MSA to Blackstar DB-9 amp switcher

[Archangel]

John,
This is an awesome board!

I am switching amp channels with pulsed cc#s
and boost & reverb with latched cc#s

programming was a snap with squerl on the mac


heres a ratty cellphone video clip
http://www.youtube.com/watch?v=OFZId...ature=youtu.be

[Archangel]

heres a clip with much better audio quality

and an Ipad synth thrown in the looper.

http://youtu.be/eZVHQpDPYro

[Archangel]

riddle me this:

how can I trigger the photorelays with external signals?
high or low? and perhaps the voltage on which pin of the msa-p's
photorelays

I want to switch with midi and external switch contacts.
and still protect the chip's outputs.

[John]

Originally Posted by Archangel

riddle me this:

how can I trigger the photorelays with external signals?
high or low? and perhaps the voltage on which pin of the msa-p's
photorelays

I want to switch with midi and external switch contacts.
and still protect the chip's outputs.

Hi Archangel, welcome, and thank you for posting the videos.

The MSA controls the photorelays with a positive-logic signal (5V = closed, 0V = open). There is a series resistor between the microcontroller and the relay signal pin. Here is the datasheet for the photorelay:

http://www.semicon.toshiba.co.jp/doc...eet_071001.pdf

Let me know if this helps.

[Archangel]

Thanks John!

in checking to see if I asked the question properly,
I answered part of the question ..

...what is the trigger to the led of the opto
and is it protected with a resistor?

and you answered both perfectly.
and the datasheet is a great help.

[Archangel]

...is pin 1 (with the dot up top)
top left like my other chips?

The datasheet strangely dosent show the mark

[Jim McDougall]

If you look at the drawings the pin1 side has a shallow side slope compared to the pin 4 side which has a sharp side slope

[Archangel]

Thanks for that!

I believe I will be able to send the boards regulated 5v and ground out a cat5 cable to foot switches

and have 6 conductors to send back 5v signals to the optos
and the foot switches second contacts turn on leds
(except 3 leds would be pulsed in this application)

and have both midi and analog control over the opto outs