EQ circuit

[samhay]

Let your computer do the drudgery...

Some of us don't run Windows and that seems to be the only way to run the software isn't it?

[Brisance]

Linux + WINE will do the trick nicely as well

[Kipper4]

I've tried a few differant eq circuits now.
and was wondering if it makes any differance or if there are any conventions regarding if the buffers / Amps on the input and out should be inverting or non inverting ?
Thanks


I've had a modicum of success and faiure.
I even tried STMs 3 band which was one of the fails. no matter which way i did it it just sounded like a misbiased transistor stage driving a nasty fuzz face.
here it is if you want a squiz
http://www.diystompboxes.com/smfforum/index.php?topic=24359.40

next on the breadboard is a weber type tonestack.


Edit
PPR I'm taking the listen to it and see approach as I'm not too sure what i want over all.
I guess it started out as a cut and boost idea.
then morphed as so often happens with my experimentation.
theres no way this babys  getting any of my coffee.
Buy it a gym membership. Hell yes I'd date it ir it did what i needed.

Things I've found i do like are a
700hz cut notch.
3khz presence notch
200-100hz cut and boost.
but as always I want it all.


Sam I've emailed you a pic of the duncan tonestack screenshot.

[Kipper4]

I forgot to say the sans amp presence works really well.
Thanks for that

[bool]

Ohh-ahh really? I can't express how surprised I am.

If you massage it a bit more, it can sound even better. The reason for that is very simple - when you look at it from a certain angle, this isn't anything else but a simple wien bridge stuffed into an opamp's NFB. Wien bridges are known good sounding circuits that take massaging well.

So go and tweak it some more. Well ... if it doesn't work exactly as you want it in the first place.

Imho you don't need any buffer at the output after the "presence" opamp.


But I fail to see what's wrong with the FMV stack? It works. It "records" well. You can tweak the range with resistors paralleled or seried with the pots (easy enough with Spice). I oftern use a "fixed" stack (no pots). It's a "sound" that everybody's used to. "Pro", but "nothing special".

Ymmv.

[samhay]

^and was wondering if it makes any differance or if there are any conventions regarding if the buffers / Amps on the input and out should be inverting or non inverting ?

Generally you want a passive tone stack to be fed from a low-Z output (op-amp or common collector/drain) and to then feed a high-Z input like a non-inverting op-amp. I guess it's a bonus if your circuit does not have a net phase inversion, but there is no harm in using e.g. 2x or 4x inverting stages.

^I even tried STMs 3 band which was one of the fails. no matter which way i did it it just sounded like a misbiased transistor stage driving a nasty fuzz face.

Did you bias it to half supply via the non-inverting inputs? If not, then it will not be very happy.

^Sam I've emailed you a pic of the duncan tonestack screenshot.

Much obliged - haven't seen that one before.

[Kipper4]

This aint over yet.
Admittedly i need to tweek it and try some differant stuff including returning the STM to the breadboard.
thanks
I did indeed bias the NI inputs at 1/2 +9v Sam. It was getting late last night by the time i'd finished messing with it and maybe i made a gaff somewhere. hmmm
Apparently the E series is found in SSL consoles, It must be true I read it on the net somewhere.
Laters

[samhay]

If you want to try something else a little different, an active 'tilt' control might be worth a listen: http://headwize.com/?page_id=741 (Fig 10)

[Kipper4]

Thanks Sam intresting article and it has all the calculus too.

Bool you are a star man.

I have work to do !!!!!!!!!!!
most helpful

[Kipper4]

I think I have it now.
I just need to work out what I did by altering the values.
I'll post up a revised schematic later.

[Kipper4]

Here's what I have on the breadboard right now and it has lots of potential tones
The scoop (notch filter) was developed following the recent AMZ article. Thanks Jack
The shelving filter (lower down the schematic) is also from some ideas from the same article.
Let's hope I can do the image thing again
           

If that don't work go here

http://imageshack.com/a/img537/4818/uHfGz0.jpg
Thanks to Freppo for the input make up stage
It's worth bread boarding IMO

[bluebunny]

Let's hope I can do the image thing again

I think the picture you posted is a thumbnail (thank you, Imageshack).  So when you add "height=" to make it not-microscopic, you get the blurry pixellation.    Here's your picture, mate:

             

[Kipper4]

Cheers Marc