Odp: [sdiy] ic question

[Rude 66]

----- Original Message -----
From: "Brock Russell" <brockr0 at shaw.ca>
To: "synth-diy" <synth-diy at dropmix.xs4all.nl>
Sent: Sunday, November 24, 2002 10:31 PM
Subject: Re: Odp: [sdiy] ic question


> Roman wrote:
> >Why would anyone want to use 2 decoders and 4016s if there's
> >4051 that can replace those 4 chips?
>
> I agree. This looks like a mid to late 70's circuit designed from
> parts on hand. A bunch of regular TTL, a 555 and a 3909?
> Not to say there weren't a lot of great designs from this era
> that still stand up today, but this isn't one of them.

i wanted to build it as an addition to some circuit bent speak & spells and
my 76477 box.. find a way to interface it. use the led's to trigger things..
i dunno. it just caught my eye..;-)


>
> >this 3909 generator can be replaced with any oscillator.
>
> I'm not sure this is true. The 3909 is driving an 8 ohm speaker
> directly and most oscillators would have some trouble with this.
> Not that I would suggest using the 3909. It is obsolete, (although
> readily available from many surplus dealers), noisy and sucks a
> lot of power in this configuration.

i'd replace the speaker anyway with a normal line out..


> >Simplest
> >would be made of one schmit gate and capacitor. Resistor
> >(pot)
> >adjusting frequency would be connected via switching 4051.
> >And you could use another scmit gate from same chip for
> >tempo
> >control, i.e. U1 replacement. Plus you need 1000s times less
> >power to run such circuit than original.
>
> Yes, this design is probably a better heater or low RF generator
> than a tone sequencer. At least there are LS and HC parts listed
> as alternatives but to suggest running the thing from a 9V battery
> makes me think it would be a good idea to figure out how much it
> costs to run per hour.

;-) thanks for the analysis.. my idea was to either run it off a battery or
a small ps..

>
> >Mail me if you need exact
> >drawing.
> >
> >This only my suggestion tho...
> >
> >Roman
>
> Take his suggestion...


i have..;-)

thanks for the replies so far.. i figured it's time to actually start
building things instead of modifying and circuit bending them.. though i'd
like the things to be sort of half circuit-bent.. or have some weird boxes
that interface with a speak & spell.. that sort of thing.

ruud