[Avro_Arrow]

I got a couple of the DS1802 Digital volume controls to play
around with and was wondering what others have come up
with for their applications. I see that you can either use it
single ended or with dual rails. I would like to use the dual
rail solution. How have you created the +/-2.5 volt supply?
 
I look forward to your comments...

 

[walangalam]

 

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See here: http://web.archive.org/web/20060717211152/http://www.pedjarogic.com/spot/index.html
I was planning to do this a long time ago, but somehow it fell of the radar. I still have my chips though. Play with it and let us know!

 

[Avro_Arrow]

Thanks, that was pretty much exactly what I was thinking of.
I will already have a well regulated power supply to tap into
so the local regulation does not have to be anything spectacular.
 
Any recommendations for a Rotary Encoder?
I'm probably just going to stick with a simple switch
for the prototype.

 

[Avro_Arrow]

Here is what I have so far...
 
I haven't decided whether to use board mounted
jacks or just wire pads and I haven't picked the
switch yet either.
 

 

[Avro_Arrow]

I decided to just go with wire pads so I could
locate the sub board where ever it needed to be.
 
Any errors? Comments?
 

 

 

[walangalam]

I came across some of my notes on this chip.  Seems that a pulse rotary switch Alpha SR10030 can be used instead of push buttons.  I have not tested this yet, but its available at Mouser .
 
http://www.mouser.com/catalog/specsheets/TW-700001.pdf
 
pricey at $6.40 though...
 
Any updates on your experiment?
 

 

[Avro_Arrow]

I'm just getting an order ready for Digi-Key...I'll have to see if they have that
or anything similar. Looks promising, thanks for the tip!

 

[00940]

I'm using a pair of DS1802 in my DAC (it's balanced so that's why I need two). As for a switch, I use a very old two decks, three positions, break before make rotary switch. I think it started its life as an input selector in a vintage amp. It was free, works perfectly for me and allowed me to use a big comfortable knob. I'm using the rotary as you would use push buttons : turning it to the left reduces volume, turning right increases, center is neutral. I mostly use it by letting it make contact for more than 1 sec in either direction though. The DS1802 interprets a long contact by changing the volume by 1 step every 1/10sec until you stop contact. It works for me, a rotary encoder would give a more analog feeling.

It is important to note that those DS1802 work best if followed by a very high impedance. 1meg or above is ok. They also don't swing much voltage (I wouldn't use those for more than 1Vrms) so don't use them after a CDP line out or add a 47K resistor inline to limit what goes in.

 

[Avro_Arrow]

I didn't see anything at Digi-Key.
 
Here is the link to the part at Mouser.

 

[Avro_Arrow]

Thanks 00940.
 
Both of the projects I want to try with this have JFet inputs.
 
My USB DAC has a pretty low output and I can lower the
output from my PCM1793 DAC so the volume control
does not clip. I have read about that nasty little trait
it has. It's too bad they could not have made it with
a little more voltage headroom...