Bug-Crusher -- Sample Rate Reducer DIY

[para]

so i found this - which is yours. there are 178 of them at $8 each like $12 to ship.

http://cgi.ebay.com/Power-One-HAA15-0-8 ... dZViewItem


and this one a HBB15-1.5-A for the same price but its +/-15v at 1.5a

http://cgi.ebay.com/Power-One-HBB15-1-5 ... dZViewItem

so should i just get the second one to make sure im covered for a while?



thanks,
steven

[expanoncolin]

Yes, t hat is the one I got from the guy I got it from.

The 1.5A one is HUGE.  So keep that in mind.  But if you are set on more amps, go ahead.

-Colin

[para]

i'm not set on more amps? i don't understand how it works? i was just under the impression that more amps meant that i could add more devices to that supply. but they aren't as expensive as i thought they would be and i don't feel like dying anytime soon as i just read that 1.5 amps can burn tissue and organs so i think im getting the 0.8 version.

[goldenechos]

Good choice. You can always add more power with the additional modules.


T

[expanoncolin]

i'm not set on more amps? i don't understand how it works? i was just under the impression that more amps meant that i could add more devices to that supply. but they aren't as expensive as i thought they would be and i don't feel like dying anytime soon as i just read that 1.5 amps can burn tissue and organs so i think im getting the 0.8 version.

More amps means more modules, I was simply warning you because the 1.5amp version is VERY LARGE and you'd have to work around that.  You wouldn't have to worry about it burning you if you were careful.

-Colin

[para]

i was just under the impression that the supply alone would cost like $50+ and thats the only reason i bothered looking for more amps. its done and over, i got the 0.8A version and its on its way.

back to the matter at hand. i noticed the power section is missing some component ID's so i asks bugs to fill me in. just in case anyone else is building this and can't figure it out for themselves ( like me) here is some of what he said. hope this is cool with you tom, just thought i would save you the time

_


"R90 - R91 - learnt off Ken Stone's site:: he uses RF Chokes to
try to cut down noise, but says you can just insert 10ohm resistors
(dunno if it actually makes much difference - probably not in a
single device, but maybe in a big system - so you could probably
ignore them)"

"C90 & C91 should be something like 10u electrolytic caps (standard to stabilise the power lines) and C92-5 are all 100nF decoupling caps - cheapy ceramic types work fine - two of these go very close to the AD781 (right by the +v and -v input pins) and the C95 I have by the +v pin of the 40106 ('cos digi chips can spit nastyness onto the powerlines)."

"I'd meant to try out the design running on two 9v batteries (probably then change the main regulators to 7808 and 7908 naturally..!..)... It may well work - one 9v alone wouldn't be enough - the AD781 needs at least +/-5v and the 40106 needs a stable +5 supply."

"And, yeah, OF COURSE --- 3 free gates in the 40106 - obvious! Its so
easy to make lofi oscs out of them - why not do three extra mod
oscs?? You can add in extra cv inputs into the TL071 - just use extra
100k resistors into the common point (like where the CVs all connect
together)"

_

and in case anyone else was interested i did successfully order free copies of the AD781ANZ and other stuff by signing up for samples at analog.com i just made sure not to give my real phone number so i didn't have to bother answering questions or anything, and ignored the emails.

http://www.analog.com/en/prod/0,2877,AD781,00.html


thanks again for making this tom and making it available to diy

[curtissquare]

Sorry if this is a stupid question but I haven't looked at the data sheet for the S/H chip, but would it be possible to build something using this chip for 9 volts? like make a bipolar power supply with 4.5 volts - and +? if not does anyone know of a sample/hold chip that would run off a 9v supply?

also it would be cool to be able to switch between narrow and wide pulses so that it could be a sample and hold or a bit crusher? Just an idea . . .

[para]

i had already asked bug that. this is what he had to say.

"I'd meant to try out the design running on two 9v batteries (probably
then change the main regulators to 7808 and 7908 naturally..!..)...
It may well work - one 9v alone wouldn't be enough - the AD781 needs
at least +/-5v and the 40106 needs a stable +5 supply."


if you run two 9v's bipolar and change the regulator then it should work like he said. but i haven't tried it yet either.

if i remember correctly the easiest way to do that is to set the 2 9volts up like this  
(+) positive wire to board (+) 9v (-) ground wire to board like a "Y" adaptor  (+) 9v (-) negative to board (-)


but you might have to actual flip the negative 9v. i tried to the find it again but i couldn't sorry. maybe let someone smarter then me double check my work.

[curtissquare]

Hey thanks, yeah the double 9 volts might work . . . hmm. Cuz I'd really like this as more of a traditional guitar pedal. I have a schematic somewhere for a basic double 9v battery bipolar power supply somewhere that I think was for +/- 5v, it's probably exactly the same as you said. I think I'm going to update my PU first and then see if I can get ahold of one of those AD781's.

are there any other chips that don't need that kind of power supply that could do something similar or is this the only thing that can do the sample and hold fast enough? Most of them probably aren't designed for superfast switching, right?

This is a very cool effect, it'll definitely be my next (probably catastrophic) experiment . . .

[para]

"+/- 5v" no i think it should literally be +9 and -9 and share the same ground.

"then see if I can get ahold of one of those AD781's. "

its pretty easy to do for free. just register over at analog dot com and add it to your sample cart. free 2nd day shipping too. dont use your real phone unless you want them to call you

"are there any other chips that don't need that kind of power supply that could do something similar"

this i can't answer as i'm still learning this stuff. but maybe someone else will come along that can

let me know if that 9v works.

[curtissquare]

oh yeah the +/- 5v was just another schematic I had seen where they needed that specifically and you can't get it from a single 9v . . . I guess I wasn't computing what you were saying, that is so much simpler! I guess my mind only really works with diagrams.

Yeah I'm still learning this stuff too . . . but it's neat fun to mess around with.

[bugbrand]

Anyone have any luck with the 2x 9v power?

Tomorrow (Fri 25th) I release the first batch of the BugCrusher production..
(pretty big job doing 15 of them.!.)




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