how do I add preset memory and digital control of analogue circuit ?

Is there a reason not to use relays for the switches?

Mouser used to sell motorized potentiometers -- I'd check there. Even if you're in Oz or elsewhere outside of the US the Mouser part may lead you to a manufacturer, which may lead you to an in-country distributor.

There are lots of ways to switch, starting with humble old relays and moving up from there. How you switch depends upon what you switch. You're the judge of the best method, depending upon your requirements.

Pots are also a concern when you mention "Pro Audio." I'd suggest you Google for keywords 'digital potentiometer' then look at some data sheets for the chips you'll find. Are digital pots compatible with your system requirements?

If not, there are motorized mechanical pots out there that have the same electrical characteristics as standard pots. One of these driven by a stepper motor might be compatible with computer control, providing repeatibility of its settings.

Once you know what switches and pots are compatible with your system requirements, we can move on toward automating the arrangement.

Assuming, of course, the folks in rec.tech don't point you to an off-the-shelf solution right off the bat.

Tom

A modern device of that nature would be DSP-based, and those settings would be DSP parameters under program control. Problem solved!

There are such things as digital potentiometers, and there are also such things as digitally-controlled analog chips that serve a similar purpose. There are definately electronic switches that can be digitally-controlled.

Check the leading manfactuers of mixed-signal chips, such as National and TI.

Ask this question in the Usenet DSP group.

One way to get where you want to go is to use digital potentiometers and switches/multiplexers such as those offered by Maxim/Dallas. You can check them out at

If I was still doing consulting/contract engineering then this is the point where I would offer my services but, alas, I am again a corporate carpet walking, cubicle dwelling, wage slave. ;-)

Roger that!

A typical logic-controlled device is the common 4066 CMOS quad bilateral switch for low-level (audio, etc.) signals. There are now solid-state devices for higher- power switching in addition to the perinneal favorite relays.

Both motorized physical pots and "digital pots" are available for logic-controlled adjustment of pot settings. For example,

Motorized pots are frequent favorites with several surplus electronic web vendors.

One of my favorite vendors is

You're really going to need a microprocessor/microcontroller to do this and you'll have to program it yourself. Are you up to that ?

Graham

There's a good place to start.

The cheap way is to use a CMOS pot replacement; Maxim makes a bunch of them that are very popular.

The expensive way is to use an attenuator built with relays and resistors. This will invariably sound better but in plenty of applications it doesn't matter.

There are all sorts of gadgets that will give you parallel port outputs from whatever source you have.

--scott

Great link, thanks.

Thanks

Thanks

Thanks

Guess we'll find out.

Thanks

That would be the ADA MicroCab speaker emulator, right? Fun coinsidense.. same username, electronics experience et al..:

Only a few days after I depicted the unreadable components for you (yes, I'm van Sinn at the depot), and mentioned I might build my own _copy_ with some controls.. At the adadepot, we all honour the ADA legacy, so please.. at least write you wish to add programmability to an ADA _recreation_ ..

Yup, not a big task with a 20-pin PIC, eeprom, a few MIDI IFC parts, a few 4066's and optocoupled pots - and some assembly programming..

Don't let Mr. Ham scare you off, once you get a fell for the little uC's, you'll wonder why you stayed away so long.. They solve many hours or design and labor..