donbenjy Posted July 20, 2006 Report Share Posted July 20, 2006 Hey, I'm looking at building something like This for a summer project, and I'm quite happy breadboarding and transfering to Point-to-point board when i'm finished, but I have a couple of questions (that the guy won't answer): Firstly, the pots, should they be lin or log(audio)? The diodes on the right; does "Si" just mean silicon? I presume I can use any silicon diode? Lastly, can someone give me standard wiring for a true bypass switch? and Is it possible to mount a normal power jack thing somewhere and run it off a 9V DC supply? I know I can try these out easily with a proto board, but I really don't have the spare cash to buy, for example, a whole other set of pots that i'll never use! Oh, and just out of interest, can someone tell me what the diode pointing up from ground is for? the one on it's own next to the 3 in a row? I can't see why they need that!? Cheers for putting up to my n00bishness! Quote Link to comment Share on other sites More sharing options...
Mike Sulzer Posted July 20, 2006 Report Share Posted July 20, 2006 "Oh, and just out of interest, can someone tell me what the diode pointing up from ground is for? the one on it's own next to the 3 in a row? I can't see why they need that!?" You want to clip both positive and negative so you need diodes in both directions. Three in series one way and just one in the other means that you have asymmetrical clipping. Quote Link to comment Share on other sites More sharing options...
donbenjy Posted July 20, 2006 Author Report Share Posted July 20, 2006 cool, thanks any info on the other answers? I suspect that I'll be using audio taper pots, but if it's wrong then it'll be far to sensitive! And I think I can use a regular power jack thingy right? Quote Link to comment Share on other sites More sharing options...
Mr Alex Posted July 20, 2006 Report Share Posted July 20, 2006 I'd start with log for the gain and volume, and linear for everything else. At worst, the adjustment wont appear linear. Quote Link to comment Share on other sites More sharing options...
Mike Sulzer Posted July 20, 2006 Report Share Posted July 20, 2006 P5 is a volume control; probably want to use audio taper. P6 is a blend; you want to use linear to get equal blending in the middle. P4 shorts the crossover "diodes"; just a guess, but I think an audio taper would give a better range. P3, P1: don't know. P2: I would try linear here. Si for silicon, yes. Just about anything should work. Small switching diodes woud be most convenient. A DC supply could be OK. I do not know if a standard wallwart would have low enough ripple. With this thing running wide open you might get some hum. cool, thanks any info on the other answers? I suspect that I'll be using audio taper pots, but if it's wrong then it'll be far to sensitive! And I think I can use a regular power jack thingy right? Quote Link to comment Share on other sites More sharing options...
donbenjy Posted July 20, 2006 Author Report Share Posted July 20, 2006 (edited) ok cool! thanks people! I'll see if i can look inside my DMM cos that has a feedback pot, check that out for P1...For the others, I'll see which type of pot is easier to find for that value edit: oh yeah, true bypass? Can anyone show me how a 3PDT switches? I can't find those things that explain about the 2 positions for a 3PDT...I suppose I could open a boutique pedal I have and take a look at that though! Edited July 20, 2006 by donbenjy Quote Link to comment Share on other sites More sharing options...
Paul Marossy Posted July 21, 2006 Report Share Posted July 21, 2006 Maybe this will be of some help with wiring a 3PDT switch: http://www.diyguitarist.com/PDF_Files/GCI-TrueBypass.pdf Quote Link to comment Share on other sites More sharing options...
donbenjy Posted July 25, 2006 Author Report Share Posted July 25, 2006 okies, thanks. Ok got about 90% of the components today (bar some non-standard pot sizes that i'll have to get from a guitar site and a cap that was out of stock) and I have a couple of questions. The diodes I ordered are really small, and don't even have lugs on. I presume I need a mounting case or something like an IC cradle? Can someone point this out to me? Is there any way of mounting to protoboard without one? Also, the LEDs I ordered are 10mm (cos I was too stupid to actually think about how big 10mm is...can you tell its my first project? ) will they draw more current, and are they big enough to mess with the circuit badly? cheers Quote Link to comment Share on other sites More sharing options...
donbenjy Posted July 25, 2006 Author Report Share Posted July 25, 2006 (edited) double post Edited July 25, 2006 by donbenjy Quote Link to comment Share on other sites More sharing options...
Mr Alex Posted July 25, 2006 Report Share Posted July 25, 2006 I think you ordered smd diodes(surface mount devices) You wont be able to use those, unless you are crazy bastard like me, who likes to repair the unrepairable, and has a tiny soldering iron tip, or smd soldering gear. According to the catalogues I have, the 10mm leds will require more current for the same output level as 3mm or 5mm leds. But you can get all sorts of current ranges in all sizes at some places like Farnell. For all I know you could have low current 10mm leds, but I wouldn't count on it. Get some 3mm or 5mm, they aren't expensive. Quote Link to comment Share on other sites More sharing options...
