[sdiy] Trimmers

Tim Ressel madhun2001 at yahoo.com
Sat Feb 28 17:46:05 CET 2009

The modern solution, from a manufacturing standpoint, is to use either DACs or digital pots to make the adjustments. A test station puts the instrument through a set of tests exercising various functions and determining the values for the DACs/pots. 

Of course this adds cost to each unit. Sometimes it is cheaper to pay a worker to make the adjustments. In this case the test station facilitates the adjustments by showing a clear indication of which direction to turn the pot and when the adjustment is correct. 

I like the solution where the thing adjusts itself. Imagine a VCO that could apply its own precise voltage and measure its own frequency. Or even better: a VCO that can measure the input voltage precisely and adjust itself on the fly all the time.


--- On Sat, 2/28/09, Tom Wiltshire <tom at electricdruid.net> wrote:

> From: Tom Wiltshire <tom at electricdruid.net>
> Subject: [sdiy] Trimmers
> To: "synth-diy DIY" <Synth-diy at synth-diy.org>
> Date: Saturday, February 28, 2009, 7:43 AM
> The Korg Poly6 voice board has 50 trimmers for six
> single-osc voices. There are seven per voice (osc, filter,
> vca and env all have trimmers) plus 8 more for the overall
> stuff.
> It's amazing that this was ever considered viable. The
> amount of time it must have taken to tune each instrument
> before it left the factory must have cost them a fortune.
> Elimination of these kind of trims from a design must be an
> important part of modern design for manufacture.
> No real point to this, beyond that startling initial
> statisitic. 50! Blew my mind!
> T.
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