Clean Boost with Midrange Tone Control Circuit needed

[jsrfo]

I am looking for a nice, simple clean boost on the order of the GGG Stratoblaster, only with the ability to push the midrange like a TubeScreamer. Any suggestions on a circuit, or a sketch of how to add tone to a Stratoblaster? I'm looking to compliment a nice OD, just to give the midrange push when desired.

[goulashnakov]

Here's one I've been experimenting with:

http://www.muzique.com/schem/projects.htm

scroll down to the "Muff Boost."  If you omit the diodes and c3, and change c1 (input cap) to 0.022 uF, it gives a nice midrange boost that is fairly clean unless you pick hard, but still sounds good when using it to drive an already distorted amp.  When I sim'd it in SPICE, it shows a fairly sharp peak at around 500-600hz.  Its low input impedance, combined with the 0.022u input cap, rolls off the highs and lows without the need for additional filtering.  To my ears, it sounds fantastic with both single coil and humbucker pickups, with the pickup's tone knob at any setting.

If you want a little more gain from the muff boost, you can add a capacitor in parallel to R4 (the 150 ohm).  Anything from 0.22uf to 22 uf -- play around to see what sounds best to you.

If you prefer a high input impedance like the stratoblaster, you could easily tack on a simple bandpass filter to the end of it.

[jsrfo]

OK, that may work and is simple enough. I know a lot of this is elementary to most contributors here, but any advice on taking that muff boost and adding a variable tone control? Not one that is basically a treble cut circut, but one that will push those midrange frequencies. Rolling off the highs and the lows is an option I guess.

I did one little circuit with two op amp stages, using one up front, and one after the tone control, but I could never get it tuned exactly right to my ears. It was basically a three band with the bass and treble at set resistances instead of pots and just a mid band pot.

[Mark Hammer]

Jay Doyle has a circuit back in 2001 called the Timbre Box ( www.diystompboxes.com/pedals/schems/TimbreBox.pdf ).  It was a low-noise all-discrete (J201, 2N5087, 2N5089) op-amp that used a gyrator circuit to provide a mid-boost, or boost at whatever frequency you wanted.  Jay provides numerous examples one could easily extrapolate from, in addition to a PC mask and parts layout.  The design permits one to add up to 2 additional cut-boost sections on the same PCB.

[Gus]

[Ben N]

How about the Anderton Frequency Booster? I don't have a link off-hand, but it must be around on the web somewhere. If not, PM me.

[Mark Hammer]

It's over at AMZ.

[askwho69]

Hello mates... any changes if we power it 9 volts and single supply?

[samhay]

A little hard to tell, but it doesn't look like it has a huge amount of gain, so it should work fine at 9V.  You will need to add an input cap and then bias up to 4.5V. The on/off to ground will either need to go to the bias voltage or have a cap to ground.

[askwho69]

I saw the complete circuit schematic . .  this one is lacking

Thanks for the reply

[Mark Hammer]

If you're talking about the Anderton circuit, Jack/AMZ doesn't show the whole thing.  If you look below, you'll see that it is originally intended to run off +9v.  One can easily add a feedback resistor and ground leg to IC1 to turn it from a unity-gain buffer, into a gain stage.  Stage 2 also adds some gain (I know, because I've built one), so all you really need to get out of Stage 1 is maybe a gain of 5x or so to have some serious oomph from the whole circuit.  A 47k feedback resistor between pins 1 and 2, and a 10k resistor between pin 2 and point C (Vref), would do the job nicely.

[tca]

Here's one I've been experimenting with:

http://www.muzique.com/schem/projects.htm

scroll down to the "Muff Boost."  If you omit the diodes and c3, and change c1 (input cap) to 0.022 uF, it gives a nice midrange boost that is fairly clean unless you pick hard

I don't see that midrange boost in my sims... (edit: probably I didn't simulate correctly the load of the circuit on the guitar pickup).

But you could try a Muffer with Garnet type tone control with a smaller input cap. P1 is tone and the 100k output resistor is the volume pot (max pos.).

[askwho69]

Thank you so much for posting the layout and schematic Mark Hammer 

[pinkjimiphoton]