SBC2 to control isolated audio Preamps...

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kevinp@sepcousa.com
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SBC2 to control isolated audio Preamps...

Postby kevinp@sepcousa.com » Fri Dec 07, 2012 2:28 pm

hello,
I am sorry if this has been posted somewhere else, I could not find it.
I am trying to make sure that there is a Phidget that will do what I need it to do and some advice on which one it might be and how to design the output circuit.
For ease of discussion, I will only talk about 1 output...even though I will actually be using 4.
what I need is some sort of "interface" that can take the place of the physical potentiometer in a Pre-amp that I am using. All the Pot does is vary the voltage that is given to the output stage of the pre-amp. I would love to say that it is from zero to 5 volts but I can not be certain as I can't find a reference ground for the device. Basically, what I need is a virtual pot inside a circuit that is isolated from the Phidget. This circuit will obviously have a static input and then two outputs, one leading to the output stage of the pre and the other leading to ground within the original pots circuit.
I hope this made sense but I will try to elaborate if needed.
ANY advice is greatly appreciated!!!

kevinp@sepcousa.com
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Re: SBC2 to control isolated audio Preamps...

Postby kevinp@sepcousa.com » Mon Dec 10, 2012 3:41 pm

OK...so...I found some new information. Maxim makes a digital pot that should work perfect for my application but I am not sure as to how I will wire it. Judging from what I have read about this chip, the DS1868, I will have to actually use 4 digital outputs from my phidget to control each of these dual-channel pot chips. 1=reset, 1=clock, 1=dataL, 1=dataR. If ANYBODY has any experience with these devices I could really use some help...I AM willing to PAY for time!!

THANKS!!

erik
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Re: SBC2 to control isolated audio Preamps...

Postby erik » Mon Dec 10, 2012 4:05 pm

While it does sound like you need a digital potentiometer, you may not be successful controlling it due to timing issues while trying to control all four digital outputs at the same time on the Phidget device. Also, you would have to pretty much program a communication protocol that is widely available on most micro-controllers (SPI).

On our 1204 TextLCD controller board, we use two digital potentiometers (part number AD5160) to change the brightness of the backlight.

kevinp@sepcousa.com
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Re: SBC2 to control isolated audio Preamps...

Postby kevinp@sepcousa.com » Mon Dec 10, 2012 4:21 pm

erik wrote:While it does sound like you need a digital potentiometer, you may not be successful controlling it due to timing issues while trying to control all four digital outputs at the same time on the Phidget device. Also, you would have to pretty much program a communication protocol that is widely available on most micro-controllers (SPI).

On our 1204 TextLCD controller board, we use two digital potentiometers (part number AD5160) to change the brightness of the backlight.


Erik:
thanks for the info. Yes, I have come to the conclusion that this is basically what I need and I have seen some samples of where it has been used with a controller and some momentary switches to do the job. I was just hoping to be able to do the entire job with a Phidget as opposed to having a device (phidget) control another device (PIC controller) to control the pots that control the final device. I guess my vehicle audio system is becoming a nightmare again...I ALWAYS do this! I love doing things outside-the-box and they almost always create something really cool but cause many headaches along the way! I guess I will control my volume the "long way" and use the Phidget 8/8/8's 8 outputs to control the 4 stereo channels through the PIC chip. SUX, but probably better in the long run!!

THANKS!!

loicco
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Re: SBC2 to control isolated audio Preamps...

Postby loicco » Fri Oct 25, 2013 10:54 am

Hello, Which pin si used for the digital potentiometer? How many ohm?
Thanks
Loicco


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