Prostheta Posted July 25, 2006 Report Share Posted July 25, 2006 Gurrrrh. I'm too drunk on Finlandia right now to recall my qualifications in electronics. Let this be a lesson to you. Gurrrrh. Quote Link to comment Share on other sites More sharing options...
donbenjy Posted July 26, 2006 Author Report Share Posted July 26, 2006 I think you ordered smd diodes(surface mount devices) You wont be able to use those, unless you are crazy bastard like me, who likes to repair the unrepairable, and has a tiny soldering iron tip, or smd soldering gear. According to the catalogues I have, the 10mm leds will require more current for the same output level as 3mm or 5mm leds. But you can get all sorts of current ranges in all sizes at some places like Farnell. For all I know you could have low current 10mm leds, but I wouldn't count on it. Get some 3mm or 5mm, they aren't expensive. ok then! Problem is, ordering the parts online comes to about 50p, and the postage is £4! I guess i'll just have to work as best I can with what I have and stick some markers where the other bits go! Quote Link to comment Share on other sites More sharing options...
donbenjy Posted July 26, 2006 Author Report Share Posted July 26, 2006 hey, i'm like 95% complete with a protoboarding, but I'm scared of turning it on incase I blow up something! I've got a few spares, but i'd rather know if this is gonna work beforehand. Basically, I've stuck fly leads where any missing parts I have go...obviously with pots I can leave them "full open" and try and step them down with some fixed resistors for changes. Anyway can anyone take a look at this and tell me if it's likely to work without the parts circled in yellow? I think the cap at the start will do something to the sound (I have a 0.1uF cap spare, should I try that untill I can get the proper one?), the lack of pots won't damage anything, so it's really just the diodes im worried about...oh yeah, and the larger red LEDS that I put in! I know it wont sound much like whatit's meant to, but I just wanted to check I've got the circuit right. Basically I'm looking for a yes or a no as to whether I can hook it safely up to an amp? Quote Link to comment Share on other sites More sharing options...
Paul Marossy Posted July 26, 2006 Report Share Posted July 26, 2006 ically I'm looking for a yes or a no as to whether I can hook it safely up to an amp? Don't worry, you won't blow up your amp with a stompbox circuit. Quote Link to comment Share on other sites More sharing options...
donbenjy Posted July 26, 2006 Author Report Share Posted July 26, 2006 i know, i was thinking more along the lines of "will it do anything remotely fuzzy like it's supposed too?!" I plugged it in anyway, spent ages being confused as to why there was no sound - fixed the dodgey soldering on the jacks...still got nothing but a quiet hum (not really like normal guitar hum maybe like a pedal with the volume turned off, and aside from the openness off the protoboard). Tomorrow i'm gonna restart it testing it bit by bit. Oh yeah, the 470k resistor infront of the opamp isn't there either...will that hurt it? Quote Link to comment Share on other sites More sharing options...
Paul Marossy Posted July 26, 2006 Report Share Posted July 26, 2006 Oh yeah, the 470k resistor infront of the opamp isn't there either...will that hurt it? No it won't hurt anything, but FYI, that's not a 470K resistor - it's a 470ohm resistor. If you don't have one of those, use a 1K there. Quote Link to comment Share on other sites More sharing options...
Mr Alex Posted July 26, 2006 Report Share Posted July 26, 2006 That will "work" with the missing parts, but the assymetric diodes are gonna be pretty important to the whole fuzz part, without them you'll have a really crumby preamp that might clip over a bit it you run it full stonk. If you have any extra leds, use those instead of the silicon diodes. Some people think they sound better than silicon diodes, but I don't agree. I don't like diode clipping circuits at all. Quote Link to comment Share on other sites More sharing options...
donbenjy Posted July 27, 2006 Author Report Share Posted July 27, 2006 Oh yeah, the 470k resistor infront of the opamp isn't there either...will that hurt it? No it won't hurt anything, but FYI, that's not a 470K resistor - it's a 470ohm resistor. If you don't have one of those, use a 1K there. lol despite my typos, i knew that was a 470 ohm resistor Quote Link to comment Share on other sites More sharing options...
Paul Marossy Posted July 27, 2006 Report Share Posted July 27, 2006 That will "work" with the missing parts, but the assymetric diodes are gonna be pretty important to the whole fuzz part, without them you'll have a really crumby preamp that might clip over a bit it you run it full stonk. Oops... I missed that LED part. Yeah, those are big contributors to the intended sound. You need to get that all straightened out. Quote Link to comment Share on other sites More sharing options...
donbenjy Posted July 29, 2006 Author Report Share Posted July 29, 2006 Update on the pedal I'm building! Finished prototyping (despite the man in the shop insisting that volume pots are linear taper ) It sounds AMAZING! Not extremely fuzzy (or maybe I've not found the settings yet), more like a fuzz factory than a big muff though. The oscillations it makes are crazy! One thing though, the gain/colour pot seems to cut at the highest end. i.e. you turn it up and it goes from sligtly distorted up to fuzzy and then the very last bit drops off back to low gain again. Is this likely to be normal? Also, the 2 LEDs that light up with certain settings, one goes fainter when I turn up the fundamental blend/octup pot and I cant work out if I should label it on the outside of the case...anyone got any ideas? Quote Link to comment Share on other sites More sharing options...
