[sdiy] inexpensive chips for oscillators (still learning...)

[Bob K]

Wow!  More stuff.

I gotta start doing some research and reading.  Hell, I don't even own
a multimeter yet.

New hobbies are expensive.

On Mon, Sep 26, 2011 at 1:45 PM, Kyle Stephens <lightburnx at yahoo.com> wrote:
> http://www.beavisaudio.com/Projects/CMOS_Synthesizers/
>
> Knock yourself out. The chips and parts used herein are cheap and can sound pretty neat - moreover, everything's readily breadbaordable.
>
>
> _Kyle
>
> --- On Mon, 9/26/11, Bob K <farfisa5 at gmail.com> wrote:
>
>> From: Bob K <farfisa5 at gmail.com>
>> Subject: Re: [sdiy] inexpensive chips for oscillators (still learning...)
>> To: "synth-diy DIY" <synth-diy at dropmix.xs4all.nl>
>> Date: Monday, September 26, 2011, 12:54 PM
>> Wow.  Thanks again for the more
>> information.
>>
>> I'm a beginner but can read schematics and am learning my
>> way around a
>> breadboard.
>>
>> The initial project is just going to be a little noise box
>> with two
>> pots, one to control the frequency and the other to control
>> the
>> volume, and no inputs.  After I get that going I'll
>> add more
>> oscillators and more knobs.
>>
>> So it looks like I'll start off with the CMOS 7555/TLC555
>> and see what happens.
>>
>> I'll take a look at the PAiA schematics and see what
>> they're doing.
>>
>> Again, thanks!
>>
>> -Bob
>>
>> On Mon, Sep 26, 2011 at 11:26 AM, Scott Gravenhorst <music.maker at gte.net>
>> wrote:
>> > Dave Kendall <davekendall at ntlworld.com>
>> wrote:
>> >>You probably know this already, but if using 555s,
>> go for CMOS versions
>> >>(7555, TLC555 etc) which draw *far* less power.
>> It's my understanding
>> >>that the regular 555 can cause problems with power
>> consumption when
>> >>switching.
>> >
>> > The datasheet I have for the 7555 has current graphs
>> that show the difference between
>> > the bipolar 555 and the CMOS 7555 while they are
>> switching.  The difference is
>> > amazingly large.
>> >
>> > In fact, the PAiA Fatman had been designed using
>> bipolar 555 timers for the two VCOs.
>> >  Unmodified, it has a notable problem of soft
>> synching the VCOs when they are close
>> > in pitch.  This is because even though the 555 is fed
>> power through a 100 ohm
>> > resistor with a 100 uF cap to -12V, there is still a
>> significant current spike at
>> > switching time that propogates to the other VCO.  A
>> fix was designed by PAiA which
>> > replaces the 100 ohm resistor with an LED.  Another
>> fix that I found after learning
>> > about the 7555 was to simply replace the bipolar 555
>> with CMOS 7555.  The two fixes
>> > work about as well as each other, but I prefer the
>> 7555 fix over the LED fix.
>> >
>> > +1 for 7555.
>> >
>> > And you can go to www.paia.com and look at the
>> schematic for how they turned a 555
>> > (or 7555) timer into a VCO.  It is a _linear_ VCO,
>> but enterprising lovers of expo
>> > could probably convert the VCO's voltage to current
>> converter to use expo instead of
>> > linear pitch CV.
>> >
>> >>On Sep 26, 2011, at 17:21, Bob K wrote:
>> >>
>> >>> Hi everyone,
>> >>>
>> >>> New here.  Hi.  How's everybody?  Fine?
>>  That's good.
>> >>>
>> >>> After skimming through the two Forrest Mimms
>> books I have and "Make:
>> >>> Electronics", both books are making a point
>> that 555 and 556 chips are
>> >>> a good (and cheap) start for breadboarding
>> oscillators.
>> >>>
>> >>> I'm planning on a bulk purchase (bulk meaning
>> around 10) of the above
>> >>> mentioned chips and was wondering if there are
>> any other cheap chips
>> >>> along the lines of the 555 and 556 that can be
>> used for oscillators?
>> >>> I'm going to search online for advice as well
>> but thought I'd run this
>> >>> question by everybody here.
>> >>>
>> >>> Thanks.
>> >>>
>> >>> -Bob
>> >>>
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>> >>
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>> >
>> > -- ScottG
>> >
>> ________________________________________________________________________
>> > -- Scott Gravenhorst
>> > -- FPGA MIDI Synthesizer Information:
>> >   jovianpyx.dyndns.org:8080/public/FPGA_synth/
>> > -- FatMan:
>> >   jovianpyx.dyndns.org:8080/public/fatman/
>> > -- NonFatMan:
>> >   jovianpyx.dyndns.org:8080/public/electronics/
>> > -- When the going gets tough, the tough use the
>> command line.
>> >
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