your DC adapter, bad solder joint, or maybe the diode put in the wrong way. With your multimeter check the voltage you're getting between 9V and ground where the two wires connect to the board. Then check the voltage you're getting between the other side of the diode and ground. If they're both ok (voltage reading after the diode should be around 0.5 to 0.6V lower than the supply reading between the two wires) then you should be getting a reading on the collector of Q2 which is directly connected to the other side of the diode. Try all that and let me know how you get on, then we can move on from there.

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  16. Thanks! I'll give that a go this evening.

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  17. Yess! The diode was faulty. I think I may have blown it while testing. Just finished and it sounds great. Very transparent though the bright and fat switches are pretty subtle. I need to have a good play with it. The voltages I'm getting are:
    Q1: D: 6.28. S: 1.08. G: 0
    Q2: E:2.41. B: 8.2. C: 2.85
    Thanks for your help.

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  18. Ok someone throw me a line here becouse I need a place to buy power supplies that don't suck and had a bunch of bad noise to the pedals I'm building...

    I've built a couple of pedals now and I'm keep getting a lot of hum and hiss and what not... I think it is the power supply I'm using which is a cheap pos but I need to know where I can get ones that work really well and are ether filtered better... or regulated.

    If no one helps I'm about to say screw it and start ordering 12vDC supplies and just regulate everything with L7809's and come large caps...

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    Replies
    1. I have a couple of Godlyke Power All's that I use for all my pedals. They're relatively cheap and I've never had a problem with noise. But you may have a dirty supply that will often have a problem with noise no matter what power supply you use, and if that is the case you're going to need some sort of power conditioner as well. You can buy them from general stores like Argos here in the UK.

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    2. Well... I am building my pedals in my college dorm and it was built in like the 60s...

      Maybe it isn't the power supply and is just crappy wiring in the dorm. Guess I'll drive over to a buddies house and see if it still gives me problems there...

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  19. hi IvIark, I am making is pedal for about 1 week.
    But I didn't make it work. It does nothing in stead of getting the LED on and exxxxxxxtrem low volume that can hardly be heard with volume of my 15W amp fully turned on.
    Since I cannot get any 2N5457 here and I cannot get some of the recommend substitute. I am now using a BF245B........ will it caused the whole thing don't even work?
    If not, can you tell me ways that I can check why?
    P.S. this is already the second one I made..... still not working....
    Hope you can help me, I am just so despond.
    Thank you, D

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    Replies
    1. http://www.futurlec.com/index.shtml

      I think you should be able to get what you need here.

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    2. I got the same type of problem. Make sure all the grounds are rooted together. The 2 grounds on thé stripboard confused me. Finaly i simply put an extra wire behind thé two 2 ground strokes then the pedal working.

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    3. I know it's been a while but I'm interested in how and if you got it to work. I'm using bf245c instead of 2n5457 and can't hear a damn thing unless I turn the amp all the way. And yes, Everything is grounded as it should be.

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  20. I just finished this build. I turn the effect on and it lowers my volume when the pot is turned all the way up. I used everything exactly as written on the design. Can I just put a different pot with a larger sweep, or is there something else wrong?

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  21. just built this one and it sounds great. the only thing is that the bass boost switch didn't really do anything at all. I tried replacing the 100u cap with a 220u, still no difference. then I replaced the 10u on Q1's source with a 1u and put the 100u back in. it works pretty good now, but since this preamp adds low end even with just the 1u cap, i'm thinking about replacing the 1u with a 470n so it'll be more of a flat boost when the fat switch isn't clicked in.

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    Replies
    1. Had the same issue with the fat control - replaced the 10u cap at Q1 source with 100n (all I had to hand), and it is now pretty much a flat boost with it switched out and fat boost with switch on.

      Great boost, now with fat/flat switch :)

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    2. after some trailing I worked out that the 3n3 for the bright should be 33n - it seems to work like a bright cut then rather than a straight bright

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    3. Sorry for the necro-post ...

