# 6-band EQ



## Robert




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## falzhobel

Ooooohhhh. Sweeeeet !


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## Knotty Pine

How do you drill for sliders?


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## daeg

Slider Pots? Are you some sort of mad-man?


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## Barry

Knotty Pine said:


> How do you drill for sliders?


That's what the face plate is for


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## Robert

Knotty Pine said:


> How do you drill for sliders?



I'm working with Tayda on a pre-drilled enclosure right now.  

But as Barry said, the faceplate makes it "easy" to do by hand....     ?


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## Caedarn

Nice! I bought a PCB a while back for a 6 band EQ that uses rotary pots, but I really prefer the sliders! Cant' wait to build this!


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## Nostradoomus

I wish more pedals used sliders like the Ibanez Echo shifter, so easy to manipulate with your foot (not in this case though  )


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## Gordo

That's very slick.  Nice job on the sandwiched PCBs.  The Tayda option would be nice, although with a faceplate that hides everything even hacking wouldn't be the worst.  I'm kinda fearless after dremel-ing out the window for the Mimir's Well.  Hated every second of it....figuring that I'd screw it up.


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## zgrav

I think having a pre-made enclosure could be a reason not to use the faceplate.  Interesting project.


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## Robert

zgrav said:


> I think having a pre-made enclosure could be a reason not to use the faceplate.  Interesting project.



I'd recommend the pre-made enclosure when it's available even if you _are _using the faceplate... Unless you just like to torture yourself. ? 

The middle 4 slots were relatively easy, but the two outer slots have to be fairly precise because of how close they are to the edge of the faceplate.
There isn't a lot of room for error in this build, a couple millimeters can ruin your day.


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## zgrav

I agree the ready-made enclosure seems like the best choice, and working out having them available from Tayda was a great idea.  Since the screws on the pots often hold the faceplate in place, is there an equivalent for this project?  Or will some adhesive be used to keep the faceplate on the box?


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## phi1

Take a look at the pic again


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## Robert

The four screws in the faceplate serve two purposes;   they keep the faceplate on and they hold the slide pot module in place.


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## benny_profane

How's the discussion with Tayda in re drilling going? Would they provide rectangular drilling, or would it be a series of circular drills?


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## zgrav

Robert said:


> The four screws in the faceplate serve two purposes;   they keep the faceplate on and they hold the slide pot module in place.


Schooled!  : ^ )


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## Robert

benny_profane said:


> How's the discussion with Tayda in re drilling going? Would they provide rectangular drilling, or would it be a series of circular drills?



It'll be slotted / milled.   The corners will most likely be rounded, but it shouldn't be an issue on a 2mm slot.

I should have a prototype enclosure soon and will post pics.


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## benny_profane

Robert said:


> It'll be slotted / milled.   The corners will most likely be rounded, but it shouldn't be an issue on a 2mm slot.
> 
> I should have a prototype enclosure soon and will post pics.


Very cool. This is shaping up to be very interesting. That’d be cool if they expanded the slot/mill option to custom jobs as well. It’d open up slide pots and switches (and rockers!) to a wider DIY audience.


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## youngflier

This is an awesome project! A quality EQ has always been one my DIY wishlist and enclosure/faceplate combo is fantastic.


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## benny_profane

I imagine that this is probably far too far along to integrate new features, but an overall level control would be a great addition here.


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## Robert

benny_profane said:


> I imagine that this is probably far too far along to integrate new features, but an overall level control would be a great addition here.



It wouldn't be an easy fit in this one, the slide pots go from wall to wall in the enclosure with no room in between.

If a 10-band version happens it'll definitely have one.


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## benny_profane

Robert said:


> It wouldn't be an easy fit in this one, the slide pots go from wall to wall in the enclosure with no room in between.
> 
> If a 10-band version happens it'll definitely have one.


Ten-band would be very cool. Any plans for a parametric EQ, or do plan on stopping with a graphic?


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## zgrav

Why does the box have two slots for each band?  Is it going to be a stereo output?  It only looks like there is one slider per channel in the pic from the back side.


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## benny_profane

zgrav said:


> Why does the box have two slots for each band?  Is it going to be a stereo output?  It only looks like there is one slider per channel in the pic from the back side.


You’re seeing the slider without a knob set in the middle position I believe.


