Portable parametric EQ?

[st5150]

Guys, I'm looking for a portable parametric EQ that can fit in an Altiods can. Are there plans for one out there?

 

[setmenu]

Perhaps this will be of help:


http://headwize.com/projects/showfil...=equal_prj.htm


Setmenu

 

[rickcr42]

I don't think it is do-able unless you want only one band of eq.
A parametric equalizer uses three controls for each band of adjustment

1-frequency (where the adjustment falls in the audio spectrum)
2-bandwidth(how wide or shallow the frequency band-narrow would be a notch or peak)
3-amplitude (the amount of boost or cut in the selected frequency)

since the volume pot is usually the single largest part in an amp (not including the batteries) it can get crowded REALLY fast both inside and out.

At most you could fit two bands of eq in a candy tin and that would still mean six controls plus power and bypass switching.Add to that the opamp required for each band plus the output opamp and you would be looking at one quad and one dual opamp just for the two bands.

A possible option could be a bass-mid band semi parametric-treble control.Still a tight fit but possible

 

[st5150]

Thanks guys. I gave a more general overview about my goals here: http://www6.head-fi.org/forums/showt...68#post1014568


As for the pots being the limiting factor, I'm prefectly okay with using small board mount pots and a small screwdriver to adjust them. I doubt I'll be changing the settings often.

 

[skyskraper]

slightly on but still not really topic, have any of you built stereo parametric eq's before? id like to have one to run in the fx loop of our dj mixer. so that we can sweep the frequency bands...... i havent really found a good schematic for one yet...... two bands would be nice, 3 nicer. size wouldnt be a concern

 

[intlplby]

http://www.gyraf.dk/gy_pd/gyraf_diy.html

CALCREC EQ

http://www.gyraf.dk/gy_pd/calreq/calrec.htm

 

[digi01]

try LM1036,it is simple.
http://www.national.com/pf/LM/LM1036.html

 

[skyskraper]

cheers, ill check out the links

 

[rickcr42]

digi,that chip makes it simple but the sound is less than ideal.

The best parametric out there is the S.A.E and the plans are floating around somewhere on the net but where i can't remember.
If you find the schema for it just substitute rotary pots for the very hard to find and not cheap slide pots.

I almopst recall others but again not from where.

i can get back on this later.

 

[skyskraper]

looking at the lm chip info it seems to be a traditional fixed frequency circuit. not really what im looking for but thanks for the link, i' might add one to my pimeta (or something with slightly better snr

)

the gyraf looks up my alley, it's a mono unit so would simply doubling the circuitry then controlling it from dual pots instead of normal ones yield stereo operation?

also would it be hard to cut it down to simply 3 band operation?