[sdiy] 555-based ADSR that refuses to work with 9v

[Scott Gravenhorst]

If the large resistors are a problem, the CMOS version (7555) might help. 
The datasheet I have says "Extremely low input currents of 20pA".  It also
claims a PS voltage of 18V (abs. max.).  However, since these are series
pots, just reducing their value by turning them "down" should cause the
circuit to work at some point - if that's what the problem is.  I can't see
anything about the circuit that would prevent it from working at 9 volts and
I don't see a reason that you even need a negative supply at all (You mention
a +/- 9V supply, are you connecting the -9V as the circuit's ground?  That
could be a problem).  I'd bet the circuit should work from a single +5V supply.



=?us-ascii?Q?Jaroslav_Lukes?= <lsh.synth at seznam.cz> wrote:
>> From: Karl Ekdahl [mailto:elektrodwarf at yahoo.se]
>> Hi Jaroslav, i've tried changing the 4.7k to Reset
>> since it seems the VCC feed was to low, but without
>
>Not that,I was think about resistors with Mohm values (A/D/S/R).
>
>> any luck. The 555's i tried are CA555CE from Harris
>> and RCA, and also a NE555N from ST. Earlier i also
>> tried NE556A from ST. I can't verify wheter this
>> circuit does actually run from a +-15 since i don't
>> have anything but a +-9V supply here (i've moved
>> recently).
>
>Hmmm. I think that you use all versions that are less or more different from
>original. Use 555 from philips or TI. In my country before many years was
>published list of differences between mfgr's for 555, but I could not find
>it now. I was remember Philips and TI only that are good.
>
>Regards, JL.
>

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