[Coco] WTB Orchestra 90 cartridge

[Jayeson Lee-Steere]

Very cool Ed.

On capacitors, I think perhaps the schematic is in error with the 0.1uF
non-polarized cap values. The smallest NP electrolytic I can find available
anywhere is 1uF, and if you look at the pic of the Orch 90 board, what
should be the 0.1uF NP caps are physically larger than what is supposed to
be a 1uF NP cap. And then there is the question of, if 0.1uF is the
intended value, why not use polyester caps as was done with the opamp input
circuit?

In fact, the caps look suspiciously like the polarized 10uF bypass cap on
the 5V rail.  This happens to be the same value as the output cap used for
Tandy's Coco 2 and Coco 3 audio out. Not the best evidence since the output
impedance of the Orch 90 DAC is indeed around 1/100th of the  Coco 2/3
circuits mentioned. Still, makes more sense to me than using a 0.1uF NP
electrolytic where a 0.1uF polyester cap would do.

Having the screw under the label sure is a curse, eh.

Jayeson

On Wed, Aug 3, 2016 at 6:47 AM, Zippster <zippster278 at gmail.com> wrote:

> Thank you.  :)
>
> After playing some tunes in your CoCo, you can just flip the switch and
> plug it into a Dragon.  Thanks to Pere Serrat’s adaptation of the Orch 90
> ROM.
>
> <https://drive.google.com/open?id=0B1sgl615FlGnNzRhNC1xSjRBSFk <
> https://drive.google.com/open?id=0B1sgl615FlGnNzRhNC1xSjRBSFk>>
>
> Just plugged into the TV speakers, but you can see it works…
>
> - Ed
>
>
> > On Aug 2, 2016, at 5:38 PM, Bill Pierce via Coco <coco at maltedmedia.com>
> wrote:
> >
> > <Applause> Good job!
> >
> >
> >
> >
> >
> >
> > Bill Pierce
> > "Charlie stole the handle, and the train it won't stop going, no way to
> slow down!" - Ian Anderson - Jethro Tull
> >
> >
>
>
> --
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>