Audible "Whistle" or "Whine" / Electronics Help Please!

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Audible "Whistle" or "Whine" / Electronics Help Please!

Postby HarmlessSaucer » 19 Jun 2015, 00:37

Hey guys,

I know this isnt exactly the right place to post this, but I thought since I have RuneAudio running on this project, I'd post it up in case an electronics nut has any ideas?

After I successfully got my iPod HiFi modded to run RuneAudio (http://www.runeaudio.com/forum/apple-ipod-hifi-raspberry-pi-runeaudio-t1036.html) my Dad was impressed and wanted something similar. I'd been wanting to get him something to go in his covered patio anyway, and something that could AirPlay would be awesome.

So, after some hunting on eBay I managed to find this "Lenco" brand iPod speaker tower. The 30pin dock connector doesnt work, but for £11 shipped, it was a bargain for the other parts! Here's a pic:
IMG_1825.JPG
The Lenco Speaker
IMG_1825.JPG (109.78 KiB) Viewed 1197 times


This thing is pretty big for it's price tag! Has six speakers and a "sub" inside. It also has a radio and clock.
I cracked the back open and found that there is LOADS of space inside to mount extra components:
IMG_1826.jpg
The insides
IMG_1826.jpg (119.81 KiB) Viewed 1197 times


Inside you can see at the top, the board that is the brains of the unit. I found the cable that plugs in here from the "aux" at the back of the unit.
This is what I tapped into.
IMG_1879.jpg
The brains of the operation
IMG_1879.jpg (97.14 KiB) Viewed 1197 times


So my project was working well. I pulled out the board, took the connector for the aux audio in off, spliced into it and attached a jack headphone plug into it. I connected this up to my phone and tested that I could get audio through here. It worked!

Then I ran into two problems:
1. The "aux" port at the back required something to be plugged in to reliably get audio from my new "internal" connector. Without something in the back, I got around 40-50% volume from my internal aux connector. Not sure why this is.

2. Whine/whistle. When the unit is running (even without the Pi plugged in or my audio cable mod) the control board makes a whistle/whine sound. As you press the volume up/down buttons on the controls at the top of the unit, this noise changes accordingly in pitch. As a test, I ran the board without the speakers plugged in. The whistle is faint, but is the same, and is audible from a component on the board.

Does anyone have any ideas? It works... but it's not perfect.

I'll keep this post updated with my findings and my progress!
Last edited by HarmlessSaucer on 19 Jun 2015, 00:43, edited 1 time in total.
HarmlessSaucer
 
Posts: 5
Joined: 27 Feb 2015, 23:07

Re: Audible "Whistle" or "Whine" on new project?

Postby HarmlessSaucer » 19 Jun 2015, 00:42

An update to this mod...
The shelf below where the "sub" bass speaker is has plenty of space for me to mount the Raspberry Pi:
IMG_1880.jpg
Shelf for Pi
IMG_1880.jpg (125.15 KiB) Viewed 1196 times


The bottom of the unit has a "figure 8" power connector cable. I spliced into this, and connected a normal UK plug socket I had lying around into this. This allowed me to easily have a detachable Raspberry Pi power supply that I had lying around:
IMG_1881.jpg
Power for Pi
IMG_1881.jpg (94.61 KiB) Viewed 1196 times
HarmlessSaucer
 
Posts: 5
Joined: 27 Feb 2015, 23:07

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