      Not sure if John ever did swap the 1uf cap on Q1 source for 470nf, but I did. As predicted, it's certainly more a flat boost that way. I settled on a 680nf, because it sounds very close to the "stock" tone to my ears, but still gives a subtle bass boost with the fat switch closed. YMMV.

      Also note: I used a J201 and 2N5088. Sounds great.

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  22. I like this one. It gets loud, but always stays relatively defined, even at higher boost settings.

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    1. While this one's not that great on bass, it's an absolute beast on guitar. It turns my friend's Blues Junior into a cranked Twin, which is no small feat. It gets really loud at 18v, almost too much in my opinion.

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  23. Is it a good idea to connect the ground on top to the ground row at the bottom

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    1. Yes, just daisy chain them. I may redo this with a ground link, there's no real reason why not to with it only being 17 columns wide.

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    3. So I just finished this build and when I turn it on it's just a little lower than unity. The pot doesn't do much. I put the pot lugs 1 and 2 onto the top ground row. I put in a new set of transistors and still the same problem. What could be wrong? Should I check voltages?

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    5. The readings I'm getting are not the same as the ones given above in earlier comments.
      Form 9v to ground: 8.8
      From cathode to ground: 8.2
      So the diode is working I think
      I'm measuring the transistors with the negative probe to ground and the positive probing the transistor leads:
      Q1:
      D: 7.67
      S: 0.34
      G: 0
      Q2:
      E: 2.48
      C: 8.29
      B: 2.94
      I have the transistors facing the way they are in the layout

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    6. Dimitri,

      Did you ever figure this out? I'm getting similar readings to what you had. I get signal from the pedal, but no gain whatsoever.

      Using the same measuring methodology as you, here are my readings. Supply voltage is 9.07.

      Q1-

      D: 8.06
      S: 0.23
      G: 0.00

      Q2 -

      E: 2.78
      C: 8.47
      B: 2.94

      Any pointers on where to start debugging would be greatly appreciated by anyone.

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  24. hi i have the same problem .... the pot and the switch's doing noting .

    ive changed the 3n3 cap to 3n9 cause that what i had and the pot is 10k log it sound good but without option to play with the sound

    any suggestions?

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  25. please help in here this thing is a beast !!! so much volume !!! and the pot is useless ... the switchs doing somthing (not sure what...) how can i restrain it?

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    Replies
    1. Change the 100R to 18k or 20K, volume will come down. The switches does something very subtle. The bass switch is still noticeable but the treble is very subtle.

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  26. Is the pedal supposed to be Unity Gain when all the way CCW? There is still some boost for me, even with the control off/down.

    I run a Wolf Computer clone before the boost and the treble switch is VERY noticeable when boosting the fuzz.

    Great boost all in all

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    Replies
    1. https://youtu.be/dt2TyzYsw6k?t=46s

      answers CCW question

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  27. Need help:( followed the Vero layout, but can't get it to boost... As of now, I've completely removed the stomp switch and LED, so it's mono input to board and mono output to board, literally how the layout shows. With that, I get a radio station from my amp haha. When I touch the input jack with my skin, the radio signal gets clearer and I hear a talk show HAHA

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  28. I've build this one using bc169c in the place of 2SC1815 - still sounds nice. Thanks for the layout.
    HNY!

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  29. The sweet spot on this is about 9 or 10 o'clock, I was wondering what I need to change in order to lower the gain a little so I can have a bit more control at the level, so touchy to dial in what I'm after that low at this point, thanks!!!

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  30. Hi!
    My Ep works but has less gain (not volume...) than those i've heard on all youtube demo's.
    What can I change to increase the gain?
    thanks

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  31. Here is a test of my build : http://youtu.be/ESWUnAIB2Q4
    This is turning to one of my favorite boosts.
    I wired both fat and bright to one switch /both on or both off/ which is on towards the end of the vid.

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    Replies
    1. That's great, thanks for sharing the vid

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  32. Hi Mark!
    in several EPB clones, there are J201 and 2N5088 transistors instead of 2SC1815 and 2N5457.
    What changes can I expect with these transistors? more/less gain? tone?...
    Thanks
    Olivier

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  33. My fat switch isn't really doing Mcg when I turn it on or off, what can I do to make it a bigger difference?

