I wired this up last night because I wanted a variable mid-scoop in a fuzz I was working on.
(http://i.imgur.com/YRLZ8.png) (http://imgur.com/YRLZ8)
This will go from a flat response to a 26 dB cut at about 400 Hz.
Moving the R's up will lower the scoop frequency (e.g. 22k ohm equals about 220 Hz)
Moving the R's down will raise the scoop frequency (e.g. 4.7k ohm equals about 1k Hz)
This is nothing revolutionary. I've even seen Bridged-T notch filters like this discussed on DIYSB's before but I thought I would post one that worked well for me.
Good luck!
EDIT: I think I'm going to try a 10k pot when I get home this evening. With the 10k at max it may not have super flat mids but I think it will have a better ratio of turn to Db reduction (if that makes any sense!).
I plan on getting a dual gang pot to experiment with making the notch frequency variable but I usually get in trouble when I have that much tonal control.
cool: i'll try this later...nice one bill.. :icon_cool:
Did you draw those resistors during an heartquake? :icon_lol:
MS paint with a mouse that sticks. That was my third try.
Quote from: alparent on November 29, 2011, 12:46:02 PM
Did you draw those resistors during an heartquake? :icon_lol:
No, I recognize those resistors, there a special log to current vairable resistance.
I will give this one a try , thanks
Quote from: Ice-9 on November 29, 2011, 03:14:42 PM
Quote from: alparent on November 29, 2011, 12:46:02 PM
Did you draw those resistors during an heartquake? :icon_lol:
No, I recognize those resistors, there a special log to current vairable resistance.
Also known as "Chicago" resistors.
Nice Bill. I'm kind of a fan of the mid-scoop. I think it harks back to the first time I heard a Boston tune :icon_smile:.
Pretty cool, thanks! Reminds me of the Mid-Notch that STM posted a little while back. Very similar low count type of thing.
@bill, just tried it...nice!...i swapped the 50k for a 10k...seems a better range over the pot sweep...nice!.. :icon_cool:
i bent my resistors to look like the diagram too... ;)
Quote from: deadastronaut on November 29, 2011, 04:49:13 PM
@bill, just tried it...nice!...i swapped the 50k for a 10k...seems a better range over the pot sweep...nice!.. :icon_cool:
i bent my resistors to look like the diagram too... ;)
I was just thinking a 10k would work better. Did you see my edit or did you try it on your own?
no i just tried it just now!....i used 10k resistors too....didn't have 12k's...
looking forward to the notch freq shifting version... ;)
Well I'm glad it worked for you.
I went home on my lunch break and tried it after a few of my dirt pedals and I thought it hollowed the sound out nicely.
Now we just need to find some 20k dual gang pots.
yeah just tried it after a distortion too, scooped it out nicely..very punchy..... :icon_twisted:
i'm not a fan of dual pots...limited knobs n all that....have you a scheme of the dual thingy then?...with wonky resistors too... ;)
Another variation is the bridged differentiator:
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=18696&g2_serialNumber=1)
Pot sweeps the frequency (although the bandwidth and attenuation will change as well).
My Beta Aivin HM-200 surprisingly has a mid-scoop control ( They call it a mid-cut control )
from 200Hz to 5KHz ... ;D
Although i could open it up and draw up a schem , i can't , 1 of the screw's chipped :icon_evil:
Quote from: Bill Mountain on November 29, 2011, 04:56:25 PM
Well I'm glad it worked for you.
I went home on my lunch break and tried it after a few of my dirt pedals and I thought it hollowed the sound out nicely.
Now we just need to find some 20k dual gang pots.
Hey, Nice stuff. I need to try this :)
btw dual gang pots, 20k. you meen a simple stereo pot?
If so here is one:
http://www.banzaimusic.com/Alpha-16mm-stereo-20k-lin.html
edit: ah ok, no you whant notch freq variable. then check the below mouser numbers.
