volume remote control module with PGA 2311

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rmaa results:

RightMark Audio Analyzer test : volumaster PGA 20110326

one of the graphs:

noise.png
 
I won't ever consider myself golden ears. I'm a lousy piece of test gear ;)

to me it sounds as good as the source. but I rely more on test gear; it does not care and has 'no dog in the fight', as they say.

we did one test at 0db and another at 3 or 3.5db (in the plus region). if anything, it was BETTER at the +3db (gained) setting. blew my mind ;)
 
Hi,

hehe...yeah....I notice you have stopped the POS comments ! ;-)

It does make me wonder what it could do with a decent PCB, power etc. It might just be all I ever need for volume control.

Anyone out there fancy doing a pure stereo in-out layout with onboard Salas shunts for a group buy ? You could count me in for 5 at least.

Cheers

Tom
 
we have not started development, but amb and I do have plans to develop and produce boards for the PGA vol control engine. it will fit into the system as an alternate choice: relays for those that like relay-attenuators and PGA for those that prefer that style of vol control. the delta1 and delta2 are planned to be regular stock items and I would think the PGA equiv would, also.
 
Hi,

hehe...yeah....I notice you have stopped the POS comments ! ;-)

I think the dialog was something like 'hey, the results just completed. its clean.'

'its clean??'

'yeah. looks good.'

'can't be. really? come on!'

or to that effect ;)

we were both a little surprised.

I did a perf board PGA project a year or 2 ago and we did a test run, then, too. that version tested better, actually, but only on paper. I doubt a single person would be able to reliably tell them apart. and my perf board version was at least attempting to follow all the guidelines with digital and analog grounds touching at the right place as per the spec sheets and so on. I did have all the right bypassing and a more 'remoted' PSU unit (nowhere near the PGA). I think I also used a TLE rail splitter to get my audio ground and I gave that a nice clean 10v, having it create the dual 5 (or really just create a really accurate midpoint). so with lots of extra effort you can get slightly better on-paper specs. I doubt its worth it unless you need bragging rights.
 
I've been following this stuff very closely and would love to beta test such a board, should it ever happen...

Hey linuxworks, have you got a schematic for how you've implemented the pga through the port expander? I'm going to bread one up for when I get my lcduino board later on.
 
no schematic yet; this all happened too fast for that; it went direct to perf board ;)

the PE is basically the same as what you'd find on amb.org's site for the delta1 or 2 controller. just half of that board since you don't need 2 PE chips.

then, the bottom 2 bits are the data bits (clock and data) and I used the next 3 bits as chip-enable bits for 3 possible chips. in reality, I always send a 111 to them and they might as well be the same wire, but just in case I want to address one chip on its own, they are all bit addressible.

there is a mute bit, too.

maybe this is useful:

Code:
// mute wire
#define PGA_I2C_MUTE_HIGH   B00100000
#define PGA_I2C_MUTE_LOW    B00000000

// chip-select wire
#define PGA_I2C_CS          B00011100
#define PGA_I2C_CS_HI       B00011100
#define PGA_I2C_CS_LOW      B00000000

// data wire
#define PGA_I2C_SDATA       B00000010
#define PGA_I2C_SDATA_HI    B00000010
#define PGA_I2C_SDATA_LOW   B00000000

// clock wire
#define PGA_I2C_SCK         B00000001
#define PGA_I2C_SCK_HI      B00000001
#define PGA_I2C_SCK_LOW     B00000000

I will also have to shoot a pic of the underside of that gold pcb. I had to do some rewiring and jumpering to get all the needed ce/clk lines to appear on one header block. they had them spread out onto another header and I didn't see the point in that, really.
 
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Great result Linuxworks. I am currently working on a PGA2320 based pre-amp. The audio and control s/w is running well (I am writing the TFT display driver now - still some weeks to go). Anyway, I can listen to the pre-amp part and It sounds superb, so I don't doubt you have a fine sounding piece of gear there. The PGA2320 is a great device and its good to hear people getting these kind of results. I am buffering mine on the input and output side as well.