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  34. John answered your question already (~ 20 posts above). I replaced the 10u at Q1´s source with a 470n and this did the trick (for me)... I consider lowering this cap a little more for more "flat" response so you could solder in sockets for more experiments....

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    Replies
    1. Thanks Heiko! Does it matter that im replacing a cap with polarity, with one that doesnt have polarity (ie 470n ceramic cap?)

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  35. Great boost circuit. Using this as an always on pedal just before my delay. I built this one without a switch and velcro'd it under my pedaltrain nano :)

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  36. Hi community,
    I've successfully build my own PCB of the Xotic EP Booster Clone. Here is the build instruction manual if you are interested in:
    https://www.dropbox.com/s/y1ds7zoig42aswo/Xotic%20EP%20Booster.pdf

    You can order this PCB by sending me a pm.

    Regards & keep on rockin'!

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    Replies
    1. looking for it and the link doesn't work...

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    2. Same here can you please put it online again?

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    3. Please, can you put online again?
      Thanks

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  37. Just finished this build and thought I'd upload a few pics of the finished product. This thing adds so much tone and really colors the sound of my amp. Love it!!

    Front- http://i57.tinypic.com/f55ao4.jpg
    Inner- http://i61.tinypic.com/116jjo9.jpg

    Thanks for the layout Mark!

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    Replies
    1. which, version did you build? the main schematic that's at the very top of the page?

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  38. I've built this pedal three times. Failed all three times. Heard a pathetic hollow sound. I tried everything I could. Referenced the layout and checked my work probably 20 times. I've made around 20 or more pedals. This is the only one I've failed at and cannot make work :( I'm going to turn the dead xotic pedals into single knob fuzz, so all is not lost necessarily :)

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  39. Great layout and fun build. Thanks! One issue: this thing is BOOMY with a ton of low end. It's great as an "always on," but adds way too much low end when used in conjunction with other pedals. I did not use the fat/bright switches. I used to have an original, which had a certain "sparkle" that my build is lacking (though I can't remember where I had the internal dip switches set). If I jumper the 100uf cap, will that bring the low end back to stock?

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  40. Can u suggest any good subs for 2sc1815? Thanks

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    1. Any NPN silicon will work fine, starting from 2N3904, 2N5088 and BC550. Just mind the pinout. 1815s are relatively easy to source though.
      +m

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    2. if you can wait for them to show up tayda has them for $0.03 each, and i know they sell them on ebay for like $4.00 for 100 with free shipping as thiashine.

      http://www.taydaelectronics.com/catalogsearch/result/?q=2sc1815

      http://www.ebay.com/itm/100-x-2SC1815-C1815-Toshiba-Transistor-USA-SELLER-Free-Shipping-/231165358500?pt=LH_DefaultDomain_0&hash=item35d28771a4

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  41. I ordered these right when I saw your post. Thanks for the heads up. They came in today

    Mine are very consistent with a gain of 180 +/- 10%

    It's always good to have extra transistors to experiment with :D

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  43. Hi,
    I finished the pedal and it boosts ok (i think) and the sound is great but when i`m not playing there is a background noise like frying eggs or something.It doesn`t get louder or goes away no matter where i have the level pot.I haven`t tried it with an amp only in my PC.
    Any ideas as to what could it be?
    Thanks

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    Replies
    1. Sounds like your power supply isn't working properly. What are you powering the circuit with? If it's a wall wart supply, try measuring the output voltage.
      +m

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    2. I've replaced every part on this circuit and still get the same "frying eggs" noise oscillation in the background. Using an isolated power supply, as well. Might just be a noisier circuit.

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  44. mine doesn't work (except, off...bypasses well ^_^).
    I'm a bit newb, what should be wiring on the lugs 2 and 3 on the Boost pot ? I've wired lug 1 to ground.
    I,ve checked 3 or 4 times the vero board to seek any bad solders, but it's Ok
    What can I test with my elctronic tester ?

