mid boost pedal recommendations

[tjdracz]

Just been watching that new Deluxe Big Muff demo: http://youtu.be/Jbx8vnj4i-U and I must say I do quite like the boost on sound! Pretty great change in tone.
As I've got fairly mid scooped pedals like Big Muff on Superfuzz on my pedalboard (okay, it's a lie. It's really just a floor), I reckon I could use some mid boost after them to get some more presence.
Any recommendations on that kind of pedals? What will get me in that territory that big muff demo shows? That control seems to have some nice options, guess it's just simple equalizer with variable center frequency, bass/cut and two choosable q's. Probably the article on geofex about simple equalizer would help me to make something like that but not sure if I can get my head around it!
So... Any suggestions for boosting my mids with some flexibility being a plus? Only diy options please ;) and no multiple band eq's. I'd like to keep it plain and simple, just mids

[Vince]

This?

http://tagboardeffects.blogspot.co.uk/2012/09/demeter-fat-control.html

[boratto]

It seems to be essential to fuzz cut through a mix in a live band situation. Do you use that in front or after fuzz box?

[tjdracz]

Yeah, I've seen Demeter and it seems like something I'd like to build. No variable  Q and frequency but should do for starters!

I'd suppose you put that after Fuzz to regain lost mids. As long as it's active design of course

[induction]

The Demeter Fat Control isn't bad, but it's more of a bass boost in my opinion. It's a fairly wide ranging low-end boost, centered around 300Hz. Here's a plot of the frequency response (blue lines) to a perfectly flat input (green line) at different settings of the Fat pot:


IvIark has a good vero for this, as Vince pointed out. Here's mine, in case anyone wants it. I included a clr for the led, and added a master volume pot so that you can control the frequency response separately from the volume boost:


For a more mid-centered boost, you could try the Blade preamp. It has a narrower hump, centered around 600Hz. See here and here for more info.





Since the original circuit was intended to be mounted inside the guitar, I updated the schematic to include power filtering and low-noise biasing (so it can be used with an adapter) and again added a master volume control, so that the frequency shaping and volume boost could be done independently:



I've built both of these into one box with a Naga Viper so I have bass, mid, and treble boosts in one pedal. I prefer the Blade for cutting through a mix, but a lot depends on the rest of your rig.

[boratto]

Does LM4580 = JRC4580?

[induction]

Close enough. Different manufacturers, I think. You can use any dual op-amp here and I doubt you'll ever hear a difference. Especially since it's just a booster and not a distortion pedal.

[tjdracz]

Thanks induction! That Zorro of yours seems perfect!

[induction]

Thanks. Credit goes to Blade, of course. It's a very nice circuit.

[tjdracz]

Actually, RG simple eq might be better for my needs Something like this:



RG himself suggested to start with about 0.033 for C1 and 0.01 for C2 and that should give range from about 400Hz to 1kHz
Also, instead of pot to change Q I thought of using SPDT to change between narrow and wide bandwith.

Might just add 100uF cap to 9V rail for filtering, but otherwise, I guess it will be good to go using 3/4 of TL074 :)

[tjdracz]

Okay, I've drawn a quick vero for that schematic. Can someone take a look and point out any mistakes? Can't see any but I'm tired, after couple of drinks and second pair of eyes is always helpful. Thanks guys!

[boratto]

What caps do you suggest for 3KHz (more attack) range?

[YerayM]

I don't think it's a good idea to left the unused opamp floating, look  at this: http://www.analog.com/static/imported-files/rarely_asked_questions/unused_op-Amp_article.html. Connect the non-inverting input to vref, the output to the inverting input and you are good to go.

[tjdracz]

boratto wrote

What caps do you suggest for 3KHz (more attack) range?

Had some problems with getting the maths right, as one of the equations on geofex website is wrong, but RG himself helped me to get my head around it at DIYSB forum and here's how the frequencies are calculated:

F=1/(2*Pi*Sqrt((R1*R2*C2)*C1) Where R1 is 470R resistor, R2 is the value of 51K and 1M pot in series and C2 and C1 are the caps. Resistors are in ohms and capacitors are in farads
So, with highest R2, around 1.05M, the frequency is lowest.
So, if my calculations are correct, C1 at 12nf and C2 at 10nF will give you range of about 650Hz to 3KHz

[tjdracz]

https://docs.google.com/spreadsheets/d/19bDMbeVJIKCFkvxbRyMaHCcM_ww1Oj7pWwG48Lv7ljs/edit?usp=sharing - here's the spreadsheet for calculations if anyone what's to have a look. Just plug C1 and C2 in farads and it will give you two frequencies.

I will redraw the layout to make sure that the unused opamp is not left floating, thanks!

[tjdracz]

Okay, here's the redrawn layout where Vref is connecting to non-inverting input of unused opamp and inverting input and outputs are connected together.
As before, can someone take a look and see whether everything is where it's supposed to be? It's my first stab at fairly compact layout so there are bound to be some mistakes, but again, can't see any really. Thanks!