Class D advice sought - powering 3 speaker drivers individually

Pygmy

Member
2016-07-01 2:58 pm
Haarlem
A while ago I spent a fair amount of time reading up on class D and eventually built an amp with a heavily modified TPA3116D2 board:

g4E5OW1.jpg


I'm using it to this day and I'm very happy with it.


Now I'm starting an active+dsp 3-way speaker project where every driver gets its own amp - and ofcourse I'd like them to be at least as good as my precious Frankensteined TPA3116 :)

On the other hand, I don't want to spend $150 per speaker just on amps.

The drivers will be 20, 20 and 100 watt.

I'm not very up to date on the latest class D developments anymore, so my question is - does anyone have suggestions for (a) cheap board(s) with at least "modded" TPA3116 quality that would suit my needs?
 
$2 Tpa3118 PBTL TPA3118 PBTL Stereo Sound 60W Digital Audio Power Amplifier Board Module c | eBay 1 per channel.

$75 TPA3251 4x100W 4Ch Class D Audio Amplifier | eBay (4x BTL, 2 chips) for a step up in SQ and power
ADAU1701 Audio DSP 2In 4Out Pre-Amplifier Board | eBay is a nice dsp from the same maker, both are very silent and have balanced connections between them.

Only 4 channel, but you can use simple crossovers for the tops, especially with the flat impedance planar tweeters you like to use.

For TPA3116 with DSP ZOUDIO AIO4CH: 4-channel amplifier with DSP and Bluetooth (~€70?) I have not used this one.
 
Hello,
choosing amplification for such a project is not as simple as it might seem.
For an active speaker you may use identical amps for all speakers, as these will sound identical and can be driven by one SMPS. So you pay a bit more on amps, save on supply.
If you use small amps for mid / high and a large one for the woofer, you may save on amps, but have to deal with more than one power supply.

If you would do a commercial design, you could use a symmetric supply and use just one amp model, only bridged for the woofer.
As an alternative, there is a custom SMPS with more than one voltage.
Last option, use an old fashioned linear supply where the transformer has different voltages for different amps.

OK, for a start that is quite a lot of options. IMO the one SMPS, high powered amps for all speakers seems to be the best option for DIYS.
If you can use low impedance woofers or two in parallel, the 3-channel 3e-audio amp with matching DSP cold be a nice option.
TPA3251-3CH-200W | 3e Audio

One very serious warning. The usual commercial active loudspeaker has the electronics integrated. Because in large scale an additional housing is more expensive than the whole electronics in it. Technically this is a very bad solution, as all the parts of an amp and DSP do not like to be hit by bass all the time. Sound and live expectancy suffer (see how many active sub woofer fail!).
So better build a neat amplifier with DSP and run loudspeaker wires to the loudspeaker cabinets. The result, in any case, should be better.
 

Pygmy

Member
2016-07-01 2:58 pm
Haarlem
Hello,
choosing amplification for such a project is not as simple as it might seem.
For an active speaker you may use identical amps for all speakers, as these will sound identical and can be driven by one SMPS. So you pay a bit more on amps, save on supply.

I've gone ahead and bought 2 of these:
Sure Electronics AA-AB35281 3x200W Class D Audio Amplifier Board - T-Amp

Eventhough "3x200W" might be "Chinese Watts", I think they should be capable of driving my TB W6 1139SIF woofers (And the Tectonic midrange, and Hivi tweeter) without any problems at the SPL I'll be using them at.
(Bedroom speakers :))

now I'm figuring out how to best power them.

My plan is to put the DSP and amps in a single amp chassis, running separate cabling to all drivers in the speakers.

This way the amps aren't locked to the speakers - I can use the amp for other speakers later on, or build a different amp to power my speakers.

Now to decide on good power supply for these two "3x200W" amps.. :)