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  45. here are some pics, I saw a solder bridge on the right down corner but it just connect the copper border of the board (I've cut it)
    http://i39.servimg.com/u/f39/13/14/75/03/dsc_4214.jpg
    http://i39.servimg.com/u/f39/13/14/75/03/dsc_4213.jpg



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  46. power drain??? I´ve build the pedal and it sounds as it should - nice tone, good boost BUT after a few minutes it changes character like it is low on battery (a fuzzy tone and uneven sustain) The thing is that I´m using a good powersupply. What could be the problem?

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    Replies
    1. Check Q2. If it´s damaged and the replacement get the same fate we have the same issue (Q2 die after some little use).

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  47. I seemed to understand that this layout has the +3db boost inside the circuit. Would it be possible to omit it, or make it switchable¿
    Best regards, Gilberto.

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  48. Finished, and sounds really good. I get a nice "hifi" grind on my old hiwatt.
    Initially I used just one on-off-on dpdt to get treble-off-treble/bass settings, but I finally settled with treble on and nothing elese, (downgrade de 10uf to 100nf to roll-off some bass), so I´d like to use the switch for swapping from 9 to 18v instead, using a "charge pump" circuit daughter board from this same site:
    http://tagboardeffects.blogspot.com.es/search/label/Charge%20pump
    I was wondering where to drop the 18v lead, (output from the voltage doubler circuit), on the ep layout. My initial understanding is that any place on the voltage row, (second one starting from above), from the hole at the right side of the 10uf cap possitive led in advance would do.
    Correct me if I´m wrong, please.
    Best regards, Gilberto.

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  49. I am getting a hum when on high volumes(from amp).should i check my solders or it's a common think for this pedal?i know that power converters are doing this hiss/hum but there is a big possibility that it's my mistake . Anyway is there any way to deal with it ? . Great pedal with great sound thanks for the share !

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  50. Check both solders/power supply. I get some hiss when crancking the pedal and treble on; nothing extreme though.

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  51. Is there mod to get unity gain at the lowest boost setting?

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  52. Hi everybody, i'm new in diy pedal, i have almost finish this pedal but i have a problem: I have no idea how to connect the 3PDT Footswitch…. there's no shecmatic for that on this page…

    Thanks

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  53. http://tagboardeffects.blogspot.com/2012/02/offboard-wiring.html?m=0

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  54. I finally added a switchable "pump charge" daughterboard to compare 9v vs 18v performance, (it sounds better at 18v). My problem now is that I get a loud pop when engaging on/off the stomp switch, (not the daughterboard switch), thing that didn´t do before at all. This is the way I wired the new spdt voltage switch:
    - 2 wires from power shocket, (to one of the outside lugs of the switch and to the daughterboard voltage input respectively).
    - 1 wire from the daughterboard output to the remaining outside lug.
    - 1 wire from the common lug to the e.p. board voltage input.
    I know the pull down resistor stuff and how to solve the popping causing by leds, but since before it worked like it should, I wanted to know if someone noticed something wrong about the way I wired the switch before starting tweeking the pedal again.
    Cheers, Gilberto.

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  55. This comment has been removed by the author.

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  57. works fine! I replace the 2n5457 for mpf102, same pinout

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  58. halo I made the booster but wert not have someone a picture where all the wires need to be closed or a good drawing of the whole proses Thanks


    halo ik heb de booster gemaakt maar hij wert niet heb iemand een foto waar alle draden aan gesloten moeten worden of een goede tekening van het hele proses alvast bedankt

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  59. Hey there,
    i build this, but the fat and the bright switch doesn´t do any thing....
    Is there a very big difference when i switch them on? i can hear nothing...
    The boost works fine....
    cheers S.

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  60. with my new clean amp (fender based AB63 clone), there is a bump of volume with knob at 0, what happens ?

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  61. If anyone else is wondering if it fits in a 1590A I've confirmed that it does. Instead of SPST switches I used a DIP Switch on a small daughter board that I wired to the appropriate FAT and BRIGHT rows. I did have to wrap the whole thing in electric tape and flip it so the bottom (solder side) of the board is facing out.

