Deleted member 46664
Edit: I just went to your blog, really interesting. Good job!
Glad you liked it. There's more to come.
So, can we subjectively compare with TPA3255? (Amir shown it was technically awesome)
I might be able to help with that one a bit ... I've been playing with these mini-amps for quite some time now. One of the things I do for friends and their friends is build "soundbar killers"... basically a mini-amp and a decent pair of speakers that you can hook up to your TV set for better sound. In the process I've used TPA3116, TDA7492, TDA7498, TPA3221 and, most recently, TPA3255 based amplifiers.
The TDA series chips provide excellent sound quality and run cooler than the TPA chips ... but they also hiss when quiescent. It's not loud, but once you hear it... you can't un-hear it, if you know what I mean.
The TPA series chips are quieter but run hotter. The 3116 is not very happy on 4 ohms. The 3221 and 3255 are more able to handle the lower speaker impedances. The 3255 is obviously the most powerful.
A secondary concern is the output filtering networks on these amplifiers. The make or break for a Class-D amplifier is the output filter. Some of the really cheap ones use little bobbin style inductors that have rather high series resistance and do not carry output currents well at high volumes. Others use dirt cheap capacitors that really don't do the job of taking down the high frequency pulse chain, allowing it to leak into the speakers. So be sure you're looking at quality parts in the output filters... or buy something else.
Listening impressions seem to bear out the practical observations... The 3116s are very impressive on 8 ohm loads but sound a bit weak on the 4 ohm speakers. The same is true of the 7492 chip ... great on 8 ohms but a bit weak on 4. The 7498 is a powerhouse chip, sounds clean and powerful no matter what you hook up to it... but then there's the hiss...
The 3255, with a proper output filter, suffers none of these limitations, It just produces really great sound.
That said... there's my notice above about the fake 5532 chips ... For best results, given the less than $1.00 cost, I would suggest swapping out the 5532s and putting in RC4558s in their place. (on any of these boards, actually)
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