how is digtial potentiometer?
May 5, 2003 at 2:02 AM Post #2 of 26
yes , but if ultimate resolution is a concern it will be the limiting componant .

Qualified by : in a strictly portable amp it should not be a limitation considering the ambient noise of the environment and the nature of listening while pursuing other functions while listening :

i:e background music or as I like to call it "my personal soundtrack with me as the star'
 
May 5, 2003 at 7:49 PM Post #3 of 26
Just saw a digital servo attenuator network on a Chinese website.
The price is pretty low, 480 yuan to 1000 yuan about 60 USD to 125 USD which depends on brand of resistors used.
It uses relay controled R-2R resistors network and totally has 4000 steps.
It sounds an exciting replacement for step attenuator.
The performance should be much better than digital potentiometer even close to a step attenuator because it use real resistors, no digital parts in signal path at all.
Anyone knows this kind design?

http://www.liteaudio.com/2003-3-22/200332205504.htm (in Chinese)
 
May 5, 2003 at 8:56 PM Post #4 of 26
PGA2310 / 2311 should be more than good enough. Perhaps better than any potentiometer. In the absence of experience it is hard to say. Stepped attenuator should still sound better.
 
May 5, 2003 at 9:37 PM Post #6 of 26
hi everyone, this is my first post in this forum but i've been in here couple of months....

Just want to tell u i've designed the digital volume control using PGA2311 with PIC microcontroller and yes the result is very good. This volume control will blown everything out... it has 0.0002% THD+N!!!!! I haven't complete the whole thing and currently i can increase/decrease and mute only... i'll add in the left-right balance as soon as i'm free... (my final exam is next week...
mad.gif
)

i'll post the circuit and the firmware when i finalize them...
 
May 5, 2003 at 9:49 PM Post #7 of 26
Quote:

Originally posted by [so]hai®
hi everyone, this is my first post in this forum but i've been in here couple of months....

Just want to tell u i've designed the digital volume control using PGA2311 with PIC microcontroller and yes the result is very good. This volume control will blown everything out... it has 0.0002% THD+N!!!!! I haven't complete the whole thing and currently i can increase/decrease and mute only... i'll add in the left-right balance as soon as i'm free... (my final exam is next week...
mad.gif
)

i'll post the circuit and the firmware when i finalize them...


that's awesome.
does that include backlight LCD display?
 
May 5, 2003 at 9:51 PM Post #8 of 26
haha... i can if u want it.... give me some time... i'll working on that after my exam...
wink.gif


p/s: actually there is a thread in headwise forum, the schematic and source code r there but that is first version work....
biggrin.gif
(not very good) the schemetic is changed a bit and the source code is totally different with the current one... current one comsumes less power (more efficient codes)..
 
May 6, 2003 at 1:47 AM Post #10 of 26
haha... tend to agree... That's y some ppl like tube sound and others just like accurate decrete logic...
biggrin.gif


However, specs is the first thing i look at when searching 4 new parts... i think volume control is one of the most important component in amp 'cos they r between source and amp. It is useless if u got gold connector but crap volume control, right?
wink.gif


Also i think TI won't simply put the specs up, although their tests is done in "clean room" and ideal case, but i think the actual performance won't run off too far from that... and of course, i've listen to that as well...
biggrin.gif
 
May 6, 2003 at 2:32 AM Post #11 of 26
Hello sohai... good to see you here. This is trespasser_guy from HeadWize.

I had created a pc board with your original schem... but it has changed as you said, and was not really as small as I had hoped. I don't know if I would design another... too many small parts to etch your own, too expensive to have made. I am interested to see the final outcome... I still have my PICx184's and PGA2311.
smily_headphones1.gif
 
May 6, 2003 at 2:42 AM Post #12 of 26
Here's a partly commercial effort to create a volume control with a microcontroller and PGA2310's:

http://www.dipchipelec.com/apox3.htm

A version of the schematic is available, as with the other relay-based (shunt and series, I believe) volume control and input switching offerings at this site).
 
May 6, 2003 at 6:16 AM Post #15 of 26
I'd like to use this chip too, got it some months ago but have no time... so I'm hoping someone will finish theirs and report back on sound quality.
 
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