unclej Posted September 29, 2004 Report Share Posted September 29, 2004 two different subjects here. first, i want to start experimenting a bit with resistors and see that radio shack sells them in either 1/2 watt or 1/4 watt. what is the practical difference between the two in a guitar circuit and which is recommended? second, i did a search here on stew mac's black ice assuming that they probably weren't too complicated inside and found what looked like it was going to be a tutorial but it was incomplete. it said that you just needed some diodes but didn't say what size or exactly how to wire them up. is there a better tutorial or link available? thanks Quote Link to comment Share on other sites More sharing options...
Gnome Posted September 29, 2004 Report Share Posted September 29, 2004 two different subjects here. first, i want to start experimenting a bit with resistors and see that radio shack sells them in either 1/2 watt or 1/4 watt. what is the practical difference between the two in a guitar circuit and which is recommended? second, i did a search here on stew mac's black ice assuming that they probably weren't too complicated inside and found what looked like it was going to be a tutorial but it was incomplete. it said that you just needed some diodes but didn't say what size or exactly how to wire them up. is there a better tutorial or link available? thanks might as well buy the higher power resistors, better to be safe than sorry. the rating determines the total power dissipation before the resistor breaks down. heres some formulas... Power = voltage*current Power = voltage^2/resistance Power = current^2 * resistance what kind of voltages and currents are we talking about here?? Quote Link to comment Share on other sites More sharing options...
unclej Posted September 29, 2004 Author Report Share Posted September 29, 2004 hey gnome, thanks for the help. since they were fairly inexpensive i went ahead and purchased a pack of each. one is 100k ohms, 1/2 watt and the other is 100k ohms at 1/4 watt. i'm going to try them on a strat going for the hendrix sound. i'm fairly knowledgeable of capacitors and how they effect tone just from practical experience but what do capacitors do and how do the higher and lower powers effect it? Quote Link to comment Share on other sites More sharing options...
Gnome Posted September 29, 2004 Report Share Posted September 29, 2004 (edited) hey gnome, thanks for the help. since they were fairly inexpensive i went ahead and purchased a pack of each. one is 100k ohms, 1/2 watt and the other is 100k ohms at 1/4 watt. i'm going to try them on a strat going for the hendrix sound. i'm fairly knowledgeable of capacitors and how they effect tone just from practical experience but what do capacitors do and how do the higher and lower powers effect it? Capacitors act like a filter, and the differences in sound you hear when using a capacitor is because some range of the sound spectrum is being attenuated, meaning that your 'knocking down' a particular frequencies range's amplitude. in a low-pass filter, for instance, your letting the original voltage of the lower (bass) frequencies through, and attenuating the higher (treble) frequencies. you can search on the net and find all kinds of diagrams using capacitors and inductors in filter design for audio electronics. if youre going to be designing anything in audio, it pays to buy the best parts possible as far as tolerances for resistors, caps , etc as far as the power goes.... most of the barrell shaped caps should be fine for what your doing... Edited September 29, 2004 by Gnome Quote Link to comment Share on other sites More sharing options...
ansil Posted September 29, 2004 Report Share Posted September 29, 2004 the black ice uses schotky diodes as they have an ultra low threshold to trigger them into clipping. in gutiar fx and guitars theres no reason to use any thing over 1/4watt. personally i use 1/8th watt on everything that isn't high voltage. preferably metal film 1 % tolerance resistors as it will cut down on any noise. by placing the diodes back to back across the tone control pot you effectively have a volume control to the diodes only at a certain point .3mv i read on one package for schotkys will the diodes conduct and there fore square your waveform from your guitar signal its the same principle as a basic guitar clipper but this is passive. most of all your distortion stompboxes have this in their design but are driven harder via opamps and transistors. Quote Link to comment Share on other sites More sharing options...
lovekraft Posted September 30, 2004 Report Share Posted September 30, 2004 What I'd like to know is which schottky diodes you guys are using - I've seen the 1N5711 recommended, and somebody mentioned (not here) the 1N5817. Has anybody tried the BAT41? It looks like it would be ideal, since it has an incredibly low forward voltage at lower current levels. Ansil, javacody, what are you guys using? Quote Link to comment Share on other sites More sharing options...
unclej Posted September 30, 2004 Author Report Share Posted September 30, 2004 thanks for the question lovekraft. i was wondering the same thing. and since i know you'll be checking back in i've got another little question about farads. i found a good little tutorial explaining pico, nano and micro farads but looking in my trusty radio shack catalog i find pf and the u with the tail. is the uf larger or smaller than the pf? Quote Link to comment Share on other sites More sharing options...
Devon Headen Posted September 30, 2004 Report Share Posted September 30, 2004 I asked the same question once. I'm almost positive they told me that uf was just a different name for mf. (that or uf was a different name for pf). Wait for someone smart to reaply though. Quote Link to comment Share on other sites More sharing options...
unclej Posted September 30, 2004 Author Report Share Posted September 30, 2004 thanks..if it's one of those it must be the same as mf because the catalog lists pf and uf. but i'm with you...i'll wait for one of the resident genii. Quote Link to comment Share on other sites More sharing options...
Gnome Posted September 30, 2004 Report Share Posted September 30, 2004 (edited) thanks for the question lovekraft. i was wondering the same thing. and since i know you'll be checking back in i've got another little question about farads. i found a good little tutorial explaining pico, nano and micro farads but looking in my trusty radio shack catalog i find pf and the u with the tail. is the uf larger or smaller than the pf? IT goes like this Farad millifarad (mf) 1x10^-3 = .001 microfarad (uf) 1x10^-6 = .000001 nanofarad (nf) 1x10^-9 = .0000000001 picofarad (pf) 1x10^-12 = .0000000000001 so.. uf has a higher capacitance than pf Edited September 30, 2004 by Gnome Quote Link to comment Share on other sites More sharing options...
unclej Posted September 30, 2004 Author Report Share Posted September 30, 2004 thank you sir. i just added that to my unclej gets smarter files. i appreciate it. Quote Link to comment Share on other sites More sharing options...
lovekraft Posted September 30, 2004 Report Share Posted September 30, 2004 Not to add to your confusion, but in the States for years microfarad has been abbreviated mfd. Since millifarad caps are both huge and very expensive, you can generally assume that any cap marked mf is microfarads, not millifarads, unless it's the physical size of a pickle bucket and really expensive. Quote Link to comment Share on other sites More sharing options...
javacody Posted September 30, 2004 Report Share Posted September 30, 2004 I still haven't built the black ice yet. I'm waiting to find a source for schottky diodes who will accept paypal. Quote Link to comment Share on other sites More sharing options...
ansil Posted October 1, 2004 Report Share Posted October 1, 2004 i got free ones from the free site from gringo's site where if you search the forum i did a topic on Free and legal diy stuff. in it links were given to gringo's site and it has all the free links in it. it was the same company i got some transistors from they sent them from maylasia for free. dont' know part no. though sorry. i think after looking at the ones lk was talking about i would try those as my recomendation. but i havent' fooleed with this thing since the last time i built one right after this was uploaded i thought it was ok but sounded about like the original black ice which didnt' do much for me either. however it is a good alternative to paying big money for little parts. Quote Link to comment Share on other sites More sharing options...
lovekraft Posted October 1, 2004 Report Share Posted October 1, 2004 (edited) That's too weird! I just ran across a place last week, completely by accident (I was hunting for germanium diodes for a fuzzbox). I haven't tried 'em, so I can't tell you how well they'd work... maybe Ansil will weigh in here with some more info, or somebody else who's built one. Here's that link: http://comtrolauto.netfirms.com/bat46.htm <edit> Well, there's Ansil (thanks, man) - anybody else got any input? Edited October 1, 2004 by lovekraft Quote Link to comment Share on other sites More sharing options...
Gnome Posted October 1, 2004 Report Share Posted October 1, 2004 where are you guys located? You could take a quick trip to the local university electrical engineering department. they usually have a good stock of parts for cheap for students. they probably wont even know youre not a student. also, http://www.partsexpress.com/ Also, back when i was a student I used to email semiconductor companies and request samples for 'student projects' even though I was using them for my own projects. i got TONS of free parts. It helps to have a .edu email address I would imagine. Quote Link to comment Share on other sites More sharing options...
ansil Posted October 1, 2004 Report Share Posted October 1, 2004 where are you guys located? You could take a quick trip to the local university electrical engineering department. they usually have a good stock of parts for cheap for students. they probably wont even know youre not a student. also, http://www.partsexpress.com/ Also, back when i was a student I used to email semiconductor companies and request samples for 'student projects' even though I was using them for my own projects. i got TONS of free parts. It helps to have a .edu email address I would imagine. other than asking the university i covered all the sites like national ti and others in the free thread Quote Link to comment Share on other sites More sharing options...
lovekraft Posted October 1, 2004 Report Share Posted October 1, 2004 While I appreciate the help, since small-signal schottkys generally run less than a quarter a piece, I really don't mind buying them - what I was hoping for was some info on which ones worked best. Oh well, guess I'll just have to buy a couple of dozen pair when I get sufficiently motivated, and decide what sounds best. If anybody else gets around to it before I do, update me if you don't mind. Quote Link to comment Share on other sites More sharing options...
Gnome Posted October 1, 2004 Report Share Posted October 1, 2004 While I appreciate the help, since small-signal schottkys generally run less than a quarter a piece, I really don't mind buying them - what I was hoping for was some info on which ones worked best. Oh well, guess I'll just have to buy a couple of dozen pair when I get sufficiently motivated, and decide what sounds best. If anybody else gets around to it before I do, update me if you don't mind. my message was more for javacody, than anyone else. he seemed to be ahving problems located them... Quote Link to comment Share on other sites More sharing options...
lovekraft Posted October 3, 2004 Report Share Posted October 3, 2004 Here we go! Some enterprising mad-scientist type has done the work for us, right down to crediting Ansil for the homebrew Black Ice idea: http://members.aol.com/ku07090/strawberry_ice.html http://members.aol.com/ku07090/strawberry_1.jpg Nice writeup, with photos and a soundclip. Quote Link to comment Share on other sites More sharing options...
ansil Posted October 3, 2004 Report Share Posted October 3, 2004 cool i am glad someone with a digital camera and more timeon their hands could help solve this dilema.i really must get a camera this year. Quote Link to comment Share on other sites More sharing options...
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