TDA7492P bluetooth amp bridging and power supply question

Thread Starter

SimpleJoe

Joined Mar 22, 2016
35
A while back i set out to make a portable bluetooth speaker using a Tda7492p 2x40 watt amp Specifically this one:
http://www.banggood.com/TDA7492P-50...ceiver-Digital-Amplifier-Board-p-1003047.html)

I did some research on the chip itself and found that they only recommend 2x25 w continuous but i also noted that this was at 8 ohms impedance. the speaker i built uses typically 1 port running a 120 watt 4 ohm 3-way home theater speaker, with a second sometimes plugged in (should i earth this out or something when not in use?). many of these amps vary their outputs with different impedances i just don't know if 4 ohms is the best as bangood recommends 8 but cannot see this anywhere on the spec sheet.

there was also some notable distortion in the bass when in high gain mode which i can only think of the input voltage that could cause this (or once again the impedance of the speaker). it currently runs a 4 cell li-ion (~16.4v) but i have been planning to upgrade to 5 or 6 cell (20.5~24.6) (is this worth it).

So just to summarise everything:
  1. should i some how increase theimpedance of the speakers (and easy way to do this would be great)
  2. should i increase the input voltage to the chip
  3. is there any way to bridge the outputs when the second is not in use or should i be doing something else with the connector
Thanks,
SimpleJoe
 

Dodgydave

Joined Jun 22, 2012
8,866
Its a Bridged output, so no you can't ground the outputs, you need to use both channels with 8ohms speakers.

Do it right, or blow it up!
 

Thread Starter

SimpleJoe

Joined Mar 22, 2016
35
So both speakers have to be connected at the same time? I thought bridged outputs were only a single pair of outputs, not a pair of pairs (R+/- and L+/-) like how the amp is setup.
 

Thread Starter

SimpleJoe

Joined Mar 22, 2016
35
That is why i asked if there was anyway to bridge the two outputs so instead of the current setup of 1 speaker only playing one side of a stereo output i could still use the one speaker but with a more powerful mono output
 
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