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## benny_profane

@PedalPCB I see this is now available. Any word on the Tayda pre-drilled enclosures?


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## Robert

benny_profane said:


> @PedalPCB I see this is now available. Any word on the Tayda pre-drilled enclosures?



Not yet, unfortunately.    

They were having some issues milling the slots properly at 2mm and were going to try moving up to 3mm and send samples of both.

I'm trying to keep the slots as tight as possible for those who _don't_ want to use the faceplate and prefer to do their own graphics.


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## benny_profane

Robert said:


> Not yet, unfortunately.
> 
> They were having some issues milling the slots properly at 2mm and were going to try moving up to 3mm and send samples of both.
> 
> I'm trying to keep the slots as tight as possible for those who _don't_ want to use the faceplate and prefer to do their own graphics.


Gotcha. That sounds like a good solution (if possible). Keep us updated with developments!


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## Musicislife6984

Are there any build docs for this yet?


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## Jbanks

@PedalPCB are there links to the specific sliders that should be used? Hopefully Tayda has them so we can get the enclosure and sliders all in one. Thanks!


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## BurntFingers

Jbanks said:


> @PedalPCB are there links to the specific sliders that should be used? Hopefully Tayda has them so we can get the enclosure and sliders all in one. Thanks!



Probably some of these bad boys:





__





						Slide Potentiometers - Potentiometer / Variable Resistors
					






					www.taydaelectronics.com


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## Robert

I'll get the build docs up as quickly as possible.   This one has a couple parts that aren't immediately obvious. (hex spacers)

These are the slide pots I used: (B50K with center detent)








						50K OHM Linear Taper Slide Potentiometer PCB Mount Plastic Shaft Lever Height: 15mm Center Click
					

ALPHA - Get It Fast - Same Day Shipping




					www.taydaelectronics.com
				




Some folks have suggested using W20K instead of B50K but I haven't personally tried them...


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## zgrav

Thanks for the link to the sliders.  What size hex spacers and how many are needed for the board?


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## Robert

4 x Standoff M3 x 8MM (A-1243) 
4 x Screw M3 x 4mm (A-1249)
4 x Screw M3 x 6mm (A-1250)
1 x 2.54mm Pin Header Strip (A-197)


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## zgrav

thank you.


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## niketplos

Do you know if there are any caps or covers that will fit the slider ends? I was going to paint them but didnt know if there was something out there that would work. 

Put it together tonight btw and you did an awesome job on the boards! Just waiting for the pre-drilled enclosure.


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## Robert

I think the pot shafts stick up a little too high for mixer-style caps to sit properly but I've seen pictures of the rubber toggle switch style caps used on them.


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## Jbanks

Any update on the pre-drilled enclosures from Tayda?


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## Robert

Jbanks said:


> Any update on the pre-drilled enclosures from Tayda?



No updates yet,  I'm still waiting to hear back about the tooling change.


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## zgrav

[





[/QUOTE]
Those toggle switch caps look like a good solution.  Impressive to see 8 different colors as well.  And thanks for posting the build docs.  I'm going to try to use my drill and dremel to see how the enclosure comes out.  Glad I have the faceplate to go with it.  : ^ )


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## Cucurbitam0schata

Would be be OK to blast one square hole in the center of the enclosure, instead of (a) waiting for the pre-drilled enclosures or (b) attempting to make the slits? That way there's more room for error? I figure the faceplate will be stiff and sturdy enough on the top... Might be a fool hardy work-around.


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## Robert

Cucurbitam0schata said:


> Would be be OK to blast one square hole in the center of the enclosure, instead of (a) waiting for the pre-drilled enclosures or (b) attempting to make the slits?



Yep, if I had to do it over again this is what I would do.    This _might _be the way Tayda ends up having to do it as well.  

The new Mesa pedals are all done like this too, FWIW.... One universal enclosure with a big cutout and a faceplate for the controls.

Just make sure you don't drill past the edge of the faceplate, there isn't a lot of room for error there.


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## zgrav

.... and don't accidentally drill out the parts where the 4 mounting screws attach.


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## Robert

zgrav said:


> .... and don't accidentally drill out the parts where the 4 mounting screws attach.



Absolutely do not, this is the only thing holding the PCB assembly into the enclosure.


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## Robert

Just an added note (I'll add this to the build docs shortly as well)....