    Anyway, hope this helps!

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  62. what do dsg and ecb stand for? new to all of this.

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  63. Those are the transistors leads: Drain-Source-Gate (DSG), Emitter-Collector-Base (ECB).

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  64. Just build my second one of these. First one worked right away, but I was going crazy with the 2nd one. The signal came through really quiet and I triple checked the whole thing...came out that I had a really bad patch of 2n5457's, where only 1 out of 10 worked :)
    But hey, they were like 2-3 bucks for 50 on ebay.

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  65. I've added a 2.2K resistor to the 4.7K in the middle of the board, it tames the 3dB Boost, and the tone is still there. Great pedal.

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  66. Hey there,
    I've already assembled and finished.
    It works well !!!!
    but...
    Fat switch absoultamente not appreciate any change.
    any ideas??
    P.S. IF switch the brigth makes its function.

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  67. Gidday. I'm planning to build this pedal soon and I would like to have two different boost levels via footswitch so that I can run it always on, but then still have a higher boost setting.

    I was planning on doing this by having two identical pots and another 3PDT switch to switch between them.

    Do you guys think this will work? Is it likely to pop when I switch between them? And if so, is there anything I can do to prevent it?

    Cheers

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  68. Built that little pedal and I love it. But.. It makes my every guitar pots scratshy. I quess it boost the right frequenses but is normal? I use volume pot to clean the distorted amp so that kinda noise isn't welcome. Thanks!

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  69. Hi, I am building this pedal, I followed the instructions about connection the 3pdt on offboard wiring. But I have a problem with the led and potentiometer doesn't work. I put a 2k2 ohm for the led. The potentiometer doesn't increase the volume. Can you please help me?

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    1. Make sure there are no bridges. Recheck your wiring. Go over the layout again and again. Of all the builds I've made there has only been one that I could not find a problem with that wasn't my fault. Most of the time it is human error. If that isn't it change q1 and 2. Make sure all the components are good before soldering them that way you get rid of that variable.

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  70. I'm new at this and would like to ask for a little help with thew wiring. There are 2 grounds. Could someone please explain where each goes.
    Cheers, Hutch

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    1. hey man. the ground wire goes to any of the ground locations off the main board. take a look at the offboard wiring section above, or just copy and paste this link:

      http://tagboardeffects.blogspot.com/2012/02/offboard-wiring.html

      don't ever worry about how may grounds there are on the board, just connect them to the closet ground location offboard.

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  71. Thanks Zach. Your quick reply is very much appreciated!
    One more question please.For the Boost Pot i see a yellow wire going to lug #3 on the pot. What goes to the other 2 lugs on the pot? I was assuming that the ground goes to lug #2. I tried that and it didn't work. I'm not getting any signal from the out jack, no hum or nothing.....I've checked all the solder joints and looked for a possible bridge of solder shorting it out and see nothing.
    Cheers, Hutch

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    1. any time man. if you look at the build notes on the bottom of the layout you'll see that it says "boost 1&2 to ground." so you'll link lug 1 & 2 of the boost pot and run a single wire to any of the grounds.

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    2. Duh..... I can't believe I didn't see that..... LOL
      Have a great day Zach.
      Cheers, Hutch

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  72. Zach,
    I'm still not getting ant signal. I checked the power voltage and it's 8.90 when I check the voltage across the diode it's 8.90 also. shouldn't it be much less?

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  73. This comment has been removed by the author.

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  74. This comment has been removed by the author.

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  75. Hi, can I use J211 JFET or any MOSFET instead of 2N5457?

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    1. Just in case it might help somebody who asked similarly: Mosfet cannot be used, J211 has to high IDSS. I used SMD (SOT23) version of 2N5457: MMBF5457. I etched on PCB adapter SOT23 to be used for PCB. Booster works perfectly.

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  76. Hi, will it be ok to use 10K linear pot instead rev log for Boost control?

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    1. Just in ase it might help somebody pt2: I used Log 10K Pot but I reversed pots pin 1 with pin 3 (so Pin 2,3 are grounded). In this case Log Pot characteristic is the same as Rev Log but Pot must be turned Counter Clockwise to increase Boost.

