SV: [sdiy] ETI447

[Anders Spontón]

Hi all!
During the summer, the Omega is down for total service. Up again and
probably under new address in august sometime.
Meanwhile, if there is anything you need, mail me and I can probably
help with you out with a file or sumpin´.

Anders, Sweden
http://omega.tellus.vallentuna.se/anders/
http://www.vallnet.nu/sponton/modulsynth.html

-----Ursprungligt meddelande-----
Från: owner-synth-diy at dropmix.xs4all.nl
[mailto:owner-synth-diy at dropmix.xs4all.nl] För Rönnberg Niklas
Skickat: den 7 juli 2004 08:54
Till: synth-diy at dropmix.xs4all.nl
Ämne: [sdiy] ETI447


Hi,

I'm working with an old ETI project. The ETI447 is the phaser and you
can find the complete article on Anders' page Cloned Analog Gear, but I
can't reach it right now... http://omega.tellus.vallentuna.se/anders/
Look in Soundries and ETI, I think that's the right way.

I have some questions about this circuit. I think that the use of IC9, a
4049 CMOS, are quite smart, but why are pin 16 connected to zero
reference voltage? As far as I know pin 16 are not used in the IC.

I have hade some problems with IC9, and I know that you guys can help me
and explain this to me. I have tried some brand new Philips HEF4049BP
and it's impossible to get these to work. So I replaced the new IC with
an old and dusty MSM4049RS, and everything is getting to work perfect.
What's the difference?

The original circuit uses 741 opamps... Can I replace these with TL071?
It doesn't seem to work as it is, so can I do any modifications to be
able to use TL071? And, what is actually the best low noise replacement
for a 741?

Best regards, and I really hope you have better summer weather than we
do in Sweden!

/Niklas