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I'm a beginner and this is my question.
I have an old KS board from before I had kids that I am just getting around to enclosing.
I noticed there is a revised build document showing a new master volume knob. I want to include this feature but noticed some values are different in that area of the circuit. I'm wondering how you arrive at the values from a design standpoint.
The original shows 1M resistor(R10) shunted to ground at the output, and the revision has a 50kA in the same place acting as a voltage divider.
The cap immediately upstream from there went from a 100n(C7) to a 1u(C6).
These are the only changes I can spot to the entire circuit.
The cap is 10x different, the resistance to ground is 20x different.
My understanding is that the cap is there to block DC from the output and also filters low frequency AC; the frequency depending on the value of resistance to ground. So if that is 'tuned' to the new resistance, that makes sense. What I don't understand is why the resistance to ground had to be reduced that much.
I had a hard time getting the original circuit down to the same level as dry signal without losing the effect- so did the output just need to be tamed?
If there's a math reason for the resistance change, or whatever else, I'm curious to learn it.

Cheers!

Exactly- except for limiting, I always felt that's the nuclear option.

Some use two compressors, and A/B between them-
One could compress the full signal, then compress the highs more-
You could do the motown parallel trick you described-
Some try sidechaining an eq-

Tried it all and I prefer the multiband approach- except that multibands are pretty much all 4 knobers, and those things never sound as musical to me as the simpler circuits like you see in ancient compressors like the Altecs, or in certain guitar pedals which we could geek on for days.

But yeah, it's all about having a setting that I can forget about and just play-

Kothoma- It's just multiband, but as it relates to the bass guitars spectrum and my playing style.

I don't like much compression anyway, but I do like the option of slightly more compression on my highs.
Say, if I wanted to slap or do something percussive- I like to have balanced tone, but that means when you do anything percussive, those things just poke out and clip more in the higher frequencies than I would like(especially if I've been DI-ed into a PA, and the vitamin root perm sound man assumes I want to sound like a machine gun).
As for the lows, I like to palm-mute a lot and go for a lower frequency percussiveness- as in mimicking the shorter attack and quicker decay of a note played on an upright. I'm pretty good at getting that bouncy swingin feel from my notes, but if I compressed that like I do the highs, it would get all smoothed out.

So- I use multiband compression to support the range of playing techniques I use. Does that make sense? I'm just looking for a version of that which is tailored for what I do rather than have 17 knobs.

The mids aren't a separate band to me- that would be going a bit nuts. On a conventional multiband I would keep mids with the lows- matter of taste I suppose. The baxendall idea is a whole different thing though, I'm not sure where that will take me.

Actually- I have tried eq + comp in parallel with dry- Read about Motown doing their vocals like that. I always felt like it was working against me though-

I can't use resistance to ground with this particular eq-

I guess it's the math for me.

I had the thought that if I were to go nuts and replace the pots with pairs of LDRs, A) they could do the compressing, but I could use pots to control the 'idle' voltages, and they would essentially set the default tone knob values. Which I think is spiffy.
And B) Id never make it work.

Yeah- I've tried doing more advanced maths and surprised myself- But the only way I can do it is to find a visualization that jives, otherwise I'm lost.

I'm definitely going with the Pro-cessor so I can have conventional results, but I also want to see where this other idea goes cause it would invariably sound different than anything else out there. Two Builds-

So, the Vactrol controlling a tone knob thing-

In the AL, the LED idles at low (or off?), and when a loud enough signal is applied, the LED brightens lowering the resistance in IC1a's negative feedback loop, and this turns the loud notes down.

At least that's how I understand it-

Instead of resisting less in a feedback loop to turn down the signal, Id like to resist more in the signal path.

Is it possible to have the LED idleing high and send it less voltage when a loud signal happens? I don't see it in any schematics for compressors... Is that just because it would eat batteries, or is it not possible?

Cheers~

I was just looking at that- It would be a nightmare to tune two vactrols to act like two halves of a pot-

I could compress the full signal conventionally and get slightly more compression on highs by using the vactrol as a tone knob, essentially.

Too many ideas, need breadboard.

Except that it would then be an expander.. brain is scrambled.

