[sdiy] Tone control questions

[David Ingebretsen]

The more I think about it, the more I'm convinced I'm just blind to an error
I made either in the schematic capture (although this is a really simple
circuit) or in stuffing the PCB. So far as loading, I'm just going into a
scope, so there shouldn't be a problem there. The tone control circuit is
built around an intermediate transistor stage which feeds an emitter
follower; so again, I don't suspect a loading problem, at least in the
design.

I'll take another long look at the PCB components and schematic when I've
taken a break from it for a few days.

Thanks everyone who responded on and off list.

David

>> -----Original Message-----
>> From: synth-diy-bounces at dropmix.xs4all.nl [mailto:synth-diy-
>> bounces at dropmix.xs4all.nl] On Behalf Of Phil Macphail
>> Sent: Tuesday, March 11, 2014 4:17 AM
>> To: Gordon JC Pearce
>> Cc: synth-diy at dropmix.xs4all.nl
>> Subject: Re: [sdiy] Tone control questions
>> 
>> I can't agree with that. Simulations tell you how the circuit you have
created
>> will behave within the test environment of the simulator. If you create
that
>> same situation in reality then the simulation and measurement will agree
>> well (how else do we have millions of chips for sale for so little?).
>> Most errors when using simulators are the use of ideal components and not
>> representing the external loads in the test harness. If you choose not to
>> represent reality in your simulations, that isn't the fault of the
simulator.
>> 
>> Returning to the question asked by Carsten, the two most likely causes
are
>> either a wiring error or the test environment is loading the circuit
>> significantly in a way that wasn't included in the simulation.
>> 
>> Phil.
>> On 11 Mar 2014, at 11:33, Gordon JC Pearce <gordonjcp at gjcp.net> wrote:
>> 
>> > On Tue, Mar 11, 2014 at 08:48:19AM +0100, Carsten Toensmann wrote:
>> >>
>> >> Leaving the question why the simulation is ok and the prototype shows
>> >> that quite obscure behaviour...
>> >
>> > Because simulations work just great for telling you how your circuit
works
>> in a simulator.  They don't bear any relationship to reality.
>> >
>> > --
>> > Gordonjcp MM0YEQ
>> >
>> > _______________________________________________
>> > Synth-diy mailing list
>> > Synth-diy at dropmix.xs4all.nl
>> > http://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>> 
>> _______________________________________________
>> Synth-diy mailing list
>> Synth-diy at dropmix.xs4all.nl
>> http://dropmix.xs4all.nl/mailman/listinfo/synth-diy