QuoteI plan on getting a dual gang pot to experiment with making the notch frequency variable but I usually get in trouble when I have that much tonal control.
and here is some dual gang 20k pots on mouser:
Mouser Part No: 652-PTD902-10BAPB203
652-PDB182-K420K203B
652-PTD902-2215KB203
(http://uk.mouser.com/images/bourns/images/ptd90_lpart.jpg)(http://uk.mouser.com/images/bourns/images/pdb18_lpart.jpg)(http://cdn.banzaimusic.com/images/T/17286_th-03.gif)
Quote from: earthtonesaudio on November 29, 2011, 08:29:50 PM
Another variation is the bridged differentiator:
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=18696&g2_serialNumber=1)
Pot sweeps the frequency (although the bandwidth and attenuation will change as well).
Something about that looks so fun. I've got to try that.
Quote from: PereatMundus on November 30, 2011, 10:15:34 AM
Quote from: Bill Mountain on November 29, 2011, 04:56:25 PM
Well I'm glad it worked for you.
I went home on my lunch break and tried it after a few of my dirt pedals and I thought it hollowed the sound out nicely.
Now we just need to find some 20k dual gang pots.
Hey, Nice stuff. I need to try this :)
btw dual gang pots, 20k. you meen a simple stereo pot?
If so here is one:
http://www.banzaimusic.com/Alpha-16mm-stereo-20k-lin.html
edit: ah ok, no you whant notch freq variable. then check the below mouser numbers.
QuoteI plan on getting a dual gang pot to experiment with making the notch frequency variable but I usually get in trouble when I have that much tonal control.
and here is some dual gang 20k pots on mouser:
Mouser Part No: 652-PTD902-10BAPB203
652-PDB182-K420K203B
652-PTD902-2215KB203
(http://uk.mouser.com/images/bourns/images/ptd90_lpart.jpg)(http://uk.mouser.com/images/bourns/images/pdb18_lpart.jpg)(http://cdn.banzaimusic.com/images/T/17286_th-03.gif)
Seems like any of those would work. I just need to include some in my next parts order (which sadly won't be until after Christmas).
Quote from: earthtonesaudio on November 29, 2011, 08:29:50 PM
Another variation is the bridged differentiator:
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=18696&g2_serialNumber=1)
Pot sweeps the frequency (although the bandwidth and attenuation will change as well).
This seems cool and unpredictable in a crazy/fun/awesome way.
Quote from: Bill Mountain on November 30, 2011, 10:33:28 AM
Quote from: PereatMundus on November 30, 2011, 10:15:34 AM
Quote from: Bill Mountain on November 29, 2011, 04:56:25 PM
Well I'm glad it worked for you.
I went home on my lunch break and tried it after a few of my dirt pedals and I thought it hollowed the sound out nicely.
Now we just need to find some 20k dual gang pots.
Hey, Nice stuff. I need to try this :)
btw dual gang pots, 20k. you meen a simple stereo pot?
If so here is one:
http://www.banzaimusic.com/Alpha-16mm-stereo-20k-lin.html
edit: ah ok, no you whant notch freq variable. then check the below mouser numbers.
QuoteI plan on getting a dual gang pot to experiment with making the notch frequency variable but I usually get in trouble when I have that much tonal control.
and here is some dual gang 20k pots on mouser:
Mouser Part No: 652-PTD902-10BAPB203
652-PDB182-K420K203B
652-PTD902-2215KB203
(http://uk.mouser.com/images/bourns/images/ptd90_lpart.jpg)(http://uk.mouser.com/images/bourns/images/pdb18_lpart.jpg)(http://cdn.banzaimusic.com/images/T/17286_th-03.gif)
Seems like any of those would work. I just need to include some in my next parts order (which sadly won't be until after Christmas).
yea, same issue here I seriously just added a mouser order yesterday..
(and an expensive one, parts for a SloClone and about 5 Fx boxes... :icon_mrgreen:
So will have to wait to try this until Xmas or later for the next order.