Assembly is much easier if you go in this order:

Install faders onto the fader module
Install all components onto the main module
*Solder pinheaders onto the fader module*
Mount fader module into the enclosure using hex spacers / screws
_6mm screws go through the face of the enclosure, 4mm screws go inside the enclosure_
Install main module onto pinheaders and solder in place
Wire it up
Equalize.   ??????


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## zgrav

FYI  -- just checking the fit for the PCB inside my Tayda 125b Enclosure compared to the template in the build docs.   The outer edges of the fader module do not fit inside the hole posts in the enclosure, and that stops the mounting holes from lining up with the template.  Looks like I will bump that part of the template down about 1/8th of an inch closer to the footswitch.


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## Robert

I'll pop mine open and snap a pic as soon as possible, I used a 125B from Tayda with this template.


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## zgrav

I see what you mean about a very snug fit inside the case.  I think I am going to mark the screw holes from the inside using the mounting holes on the fader board as a guide.  And then line the template up with those holes.  That seems about as fool proof as I can try to make it.


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## Robert

Yep, do what you're most comfortable with.  

One thing to keep in mind is that the sides of the enclosure (and screw supports) are slightly tapered, and the PCB isn't going to sit all the way in the bottom of the enclosure.

Temporarily attach the hex standoffs to the fader board and drop it in the enclosure to get an idea of where it's going to sit.


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## zgrav

thanks.


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## Barry

I have a couple enclosures fails from when I first started drilling my own I can experiment with and possibly salvage!


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## Mothman

What happen if I use common potentiometers?


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## Robert

Mothman said:


> What happen if I use common potentiometers?



I've considered a standard 6-knob version with regular pots.    

You could wire them up to the existing board but it'd be a little messy, it'd be much better with a dedicated PCB.


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## dmnCrawler

Robert said:


> I'll get the build docs up as quickly as possible.   This one has a couple parts that aren't immediately obvious. (hex spacers)
> 
> These are the slide pots I used: (B50K with center detent)
> 
> 
> 
> 
> 
> 
> 
> 
> 50K OHM Linear Taper Slide Potentiometer PCB Mount Plastic Shaft Lever Height: 15mm Center Click
> 
> 
> ALPHA - Get It Fast - Same Day Shipping
> 
> 
> 
> 
> www.taydaelectronics.com
> 
> 
> 
> 
> 
> Some folks have suggested using W20K instead of B50K but I haven't personally tried them...



I believe the PTL30 Bourne slide potentiometer with LED from Mouser would work as well. Correct? These would let me see the setting in the dark or on stage.


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## Robert

The board wasn't designed for the LEDs.    It could be done in a future revision though, I've considered it.


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## dmnCrawler

Robert said:


> The board wasn't designed for the LEDs.    It could be done in a future revision though, I've considered it.


Right, no power.... it would have to be a hacky mod right now. Which would be tough in such a tight space. That quick reply saved me $20.


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## jubal81

dmnCrawler said:


> Right, no power.... it would have to be a hacky mod right now. Which would be tough in such a tight space. That quick reply saved me $20.



I looked at those, too. Don't think the pinout matches at all.


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## dlazzarini

Looks like my run of stuffing builds into a 1590b has come to an end.


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## Robert

dlazzarini said:


> Looks like my run of stuffing builds into a 1590b has come to an end.



How about a 4-band EQ?     ?


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## BurntFingers

Do you think you could fit a 6 knob eq into a 125b? Just using regular pots I mean. I'm curious if the 2 x 074s would be able to fit along with the switch and gubbins. Maybe 1/8w resistors? Not as cool looking as sliders though.


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## Robert

BurntFingers said:


> Do you think you could fit a 6 knob eq into a 125b? Just using regular pots I mean. I'm curious if the 2 x 074s would be able to fit along with the switch and gubbins. Maybe 1/8w resistors? Not as cool looking as sliders though.


Yep I don't think it should be a problem.     Worst case scenario we can just make a 16mm pot module for the existing signal board.


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## BurntFingers

Robert said:


> Yep I don't think it should be a problem.     Worst case scenario we can just make a 16mm pot module for the existing signal board.


Yeah good call. I might have a play around. Add a level control and it's a ge7 that doesn't suck.


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## dlazzarini

Robert said:


> How about a 4-band EQ?     ?


