donbenjy

not exactly an expert with EMGs, but I thought they would only plug in one way...try flipping the connector round and it should slip right in!

hey, I've had a reaally slowly moving Fuzz project on the go since the summer, and a break in my regular fuzz kickstarted me into mounting my circuit into a cake tin the morning before a gig anyway it works about 80% of how it should (when it was on the protoboard) and I've never had a problem like this before (usually it either works perfectly, or it doesn't, n i just have to find a short or loose connection) but I have no idea how to check this is running well! here's the circuit: Basically, it's soldered to a stripboard using a painstakingly drawn up spreadsheet, along with some help from Stripboard Magic. Anyway, it fuzzes a little bit: about where you'd expect a normal fuzz to work if it was set at 9 o'clock. The octup knob does do the octave effect, but it sounds dodgey with the rest of the circuit right now...On the protoboard, the feedback knob would start feeding back at about 12-1 o'clock, but now it only works maxed out, with the tone/gain up to just below max...and this is a single, very high pitched, uncontrollable squeal. Turning the pedal on results in a drop in volume even with the volume at maximum. Oh, the 2 clipping LEDs don't light either, whereas they would do at higher gain settings before. What would an overheated opamp sound like? I didn't have any IC mounts so I really quickly soldered direct to the board - not the best connection, but it seemed ok! How can I test it to see whether it works or not? (resistance, expected voltage readings etc?) So bascially, any suggestions as to what the exact problem might be would be really welcome, but I'm expecting just a few pointers for how to test my circuit works well using a multimeter? and how to check if the diodes, caps, opamp are in working order? I can post my soldering for the stripboard too, if anybody would be kind enough to check it over? would the type of pot(i.e. log/lin) affect this? I doubt it, as with all the pots maxed, there would be neglible resistance along the signal path? cheers for any help! I'd relly appreciate any info/advice as I've never had to troubleshoot an audio circuit, and I'm not even sure which components do what!

yeah I know, but its pretty solid! I checked conductivity though, and it's all good we'll soon know if it worked, but I think it'll be fine tbh!

cheers, that's what I was doing though! Maybe i didn't get a good connection or something...I'm currently about 80% finished with the stripboard now, so I'll test it off that. I decided to solder the Ic direct to the board, and it doesn't smell or look scorched - my soldering iron tend to create little balls of solder if I tin it too much so i used them and just dropped them onto the legs. Is there a surefire way of testing the chip to see if it works short of actually building the circuit in full? Yeah cheers for the link, but I'm gonna get everything I need from small bear once I get back from iceland

does anyone know how to test current draw on a pedal (well of course you do ) I've tried it in series and parellel with the battery and it still comes up with 0A on the multimeter set at 200uA- DC!!! I've tried it while strumming the guitar and everything, but nothing happens! :S I assume it goes in the the path of the power, rather than the signal path? If I can't find it, anyone know what the typical current draw will be for a dual opamp circuit then? (like 10ma or 100ma for example) cos I don't wanna overload my power block thing! Although My distortion draws about 24ma and the wah is 300ma so I guess with something of the same nature, it'll be small! I'll be ok if it's under 100ma

cool! Thanks for beating me I can't box it up yet cos I havn't got the money for the box! I think I'm gonna get my girlfriend to paint it ZVex style & call it the Possum The 2 red LEDs can be the eyes!

nothing could be easier to wire! Follow the diagram exactly, then just solder the 2 wires that are already soldered together (black and white, according to that diag) onto the middle lug of the switch and the bottom or top to ground! it looks like this: 0 0 0 0 < solder black and white wires here. 0 0 <solder to ground. The other 4 terminals remain empty. Do the same for the other pickup, on the other pot. as for lin/audio short answer = you need audio. long answer=Linear and Audio (or log) refers to the potentiometer part, not the switch bit, and determines how the signal responds to the movement of the pots, linear is a standard movement (i.e. setting a 500k pot at halfway is 250k), audio taper means that is increases logorithmically, which is better for volume basically!