However, as far as knobs to go with the dual gang pot I've always liked these below:
[Edit: that is of-course if you whant the dual/stereo pot with seperated control so you can use concentric knobs, , guessing NOT cause you wish to vary the both resistor values at the same time, no? ]
and here is a great hint. to make it nice.
the notch in both lower and upper control of the knob, take a drill and make a 1-2mm hole there instead, and glue a Led in that spot.
(http://uk.mouser.com/images/rohmsemiconductor/images/slc-22mg_1.jpg)
Mouser Part No: 755-SLC-22MG3F
755-SLC-22VR3F
755-SLC-22DU3F
these are GREAT for that due to their shape, able to press the flat top led through the hole and fasten it safely.
I've used this in the past when I REALLY whant to see the knob setting.
Its seriously cool looking and useful. particularly in stacked knobs.
(http://www.guitarfetish.com/assets/images/products/cochkn.jpg)(http://www.guitarfetish.com/assets/images/products/coknbl.jpg)
http://www.guitarfetish.com/Concentric-Chrome-Knobset_p_174.html | http://www.guitarfetish.com/Concentric-Knobset-Black_p_177.html
I would only need one knob for a dual gang pot. Are you thinking about a dual concentric?
Following up a previous post , does anyone have an idea how to remove a chipped screw , it's so badly chipped my largest screwdriver can't handle it .
Try this:
http://www.wikihow.com/Remove-a-Stripped-Screw
Quote from: Bill Mountain on November 30, 2011, 12:28:22 PM
I would only need one knob for a dual gang pot. Are you thinking about a dual concentric?
yeap yeap, I was thinking on other stuff there. My mistake.
[I'm a Swede, not a native English speaker. When I read "Dual" I thought about a pot where you'd use concentric knobs to control it independently.]
To me a Dual pot with locked levels of both shelves is called "stereo"-potentiometer, not "Dual"-potentiometer
"Dual"-pot > concentric independently controlled shelves
"Stereo"-Pot > locked equal level controlled *What would be used in this circuit*
"lost in translation" there
@bill: i was thinking seperate pots......not concentric or dual..i don't like any dual knobs/pots..but hey thats just me i guess!......schemo?.....just to play with..... ;)
Quote from: deadastronaut on November 30, 2011, 01:05:13 PM
@bill: i was thinking seperate pots......not concentric or dual..i don't like any dual knobs/pots..but hey thats just me i guess!......schemo?.....just to play with..... ;)
Isn't the point to have one regular 50k-10k pot for the scoop control.
and then instead of >Both< the 12k resistors have one. locked dual pot. Stereo pot.
and that would let you have 1pot for scoop and 1 pot for freq.
that was How I understood it anyway.
*just got lost in my own thoughts in the second to last post I did anyway.
Edit: for 2 pots for the 12k resistors (one for each) would be useless no? or?
Quote from: deadastronaut on November 30, 2011, 01:05:13 PM
@bill: i was thinking seperate pots......not concentric or dual..i don't like any dual knobs/pots..but hey thats just me i guess!......schemo?.....just to play with..... ;)
Just 2 pots. Frequency & Depth
I don't have time to do a schematic right now but just replace the 2 x 12k resistors with a dual gang 20k linear pot wired as two separate variable resistors. Maybe put a 2.2k in series to set a minimum notch frequency.
I can draw something tonight and figure out some usable ranges for the variable notch frequency.
Quote from: Bill Mountain on November 30, 2011, 01:16:01 PM
Quote from: deadastronaut on November 30, 2011, 01:05:13 PM
@bill: i was thinking seperate pots......not concentric or dual..i don't like any dual knobs/pots..but hey thats just me i guess!......schemo?.....just to play with..... ;)
Just 2 pots. Frequency & Depth
I don't have time to do a schematic right now but just replace the 2 x 12k resistors with a dual gang 20k linear pot wired as two separate variable resistors. Maybe put a 2.2k in series to set a minimum notch frequency.
I can draw something tonight and figure out some usable ranges for the variable notch frequency.
