Single frequency boost

[omt]

What i want to do is build a one band eq that can boost or cut around 1100 Hz can anyone point me in the direction of how to do this?

[R.G.]

How tight a range around 1100 Hz (i.e. what Q value for the filter?).

The simple thing is to make a one-band graphic EQ either of the inductor/capacitor sort or a constant-Q version. Both can be done without real inductors, but the constant Q version is probably better for higher Qs, above 2-3.

[omt]

If a a q-range is what i think is what i think it is i am looking for a range on 100-200 hz

[Ge_Whiz]

State-variable filter.

[Mr.Huge]

Here's an oldie but a goodie!
Now, this only boosts...

http://aronnelson.com/gallery/album12/Freq_booster

-Mr. Huge

[phaeton]

Here's an oldie but a goodie!
Now, this only boosts...

http://aronnelson.com/gallery/album12/Freq_booster

-Mr. Huge

OMG!! Craig with hair! 

[Mark Hammer]

OMG!! Craig with hair! 

And no beard...
It's good, simple, flexible and quiet, but it doesn't offer tons of boost.  In fact it provides less than a typical graphic EQ slider.  If that's enough, go for it.

[phaeton]

OMG!! Craig with hair! 

And no beard...
It's good, simple, flexible and quiet, but it doesn't offer tons of boost.

Craig's beard, or Craig's circuit?

Btw, I assume someone just as easily drop in a TL0?2 or similar instead of the LF353....  And/or use a quad chip- build this one one half and use one of the others for another boost stage, etc..

[Mr.Huge]

This is one of the first projects I build as a young lad!
-Mr. Huge

[Mark Hammer]

Btw, I assume someone just as easily drop in a TL0?2 or similar instead of the LF353....  And/or use a quad chip- build this one one half and use one of the others for another boost stage, etc..

Good point.  In fact, there is no reason why several stages couldn't be cascaded with the option to apply boost all over again at the same centre frequency.  You can pretty much string 'em out as far as you want, within reason, and give them the same boost frequencies or different ones or both..

Grab yourself a TL074, and wire it up for an input buffer, two cascaded frequency boosters and a Dist+ clipper at the output.  It'd be a helluva tone monster, with nice ZZ Top "gronky" sounds at the touch of a toggle or stompswitch.

In fact, this thing that I made last summer and presented to David Lindley is a combination tube sound fuzz and frequency booster.  I had the extra op-amp just sitting there.  I figured "What the hell".
http://img.photobucket.com/albums/v474/mhammer/49-er-A.jpg
http://img.photobucket.com/albums/v474/mhammer/Forty-Niner.gif

You will note that the unit has a bypass for the whole thing and an engage/disengage switch for the booster. (I used a SPDT but a 3PDT could engage 2 boosters and a status LED).  Gives a lot of nifty sounds, not the least of which is an "instant Mercury Blues".

[RDV]

You mean Craig doesn't look like that anymore? I must be really old now.

RDV