[sdiy] Roland BA662 color code meaning?

[rsdio at audiobanshee.com]

D'oh! Sorry, but I completely misread your original post.

When you said "higher" and "lower" - I totally thought you meant quality. But reading it again now, I see that you specifically mentioned ranges.

Yes, I agree, it would be totally useful to know what those ranges are. I noticed that the BA662 clone designers didn't even discover an official threshold for the "A" versus "B" quality ratings, so it seems rather hopeless to find any details on the colors. However, I still wish you luck.

And, thanks for bringing up the topic, because I grabbed those BA662 clone open design documents for archival. They could prove useful down the road…

Brian


On Feb 7, 2016, at 8:32 PM, Amos <controlvoltage at gmail.com> wrote:
> I am not asking about quality; I know the colors have nothing to do with quality and that binning is concerned with parts-matching.
> 
> So two BA662A marked in blue have a very similar "gm" measurement to one another; ditto two which are marked in yellow... but a blue one might not be a good match with a yellow one... I'm clear on the basic concept.
> 
> Just wondering if any Roland service info decoded the color code in terms of what numeric ranges they were measuring when binning these components.
> 
> On Sun, Feb 7, 2016 at 9:05 PM, <rsdio at audiobanshee.com> wrote:
>> I'm no expert on these particular parts, but in general "binning" only refers to matching, not quality. They're all potentially of the "highest" quality. I assume that you simply want to have all voices with the same color to keep your synth in tune and sounding like a proper polyphonic.
>> 
>> Reading the schematic that you provided, it seems that suffixes "A" and "B" refer to quality, with "A" being superior quality. I don't get the impression that color means anything about quality.
>> 
>> Hopefully there is more information somewhere.
>> 
>> Brian
>> 
>> 
>> On Feb 7, 2016, at 5:26 PM, Amos <controlvoltage at gmail.com> wrote:
>> > I have an assortment of BA662A here, and my reading tells me that they were tested and binned according to "gm" range, with matching color indicating similar "gm" :
>> >
>> > http://yusynth.net/gear/ROLAND/R100-schematics/M-140-sch.pdf
>> >
>> > However, I've found no indication as to what colors correspond to what range.
>> > I have parts marked in blue, red, yellow, and white, but I have no idea which colors mean "higher" or which mean "lower" or what the ranges are.  Do these data exist somewhere?
>> >