I’ve combined my 505 with a cheap analog module, to replace the crappy bass drum with something more respectable. The analog module and the cmos are both leaching straight off the 505′s 9 volt supply, so it’s a dirty set up really..
I’ll bolt on some de-coupling caps around the IC and the power lines this week and hopefully that might solve the problem. Otherwise I may have to hassle you again for more advice!

BTW, your ‘food for thought’ sounds amazing!

cheers………..Dave

i use for most things these days, and they are partial to sourcing stuff as well if they dont stock it if they think they can shift enough of them to warrent it, which is nice.

ah, the old 505 mods! you beat me too it! i have one sitting in the cupboard awaiting bending and tinkering. some of the sounds of the 505 are linked to each other, if i remeber correctly from the last one i did, tom/timbales are linked and the rim shot/clap are too. i think i may have added resistors in series to the output of the oscillator and the pins. try some thing small like 1k.

are you sure you have soldered the correct pins to the oscilators? its easy done, if you look at the chip, it has a small dot in one corner, the long side underneath this dot starts with pin one, its the short side you want, the last pin (pin 60 or so) i know is clap/rim shot, after that you are on your own with which one does what, but i’m sure the yahoo circuit benders group will have some info, or even the boys from burnkit2600 on their site.

its odd that several unlinked sounds are pitching though, do you have any bends connected at all? what size cap are you using? i think some thing really small is required, nowhere near what i was used above on this page, they are huge in comparrison for audion rates, although that shouldnt affect it. also, what power source are you using? i tapped it off of the board itself instead of a seperate battery. i dont even have the one i built to check as i gave it to a friend.

let us knbow some more details,

cheers,

bod.

Yep, maplin can suck my balls if they think I’m gonna silly money for crap components and bad advice! I actually managed to find all I needed from ebay. I just wasn’t searching properly. I’ll give RAPID a try when I have a spare 50 quid to spend in one go.

Right, all works great with this CMOS synth. I have a related question though. It’s been troubling me for some time now, and it’s something I need to figure out -

Using a cmos 40106, make 3 simple HIGH FREQUENCY oscillators using caps and pots (double inverted, so 3 oscillators from each IC). Feed the oscillators into my tr-505 to control the pitch of the drums (obviously disconnect the 505′s default pitch oscillator). OK, sounds simple enough and works fine when I just connect 1 oscillator. The problem is that when ALL 3 oscillators are connected something goes horribly wrong…. Turning 1 pot seems to affect the other pots, ie when I pitch the congas, the cowbell ALSO pitches and the claps just distort horribly!

Now I’ve checked the soldering a hundred times, as well as the wiring. There is no fault that I can see there.

What’s going on here?

I’m very new to electronics, and I suspect that I’m overlooking something really simple here.

Can you help? …………………cheers…………

I use rapid in the uk, cheap and reliable, or you could try maplin, but then you could also drop your jeans around your ankles and asume the position over their counter while the spoty, clueless tw@ts all take turns… thats if they even have them in stock in the first place, and most components tend to be double most other places prices. sorry, ill get back to the point.

here’s rapids page for the 4000 series IC’s. no minimum order, but delivery is 5 quid unless you spend £30 i think, so you might as well stock up on a few bits and bobs while you are at it.

http://www.rapidonline.com/Electronic-Components/Integrated-Circuits/Logic/4000-series-CMOS-Logic-family/77018

have fun! and let me know how you get on, or post some links for your work.

cheers,

bod.

I’m having some problems sourcing a 4040 though, , can you recommend a reliable supplier (preferably UK) ?

…thanks…