I’d rather stick with 6. I’ll admit defeat. I’m perfectly happy with that


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## BurntFingers

Just wondering is this the same as the mxr 6 band?


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## Robert

BurntFingers said:


> Just wondering is this the same as the mxr 6 band?



It's based on the older blue MXR 6-band EQ.


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## BurntFingers

Robert said:


> It's based on the older blue MXR 6-band EQ.



Gotcha thanks. Presumably the 10 band is the same but with a few more stages.


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## niketplos

Any updates on a pre-drilled enclosure?


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## megatrav

Pre-drilled enclosures or a version with Pots would be awesome!


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## Mike McLane

Tom Bukovac had some outfit re-engineer the Boss GE-7 to concentrate the EQ bands in the mid range. . . . 








						XTS Midrange Graphic Modded GE-7
					

The XTS Midrange Graphic Mod was developed with Tom Bukovac. The session ace wanted an eq pedal centered entirely on the guitar's midrange frequencies. To that end, we take a full-range Boss GE-7 graphic eq and modify the frequency bands to focus on critical midrange frequencies. With the...




					www.xacttone.com
				



.  A mod that subs parts to accomplish the same things (like the different "flavors" for the Ice Scream) would be very cool.


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## Robert

Mike McLane said:


> Tom Bukovac had some outfit re-engineer the Boss GE-7 to concentrate the EQ bands in the mid range. . . .



That sounds like exactly the sort of thing I'd be interested in.


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## Robert

megatrav said:


> Pre-drilled enclosures or a version with Pots would be awesome!











						6-Band EQ (Potentiometer Version) - PedalPCB.com
					

6-Band EQ




					www.pedalpcb.com


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## Mike McLane

If you did the "mid-range thing" could it be possible to leave one band for an overall volume slider (like the GE-7) or would that require a completely different schematic/PCB?  I was thinking in terms of a booster that could kick in to hit your drive pedals with some additional volume and mid-range for solos.


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## yazooligan

Robert said:


> 6-Band EQ (Potentiometer Version) - PedalPCB.com
> 
> 
> 6-Band EQ
> 
> 
> 
> 
> www.pedalpcb.com



Awesome! The EQD Tone Job is my favorite EQ/sweetener, and I’m just not into faders for my pedals, so this is definitely one for me!


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## daeg

Definitely will build the Potentiometer version, but with modified bands. The XTS GE-7 mod looks interesting.

400hz | 800hz | 1.2khz | 1.6khz | 2.0khz | 2.5khz | 4.0khz


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## Robert

daeg said:


> Definitely will build the Potentiometer version, but with modified bands. The XTS GE-7 mod looks interesting.



I want to try this one too. =)


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## Gordo

So if the first five bands are Sallen-Key Hi Pass Filters the parts values would change to:

400HzC568nC6220nR1122k800HzC733nC8120nR1322k1.6KHzC915nC1068nR1520k2.0KHzC1112nC1256nR1724k2.5KHzC1310nC1439nR1922k4.0KHzC1647nR20820r

But how is the frequency determined in the last band???


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## Gordo

What am I missing?  Is the last band a simple Hi Pass? and if so the math should come out to 2.0Khz but I know the stock design is 3.2KHz...


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## daeg

Gordo said:


> What am I missing?  Is the last band a simple Hi Pass? and if so the math should come out to 2.0Khz but I know the stock design is 3.2KHz...


Yeah, if you look at the MXR 6-Band EQ schematic, it's not a gyrator. It's just a LPF placed across the differential amplifier.

Thanks for figuring out the bands. I really do like the idea of a mid-focused EQ and the 6-band might be the right platform for it.


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## p_wats

Hmm. The potentiometer version is making me think of a stereo build, using two boards, but a single set of dual-gang pots. ?


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## Robert

p_wats said:


> Hmm. The potentiometer version is making me think of a stereo build, using two boards, but a single set of dual-gang pots. ?



It might be useful to keep them separate so you could stagger the two EQs differently on each side.


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## Gordo

Was a bit of a bugger trying to get the two boards apart and then remove a bunch of the caps and resistors but I've changed it all over to the XTS frequencies using the values I posted above and it sounds really nice.  I'm looking forward to getting this on my live rig but am not playing for another couple of weeks.


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## BuddytheReow

Would it be possible to add a level control as well like on a Boss EQ for future builds?


