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implementing presets

Started by jon_bondy, May 01, 2019, 04:26:45 PM

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jon_bondy

I'm designing an amplifier based on the Orange Crush series.  The only problem I have with that amp is that there are only two presets (clean and dirty) and the tone controls are shared between the channels.  I want perhaps 5 or 10 presets, each of which uses a different set of values for the various pots.  I could use a huge switch and switch in a bank of pots, but that seems both unreliable and difficult to implement.

Has anyone on this board attempted to implement presets?  What approach did you take?

phatt

Hi Jon,, welcome :)
Not a simple project xP  You will need relays, dedicated foot control switches and a one off circuit which may require more power than the tiny 10 watt amp can deliver.
So in my observation it's *False economy* a whole lot of work for little return. :'(
When you can buy a nux pedal (or similar) with 100 user settings for under $100Au
then it's a no brainer. 8|
I'm aware that a lot of players like the idea of an *All in one* amp that does it all but it's rare to find and ones that are capable are likely to cost a small fortune. :-X

As much as I hate the idea of pedal boards they are extremely useful and cost effective.
Also allows for swap and go changes to get other capabilities. Dedicated *Do it all* Amps are not swap and go friendly.
Phil.

jon_bondy

Hi, Phil.  Thanks for your comments.

I found these

https://www.analog.com/media/en/technical-documentation/data-sheets/AD5228.pdf

https://www.analog.com/en/parametricsearch/10982

Seems that one can now setup a circuit board that usually uses a pot, and replace the pots with these circuits.  Should allow fairly straightforward presets.

I'm just playing around with this project.   And it could well evolve.

:)

Loudthud

#3
Programmable pots open up a lot of possibilities. You could even make some of your stompboxes programmable. Beware that many programmable pots don't like signals that go beyond the rails so you need +/- supplies when the pot has an AC signal on it.

Jazz P Bass

Sounds like a fun project.

Although it will take a lot more than simple potentiometer changes to get useful presets.

jon_bondy

@Jazz P Bass:

What do you mean by "it will take a lot more than simple potentiometer changes to get useful presets"?  Can you give me a few examples?

jon_bondy

#6
The amp design is taking shape, and it is likely to be very controversial.  I would appreciate feedback.

The basic idea is to take an Orange schematic, replace the pots with digital pots, and add an Arduino to allow control of the digital pots.  The Arduino would read the pot settings for each preset from a text file present on an SD card.  WiFi or bluetooth connectivity would also be implemented on the board, but I would not want to have to write an Android app for just one amp.  There would be (say) 7 buttons to select one of 7 presets, plus a pot for reverb intensity, a pot for master volume, a pot for amount of lead boost, and a push button to enable/disable lead boost.  Very few controls at all, and none of them related to a preset (although I suppose I could put the lead boost pot into the presets).  All of the configuring would be done ahead of time by editing the text file and copying it onto the SD card in the amp.  Provision for a foot board would also be made (preset selects, master volume, lead boost).

I have no idea how much I would like this level of increased flexibility coupled with increased inflexibility.  That is, this would be an experiment.

Any reactions?