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DIY Stompboxes => Building your own stompbox => Topic started by: timd on September 15, 2012, 07:09:38 PM

Title: Totally Obscure IC's
Post by: timd on September 15, 2012, 07:09:38 PM
I salvage alot of old electronics such as broken TV's, stereos, etc. and I have tons of random very specialized IC's. I've looked up datasheets on some, and they control really narrow things like vertical balance on a TV for instance. Are these even worth keeping? I know IC's can be "misused" to create interesting sounds, but is it worth it to tinker with these?
Title: Re: Totally Obscure IC's
Post by: cloudscapes on September 15, 2012, 07:28:35 PM
sometimes old stereos and TVs have "sound enhancer" ICs, like stereo seperation  :icon_mrgreen:
Title: Re: Totally Obscure IC's
Post by: Jazznoise on September 15, 2012, 07:57:11 PM
It depends. Some of them will be MUX'ers and stuff. For the space they take up, I'd hold onto them and do a little reading!
Title: Re: Totally Obscure IC's
Post by: timd on September 15, 2012, 08:05:25 PM
Sorry for noob question, but what is an MUX'er?
Title: Re: Totally Obscure IC's
Post by: amptramp on September 15, 2012, 08:27:35 PM
A MUX'er is a multiplexer which allows you to select one input from a number of them to go to an output.  This would be used in home theater where the user selects one of TV, DVD, CD, tape, tuner etcetera inputs to go to the sound.  You could make effects or untrue bypass systems from these.  Think of having a number of effects in series and using this device to take an output from the lines between the effects so you could have, say, effect bypass, then a wah output, then a wah plus fuzz output then a wah plus fuzz plus delay and so on.  It is not necessarily unlimited permutations and combinations, but for many users, it would be perfectly adequate and all permutations could be obtained by plugging things in in a different order.  Good for a studio, not necessarily good live.

Colour demodulator chips make good Gilbert cell modulators that would do the work of a Green Ringer without the need for audio transformers.

Datasheets are available on line for most parts, so do a little light reading to figure out what you have then do a little creative thinking to figure out what you could do with them.
Title: Re: Totally Obscure IC's
Post by: Jazznoise on September 15, 2012, 08:43:17 PM
You can also switch between two MUX where only is held low for a very simple square wave/ring mod. Abit wasteful, but hey, this is audio!  :icon_wink:
Title: Re: Totally Obscure IC's
Post by: timd on September 15, 2012, 08:53:18 PM
Time to hit the datasheets. Thanks!
Title: Re: Totally Obscure IC's
Post by: gritz on September 15, 2012, 09:03:03 PM
I guess (and this is completely off the top of my head and inspired by this thread) that Dolby chips rescued from old tape decks *might* be used to help the signal/noise ratio in e.g. echo pedals (if given due regard to their spec sheets).

Possibly. :)
Title: Re: Totally Obscure IC's
Post by: Jazznoise on September 15, 2012, 09:27:58 PM
Quote from: gritz on September 15, 2012, 09:03:03 PM
I guess (and this is completely off the top of my head and inspired by this thread) that Dolby chips rescued from old tape decks *might* be used to help the signal/noise ratio in e.g. echo pedals (if given due regard to their spec sheets).

Possibly. :)

There at least might be some companders which would work well at the input stage for a delay too.

Just thought that a MUX and a set of RC networks might be cool as a filter sequencer.. Some of these oldies must have some LC tanks too, worth taking a look at.

Trying to think of what you'll find in an FM Demodulator that'll be of use. In the unlikely event that one is a Mod/Demod, there's fun to be had there.