donbenjy Posted July 30, 2006 Author Report Share Posted July 30, 2006 hi again, So now i'm ready to start soldering stuff! Anyway, I have a few more questions (sorry! ). I'm using this Dc power jack for a PSU, and it has only 2 terminals. All the other I've seen have three, although I presume that the 3rd is the ground for the shell? in which case, the top lug sorts that out I assume? Also, which is better to use, trackboard/matrix board, or point to point? I have board for both, and I can cut out tracks on the matrix to split the rows up (i.e. for the opamp), but most handmade pedals use PtP. Is there a reason for this? 3rdly, with the opamp, I found that i'd ordered a cradle for surface mounting ICs and the legs are far to short to solder to or to mount up...I have seen certain ICs in stompboxes soldered directly, do you think I'm ok soldering direct to the opamp with a 12W solering iron, or will that melt stuff? Is there a good way to heatsink it? I know about grabbing the leg close to the component with pliers, but I don't think the legs are long enough on the chip to do that! I have 2 spares though, so I can always try it out first, but It's gonna be hard to check it works properly in the circuit without having to fully wire it up first! If I follow this wiring for true bypass - I'll always need a 3PDT switch to have an LED power light right? Unless I can find an LED footswitch (ha!)? Will that wiring cut the 9V battery then too? Crap...I think I just figured out why there's a 3rd terminal on some DC power jacks, it makes a contact when there isn't anything plugged in right? So I can't use my jack in that way?! Anyone know a way to use a 2 contact dc jack to cut the power from a battery? Oh and I really can't find the max voltage rating for the LEDs I'm using (except that the reverse voltage is 5v max), so is it safe to connect directly to 9V, or does it need a resistor (in which case, I'll start at 100k and work down )? Lastly, can anyone tell me if i've forgotten anything for mounting the finished circuit in it's case: 1. 1 x IC cradle (possibly) 2. 3 x 3mm led mounts 3. 1 x 8mm led mount 4. 1 x Case (min 120mm length) 5. 6 x knobs 6. 1 x dpdt/3pdt footswitch. I read about someone using the footswitch to secure the board in the case, trapping it between the case, and using a plastic washer to isolate and protect t from shorting against the case, Is this the best way to do it? I don't really wanna do anything like glueing it in, so I thought somethng like that, or insulating one side with tape, and tapign it to a random space, I think with 6 pots, It might be a tight squeeze!. Practically, should I bother compacting the circuit up into the smallest space possible or not? Quote Link to comment Share on other sites More sharing options...
weezerboy Posted July 30, 2006 Report Share Posted July 30, 2006 firstly, i'd buy a dc jack that you know fits in with what you need (ie. one with 3 pins) because, as you figured out, one of the pins is to disconnect the battery when a cable is inserted. secondly - i believe the main reason for using point-to-point on perfboard is that making a layout for stripboard can be quite troublesome, so doing it point-to-point virtually eliminates any layout problems. thirdly - you might get away with soldering the IC directly to the board, but you won't be too happy if you do fry it...they're not really a pleasure to remove. so again, find an IC socket that will actually work. fourthly - personally i'd make my life easier with this one, and just buy some 3pdt switches (although good luck finding them in the UK - diystompboxes.com or smallbearelec.com are the best to get them from though) anywho, enough rambling. Dan. Quote Link to comment Share on other sites More sharing options...
donbenjy Posted July 30, 2006 Author Report Share Posted July 30, 2006 yeah, I was expecting most of that! It's just really tricky getting parts around here, as postage costs like £4 for most parts, and the parts alone cost about 40p - 10 times less! As for the stripboard, would it be stupidly too big in comparison if I just copied my protoboard onto the matrix board and cut the tracks across the middle? I know a site to get 3PDT switches here, are they annoyingly expensive for a footswitch in america? cos they are here! Quote Link to comment Share on other sites More sharing options...
weezerboy Posted July 30, 2006 Report Share Posted July 30, 2006 they're not too expensive to get from the US, about £3.80 + shipping. where are you finding them in the uk? i searched high and low and couldnt find any Quote Link to comment Share on other sites More sharing options...
donbenjy Posted July 30, 2006 Author Report Share Posted July 30, 2006 (edited) a guy named stuart castledine who does wah mods sells them: http://www.wah-wah.co.uk/ unfortunately, he charges £6!!! Might be cheaper to get the stuff from america...the case, knobs, switch, and some pots I need for my strat would make the shipping worthwhile, providing I can find somewhere that sells all of them! edit: oh yeah, any idea where I can get a 3PDT switch along with a case, led mounts etc. (i.e. an electronics store that sells the footswitch, that being the only really guitar specific component) from the US? Edited July 30, 2006 by donbenjy Quote Link to comment Share on other sites More sharing options...
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