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digital attenuator


kevin gilmore
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  • 1 month later...

You'll get a tighter match to the ideal resistance curve of the attenuator. Whether it will be audible or not, doubtful. 0.1% should be good enough.

Some might say using the naked Vishay s102/z102 would be the best (and most expensive), but I don't think these are available in surface mount.

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  • 10 months later...

I've got my controller boards working pretty well now with the digital attenuators.  I like the larger one because it has a really nice feel as you turn the volume knob (...yes I see it :P).

I went and added a USB input to the board itself, though this is really overkill - which is why I did it.

IMG_0315.thumb.JPG.0d463cef57a0e76e4e32c49ab3835d8b.JPG

 

Here I'm updated with the TX / RX LEDs blinking away.

IMG_0313.thumb.JPG.f843a2dd0446734d726b1df0d22eb590.JPGIMG_0314.thumb.JPG.49108924af68518ce41335f0f66addb4.JPG

 

EDIT: I've got to do one more round of cleaning...

Edited by Kerry
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Here's the code.  Just rename the PDF to Zip and expand it into a folder under your .../Documents/Arduino directory.

The code works well now, though there are a few things I'd like to keep working on.  It will drive one of the I2C 1" OLED displays.  I typically comment this out at line 101 in the main program (EDIT since I don't use the display in the amp)...

  //  If not using display just don't create it
  activeOLED = new OLED (128, 64,SSD1306);                                                        // I2C Display
  //activeOLED = new OLED (128, 64,SH1106, OLED_MOSI, OLED_CLK, OLED_DC, OLED_RESET, OLED_CS);      // 1.3" SPI Display

 

I'm happy to keep working on it.  I can post the Gerber files as well at some point.

 

VolumeController.pdf        ->  rename to VolumeController.zip

 

EDIT:  I just wanted to add a note that this will work on an Arduino UNO or Pro Mini.  Pretty much anything with an Atmel 328P.  Could probably support other chips as well.

EDIT 2: This code will run the older and larger I2C boards (requires a slight code change) as well as version .4 and .5 of the current SPI boards.

Edited by Kerry
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  • 4 months later...
On 3/19/2017 at 4:23 PM, Kerry said:

I've got my controller boards working pretty well now with the digital attenuators.  I like the larger one because it has a really nice feel as you turn the volume knob (...yes I see it :P).

I went and added a USB input to the board itself, though this is really overkill - which is why I did it.

IMG_0315.thumb.JPG.0d463cef57a0e76e4e32c49ab3835d8b.JPG

 

Here I'm updated with the TX / RX LEDs blinking away.

IMG_0313.thumb.JPG.f843a2dd0446734d726b1df0d22eb590.JPGIMG_0314.thumb.JPG.49108924af68518ce41335f0f66addb4.JPG

 

EDIT: I've got to do one more round of cleaning...

That is just all kinds of cool!

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7 hours ago, ti5002000 said:

Hi guys 

Does someone have boards that don't need and can sell it to me? 

They can be only the pcb and also can be already populated. 

Thanks for the help 

I think I have a couple boards I could sell you.  Send me a PM.

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  • 2 weeks later...
  • 1 year later...
On 7/23/2015 at 10:59 PM, kevin gilmore said:

for the V2 attenuator, there was one missing wire, will fix soon.

 

 

fixed

 

http://gilmore.chem.northwestern.edu/boards/attenuatorsmtv2.zip

 

http://gilmore.chem.northwestern.edu/attenuatorsmtv2.pdf

i have a question. i have tried to get quote for this board, and when i have uploaded the gerber file, system detected 3 layers. i can choose between 2, 4, 6. if i were to use 2, what happens if this inner layer is discarded? or in case of 4 layer, i suppose this inner layer is then duplicated and then there are two 2-layer boards pressed together with same inner layer?

thank you

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Did anyone ever put this together with the selector boards that were run?  I was looking at AMB's setup for volume and selecting sources but I seem to remember somebody saying that his attenuator won't work with the amps here.  It would be cool to put this together with the SE/BAL to BAL/SE board

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On 6/6/2019 at 4:09 AM, sbelyo said:

Did anyone ever put this together with the selector boards that were run?  I was looking at AMB's setup for volume and selecting sources but I seem to remember somebody saying that his attenuator won't work with the amps here.  It would be cool to put this together with the SE/BAL to BAL/SE board

I got a set of two boards I’m planning to build soon - too many projects but this has come back on the radar

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On 6/14/2019 at 9:49 PM, randytsuch said:

Decided I'd like to give this a try if I can get my hands on the boards.

If you can't find spare boards then you could just add a 4th layer (like just duplicate the middle layer) then you could get new boards made quickly and cheaply at a place like https://oshpark.com

Otherwise 3 layer is less commonly available and you might have to go to a more expensive PCB manufacturer.

 

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