[sdiy] matched FETs for phaser

[anthony]

I have a strict policy about trying to use parts I already have. Especially 
since I have a huge amount of neat parts that I've scavanged.

I'm not averse to buying parts, but often my projects take interesting 
detours trying to adapt what I have that would not have occured otherwise. 
There /is/ a pointof diminishing returns though.

What actually got me thinking about this was my plan to use a matched pair - 
something similar to a 2SC3958 that came from a piece of tektronix gear - 
for a clone of MXR's Phase 45. Since I have two of these I wondered how a 
Phase 90 would sound _using_these_parts_.

At the heart of these ponderings was a question of theory: do ALL FET's in 
a phaser need to be matched or just matched in pairs?

----- Original Message ----- 
From: "Jaroslav Lukes" <lsh.synth at seznam.cz>
To: "'anthony'" <aankrom at bluemarble.net>
Cc: <synth-diy at dropmix.xs4all.nl>
Sent: Monday, January 30, 2006 3:01 PM
Subject: RE: [sdiy] matched FETs for phaser


>> From: owner-synth-diy at dropmix.xs4all.nl [mailto:owner-synth-
>>
>> I know it's not that hard to match FETs for use in a phaser, but I was
>> wondering if one used two matched pairs that weren't matched to each 
>> other
>> if you would have good results.
>>
>> What I mean is it seems like it would be most important to match each 
>> pair
>> for two stages for each peak/notch. How do 2 seperate phasers connected
>> serially controlled by the same LFO sound?
>>
>
> Here are at discount sales 6 matched (ie., 6 on single chip, not matched 
> by
> measure, but they have very small differences) transistors in single chip:
> MH2009 and MH2009A
>
> See http://io.freehosting.cz/166.gif
>
> And you can buy it at http://www.mkelektro.com/index_uk.html
>
> Origimally, it was designed for switching apps, but at analog apps it is
> very good too. It was used as signal switchers and mixers, VCA+VCF at 
> famous
> construction of Dolby B compander by Jaroslav Belza etc.
>
>
> Regards, JL.
>
>