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  77. Hey!

    I've been building this with success.
    But I wonder how i can get a little more volume/boost out of it.
    What components need to be changed for that?

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  78. I build this one with the J201 instead of the 2n5457. I think the J201 has a more clear sound, less boomy and has (atleast in my pedal) way more clear high.

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  79. Isnt there a complete wiring diagram that includs the input jacks, switches on/off switch etc.
    Magnus

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  80. Check the offboard wiring tab at the top of the page. The reason it isn't shown in every layout is that the offboard wiring is pretty much always the same, so once you understand how to wire a pedal it becomes redundant to include that info in every layout

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  81. ok this is my first pedal build and i havent a clue about offboard wiring!

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  82. Is there a way to modify this pedal to have zero dB boost when knob is turned down? It feels like it boosts at least -3 dB now with the knob turned down.

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    Replies
    1. Try upping the 8K2 for 12-15K or try a bigger value pot.
      +m

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  83. I've got it working and it sounds great. But as it is, it doesn't start breaking up until the boost pot is cranked. I'd like it to get a little crunchy at halfway, and to have room for more distortion the rest of the way up. I used a 2n5458 instead of the 2n5457. Would switching to the 2n5457 give me significantly more distortion? Or could i just swap one of the resistors for a lesser value to make it break up more easily? This is my first pedal, so i'm just guessing.

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    1. I switched the 33k resistor going into the JFET gate for a 15k, thinking it might send a hotter signal into it, and it actually added a good bit of clipping. I can still get a very minimal amount of distortion at 12 o'clock, but it sounds significantly overdriven with the boost knob cranked now, so i'm pleased as punch. Besides that, it responds to playing dynamics well and just sounds great.
      Also, i planned on adding a volume pot offboard, before the output, since i don't really need a big decibel boost, but the 100k and 10k pots i tried made it sound a little bit muddier in the before and after i recorded (even at full volume on the potentiometer). So i'll just go without it and keep those really high frequencies intact.
      I left the fat switch off and ran a jumper wire across the bright switch connections, so it's always on now (if i'm not mistaken). I'm writing all this, thinking it might help out future builders. A lot of the comments here helped me a ton. Great stuff.

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    2. Hey Ben! I know it's been a couple months, but I had some luck tinkering with a volume knob. The 100K pot changed the output filter cutoff frequency from 0.3388Hz to 0.1083Hz and with it some of the 'sparkle' disappeared. To fix this I yanked the 100R and 47k resistors completely (replaced by the Pot) and replaced the upstream 10uf electro with a 4.7uf. At full volume the new high pass output filter cutoff calcs at exactly 0.3388Hz again. It will obviously change as you roll off volume, but I'm happy with it.

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  84. This comment has been removed by the author.

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  85. Small comment - new EP booster does not have Fat switch anymore. Instead it has Unity gain switch. Once it is on it will give +3dB when Boost pot is at Min position. Resistor 8,2 k is exactly chosen to give +3dB. To have unity gain this resistor should be switch to around 5,2 k. I used Fat switch (SPDT) to choose between those resistors thus it gives newer ver of EP booster.

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  86. This thing sounds mad good - I love it.

    Though, instead of the low/high boost switches I built DIP switches in the back to keep the front clean!

    Take a look, guys: https://www.instagram.com/p/BkDqdg6AJwi/

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  87. what does the dsg stand for?

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    Replies
    1. D = Drain
      S = Source
      G = Gate

      As in names of the terminals of a FET.
      +m

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  88. Hi thanks for layout, with which values ​​can I replace the 15 K resistance and the 100uf capacitor to increase the presence of the fat switch and bright? thanks for reply

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  89. on the 4th line, why you did that cut? (before 10 uF)

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  90. it sounds like overdrive. i use the same components. problems with q1? do i need to change 33K resistor? please help - what can i do now?

