Class D/Tripath amp recommendations?

[Hemisphere]

Hi,

I'm thinking about using some class D (or class T, or anything else lightweight for that matter) amps for an upcoming DIY project, and was hoping someone here could help me pick a good amp (or two amps, actually)

These are the speakers I'll be driving with the amps:

The Monacor SP12a-300neo:
MONACOR INTERNATIONAL:Product detail page

and

Monacor MHD-230RD
PA Horn Tweeter MHD-230/RD Stage Line PA Horn Tweeter MHD-230/RD 1" 8ohm 80w 103430 - Stagebeat - 1" 8ohm 80w 103430 Horn Speaker MHD230/RD 10.3430

I presume the SP12a can take 1200w peaks (600w music power is stated), but that's irrelevant as my design exceeds xmax at 850w, which is probably also irrelevant because I need an amp that will operate without a heatsink (but it may be possible to ventilate it if necessary).

One option I looked at for the SP12a is the CD-NX400 (http://www.classd.ltd.uk/Datasheets/...D%20NX%27s.pdf) by the aptly named (but inappropriately in this case) Class-D Design.

According to the spec sheet it puts out 300w at 8ohm. Not sure how that will work out in the real world though, or if it will need a heatsink or not.

It does have the attractive price point of £48 with free shipping though

I don't have any soldering experience, and although I'd be willing to give it a shot if absolutely necessary, I'd rather find a preassembled package if possible.

Once I've got a few more specifics sorted out I'll make a proper thread for the project just need to make sure it's feasible first!

[theAnonymous1]

For pre-built high power Tripath boards there is really only one source, and even then only two options (TA3020 or TA0105)......

Connexelectronic

For some nice TI and IR based class-d boards, check out this place.......

Class D Audio Home page

[wwenze]

If an amp is say 90% efficient, when outputting 300W of power the chip itself will emit 33W of heat. Quite impossible to cool without a heatsink.

[Hemisphere]

If an amp is say 90% efficient, when outputting 300W of power the chip itself will emit 33W of heat. Quite impossible to cool without a heatsink.

True, but I'll mostly be playing music with my amplifier, so on average probably closer to 8 watts of heat.

Ideally the amp would be about 600w, so about 16w of heat, but as I said weight is quite a concern. Honestly I'm not even sure how much weight a heat sink would add!

Will check out those links Anon, cheers! - still got a lot to learn about these amps

[fb]

How much weight is too much?

[Hemisphere]

Ideally I wouldn't be using more than 400 grams on amplifiers. Again not really sure how realistic that is. I need at least 300 + 50 watts, both 8ohm. More than 300 for the woofer would be great, but if that requires significantly more weight I'd go without

[Cristi]

the TA3020v3b amplifier weights just 365 grams together with the heatsink. and with the IRFP4228 MOS-FET's can deliver up to 400W on 4R or over 1KW in BTL mode.
Connexelectronic

[Hemisphere]

Originally Posted by Cristi

the TA3020v3b amplifier weights just 365 grams together with the heatsink. and with the IRFP4228 MOS-FET's can deliver up to 400W on 4R or over 1KW in BTL mode.
Connexelectronic

Hi

The amp you showed looks quite good, but can you help me to understand which conditions it should be run in to actually achieve close to it's power potential without overheating?

The documentation says the heatsink operates at 3.2 degrees C per watt. If we assume the heat sink shouldn't be exceeding 75 degrees, then wouldn't that mean a maximum of around 12 watts RMS per channel?

With the amount of headroom some music has these days, that would probably mean safe peaks of about 60 watts per channel. Will the optional fan cooling help to significantly increase this figure?

Unless I can achieve significantly higher watt levels without overheating (or without adding excessive weight for massive heatsinks), it seems hard to justify the extra expense over cheaper, low power amps, which presumably would be less prone to such issues.

[Hemisphere]

Erm, scratch most of the content of the above post. I never did have a head for physics (that IS the area of science we're dealing with, right? )

So.. if the amp is 90-95% efficient (95% efficient at 2x160w @ 8ohm sounds good to me, I'd probably use that most of the time), then for 320 watts of output there'd be 16 watts of heat, or about 4 watts for standard music program.

So.. the heatsink can dissipate that at an increase of just 12.8 degrees C? Sounds pretty good to me

Again.. waiting to be told I've completely misunderstood

Cheers,
Jonathan

[Cristi]

with the ambient temperature of 25-30*C, the heatsink temperature at idle can go up to 35-40*C especially if is inside a non-ventilated enclosure. with full load the temperature can reach 70*C without forced air cooling. by adding a small fan, the temperature will drop at room temperature at idle and up to 35-40*C at full load. the fan can be a 12V model powered with just 5V running at low speed for low-noise.
i consider the ambient temperature, the temperature near or in close proximity to the amplifier (less than 10cm) which can be higher than the enviroment temperature. if you have an amplifier sealed into a wooden enclosure, the temperature will build-up to tens of degrees with just few watts dissipated inside, even if outside is winter-cold.