This post is wrong on so many levels, with that said, let's get to it.
neil.johnson wrote: ↑
Sat Nov 21, 2020 3:11 pm
I keep seeing so many posts where folks say such things as:
A typical Eurorack input has an impedance of 100k.
What's wrong wth this? It's more true than not. Your example below is for inputs with typical attenuating pot architecture. But are those the most typical?
I think not, though it would fun for someone -not me!- to go to modular grid and count them vs what I think will prove to be for more common. Bare inputs leading directly to a 100K input resistor.
The more I see this, the more I realise this is such a dangerous assertion.
Very rarely is this assertion actually correct,
see the more likely truth above. I believe it's your intial hypothesis that's off.
and so any discussions based on it are likely wrong from the outset.
Again, there are PLENTY of examples of true 100K inputs in all formats of the synth kingdom
It's not even worth pointing out any one example of where this is not true -- there are too many!
Something we can agree on. there *are* many examples of module inpuits which are *not* 100K . But that's a FAR cry from your ignoring all of those which ARE.
It's not about shaming or exposing,
Good. Because there's nothing to "shame" or "expose"<-- Well, I do think it's good you pointing out that there are differences. But to put such a bias on it works against your goal. It's too easy to shoot down the faults in your position, and unfortunately that also keeps the good part of your message from getting the exposure it needs and deserves. More on that later.
No, it's not
it's about poor design, especially in places where it matters: CV inputs.
. And no, those aren't "special places where it matters". If you'd said pitch
CV inputs then maybe I'd back off<-that part. Using appropriate circuits in both cost *and* function does not mean one always chooses the electrically 'best' design. Best depends on a matrix of options and results. Any good designer-engineer knows that to their core.
I would be curious to understand why, when it is relatively straightforward to buffer an input before using it, that many designs simply don't?
Are you? really? curious? You know damn well why. At least I hope you do!
Is it cost?
. Why on earth should I or anybody else buffer every
input? Next you'll be tellng us every synth needs to have balnaced inputs and outputs on every jack or audio connector..
Straightforward is not the only or best choice.
Is it lack of understanding?
. It is well understood by those with even a meager electronics background. You know that.
Is it not as important as I think it is??? Curious to understand...
. Ding! Ding! Ding! We have a winner. Chicken dinner!
We have half a century plus of proof that the people like yourself who keep bringing this up as some sort of pox on the synth universe <--It's NOT. are simply sharing an opinion of their position on the matter's value.
Haven't we learned from too, too many human arenas that 20% solutions satisfy 80% of customers? That better doesn't usually matter if the "problem" isn't perceived as such by the 80%?
We've also learned -and most of us watch out for- the first step in changing something is to elevate it -often artificially so- as a problem. Our gut check says, Hey, wait a minute. That doesn't really matter.
Like I said above, you have a good message and goal. Framing it as if we're all lost without embracing it is quickly seen for the falsity it is, and the meat and potatoes of your message is lost in the mix.<--Just like the results of all those "not really 100K's" is ALSO lost in the mix. Literally.
In adapting the 1003 to my new format, I noticed that there was room on the bus IO -and panel- for the inverter which is otherwise buried in the output circuit. I decide to break it out to be used at will. When Dennis Colin designed it, he used a 10K input and feedback resistor for this typical OPA inverter. I changed those to 100K, knowing full well that DC had used 10K to reduce noise. Because when it was embedded, there was no need to condition for naked expectations. But had I not mentioned it here, no one, and I mean no one, would have ever noticed or questioned it. Because while the difference going from 10K to 100K for those two resistors *will* increase the noise, the end result increase will. not. ever. matter. That's not bad design. That's desiogning for the reality the module will face, and for the customer;s it's intended for, and at the price level they expect. <--Price here not really a thing. But still part of ANY good design. Oh, and that inverter input now IS 100K.
e pluribus unum. One of many