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  91. Hey, thanks for the layout!
    I can't get it to work tho... I am using it on breadboard and can't hear a damn thing unless I turn the amp volume and gain all the way.
    Instead of 2n5457 I'm using bf245c. It may be the culprit since the pot doesn't seem to do anything. (Can't be biased correctly or whatever, this is my first pedal and I'm fairly new to this stuff so I might be talking nonsense) I'm gonna wait for 2n5457 to ship and try replacing it then.

    On the other hand there might be something I'm missing, so I will send you the picture of breadboard soon.

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    1. 2n5457 arrived this morning, and swapping it out with bf245c seemed to fix it.
      Another thing that I might have missed was a bad 47n cap connection. Either way, when I fixed the cap, the output was way too low to drive a high gain amp properly (sounded like it was on the verge of breakup). I think that there was ~4v difference on the drain.
      I have also swapped out the 8.2k resistor with the 5.6k one and removed the fat mod as I didn't like it that much. The resistor mod is to avoid +3dB boost on the output because I'm planning to use it as an always on pedal.
      In case you want a dip switch to choose between 3dB boost on/off, you can do it fairly easy by running something like a 15k resistor in parallel with the 8.2k one. The idea is to jumper the 15k resistor to 8.2k while the switch is on.

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  92. Thanks for the post checkout the best sound booster app for android.

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  93. Successfully built this one for my bandmate guitarist, it sounds really nice !
    As mentioned abose, the "fat" switch doesn't seem very efficient but I was too lazy to try the suggested mods.

    My mate also wanted an always on booster so I fitted the AMZ Super Buffer into the enclosure. Shitty quality pictures : https://imgur.com/a/GXON966

    Thanks for sharing the layout !

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  94. Can it be run on 18v with 1/4W metal film resistors? All my capacitors are rated 50v so thats not a problem.

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  95. Cut in between the JFET drain and the 8K2 resistor shouldn't be there.
    Where is it?

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  96. That 10u + 100u does nothing noticable. Simply because the frequency it sets is waay below the audible range already with the 10uF. If you swap the 10uF to a much lower value, then it introduces a low cut (high pass filter), a'la tubescreamer.

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  97. I finally got mine working! :D This build was the hardest one yet for me. For any other newbies like myself taking this project on, I have a few crucial pieces of advice:

    1) Read the comments carefully. All of them. Most of your questions will be answered somewhere in the comments.
    2) If using SPDT switches, do not ground them. I did this because I had the extra lugs and I assumed I should ground the switches like everything else. Wrong, wrong, wrong. If you do this, your circuit will not work. This was the main problem I ran into and believe me when I say it took hours upon hours to figure it out.
    3)Use a much smaller value cap at Q1 source; if you use 10u as instructed in the layout, your 'fat' switch will do nothing (you will find many comments complaining about this). One commenter recommended 100n. I used 220n (what I had on hand) and think the fat is plenty fat.
    4)The 'bright' switch is subtle but definitely noticeable. If yours isn't doing anything at all then something is wrong, but really give it a good listen and cycle through your guitar's pickup configurations before you decide it's not working. I personally found mine immediately noticeable.
    5)Some commenters say this will fit into a 1590A enclosure, and they're not wrong. It might be easy for the more experienced among us, but if you're new to this like I am, use a 1590B. I spent practically an entire day trying to get everything to fit into a 1590A and it was maddening and unsuccessful. I tried again with a 1590B and it fit easily but without any wasted space.

    I hope others will avoid some of my rookie mistakes! I appreciate this website a lot, I'm having a blast making these pedals.

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  98. It's my first pedal.
    I don't know how tu connect it.
    Can you make a video on YouTube please?

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    Replies
    1. Everything circuits are connected the same way. You will find the offboard wiring explainations on the site.

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  99. Hi, how to wire the 10k rev log boost pot? cant find any instruction.
    . sorry if i miss something. thanks!

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  100. tried this project...but no luck...
    how to wire the boost pot? i can only see one Boost 3 wire. Where do the other two came from? Thanks!

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  101. OK. I found the answer in the comments. 1&2 to ground

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  102. how to get rid of the buzz? it sounds like "Hummm" in this scheme

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