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My new preamp design: Arduino, 6 input selector, MDAC attenuator, IR etc
My new preamp design: Arduino, 6 input selector, MDAC attenuator, IR etc
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Old 13th November 2016, 10:57 AM   #1
maxw is offline maxw  United Kingdom
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Default My new preamp design: Arduino, 6 input selector, MDAC attenuator, IR etc

I've made a new design where the MDAC attenuator, input selector and RCA board all sandwich together into a nice compact unit:

Click the image to open in full size.

Click the image to open in full size.

My last preamp project had only 3 inputs which was a little annoying so I designed a new one with 6 inputs and mute:

Click the image to open in full size.

I've written the initial Arduino code for two rotary encoders, one for volume and one for input selection, infrared and start up mute. The code is here:
https://github.com/FutureSharks/preamp-two

For now I'm using an Arduino Pro Micro 5V but I think I'll switch to something more modern like a NodeMCU or something that uses an ESP32.

PCB layout files are here:
https://github.com/FutureSharks/prea...ee/master/PCBs

The power supplies I'm using are these two:
A simple LT1763 based 5V PSU
Compact DIY friendly dual TPS7A3301 power supply
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Old 13th November 2016, 11:02 AM   #2
maxw is offline maxw  United Kingdom
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Here it is in a temporary "enclosure" made from Makerbeam
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Old 13th November 2016, 11:05 AM   #3
maxw is offline maxw  United Kingdom
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And measurement taken with Arta
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Old 13th November 2016, 11:10 AM   #4
maxw is offline maxw  United Kingdom
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A couple questions:
1. Can anyone recommend a company for machining small quantity aluminium parts in Europe? I would like to get a front panel made from 20mm thick aluminium.
2. Has anyone used a bluetooth 4.0 / BLE remote with an Arduino?
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Old 13th November 2016, 11:14 AM   #5
thimios is offline thimios  Greece
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My new preamp design: Arduino, 6 input selector, MDAC attenuator, IR etc
Great job,i like it!
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Old 13th November 2016, 02:08 PM   #6
rainwalk is offline rainwalk  South Korea
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Hi Maxw,
it's also seemed great project! What type of the display for this amplifier?
Still neopixel?? I hope the LCD or FND!!
also more cheaper encoder is profered.
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Old 13th November 2016, 03:38 PM   #7
maxw is offline maxw  United Kingdom
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Quote:
Originally Posted by rainwalk View Post
Hi Maxw,
it's also seemed great project! What type of the display for this amplifier?
Still neopixel?? I hope the LCD or FND!!
also more cheaper encoder is profered.
Thanks. For display I don't know yet. I think LCDs look cheap so not so keen on that idea.

You can definitely use cheap encoders! I don't know what problem you had in the other thread but I've used many cheap encoders before without issues. Sometimes they need some hardware of software debouncing but it's definitely possible
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Old 13th November 2016, 03:42 PM   #8
rainwalk is offline rainwalk  South Korea
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Quote:
Originally Posted by maxw View Post
Thanks. For display I don't know yet. I think LCDs look cheap so not so keen on that idea.

You can definitely use cheap encoders! I don't know what problem you had in the other thread but I've used many cheap encoders before without issues. Sometimes they need some hardware of software debouncing but it's definitely possible
Okay. I'll try again and let you know.
Thanks!!
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Old 13th November 2016, 03:47 PM   #9
maxw is offline maxw  United Kingdom
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Quote:
Originally Posted by rainwalk View Post
Okay. I'll try again and let you know.
Thanks!!
Try the code in this post here:
https://forum.sparkfun.com/viewtopic.php?t=13956#p65052
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Old 22nd November 2016, 10:27 AM   #10
AlanElsdon is offline AlanElsdon  England
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Max,

Files downloaded, I will let you know how I get on.

Alan
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