digital pot for bass/treble/balance cntrl

[Doovieman]

Has anyone used a digital pot for bass/treble/balance control? If so, do you have any recommendations? Thanks,

Doovieman

[jackinnj]

Originally posted by Doovieman
Has anyone used a digital pot for bass/treble/balance control? If so, do you have any recommendations? Thanks,

Doovieman

Lots of choices -- Analog Devices, Dallas Semiconductor (now owned by Maxim), National Semiconductor, TI, Microchip Technology, etc.

[Doovieman]

Yes, I know that there are several companies that manufacture digital pots. My question is if anyone has any recommendations of specific parts. I requested samples of AD5231. I realize that 10 bit resolution is a little extreme, but I want non-volatile memory, SPI interface, and single channel. Either way, I'll write my firmware such that there are much fewer than 1024 steps... Any suggestions? Thanks,

Doovieman

ps Data sheet: http://www.analog.com/UploadedFiles/...70AD5231_a.pdf

[jackinnj]

the Nat Semi and TI devices use logarithmic steps but are not of the non-volatile variety. In particular, the PGA2311 is probably the lowest distortion (0.0002%) digital pot available.

[Doovieman]

Thanks for that link...those are some very nice specs. I wish it opperated on +3.3V, but oh well. Thanks for the info.

Doovieman

[goering]

Dallas has a digipot that can be used with push button controls instead of a microcontroller.

Here's the link:
http://www.maxim-ic.com/appnotes.cfm/appnote_number/606

Can the PGA2310 or 2311 be used the same way? Could anyone describe how?

Thanks

[jackinnj]

it isn't difficult with discrete devices, but it's much, much easier with a micro-controller. the timing diagram is (of course) right there

You need a clock pulse string, a counter (which sends the 8-bit pot setting) and a flip-flop for the chip-enable. Right and Left settings are sent in one 16 bit packet so you have to stop the clock (but not bring the Chip Select high) to send the 8-bits of LEFT potentiometer settings.
Well, you actually could use two counters, if you want the RIGHT and LEFT to be the same you save the first setting in in one, then spill it out.

There are any number of micro-controller kits out there -- Basic Stamps (www.parallax.com), BX-24 www.basicx.com, Rabbits, Atoms, OOPICs etc. -- most program in easy to learn high-level languages. I started using the Stamp eons ago and now program PICs. The Stamp has a real easy to use "de******" which allows you to correct problems on the fly. (Note -- the web nanny will not allow you to use the technical term -- ergo hoc the asterix -- for catching errors in real time, has something to do with their fear of scatological terms.)

or get the Dallas semi chip (now Maxim)

[audiosteve]

Just an FYI; I've used the Cirrus CS3310 and think it sounds great. I did an AB test between it and my high end Tandberg pre-amp and the 3310 sounded cleaner to me. In the interest of full disclosure I should point out that I work for Cirrus BUT I used the CS3310 long before I became a Cirrus employee.

[drdagor]

Dallas Max just sent me info on their MAX5457

Dunno if the part is exactly what I need but theirerature had some interesting ideas in it.

Basic part is a pair of digital volume controls with up down and balance inputs built into a package. Has audio taper. Claims low noise and distortion, but then again, doesn't everybody?

Hope this helps.