"Joe Meek" compressor secret

[Tim Ressel]

Yes, This was an interesting technique. It involves varying the impedance of the
diode by varying the DC voltage across it. This impedance determined the cutoff
frequency of a filter. The Paia EGG used this. I saw the schematic somewhere
online. If I find it again I will post the address.


> ----------
> From: 	Thomas Hudson[SMTP:thudson at cygnus.com]
> Sent: 	Monday, June 14, 1999 9:54 AM
> To: 	Paul Perry
> Cc: 	synth-diy at mailhost.bpa.nl
> Subject: 	Re: "Joe Meek" compressor secret
> 
> Paul Perry wrote:
> 
> > Further, has anyone experimented with filter structures with
> > grossly non-linear components, such as replacing resistors with
> > resistot/diode combinations?
> > 
> Funny you should mention this. I spent this weekend looking at
> guitar distortion circuits that use diodes either in the opamp
> feedback path (TS909) or to ground (MXR Distortion+). On
> Jack Ormans site (http://www.muzique.com/amz/index.html), 
> he has an article (http://www.muzique.com/amz/latch.htm)
> about putting a resistor in series with the two diodes in the 
> opamp feedback path to reduce differences in using various opamps.
> 
> This led me to start thinking about the technique John Simonton
> used in the 2700 series filters using diodes. I read an article 
> online about this, but now I can't seem to find this article.
> I am probably wrong on this, but wasn't it feeding current into the
> diodes to change the cutoff of the filter? Anyone know where this
> article and schematics are?
> 
> I am interested in varying the series resistance for each diode 
> independently, hopefully producing different amounts of even 
> harmonics in the distortion, possibly dynamically based on envelope.
> 
> Thomas
>