I have reworked the board a little, i think it would be best to use the 2311 and go 5V only, this means standard 12v wallwarts can be used as i will split the supply on board.
Hi rhysh,
nice idea and good design. I have build a 6 channel volume control with the PGA2310 and I am very happy with it. I am not able to do the chip programming by myself so I decided to buy a control board from Dantimax:
http://electronics.dantimax.dk/Kits/Control_boards/index.html
The Control2 board delivers the signals for the PGA's. I can use a remote control and a encoder to change the volume. But I found only cheep mechanical encoders so far, not optical. But maybe someone has a good source for optical encoders?
For the design it is important to take care on the separation of the digital and the analog part including the ground planes. I am using the PGA with a maximum volume setting of 0 dB volume settings above create extra noise. So I think the unregulated signal should be high ennough and the PGA should be used as attenuator but not as amplifier.
nice idea and good design. I have build a 6 channel volume control with the PGA2310 and I am very happy with it. I am not able to do the chip programming by myself so I decided to buy a control board from Dantimax:
http://electronics.dantimax.dk/Kits/Control_boards/index.html
The Control2 board delivers the signals for the PGA's. I can use a remote control and a encoder to change the volume. But I found only cheep mechanical encoders so far, not optical. But maybe someone has a good source for optical encoders?
For the design it is important to take care on the separation of the digital and the analog part including the ground planes. I am using the PGA with a maximum volume setting of 0 dB volume settings above create extra noise. So I think the unregulated signal should be high ennough and the PGA should be used as attenuator but not as amplifier.
I have added optocouplers to keep noise down. Also i will leave headers for seperate analogue and digital supplies.
Don't forget
- it's a good idea to add ESD and HF-filters to the Input, because the PGA are not cheap and SMD is not easy to change
- the PGA need low-resistor-source driving
- it's a good idea to add ESD and HF-filters to the Input, because the PGA are not cheap and SMD is not easy to change
- the PGA need low-resistor-source driving
Kay said:
I may change the PGA to DIP instead of SMD, and also i will buffer the input maybe...
Rhys
Rhysh,
Are you ever going to offer boards of the original PGA2310 volume control? I could use a couple.
I was looking at the TI site and did not see as many options for DIP chips as for the SMD parts. What chip was used on the first units you built.
If you use totally separate supplies and grounds for the analog and digital sources is noise still a big issue here? The specs for the individual devices put noise at 95db or better. That is damn quiet. Of course optical isolation would probably be the best performance. The optical encoders on EBAY are pretty cheap.
Tad
Are you ever going to offer boards of the original PGA2310 volume control? I could use a couple.
I was looking at the TI site and did not see as many options for DIP chips as for the SMD parts. What chip was used on the first units you built.
If you use totally separate supplies and grounds for the analog and digital sources is noise still a big issue here? The specs for the individual devices put noise at 95db or better. That is damn quiet. Of course optical isolation would probably be the best performance. The optical encoders on EBAY are pretty cheap.
Tad
rhysh said:
I assume anyone would put the micro into sleep mode while volume is not being changed, so how would this isolation help? You mean to say you are more paranoid than me? And just to make a midfi circuit happy 🙂
I am adapting this board to a slave board only, no microcontrollers will be on board. This allows the board to be used with a large number of projects that interface with the PGA. I have added OPA2134's to buffer the PGA for best performance.
I will be making the smaller board that contains the AVR so the boards can still be used together.
I will be making the smaller board that contains the AVR so the boards can still be used together.
Rhysh,
As stated above to get the volume control to function you will need power supply and encoder only -- correct? I have been searching on EBAY for an encoder. Is there a specifie type of signal needed or just a plane encoder type switch. Example: maybe. As you might have noticed this is NEW to me. Trying to learn something here.
Much thanks Tad
As stated above to get the volume control to function you will need power supply and encoder only -- correct? I have been searching on EBAY for an encoder. Is there a specifie type of signal needed or just a plane encoder type switch. Example: maybe. As you might have noticed this is NEW to me. Trying to learn something here.
Much thanks Tad
I have redesigned the volume controller, but the basic functions are still the same.
There are now two boards, the PGA is now in DIP format, all the digital stuff is on one board and the PGA's + buffer is on another, connected together by a ribbon cable.
This allows the volume control board to be mounted directly on a rear panel and the AVR and digital connections elsewhere.
You need a standard rotary encoder, you can find these for less then $1.
I will upload images of the new design shortly, but yes, all you need is a rotary encoder, ribbon cable and power supply.
There are now two boards, the PGA is now in DIP format, all the digital stuff is on one board and the PGA's + buffer is on another, connected together by a ribbon cable.
This allows the volume control board to be mounted directly on a rear panel and the AVR and digital connections elsewhere.
You need a standard rotary encoder, you can find these for less then $1.
I will upload images of the new design shortly, but yes, all you need is a rotary encoder, ribbon cable and power supply.
An externally hosted image should be here but it was not working when we last tested it.
The brains of XAR, at only 40mmx20mm, it connects to XAR via the ribbon cable. This allows the XAR to be integrated into any digital preamp setup without being held back by onboard logic.
rhysh said:
The brains of XAR will come as a kit, with a pre flashed AVR, tested and working.
This little board also regulates 5v for the AVR and also for the PGA's, the 5v is sent over the ribbon.
An externally hosted image should be here but it was not working when we last tested it.
Here is the latest version of XAR, with no input buffers. I may leave them out yet , i have not decided. Decoupling has been added to the PGA's, a film/ceramic cap should be soldered to the bottom of the electrolitic's.
The XAR can be connected to its brain, or to any other control circuit using the standard PGA method, via the ribbon connector.
All that is needed to make the XAR 'work', is its brain and a 15v +/- supply.
If needed, the brain can be soldered directly onto the pga board if a long enough pin header can be found.
Here is the version with buffers.
The same decoupling trick applies to the opamps. Solder the film/ceramic to the pins of the existing decoupling caps.
An externally hosted image should be here but it was not working when we last tested it.
The same decoupling trick applies to the opamps. Solder the film/ceramic to the pins of the existing decoupling caps.
- Status
- Not open for further replies.