It's really easy to wire both a battery and 9V jack into the circuit (like this), just make sure to get a jack with 3 terminals, not 2 like I did Check out my thread further down the page to see if any questions you have have already been answered I use a battery for testing though...not likely that anything will go wrong, but better safe than sorry

what do you actually want the switch to do? that'd be really useful Which positionswill do the tapping? and which coils do you want to be on or off? I would suggest if you really want to do a coil tap (as opposed to not wanting to buy a new 3 way switch) is to get 2 DPDT push/pull pots and use them to split the coils, along with a 3 way switch. Anyway, diagam 7 on the Hz wiring sheet - here shows a 1 vol, 1 tone but with a 3 way selector. IMHO, push.pull pots are far more versitile and worthwhile as you can mix either split coils and such, effctively giving you the configurations of HH HS SH and SS!

cool, thanks! small bear has everything I need! gotta find £20 somewhere now! This pedal has been alot more than expected really! But I guess that includes stuff like a new soldering iron etc.

lol, thanks! That's really useful! Now I just need to find someone who's taken a P90 similar to mine apart to find out how much space there is inside! I guess I could start out by prototyping the amp and winding a basic driver and then just sticking it to the top of the P90 for now anyway...the long-term implementation will have to wait abit I guess...I'm poor right now anyway

lol, thanks! That's really useful! Now I just need to find someone who's taken a P90 similar to mine apart to find out how much space there is inside! I guess I could start out by prototyping the amp and winding a basic driver and then just sticking it to the top of the P90 for now anyway...the long-term implementation will have to wait abit I guess...I'm poor right now anyway

Yeah, I'd say protoboard is a must, especially if you want to design your own, or the schematic doesn't come with a PCB or stripboard layout and you have to sort out your own! I've just finished prototyping my first pedal from a schem I found online, it's actually really good! It's an opamp fuzz, but it has alot of "extras," the oscillations and other extra bits are as weird as a ZVex Fuzz Factory! Anyway, I've built it on the protoboard, and now I'm trying to decide whether to use point to point, or stripboard to finalize it. Both have their advantages and disadvantages, but with a craft knife, you can turn a stripboard into a copy of a breadboard, so you could in theory just push components through that whilst you prototype, and then when you're ready, remove the breadboard from behind and solder it all in! Do you have easy access to PCB manufacturing? I really don't like using PCBs when I can avoid it, as there's so many things that can go wrong, and if I can't use my colleges etching tanks then I have to wait months to get a board etched for me!

Hey, thanks for the reply! i don't think putting a driver next to the P90 is feasible, since the strat is routed HSH and I wouldn't imagine either the P90, or the driver would suit being in the middle position (although I guess if i took away the divider between the midle and neck pockets, the P90 might be ok shoved over right next to the driver, but I'd rather try to stack it! Sorry, do you mean 3mm in height (i.e. going down into the body), so I could route about 5mm down into the cavity and it'd be sorted (the pickup is annoying close to the strings, as it's fairly deep anyway). I don't see a problem with having the driver on top of the pickup, although would this hinder the P90's capability as the pole pieces will be below another magnet and coil (from the driver). Not sure if I can even get the pickup apart yet, it's a KA P90 and it looks like this . If i can find really long pole peices, would it be possible to extend them above the pickup, and place a bobbin for the driver around them? Has anyone tried a driver with pole peices instad of a rail? Ideally, It'd be good to see if there was room under the cover to put the driver in, but if not, I'm happy to mount it on the top. Cheers for the help! Oh yeah, does the cavity need to be shielded to use the driver well? I do have copper shielding, but the bottom will need to be removed when I route downwards!

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?

Hi, I tried searching, but I don't think the search tool likes me, and 99 pages is alot to browse through Anyway, I was wondering if anyone has tried making a driver in a humbucker shape? (i.e. stacked ontop of it, not in the 2nd coil position)/ I've got an old strat project with a P90 neck (humbucker sized, hence the question) and a motherbucker bridge...I guess that there's already alot of information, so sorry if this has been asked before, but how does a wider driver perfom, compared to a single coil sized one? Does my idea sound practical? I haven't really ever looked inside this pickup, and my experience with guitars and electronics stops shrt of knowing whether the P90 is suitible to "butcher" to get a driver ontop! Would it mean unwinding the coil and starting again with a blade? as that's not really feasible...I does have adjustible polepeices though...I wonder if I could lower the P90 by routing the cavity lower, and then extending the polepieces high enough to let me wind the driver around them?

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!

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?

yeah, it'll be fine! Bear in mind though, depending on the pickups you buy, you mgiht have completely unusible combinations. I'd recommend thinking very carefully about the choices of pickups before you buy, and why you do infact want 3 brands...I would think that most brands cater for about 90% of pickup needs, and the only reason to have different brands would be for pickups specific to the brand that are very different. (like the Kent Armstrong Motherbucker, but even that has to contend with "quad rails" pickups )

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?

no, i meant thick foil over the copper tape you can get or thin foil...mine was really a sheet

dont use copper foil! I really messed up my strat with that! Tape is ok, but the foil I used was about a quater of a mm thick and It just took up too much space in the cavity and pushed the scratchplate up to an annoying distance from the strings so its harder to pick!

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

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?

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?