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## beachbum

Tayda seems to have been out of the sliders for a while. Anyone know any alternatives that work?


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## Guybrush

zgrav said:


> [


Those toggle switch caps look like a good solution.  Impressive to see 8 different colors as well.  And thanks for posting the build docs.  I'm going to try to use my drill and dremel to see how the enclosure comes out.  Glad I have the faceplate to go with it.  : ^ )
[/QUOTE]

Does anyone know where these are available from?


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## Bricksnbeatles

beachbum said:


> Tayda seems to have been out of the sliders for a while. Anyone know any alternatives that work?


+1 on that. mouser seems to be out of stock too, and I can't find any other brands with the same pin spacing


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## Robert

https://www.mouser.com/ProductDetail/652-PTA3432010CIB503/
		


You can use these Bourns but you have to install them on the wrong side of the board then cross the two wires at the bottom that connect the fader module to the main board.


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## Bricksnbeatles

Since it’s safe to assume that Tayda is never getting those B50k slider pots back in stock, is anyone with the relevant smarts (*cough* @Chuck D. Bones *cough*) able to take a stab at what differences, aside from taper of course, W20K pots would have in the circuit from a technical standpoint? 
If I’m being honest, I still don’t really understand what difference the pot values make when acting as a voltage divider in this particular sort of application.


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## music6000

Bricksnbeatles said:


> Since it’s safe to assume that Tayda is never getting those B50k slider pots back in stock, is anyone with the relevant smarts (*cough* @Chuck D. Bones *cough*) able to take a stab at what differences, aside from taper of course, W20K pots would have in the circuit from a technical standpoint?
> If I’m being honest, I still don’t really understand what difference the pot values make when acting as a voltage divider in this particular sort of application.


Another Option:








						6-Band EQ (Potentiometer Version) - PedalPCB.com
					

6-Band EQ




					www.pedalpcb.com


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## phi1

Bricksnbeatles said:


> Since it’s safe to assume that Tayda is never getting those B50k slider pots back in stock, is anyone with the relevant smarts (*cough* @Chuck D. Bones *cough*) able to take a stab at what differences, aside from taper of course, W20K pots would have in the circuit from a technical standpoint?
> If I’m being honest, I still don’t really understand what difference the pot values make when acting as a voltage divider in this particular sort of application.


I’d have to learn more to answer about how the different values effect the sound in this spot of the circuit. But, I can tell you that the 1776 Effects (currently not taking orders) has a six shooter project which is the identical circuit as Pedalpcb, except it uses all w20k pots


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## Big Monk

The output level control could be a simple retrofit with a standalone pot.

Looks like the output voltage divider is a simple 50/50 split:





Signal Level (%) = R9/(R8+R9)

Signal Level (%) = 10k/20k = 50%

Simply forego R8. You can use a R9 limiting resistor from Lug 3 of a 100kA pot to the ground pad for R9 to set the maximum output signal %.

Here is the Alpha "A" Curves. I assumed an 80/20 taper:





We can now use the value of the limiting resistor and the taper curve to show our performance across the dial. For instance:














I've been searching for a way to get the XTS modified frequency bands without breaking the bank and I think I'll add this to my 2022 list.


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## Bricksnbeatles

Just did a dry fit of the slider assembly with the W20K pots that were suggested (the screws are backed off equivalent to the thickness of the enclosure itself, the red line indicates where the faceplate will sit relative to the slider shafts) and the shafts seem much longer than what I’ve seen in others’ builds. I’ll see about getting slightly longer standoffs and seeing if I can still fit the assembly without getting in the way of the jacks. Could anyone take a pic of the side profile of their completed EQ so I can see how much the sliders stick out? Just a little concerned since it seems like they’d be easy to hit into with how high they stick up, and since they’re thin plastic shafts, it seems like they’d be at risk of snapping off with just a single light bump the wrong way.


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## Vipersassasin

I am a bass player and was wondering if there is an EQ chart specific to this design for obtaining lower Frequencies than the pedal is built for?

Slider 1 looks to be the only frequency that doesn't utilize an IC so my thought is that specific hz is determined by ONLY a resistor and capacitor while the others are determined by the caps and the voltage resistor. It looks like the 470R resistor stays the same across all frequencies.

I would rather wait for a SansAmp PCB to come out but building my own EQ has always been on my project scope so this one excites me a little.


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