Digital Volume Control Voltage Reduction?

[Arn C.]

Howdy Folks!

      I am building a digital volume control using a DS1669, which I just received from Future Electric.
The input voltage calls for +5 to +8 vdc .   I have an ultra power supply I built that has 9volts output.  What value resistor and wattage should I use to reduce the 9 volts to 6 volts?   

Thank you for your help!
Arn C.

[Paul Perry (Frostwave)]

I'm not sure that using just a resistor & cap will do, because the current (from a brief glance at the data sheet) seems to vary from practically zero to 2mA.
So I'd be thinking of a 6v zener, fed from a 1.0 K resistor.
Or use an adjustable regulator, set to 6V, you have enough headroom (but that would be overkill, I admit).
And check out the application notes on the Dallas website..

[Arn C.]

Thanks Paul !!!!

Peace!
Arn C.

[RedHouse]

I'd pop in an LM78L05

[Arn C.]

I ended up putting in an LM78L05.   I will test it out tonight at home to see how it works.  It is a digital volume pedal with 64 steps up and down.  I will still have my passive morley volume pedal inline set for max volume level that I want.  This way I can go up or down in volume incrementally, since I seem to have a problem raising and lowering volume slowly while playing.

Thanks folks for your help!

Peace!
Arn C.

[A.S.P.]

series-diodes can be used to drop volts...
(~0.7V per 1N4148; ~2V per LED...)

[Arn C.]

Well, I tried it out and NADA, NOTHING, ZILCH, etc...

I will have to check it out tomorrow.  It may be my 9vdc power block connector, not matching up with the connector I put in the box.   so many could be this or that.  Back to the drawing board!

Peace!
Arn C.

[A.S.P.]

how do you "control" (address) that chippy?

[Arn C.]

 

I suspect by your reply I am leaving something 'important' out of this circuit, that I probably no nothing about.

I can take it!

Peace!
Arn C.

[Paul Perry (Frostwave)]

how do you "control" (address) that chippy?

http://www.maxim-ic.com/appnotes.cfm/appnote_number/168 reveals all.
You don't need a micro or anything, there is a "button" mode, where you just have an up & down button.
I thnk this is a perfect app for two 'reflection' sensing IR optical switches, but that's just me. I'm sure traditional stomp switches would be too clunky, though.

[Arn C.]

http://www.electronics-lab.com/projects/audio/033/

The above is what I used.  I guess I must be missing something.  That circuit is what I built and used 5voltsdc regulated with an LM78L05 and I get nothing.  I did miss where it said to use a dual polarity power supply to cure clipping problems(I didn't do this).
There must be more to this, but I don't know what it is.  I used two N.O. momentary stomp switches.
I'm Lost.............

Arn C.

[A.S.P.]

what`s the suffix # of your DS1669?
if it`s "10", and you hooked your guitar directly to it,
it is loaded by a parallell R of 10k...

[Arn C.]

Yes, it is "10".  So, does this mean that the signal is loaded down to the point where the signal won't go through?  If so, is there a remedy for this?

Thanks!
Arn C.

[A.S.P.]

not that nothing goes thru,
but that there`s nothing left right up front, to be divided down.

in this case you need a buffer in front of the digi-pot;
or hook the pot after your first pedal in the chain.

you can test the functioning of the pot itself, by hooking a cd-player or the like to it.

[Arn C.]

So, are you basically saying that I need the signal to be boosted before it goes into the digital volume pot box?

Thanks!
Arn C.

[A.S.P.]

not neccessarily boosted, but buffered


the status quo you got now,
is having the guitar going into a 10k pot...
(as opposed to 1M or 470k usual impedance of amps/FX)

[Arn C.]

So, if I build a small buffer circuit, I am sure there are some around here, and place that in the beginning of the audio signal then into the ds1669 chip, it should work?

Thanks a bunch for your help on this.
Arn C.

[A.S.P.]

yes

[Arn C.]

Thanks A.S.P. for your help!  I will give it a try...

Arn C.

[Arn C.]

"IF" I get clicking when I depress either switch, how could I eliminate that?

I built the buffer from GGG, the transistor one.  I won't be able to try this until I get home this afternoon.

Thanks,
Arn C.