Good then I atleast understood you corretly, even though I completely messed up my part of the communication and got lost in other thoughts :icon_mrgreen:
thanks again for your Idea, it seems VERY interesting..
...will have to go through boxxes tosee if I can't find parts for it at home after-all.
thanks
no worries bill, i'll mess around tomorrow....no time today/night...
btw, does anyone know how to fix an oil sensor on a 1993 -000 skoda fabia 1.4...with really nice patterened seats?....ooopps wrong forium!!!!.... ::) :icon_mrgreen:
I meant to say that you should put a series resistor with the pots to keep the pots from shorting out but doing so will also allow you to set the max and min frequencies for the control.
I went to edit my post and it had already been quoted. I should learn to proof read stuff before I post.
ha ha...no worries... :icon_redface:
edit: any skoda tips anyway?.... :icon_mrgreen: :icon_mrgreen: :icon_mrgreen:
Quote from: deadastronaut on November 30, 2011, 01:23:10 PM
no worries bill, i'll mess around tomorrow....no time today/night...
btw, does anyone know how to fix an oil sensor on a 1993 -000 skoda fabia 1.4...with really nice patterened seats?....ooopps wrong forium!!!!.... ::) :icon_mrgreen:
Try Here:
http://briskoda.net/forums/
lol...yeah i'm a member....i was only joking..... ;D
Quote from: deadastronaut on November 30, 2011, 01:26:40 PM
lol...yeah i'm a member....i was only joking..... ;D
So was I.
One of my other forums has requested that when making jokes you must put a :) in order to keep from offending members lacking any ability to detect humor/sarcasm.
:icon_mrgreen:
Hey Bill or Deadastronaut, how much insertion loss does this mid cut circuit have?
When I simulated it using http://www.falstad.com/afilter/ there was zero loss. Also, when I put it after a buffer I couldn't hear any loss but when I plugged my passive bass straight in it seemed to dull the tone some which is probably due to the 6k input impedance that my guitar sees.
It seems like a good compromise might be a push-pull pot, no?
http://www.bestbassgear.com/pots.htm (http://www.bestbassgear.com/pots.htm)
I mean, at least how its listed here a 25k DPDT push-pull is a 20$ purchase (!!!), but the benefit would be being able to switch between 12k and maybe the 4.7k mentioned earlier. Wiring should be pretty straightforward. It would certainly add to the versatility of the circuit... going from more of a rock/metal cut to more of a Big Muff/fuzz style cut, that is.
I like that idea instead of using two pots. Personal preference, I like wiring it all to the pot instead of using space on the circuit board. I'd also rather have a concentric knob rather than two, if I had to choose. Again, in the interest of saving space, more "bang for your buck", fewer knobs to clutter a pedal.... or freeing up a knob to do something else!
Quote from: sault on November 30, 2011, 02:43:22 PM
It seems like a good compromise might be a push-pull pot, no?
http://www.bestbassgear.com/pots.htm (http://www.bestbassgear.com/pots.htm)
I mean, at least how its listed here a 25k DPDT push-pull is a 20$ purchase (!!!), but the benefit would be being able to switch between 12k and maybe the 4.7k mentioned earlier. Wiring should be pretty straightforward. It would certainly add to the versatility of the circuit... going from more of a rock/metal cut to more of a Big Muff/fuzz style cut, that is.
I like that idea instead of using two pots. Personal preference, I like wiring it all to the pot instead of using space on the circuit board. I'd also rather have a concentric knob rather than two, if I had to choose. Again, in the interest of saving space, more "bang for your buck", fewer knobs to clutter a pedal.... or freeing up a knob to do something else!
Some one find a push/pull-concentric-with-a-single-10k-and-a-stereo-20k-pot.
http://www.aronnelson.com/gallery/main.php/v/WGTP/Midrange+Madness.jpg.html
I've been messing with this one for several months. It does all size notches from 300Hz to 1500Hz. ;)
Well look at the pedal in my sig ... It uses another pot :icon_mrgreen: