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29.11.09
WAMPLER - CRANKED AC
recently while browsing a certain clone kit site, i stumbled across the schematic for brian wampler's cranked ac design. having been on a serious ac kick a while back, i was never able to find the schematic, so this was kind of a cool find. the cranked ac at first looks like your run of the mill jfet type distortion box until you notice that wierd parallel fet configuration. ecaxtly what this is supposed to do to the sound i don't know, but it is a rather interesting little tweak. i'm sure that this could be adapted to just about any transistor type, and wonder if it has any of the same kind of properties as stacking ic's.
i redrew the schematic and made up an eagle verified pcb layout which should work ok. if anyone gets it built please let me know . you can keep up with all of the latest on this subject HERE.
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28.11.09
LISSAJOUS FIGURE VID
browsing the really cool EXPERIMENTALIST ANONYMOUS BLOG, i found this great video of a LISSAJOUS FIGURE portrayed on an oscilloscope. from what i gather, a lissajous figure can be generated using a scope by injecting one wave ionto the x axis, and another onto the y axis. summing them together, you get this 3D effect. the maker of the video put the left channel through the x axis, and the right through the y, all the while tweaking multiple effects. as i finally picked up a scope recently, i find this sort of thing fascinating. unfortunately, the cheapo 40 dollar scope i got only has a single channel, so you won't be seeing any lissajous figures from me in the near future.
27.11.09
SOME COOL PARTS SOURCING SITES
here are a few kick ass sites to source parts on the cheap. the first is EVITA. they are a great source for any russian parts that you might want, and are even cheaper than what you can find them for on ebay. plus you don't have to buy a box of 100 of a single type, you can mix and match as you please. i have heard that they have reasonable shipping, and EVITA has all of the datasheets available for download on there sight, so you have some idea of what you are getting into.
as you can probably tell, i have a serious passion for these russkie germanium trannies, as many types are about as consistent as any silicon transistor out there, and unlike euro, american, or japanese trannies, many types have absolutely no leakage. the consistency of russian ge transistors is pretty much unparalleled around the world. i think this must be due to the fact that the soviets were producing germaniums well into the 80's where other sources had stopped long before. also they used them for many military uses as well, so their standards were set very high. you can tell the transistors and other parts meant for military use as they have a small diamond printed on the side.
along with transistors, there are many excellent russian teflon, paper in oil, and polystyrene capacitors offered at EVITA, so if you have an urge for cheap, quality soviet parts, now you don't have to be a slave to ebay.
if you have ever built an analog delay, you know how hard it is to source bucket brigade delay chips. you can end up paying a hefty price for what may end up being total counterfeit crap. you can go to a parts sourcer, but there may be a large minimum order that puts buying the parts well out of your price range. well, i recently was turned on to UTSOURCE, who source hard to find, out of production parts with very small minimum orders and good prices to boot. give em a shot if there are some rare chips you can't find.
lastly, is TEDDS.COM. they have lots of cool vintage capacitors and other parts with only a ten dollar minimum. also, they have pics of every cap in their inventory so you don't have to have every model number memorized. good stuff.
as you can probably tell, i have a serious passion for these russkie germanium trannies, as many types are about as consistent as any silicon transistor out there, and unlike euro, american, or japanese trannies, many types have absolutely no leakage. the consistency of russian ge transistors is pretty much unparalleled around the world. i think this must be due to the fact that the soviets were producing germaniums well into the 80's where other sources had stopped long before. also they used them for many military uses as well, so their standards were set very high. you can tell the transistors and other parts meant for military use as they have a small diamond printed on the side.
along with transistors, there are many excellent russian teflon, paper in oil, and polystyrene capacitors offered at EVITA, so if you have an urge for cheap, quality soviet parts, now you don't have to be a slave to ebay.
if you have ever built an analog delay, you know how hard it is to source bucket brigade delay chips. you can end up paying a hefty price for what may end up being total counterfeit crap. you can go to a parts sourcer, but there may be a large minimum order that puts buying the parts well out of your price range. well, i recently was turned on to UTSOURCE, who source hard to find, out of production parts with very small minimum orders and good prices to boot. give em a shot if there are some rare chips you can't find.
lastly, is TEDDS.COM. they have lots of cool vintage capacitors and other parts with only a ten dollar minimum. also, they have pics of every cap in their inventory so you don't have to have every model number memorized. good stuff.
26.11.09
EFFICIENT CALCULATOR USE FOR ELECTRONICS FORMULAE
HERE is a great post by electronics wizard Tonmann over at the circuit workshop forum. it breaks down and totally demystifies the process of working on electronics formulas. it's a great little tutorial, and hopefully, tonmann will have his larger tech tutorial done soon.
OPAMP BASICS
mystified by that tube screamer? in a conundrum over the klon? THIS course at Elliot Sound Products has all of the basics about opamps covered. all the common configurations, power applications, filters, and formulae are there for the taking. they have a shitload of other great articles and projects over there too, so be sure to check out the rest of the site.
8.11.09
3PDT DAUGHTER BOARDS
recently i've gotten right sick of trying to jam my nice, thick, 22 gauge, solid core wire into switch contacts. many times i'd end up marring the insulation, or just not liking the appearance. a remedy was to design a daughter board to connect all of the wires to the switch. after a bit of talk with my friends over at FSB, i decided to expand on the idea, and built a few different versions. V1 is a simple board with connections for each lug on the switch. V2 has a resistor added for limiting the power to the LED. version 2.1 adds a pad for connecting DC and the other side of the LED. finally, V3 adds to this a spot for a power filtering electrolytic capacitor, and polarity protection diode. in the future i may add more designs, possibly adding R.G. Keen's MOSFET polarity protection scheme, and a voltage divide for use with op amp circuits. there has also been some talk of making a group buy for printed PCBs. we'll see if that ever comes to pass in the future. you can check out all of the layouts and keep abreast of the latest news HERE.
6.11.09
MONTARBO PB-2 FUZZ SECTION
hey if anyone is out there, sorry it's been so long. been kinda denying the blog love lately, hope to get back into it with some cool stuff to add.
here is a little italian fuzz circuit that i thought looked interesting. it's from the montarbo pb-2 fuzz/phaser combo pedal. i like the negative feedback diode configuration. at first it looks a bit like a muff, but there are some differences when you look closer. you can see that the diode loops are separated by capacitors effectively isolating them from the DC that is used to bias the transistors, where as in the big muff, the diodes have their own dedicated blocking caps, filtering the frequencies to be clipped. also, there is a 47K resistor to ground on the first tranny's diodes that may introduce some harsher clipping by pulling the diodes closer to earth. it looks like a fun little way to adjust clipping, and i plan on giving it a shot in the future. if anything cool comes of it, i'll be sure to let you know on the blog.
cheers!
here is a little italian fuzz circuit that i thought looked interesting. it's from the montarbo pb-2 fuzz/phaser combo pedal. i like the negative feedback diode configuration. at first it looks a bit like a muff, but there are some differences when you look closer. you can see that the diode loops are separated by capacitors effectively isolating them from the DC that is used to bias the transistors, where as in the big muff, the diodes have their own dedicated blocking caps, filtering the frequencies to be clipped. also, there is a 47K resistor to ground on the first tranny's diodes that may introduce some harsher clipping by pulling the diodes closer to earth. it looks like a fun little way to adjust clipping, and i plan on giving it a shot in the future. if anything cool comes of it, i'll be sure to let you know on the blog.
cheers!
