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| Stephen Giles | Stripboard ADA flanger As I mentioned a week or so back, I decided to solder up an ADA flanger clone on stripboard of a size that would squeeze into sensibly sized stomp box. A proper PCB was out of the question as I neither have the time nor the patience to draw one up, although after reading Mark Hammer's procedure of drilling the holes first, I was tempted to try. I reported earlier that the unit I built a couple of months ago took up a piece of stripboard 11" x 4", but everything was given plenty of space to allow for trouble shooting, which funnily enough didn't amount to much, apart from the couple of strip tracks I forgot to cut causing havoc in the input section. I drew up an area of holes on Excel representing the size of stripboard I wanted to use and overlaid component shapes to give me an idea of how small I could go. That seemed to indicate that I could go to 4" x 4", using 2 MC3403 for the audio path and the manual sweep amp, LM324 for the LFO and other CV processors, 4007, 4047, 4049 and BBD. The 3403s are on top, 4049 and BBD in the middle and LM324, 4007 and 4047 at at the bottom. I have now built the input section, LFO and clock generator up to the 4047 and sod's law has already crept in because I hadn't allowed space for power lines and decoupling capacitors, so I'm now looking at a board 4" x 5.25" which isn't too bad. Now, I've also built this beast twice on breadboard so you would think that any potential problems would have reared their ugly heads by now - wrong! I had extreme difficulty in getting the LFO to work, in fact the first time I looked at the LFO output my digital multimeter read 0v. I already had the input section working OK at the top of the board, using incidentally the passive limiter from Rev3, so I decided to desolder the LM 324 and try another - but tired eyes managed to desolder the 3403 instead! It's easy to take out the wrong chip when the board is upside down - I tend not to use sockets for opamps although I do for cmos and BBDs. I then checked the 324 on another board and found that it was dead - a brand new chip. So with another 324 in place which I knew was working, I tried for LFO voltage again but this time a static voltage, so some progress. I then replaced each component making up the LFO and it was not until I replaced the 33uf capacitor (again brand new) with an old 10uf,that it worked. I then tried each of 5 other 33uf caps I bought at the same time recently and none of them worked! Upward and onward, the clock generator came next and I copied the layout from my other board. The 4047 is positioned 1 row below the 4007 so that pin 12 of the 4007 lines up with pin 2 of the 4047. I also managed to get a 22p - 65p variable capacitor from Maplin Electronics (wonders will never cease!) which will allow me to play around with the max and min delay. This worked first time, giving out roughly 6.4v at each of pins 10 and 11 of the 4047. If the voltages at those output pins are not the same, the BBD will not work - believe me. That's as far as I've got folks - one thing to remember when designing stripboard layouts is to allow plenty of space for electrolytics, unless they are very small you need to allow an area of at least 3 x3 holes, and preset pots take up more space than you think. |
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| Stephen Giles | Nobody interested - I'll go back to my fuzz box then! |
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| Peter Snow | Yeah Stephen, I'm interested - please keep going. I enjoy reading your posts on this, though I am not technical enough to make any sensible comment. Peter |
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| Mark Hammer |
I imagine folks are *very* interested. They're just all over at Aron's. I keep leaving notes for him to fix things for you. You guys have got to get this worked out. |
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| Stephen Giles | Ah, thanks for respondez-vousing here. Actually I got the thing working more or less Ok on Sunday, so I'll write up the next instalment and post it later in the week. I did get an email from Aron who thought there may be a problem with AOL, but meanwhile I'm uncle boko over at Aron's site which I can only post to from a library terminal (when I can get there) Incidentally uncle boko was a children's entertainer who used to advertise in our local paper in the 60s. Needless to say, the ADA board produces wonderful flanging with an incredibly wide sweep. Stephen |
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| Mark Hammer |
Ahhhhh, so *you're* Uncle Boko. I should have checked. That wide sweep IS delightful. Mike demonstrated his to me, and one finds one's self listening and thinking, "Okay, isn't this the spot where it runs around and goes the other way?", and it just keeps going and going. My PAiA Hyperflange has been sitting there gathering dust for the last 10+ years, and I have yet to fire it up. It is the could've/should've that taunts me. I should just take all semi-complete perfboard and PCB projects, all the pedals in need of repair, all my spare blank perfboard and copper board, and ANYTHING that remotely resembles a pedal, stick them in a huge chest with a padlock, give my increasingly forgetful elderly aunt the key, and hunker down with the Hyperflange and finish the damn thing before I am permitted to lift another finger to anything else. Theoretically, this thing should have staggering sweep possibilities. I've just never heard them. |
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| Stephen Giles | Mark - the Hyperflange I built didn't have particularly staggering sweep, I need to fire mine up again to see what else can be done. I built that one on a PCB made up by a friend from Birmingham in England years ago, and of course it is very quiet. I have to pick up my wife from her teaching centre in one of the more dodgier parts of South London in a short while so maybe when I get back. It doesn't have the rawness of the ADA though. Funnily enough, I seem to have missed out the 5k/.01uf filtering components from the output amp on my small board (and the 4k7 on the large board) so it is probably more raw than it should be. I'll do some sound samples at some point. |
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