Hi Guys, I want to make a reasonably simple digitally controlled volume control. I was looking at a VCA, but the chip I intended on using (SSM2164) is no longer avaliable, and im no longer sure that a VCA is the best option for Hi Fi systems.
*Just to fill in the background - I have buit a prototpye amp, and now want to make the volume control to ensure it all works as wanted before moving on. Music source will be an ipod/computer, and there will be between 4 - 6 rooms, each with two amps and seperate volume control.
Can someone please suggest a circuit for the volume control? I have used pic chips before, and will use one to control the volume (with a digital - analog converter if need be!)
Thanks
*Just to fill in the background - I have buit a prototpye amp, and now want to make the volume control to ensure it all works as wanted before moving on. Music source will be an ipod/computer, and there will be between 4 - 6 rooms, each with two amps and seperate volume control.
Can someone please suggest a circuit for the volume control? I have used pic chips before, and will use one to control the volume (with a digital - analog converter if need be!)
Thanks
Thanks for your replies!
The PGA2311 looks like it is the right thing for the job, has anyone used this or have any idea of how well it works?
For power supplies, I would have used a spare computer power supply to generate the +/- 5v (analog) but where do I get +5v digital from?
Also, if anyone has used this, can they please discribe what they used as a controller?
Thanks
The PGA2311 looks like it is the right thing for the job, has anyone used this or have any idea of how well it works?
For power supplies, I would have used a spare computer power supply to generate the +/- 5v (analog) but where do I get +5v digital from?
Also, if anyone has used this, can they please discribe what they used as a controller?
Thanks
Use either PGA2310 or PGA2320 - these use +/- 15v analog supplies which is pretty standard, and what you will be using if you have further opamps in your circuit.
Do not use any switch mode PSU in a preamp - the noise will be dreadful. Use a simple linear PSU, using LM317/337 will do. 5V for digital use should be a seperate regulator (7805 will do) and preferably a seperate transformer.
Programming the PGA chip is over a 3-wire serial bus. This is quite simple from any microcontroller. I would recommend Atmel AVR micro's personally but if you have used PIC, stick with that
Do not use any switch mode PSU in a preamp - the noise will be dreadful. Use a simple linear PSU, using LM317/337 will do. 5V for digital use should be a seperate regulator (7805 will do) and preferably a seperate transformer.
Programming the PGA chip is over a 3-wire serial bus. This is quite simple from any microcontroller. I would recommend Atmel AVR micro's personally but if you have used PIC, stick with that
If you go with PGA23xx or CS33xx, you can read some of my experiences here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=124488
Thanks for the replys, turns out that the PGA23xx have been discountinued! or at least they are difficult to get in Aus... the store I spoke to (rs-electronics) said their on back order for March '09!
Now looking at the DS1666, any suggestions about this or any other ideas?
Does anyone have a circuit for the DS1666? there doesnt seem to be one in the data sheet
Thanks
Now looking at the DS1666, any suggestions about this or any other ideas?
Does anyone have a circuit for the DS1666? there doesnt seem to be one in the data sheet
Thanks
They're not discontinued as such but there seems to be a shortage. Farnell UK have them down as a "Order from US" item. They have good stock of PGA2310 and PGA2311 however.
The DS1666 is just a potentiometer, so you would use it as you would an ordinary potentiometer in a preamp circuit. The only thing I don't like the look of, is how it is controlled - you can only increment or decrement steps one at a time. Presumably they did it this way so that you could use a rotary encoder with only some logic, and not have to use a microcontroller.
The DS1666 is just a potentiometer, so you would use it as you would an ordinary potentiometer in a preamp circuit. The only thing I don't like the look of, is how it is controlled - you can only increment or decrement steps one at a time. Presumably they did it this way so that you could use a rotary encoder with only some logic, and not have to use a microcontroller.
day1118 said:
Are you looking for DIP or can you work with SOIC? I have a large amount of PGA2320 if you are interested.
I also have a completed mini volume control I could sell you if you wanted to audition the IC before putting any effort into your own design. The programming and board design was done by another forum member.
An externally hosted image should be here but it was not working when we last tested it.
Sorry, I did have a look, but with 40 pins it seemed like an over kill, and I have not done any work with surface mount as of yet. Also, the electronic stores I was hoping to buy from do not carry the chip (or any CS chips I think).
I am now thinking that I will have to order from overseas (can anyone suggest a store that would ship to Australia that has reasonable prices?) so any chip can be considered, however is there a simpler/smaller version of the CS3318 in a DIP package?
Thanks for everyones help!
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