[Voyage-linux] Control amplifier volume control through MPD: solution

[Muffinman]

Hello Lars,

That's a good sign. If the command 'apt-get' works that would be great,
but maybe that's pushing it. If that works it is mostly following the
INSTALATION.txt file. Otherwise, the packages need to be downloaded
manually from Debian.

In addition you need to check if you can free up the serial port on the
back of the BDP-1. Currently it is used by Bryston software. You can
check who's using it by entering the following:
lsof | grep /dev/ttyS0
lsof | grep /dev/ttyS1

Most likely the S0 is the serial port on the back and the other one
unused or used by 'getty'. Try to kill that (not getty) application
(killall usually does it, check if it is indeed gone) and see if the
BDP-1 still works as intended (buttons on the front, etc.). If the
device does not work as intended anymore you can't use that serial port
unless there is a configuration file somewhere which you can adapt. Most
likely there is a second serial port inside the device, but then you do
need to find a way to get that cable outside of the box (possibly
removing the BNC connector?).

But before doing that, two notes.
1) The RS232 manual of your amplifier says there is a 1/2 sec delay
between every command received. Thus, 1 second per ~2dB change (unless
you set the resolution lower, e.g. steps of ~3dB instead of 1dB). For
many commands that would make sense, input, power, etc. For volume that
seems a bit silly. Nonetheless, if the manual is 100% correct, volume
response may be slow. Maybe it is an idea to hook it up to a computer
and see how it responds when you send out a bunch of volume commands.
2) According to the RS232 manual positive volume levels need to have a +
sign in front of it. Currently the application can not do that. It's
quite easy to add that but I need to see if there is a better/cleaner
approach than what I have in mind now. Nonetheless, your amp has a range
of -90 to +15, so the range +0-15 is probably very loud, isn't it? Maybe
the + sign isn't even necessary, manuals aren't always that accurate.
Anyways, try it out and if necessary I can add that without much trouble.

Kind regards, Maarten

On 08-05-14 14:33, lars svartdal wrote:
> Hello Maarten.
> 
> Thank you for your reply.  I just tried to ssh into the bryston, and
> when issuing gcc i got this reply; " gcc: fatal error: no input files
> compilation terminated." and for dpkg; "dpkg: error: need an action option
> 
> Type dpkg --help for help about installing and deinstalling packages [*];
> Use `dselect' or `aptitude' for user-friendly package management;
> Type dpkg -Dhelp for a list of dpkg debug flag values;
> Type dpkg --force-help for a list of forcing options;
> Type dpkg-deb --help for help about manipulating *.deb files;"
> 
> so it seems i can do both ! When login on to the Bryston via ssh it
> states the following;
> 
> Linux bryston-bdp-1 3.12-0.bpo.1-486 #1 Debian 3.12.9-1~bpo70+1
> (2014-02-07) i586
>                                 Bryston BDP-1
>                            Powered By Debian Linux
> 
> Best regards
> Lars
> 
> 
> 
> 8. mai 2014 kl. 10:54 skrev Muffinman <news at koster.tk
> <mailto:news at koster.tk>>:
> 
>> On 26-04-14 22:28, Lars wrote:
>>> Hello.
>>> This seems very interesting, i have a bryston bdp-1 
>>> And a cary cinema 11a, both have rs232.
>>> would it be poossible to configure the bdp-1 to control 
>>> volume on the cary diectly via rs232. I
>> Hello Lars,
>>
>> Controlling the amplifier shouldn't be a problem. However, is it
>> possible to compile the application on the BDP-1? For example, can you
>> execute the command 'gcc', or else ' dpkg'?
>>
>> Kind regards, Maarten
>