IC-based one knob tone control

[aron]

I gotta try it along with the 1.5H inductor mid control.

http://members.tripod.com/roymal/ReverbTone.htm

[Mark Hammer]

So does this behave sort of like the "ultimate BMP tone control", but without the mid notch in the centre pot position?

[toneman]

that's what it looks like, Mark.
Now, to make it 9V unipolar......:shock:
staytoned
tone

[Chico]

Aron:

Thanks for sharing this circuit.  I had not seen that site before.  

Just FYI, there are other, similar topologies that appear to perform the same function as that posted above.  For example, check out the "tilt" control at headwise.

http://www.headwize.com/projects/showproj.php?file=equal_prj.htm

The tilt control looks a little different, but functions in the same general manner, that is, a wide range, generally symettrical adjustment.

You can also see variations of this circuit scattered throughout numerous solid state bass amplifiers made in the 80s.

I have built a variation of the headwise "tilt" and it is more effective than you may think.  I think of it not so much as an "EQ" but as a "room balance".  If the room you are in is a little woofy, simply "tilt" your tone a little brighter and vise versa.  Its a great adjustment that does not muck with your overall tone.

Another cool thing is that it is relatively easy tweak out.  For example, again with reference to the headwise tilt, I added a blocking cap to roll off the lows, and strapped a small cap (100pf) across the inverting input to output to roll off the high frequencies.   It is also easy to relocate the "pivot point" of the tone control.  (I shifted mine down to around 750hz).

Toneman:  As a starting point, to make the circuit 9v compatible, try biasing the noninverting input of the opamp to 4.5v instead of ground.  Connect the +supply to 9v and the -supply to ground.  Just watch your signal levels with only 9v.

Best regards

Tom

[Mobisimo]

Aron, this mid control sounds nice.  Do you know where can I find the schematic?
Also, has anyone made any versions of these into a guitar tone control that fits into the body?  I have a strat (which I love) but I really think I could get a lot more out of it if I had something better than TBX or low-pass tone controls.  Practically speaking, would the impedances work without some adjustment?

Aaron

[aron]

I will have the mid EQ up as soon as I get my inductor. BTW: I ordered a few extra in case it works.

Aron

[Renegadrian]

what an old topic...more than 10 years...
anyway, I stumbled on the roy mallory page (link above) and tried that circuit, tl071, fed with a voltage divider to pin 3, pin 4 to ground pin 7 to 9V. got a 1µ at the input and the output. frequency caps are 47n as suggested.
now, I got a very low output (and yeah I got it, signal goes thru res and caps directly to the output) but no major tone tilt, and a drastic volume drop. Am I missing something?!
I may post the vero I used for that if needed.

[GibsonGM]

Going to watch this one.....it looks like a useful snippet 

Are you feeding it right from the guitar, Adriano?  Maybe it needs a gain stage first? 

[Scruffie]

It's just a Tilt EQ, a buffer up front should suffice.

Have a look at the schematic for the Diamond Compressor, you'll see it used there at 9V single supply, albeit with some additional superfluous components.

[Renegadrian]

yes straight from the guitar...signal is too low, I was expecting it to act like a buffered tone, as it says it has a gain of one...guess I have to use a 072 and use the other part as buffer then.

[samhay]

Here's another recent implementation:
http://www.diystompboxes.com/smfforum/index.php?topic=112900.0

The tilt EQ has low input impedance, so definitely needs a buffer of some sort.

[PRR]

The naked tilt has input impedance like 20K or 2K.

When fed from an opamp, as in the hi-fi world, that is fine.

Guitar has internal impedance 5K to 200K. When loaded in much-lower impedance, output is way down. The unity-gain amp passes what it gets; but it isn't getting it all.

As opamps generally come in 2-packs, a basic buffer seems best. (And you already have the voltage divider needed for one-battery operation.)

[Renegadrian]

made another layout, basically the first one adapted for a dual ic using the first as a buffer.
not bad, nothing so impressive but it works - I followed roymallory schem, with a voltage divider to pin 3 and 5, pin 4 to ground pin 8 to 9V. got a 1µ at the input and the output. frequency caps are 47n as suggested. resistors as the original 2.2k and 10k. it's fun to try after all you have like 4 caps and 6 resistors...

[Renegadrian]

Actually I can't get a perfect sound out of it...I got a 250k trimmer in the buffer loop to set the gain of it, with lower values I get distorted and fuzzy sound at some points of the pot's travel. setting the trimmer at circa its middle point, output is loud but too gainy...