STD-1 Hi-Cut pot (selected)????

[armdnrdy]

Hi all,

I'm working on a redraw of the ADA STD-1. The first draft will be an exact replica, true to the factory drawings which are difficult to read.

From there....who knows!

For those of you not familiar with the STD-1, it is a rack mount chorus, flanger, delay thing which incorporates the intriguing MN3011 6 tap delay IC.

While working on this project, I came across something that I haven't seen before. The Hi-Cut pot (P5) is listed as a B10K (selected)

Selected? By examining the circuit, can anyone tell what they may have been looking for in the selection process? A 10K that actually measures 10K? or perhaps a pot when counter clock wise measures as close to zero as possible? This one's got me!

Any ideas?

P5 is at the top center of the cropped drawing:

[armdnrdy]

I cleaned up this part of the schematic a bit.....so I thought I'd throw it out there again.

[Johan]

I would be surprised if any b10k didn't work

[armdnrdy]

Is it an engineer being completely anal or does it make an actual difference?

[Mark Hammer]

1) If R124, to the left of that pot, was a 1% resistor, then it might make sense for the pot to be selected for a precise value.  But we can safely assume that the brunt of resistors in there are standard 5% types.

2) If the pot had a centre detente that truly reflected the actual midpoint we wouldn't need to be concerned with its "real" (as opposed to spec'd) linearity.

So, my guess is it doesn't make much of a difference so long as the pot ia pretty close to linear, and pretty close to 10k.  That is, a 9.46k pot with 4.52k on one side of the midpoint and 4.94 on the other is probably just fine for one-offs.  If a person wanted predictable performance for production purposes, that's another set of considerations.

I, for one, would look forward to being able to make one of these legendary beasts....though I better finish up all those other things before taking on a commitment that large. 

[Johan]

Well. English is not my first language and the scan isn't very good..could it be any other word that just looks like "selected" on this scan?  Is there any other word for dented or steped for example?...

[armdnrdy]

Thanks for the reply Mark (we'll be talking about this) and johan.

Johan,

On the PDF I can clearly see that it says selected.