M-DIY-BL1200 Review and Install

M-DIY-BL1200 Review and Install

Please find below notes on M-DIY-BL1200. 

M-DIY-BL1200 - Intro

The M-DIY-BL1200 is a Bluetooth receiver module. It is quite an attractive offering as it have many additional features over rivals they include:

• Audio Input (automatically switching when audio input lead is attached)
• Audio Output (to amplifier)
• 12v to 25v input voltage
• 5V connector (not sure if output or input) maybe both!
•  Various extra connetion points for volume, and track skip buttons etc.

Video overview (terrible sounds and video quality soz). This video was made before I fitted the module / board, so is a bit light on detail.

M-DIY-BL1200 - Install

One of the most attractive things about this module is that it come supplied with detachable wires, which make soldering it a cinch. It is ideal for TPA3116 as the 24v voltage matches upper voltage of TPA3116, so that is ideal. 

Things go down hill from here.

M-DIY-BL1200 - Noise (Ground Loop)

So when I first fired this thing up there was all kinds of noise coming out of the speaker, before I had even started so I googled and I found: 

What we have is a problem with sharing the same power supply as the amplifier, which cuases "ground loop" I had a few spare components  lying around so I experimented to see what would help.

• I used a step down convertor to power the M-DIY-BL1200 at 12v. The main power supply is a 24v laptop brick (Minger). I guessed that the convertor may incorporate some sort of filter. I guessed wrong. Ground loop noise still present.
• I ran the M-DIY-BL1200 from a separate battery. This wasn't a fix as such, but just to try and diagnose problem. The ground loop noise went away. BUT there was another noise. . . .  .

 M-DIY-BL1200 - Noise (Buzz)

 

The other noise sounds like a amplifier when you have a lead plugged in, but no input. It is a steady hum or buzz and is quite loud. It was enough for me to abandon the project, remove the M-DIY-BL1200 module and revert to using a wired connection.  

M-DIY-BL1200 - Powered by Step Down Convertor

M-DIY-BL1200 - Intro Jingle

Whilst I can forgive design flaws as above (after all the board still does what it is supposed to do . . . .  badly), there is one feature that is unforgivable, that is the jingle that plays when the bluetooth is connected. Bling, bling BLOoOoOM. It is SOOOOOO loud, it distorts the speakers, even when the volume is turned down.

In order to avoid this, I had to mute the amp, connect / pair bluetooth, and then un-mute. This is a terrible feature, and I would avoid this board on that basis.

M-DIY-BL1200 - Conclusions

A DIY friendly board rendered unusable  by connection jingles and mystery humming noises. 

Preliminary Ecological Appraisal 

Environmental Consultants Bristol