Author Topic: Analog Devices new digital pot  (Read 3471 times)

Transmogrifox

Analog Devices new digital pot
« on: March 18, 2006, 11:00:45 PM »
Anyone check this out yet?

http://www.analog.com/UploadedFiles/Data_Sheets/101658858AD5290_0.pdf

Pretty sweet.  They're up to +/- 15V supply now (30V single-supply).  More than enough for a Mutron or similar.  They're about $1.60 each which is pretty cheap.  Only thing is they only come as surface mount parts.  That isn't a huge deal, either, since many of you have been doing surface mount.  I think they'll be great for tremolos and filters. I think they would also be fine as ring modulators.
trans·mog·ri·fy
tr.v. trans·mog·ri·fied, trans·mog·ri·fy·ing, trans·mog·ri·fies To change into a different shape or form, especially one that is fantastic or bizarre.

Peter Snowberg

Re: Analog Devices new digital pot
« Reply #1 on: March 18, 2006, 11:09:54 PM »
THEY'RE HERE!!!! :icon_mrgreen:

This is the step that I believe will bring easy analog presets, at least for any circuit that makes use of 10K, 50K, or 100K pots.

The +5V voltage restrictions before were just not convenient for our 9V world.

With 256 steps, they're still a little crude for active modulation. Zipper noise will be a problem in some places.


Thank you VERY much Transmogrifox for bringing this to our attention! 8) 8) 8) 8) 8)
Eschew paradigm obfuscation

MetalGuy

Re: Analog Devices new digital pot
« Reply #2 on: March 19, 2006, 04:38:04 PM »
This is not really news but it is a good reminder. The price at Digikey is $4.86 the piece though.
I would be happier to see a programmable all tube preamp where you'll be able to choose between many different well known guitar preamps.
 Unfortunately I doubt that even these pots will be able to take the voltage swing  present at a regular guitar amp tone stack not mentioning that TS itself will need to be modified in order to get the same ferq. response with these values. And what about a 250k-1M Drive/Gain pot ?

Transmogrifox

Re: Analog Devices new digital pot
« Reply #3 on: March 19, 2006, 06:03:53 PM »
It depends where and how you used it in an all-tube amp.  It is true there would be some modifications necessary since you would have to divide the AC signal down significantly to use them in a tone stack...then use another tube stage or two to amplify it back to an acceptable level.....more trouble than it's worth, I admit.

I was going to say that for a TS or something that you could use a number of them in series/parallel combinations to get the values you wanted, but again at $4.68 each, it could get expensive quickly.

I'm still thinking phasers, envelope filters, tremolos and compressors.

The 8-bit resolution has a work-around.  If you put two pots of different values in series, and write the series pot at the correct intervals, then you may be able to get up to 16 bit resolution (for 16-bit you'd need a factor of 256 difference between the two values).  I would probably just go for potA =2*potB and use it just to double the resolution  This would be for the variable resistor configuration where you use it with the wiper shorted to one of the legs.

To increase resolution using a wiper'd pot, I think it would take four digital pots, or a strange parallel configuration.
trans·mog·ri·fy
tr.v. trans·mog·ri·fied, trans·mog·ri·fy·ing, trans·mog·ri·fies To change into a different shape or form, especially one that is fantastic or bizarre.