BTW, what sound card are you using?
 
strictly development-mode stuff, but a direction we're going in:

5608230432_05cdcdb3ab_b.jpg


yes, remote control of the remote control (lol?)

a web CGI interface that gives fairly detailed control (more than what is shown here) of the LCDuino system. I have 2 browser windows open to 2 webservers; each one has a serial connection to an LCDuino system. one webserver could support many of these; just use a separate FTDI serial cable and you'll get /dev/ttyUSB0, 1, 2, etc, in the /dev directory). then specify the right '/dev/' number when invoking the CGI.

you can click the up/down/left/right buttons to change volume (up/down are big volume jumps and left/right are smaller jumps). center button refreshes display (it does not auto-refresh; but could if you wanted it to).

the first software release will have this code in the trunk but not enabled by default. however its simple to enable at build-time (it will be documented how to do this).

I can already control my volume from somewhere else in the house, using wifi and a touch tablet or netbook. its fun!
 
finally, the day has arrived. we are annoncing our LCDuino project:

The LCDuino-1 Display I/O Processor

source code link should be up shortly; the rest of the info on the design and construction is there, now.

while the PGA chip is not officially supported in v1.0, I will say that its what I personally and I always test against my own PGA board. same with the spdif switch; not officially part of the 1.0 product set but it does work and a supported version of the pga and spdif switch hardware will follow. remote network access will also continue to be developed in the 1.1 source tree.
 
amb's site is still being updated. maybe another few days until its all there (his web store will have the boards for the lcd module and relay attenuator and relay input/output selector. that's the first config that we will support for the v1.0 firmware.)

I use a PGA board that I adapted and that will also be supported if you are willing to build your own PGA board and an adapter port-expander. its not offered at amb's store yet as we will be starting on the pga part of the project shortly; but the controller DOES talk to the pga chip and I've been using mine for a few months now with good success.

the boards that are ready now (and will be in the online store) are: A10 backplane, A20 buffers, LCDuino1 controller, Delta1 relay attenuator, Delta2 i/o selector.
 
also, working on this setup for the next version of firmware:

5709361778_b325d13c7d_z.jpg


its an xbee radio link that will let you put the controller in one system and a back-end (with another lcduino controller) in another system.

could even be a battery powered remote with lcd, (motor)pot but using a radio link from the 'handheld' to the base station.

...coming in the v1.1 firmware (working on it now).
 
this might be a nice cheap PSU for the ebay boards: search on fleabay for '17122B' (hp/att wall wart power supply).

its dual 10v ac (4wires). seems like a pure trafo with nothing 'in the way'.

the ebay PGA boards all expect dual ac in and this looks like a nice UL solution that costs very little and saves a lot of building time. cut the connector off and put some other 3 or 4 pin one on.

fwiw
 
update: I've gone 'hardcore' (lol) and had a proper metal chassis milled and shipped to me (front panel express).

An externally hosted image should be here but it was not working when we last tested it.


I'm pleased with the overall result and will be investigating doing a small production run of units something along this line.

here it is at burning-amp 2011 with the rest of its usual stack (behringer stuff for active crossover and EQ):

6204332757_024f6ce83b_b.jpg


its still using the ebay PGA board inside but I am going to be making my own board from my own layout.

the front panel buttons and rotaries were added just this week so its a very recent addition. the menu system is now accessible from the front panel and so if the handheld remote is not nearby (where DID I leave that thing, anyway?), its not a problem anymore ;)
 
thanks. I was going to litter it with more buttons but my friends told me to cut them to a min. we compromised and so we have 'some' but not a litter-ful of buttons. the knobs were supposed to sink into the panel a bit more but we used what we had onhand (imports from a previous project). some people said it should have been all silver but I'm not sure, myself. are the black knobs 'too much' visually? suppose they were the same diameter but just half as long, sticking out?
 
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