10 band EQ

[byoc]

Simple circuit.  Difficult physical layout.  Guess that's why you don't see any handbuilt or booteek graphic EQ's.

[zjokka]

 

Wow, terrific metal work. Very nice.
How is it noise-wise?

j

[byoc]

Wow, terrific metal work. Very nice.
How is it noise-wise?

j

Compared to other graphic Eq's, this thing is extremely quite.  At +/-0dB accross the boards, it's dead silent and completely transparent.  Even when it's after a distortion, it adds very little noise.  Only when you max the higher frequencies does the noise get really bad, but this is after a distortion.  By itself, it still has a little noise with all the frequencies turned up, but relatively speaking, it's still very quite.  It's also got quite a bit of boost.  The 470k resistor can be changed for more or less gain.

[guyg]

That's pretty cool

[JimRayden]

Wow, terrific metal work. Very nice.

Take into consideration that it propably wasn't done with drills and chisels.
http://youtube.com/watch?v=UoSVAeMCoY4

Nice circuit and I love the look of the completed pedal.

--------
Jimbo

[rockgardenlove]

Would you ever consider selling individual boxes along with PCBs?

[BrianJ]

Nice router.   Did you design that fixture for holding all the boxes?  It looks like it does the job well. 

[byoc]

Would you ever consider selling individual boxes along with PCBs?

That's the idea.  Put "byoc" in Google.  Click on the #1 return.

[byoc]

Nice router.   Did you design that fixture for holding all the boxes?  It looks like it does the job well. 

Yeah.  I designed that jig.  It does the job, but I'd like to remake it out of high density urethane.  It's made out of MDF right now.  It's getting worn out fast.

[byoc]

Would you ever consider selling individual boxes along with PCBs?

Just to be clear, I didn't post this to spam.  Only to diseminate a project that is lacking in the DIYFX community.  Hopefully someone can make good use of it.  Unfortunately, even a 5 band graphic EQ with sliders is beyond the grasp of a lot of advanced builders.  It has little to do with an understanding of electronics and more to do with your aptitude for layout/PCB design.  And cutting your enclosure for the sliders presents a challenge that most people don't have the tools for.

All the pots are B100k, so one could easily find panel mounted pots that are smaller than your typical 16mm alpha....so MAYBE you could fit it in a 1590b.  That would be much easier and feasible than using sliders and fitting it in a 125b.

Here's a look at the guts of my EQ.  I would think that it's almost manditory that you'd have to mount parts on both sides of the PCB if you were to use sliders. The first pics are of the first prototype.  The last is of the current prototype.

[dano12]

Hey Keith, that is a one of your nicest boards to-date and that's saying a lot. And 10 bands? Yeah that would be really fun to build.

Would it be possible to add a jumper on the board to allow it to be configured as two 5-bands? I.e. stereo....

[markm]

Hey Keith, that is a one of your nicest boards to-date and that's saying a lot. And 10 bands? Yeah that would be really fun to build.

+1 Keith, I must say it is VERY impressive indeed.
Nice Work! 

Would you ever consider selling individual boxes along with PCBs?

That's the idea.  Put "byoc" in Google.  Click on the #1 return.

I don't see the EQ listed on your site?

[byoc]

Hey Keith, that is a one of your nicest boards to-date and that's saying a lot. And 10 bands? Yeah that would be really fun to build.

Would it be possible to add a jumper on the board to allow it to be configured as two 5-bands? I.e. stereo....

Thanks Dan,

Unfortunately I didnt' really have that idea in mind when designing the board so it would be quite a simple as adding a jumper, but it can be done now that I've thought about it more.

If you look at the scheme I drew, you'll see several N.C. pins.   10, 12, and 14 of ICB would be the output for your second channel.  It would also require cutting a few traces to split it into 2 seperate 5 bands and you would probably want to rethink the frequency spread.  Just configure it like the other output buffer.  Don't use the second input buffer unless you want to make it a stereo input as well.  Take a look at the data sheet.  www.buildyourownclone.com/ba3812L.pdf  It's a pretty simple IC. 

[markm]

Hey Keith, that is a one of your nicest boards to-date and that's saying a lot. And 10 bands? Yeah that would be really fun to build.

+1 Keith, I must say it is VERY impressive indeed.
Nice Work! 

Would you ever consider selling individual boxes along with PCBs?

That's the idea.  Put "byoc" in Google.  Click on the #1 return.

I don't see the EQ listed on your site?

I STILL don't see the EQ listed on your site? 
Do you have plans to offer up this project?

[newbie builder]

He posted on the BYOC Forums that since there is a lot that could go wrong if somebody messed up a slider (all the resistive material is exposed) or screwed up a solder joint that he wasn't going to put it up for a while, but it would eventually be sold.

[rockgardenlove]

I'm not really interested in the kit, just the PCB and the box...

[R.G.]

The biggest problem with multi-band EQ chips is that they're essentially impossible to find for the DIY-er.

There is a circuit and layout for a similar deal, a 7-band EQ based on the KA2223 at GEO, from about five years ago. It's set up to use either sliders or trimpots for an internal voicing unit, as well as running wires to external pots.

The funny thing about these chips is that they contain a couple of opamps and a bunch of voltage followers to implement gyrators for the EQ bandpasses. In the case of the KA2223, it was just emitter followers.

I did a second layout using a dual opamp and seven discrete transistors. It was actually easier to wire than the dedicated chip.

An N-band qraphic EQ takes two opamps and N gyrators, or N bandpass filters of one opamp each.

What's unusual here is the tight packaging of ten slider pots and the use of a milling machine to mill the box.

What's availability like on the EQ chips?

[Izzy]

@ BYOC

I absolutely loved your pictures! Hope to see some more pictures like that.

One question where did you buy those Green capacitors?

[dano12]

The biggest problem with multi-band EQ chips is that they're essentially impossible to find for the DIY-er.

What's availability like on the EQ chips?

I am constantly amazed by Small Bear's chip selection.

Steve has 'em for $ 1.75.

http://www.smallbearelec.com/Detail.bok?no=570

[byoc]

@ BYOC

I absolutely loved your pictures! Hope to see some more pictures like that.

One question where did you buy those Green capacitors?

Greenies?  Man...they grow on trees.