DEMO EQUILUX BUILD. Yes yes yes.

This post contains an audio or video demo
Excuse my ignorance, but what does an EQ like this do that a graphic equalizer can't?

Also what's the deal with both cut and boost controls on the low freq, wouldn't they just cancel each other out?
 
Excuse my ignorance, but what does an EQ like this do that a graphic equalizer can't?

Also what's the deal with both cut and boost controls on the low freq, wouldn't they just cancel each other out?
Graphic eq you are boosting/cutting direct bands of frequency. This has more of a Q range that you can focus or widen around select bands. The cut and boost of the lows does seem like nonsense but since the cut and boost frequencies are slightly different from each other you are basically able to tighten or loosen the the Q of the lows as well.

For my own pleasure I plan on running this into my daw and watching the frequencies as I adjust the knobs, I will record the screen and share because I feel like once we can see it in action it will be an ah ha moment. I think the reason it sounds so good is that they choose the classic frequencies that have been used for years in all the recordings we grew up listening too. So part of the “goodness” is just the fact that the guitar sounds familiar and a lot of the junk and mud is cut out.
Just my thoughts on it.
 
Excuse my ignorance, but what does an EQ like this do that a graphic equalizer can't?

Also what's the deal with both cut and boost controls on the low freq, wouldn't they just cancel each other out?

The separate cut/boost controls on each band is a pretty classic aspect of the Pultec EQs. Boosting and cutting the same frequencies doesn't end up being a net-zero, the frequencies aren't exactly the same nor is the Q. So you get interesting interactions in a particular area, which is part of the magic of the original boxes.
 
Audio samples. I realized my issue last time I tried to capture some sounds for you guys. I was too loud and the iPhone couldn’t deal. I went quite today and it worked out. Again these are subtle differences but make a huge difference in real life and in the wave itself. Cutting out the junk makes it sound a shit ton louder as well. Delay, clean, and drive all three before is without the Equilux.
Sample
 
Excuse my ignorance, but what does an EQ like this do that a graphic equalizer can't?

Also what's the deal with both cut and boost controls on the low freq, wouldn't they just cancel each other out?

Different circuit topology (one of my open source ones meant for bass), but take a look at what happens to the bass peaking frequency if you apply a mild bass boost and then sweep a variable HPF (cut only) across its full range:

PW7B2_HPFsweep_B7_5.JPG

The classic Pultec circuit was definitely a big part of my inspiration for this format, but I tend to love highly interactive tone controls in general as well. So the Equilux might very easily become my first PPCB build, I reckon.
 
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Great build! I’ve got the parts coming in with my next orders, and will just have to wait for the board… Even ordered a few jewel covers.

The bass cut and boost are different orders—one is first order (6db per octave) and the other is second order (12db per octave). As far as I understand it, the center frequency is the same, but because of the difference in slopes, you get various peaks and troughs as you adjust them. There are also phase issues that each order has, and I’m sure these add some to the magic. I’m really looking forward to this.
 
Pretty sure the charge pump pumps it up to 18V.

Correct. The Equilux should be powered at 9VDC. The required 18V is generated internally by the charge pump.

You could, of course, omit the charge pump if you wanted to use your own 18V supply instead.
 
Correct. The Equilux should be powered at 9VDC. The required 18V is generated internally by the charge pump.

You could, of course, omit the charge pump if you wanted to use your own 18V supply instead.
Is it just a matter of not installing the chip, or are there jumpers needed, and any attached passives that also get omitted? (No schematic, but even with one I might still have the same questions. I‘m a bit confused about charge pump usage.)

And (unrelated, but also about the Equilux), do the switches used have an indexing pin that should be drilled?
 
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Is it just a matter of not installing the chip, or are there jumpers needed, and any attached passives that also get omitted? (No schematic, but even with one I might still have the same questions. I‘m a bit confused about charge pump usage.)

And (unrelated, but also about the Equilux), do the switches used have an indexing pin that should be drilled?
Going to possibly answer my second question, but if I’m wrong, I’m sure someone will step in to let me know. The switch info shows the layout for the index. On the circuit board, each switch symbol has a small rectangle along the perimeter—my assumption is that this shows the orientation for the index.
 
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Going to possibly answer my second question, but if I’m wrong, I’m sure someone will step in to let me know. The switch info shows the layout for the index. On the circuit board, each switch symbol has a small rectangle along the perimeter—my assumption is that this shows the orientation for the index.
Just make sure you don’t put them on the wrong side of the board like I did my first build. I feel like that graphic should have been printed on the back side not the top side. I orientated mine to that little square. But flipped sides.
 
Just a heads up, it looks like you missed a lug on the far right rotary switch ;):
There are no connections to that side of that particular rotary, so no need to tear it back apart to solder the pin.

The switch info shows the layout for the index. On the circuit board, each switch symbol has a small rectangle along the perimeter—my assumption is that this shows the orientation for the index.
The silkscreen does show the index, but it's just for graphical representation (unless of course you decide to drill holes in the enclosure rather than clip them off)... The 2P4T rotary switches are symmetrical so it doesn't matter which way you install them.
 
My pedalboard positively has NO space for this guy and I'm not sure I "need" it but boy do I wanna make one...


...I am in the process of getting ready to start on a bass board, though...
 
My pedalboard positively has NO space for this guy and I'm not sure I "need" it but boy do I wanna make one...


...I am in the process of getting ready to start on a bass board, though...
Yeah the size is the “only” issue with this one. Such a bad ass pedal but doesn’t fit on my board either, unless I kick off two other pedals. I just have it sitting on top of my cab.
 
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