But how about a different approach-
Could I use an Afterlife's Vactrol as the variable resistor in a tone control instead of for controlling the afterlife's gain?
Because I really like Ampegs use of the Baxendall in their B15, and I was going to be shooting for that voicing anyway-
If I don't need the resistor side of the vactrol hooked up as drawn in order for the afterlife to control the vactrol, would I be in business?

Vallhagen-
So I (sort of) understand now how the Linkwitz-Riley corrects the phase, with two lines of two stages which turn 90 degrees in opposite directions, and then 90 degrees again. I don't understand why there is a phase shift of this type in the first place, but there's probably some math involved?

That makes the Pro-cessor (also linked to above) a better place to start to see how this idea works-
I was starting to wonder if I will like the notch, but I can always put one in later.

Yeah, if it were an effect I would probably try it with a nasty notch, but I want to be able to leave it on- Then again, the notch filter on an acoustic amp is apparently how Albert Kind got that weird sound-

Found this on one of the above links-
The Mad Box http://diy.thcustom.com/shop/madbox-v3-1-pcb/
It seems like it would be the simplest approach for me if it works. It's just a two channel effect send, and a two channel effect return with a blend knob. I would put the Afterlifes(with mods to bandpass them as above) one in each loop.

Does that sound feasible? And does Mad Bean have anything like this?

And here's a rough picture of that idea- sort of- just wanted to make sure I understand.
Forgive me for just chopping up those schems, I don't have a drafting app.

Buffer from KS split into 2ALs, with Jons cap suggestions, sans side chain, one master volume, into the rest of the KS. I left out all the power sections-

Jon, your cap locations, I'll have to filter the sidechain audio separately if I don't want them to track full range, yes?

Bengt- I just read yours but will check it out as well as I'm heading to bed over here-

Cheers- Ben

Cool- I understand that-

I happen to have a karate shop laying around, which has a buffer in it- maybe not the right transistor for this application?
I was trying to use that effect before compression as a semi-parametric low/mid booster.. but of course that combo gets super noisy.
Now I'm wondering if I can (boxing them together) use the KS buffer in front of the AL's (in the way you described) and feed the compressor output into the KS post buffer...
KS transistor is a 2N5457, but I suppose I could change it out with a more appropriate part if necessary.

Seems like the buffer for the KS would be superfluous given the output of the AL, and the fact that I don't intend on switching parts of this contraption on and off. But I could be wrong?

Hey Jon, thanks for the thoughtful response- Your demo videos are what got me on the madbean site in the first place-

You may have answered my question-

I should probably explain more what I'm going for, apologies if I sound redundant.
I'm a bass player, and I want a 2band dynamic eq. It would be my compressor, and my eq. So I'm not just looking to regain my highs, I want to compress and control each band separately. I need both Compression knobs, and both Volume knobs, and I would probably add your sensitivity control to each side as well.

There's quite a few units that do something like this, and I have a couple, but they're mostly designed more for general PA use than an individual instrument(I don't need a lot of range of controls, I'm never going to put a vocal through it). I know of two bass specific pedals, one with a million knobs and another with none. For a bass compressor(or eq), I just want a few knobs that are musical and to fiddle with a few component values until I'm happy with the way it works- which is why I like the AL.

From what you're saying, I need an extra stage in front of each compressor, perhaps there's a better compressor build for this to start with? I really like the opto, though- I'll have to research what you're talking about with emitters and followers before I attempt to ask a real question about that-

Thanks!
Ben

Hey there-
First post, probably dumb question.

What I'd like to do is elegantly modify two Afterlifes to give myself dynamic control over Bass and Treble.
So- one AL just doing highs, another just doing lows, and running in parallel.

I figure there must be some sneaky places to insert a couple caps so they wont interact across the units-

It seems like Highpass would be easy, just change the value of C1 in one unit, or add a cap coming off of pin1 of IC1a, filtering it's lows without affecting the other compressor..
But for Lowpass- Can I get away just shunting the highs to ground on the positive side of C2? Or will I have to use the negative feedback loop of IC1a somehow?

Also, if that works- I should be able to make a mid control.. yes?

I have an AL, and I'll poke around with that this week, but any thoughts would be welcome-
Thanks!