[FS UK]: Some really tiny 50W+50W amps for portable speakers (All gone)

[IO390]

I've been playing around with the TPA3132 (TPA3116 in a QFN) a lot and this is my latest thing. Only has ferrite beads on the outputs so you need short speaker wires, but it is 25x38mm in size and has screw terminals so no soldering needed. I built 10 just as a personal project, but figured I may as well try and recoup my looses on the boards. A few have already been sold on other forums, but I've got 4 left here so if anyone is interested, drop me a PM. Price is £18 each plus postage (93p first class to the UK, £3 royal mail international standard to EU). Includes a audio input pigtail.

Output power is 50W/channel into 4 ohms, 25W into 8 ohms. Input voltage between 4.5-22V, barely gets warm either. Sound quality is good, perfect to drive a couple speakers in a box for taking outside or something similar.

Edit: All gone. The next version will feature full LC output filters so worries about short speaker wires, and will be priced at £20. Will not include output terminals, but 100th pin headers instead due to lack of space. Should have them made in 2-3 weeks, only making 10 again so if you want to reserve one send me a PM.

[TheBay]

Looks fantastic, I love messing around with Audio, I have been playing with Tripath TA2020's which sound amazing and also building TI/Burr Brown dacs.
Love the work, how do they sound?

[IO390]

Looks fantastic, I love messing around with Audio, I have been playing with Tripath TA2020's which sound amazing and also building TI/Burr Brown dacs.
Love the work, how do they sound?

With all the raving about Tripaths I'm surprised I've not played with one yet. The external component count is a fair bit higher though.

The sound is not far off my LM3886 composite amp. My speakers aren't the best so I can't pick out anything bad in particular. Still I'd be more than happy with one as my main amp, which is what I've been doing for the past few days. Really impressed with these little TI chips.

[TheBay]

Looks fantastic, I love messing around with Audio, I have been playing with Tripath TA2020's which sound amazing and also building TI/Burr Brown dacs.
Love the work, how do they sound?

With all the raving about Tripaths I'm surprised I've not played with one yet. The external component count is a fair bit higher though.

The sound is not far off my LM3886 composite amp. My speakers aren't the best so I can't pick out anything bad in particular. Still I'd be more than happy with one as my main amp, which is what I've been doing for the past few days. Really impressed with these little TI chips.

It's amazing how it all fits in a single chip solution, I'm sure that's how they sound so good. Such a small board you have there, so many applications and a bargain price! Someone buy these

So these need no DC Bias? or is that done via component value?, Volume adjustment done at source level with your design, is there a point on the IC to put a pot for volume/pre-level adjustment?

[IO390]

So these need no DC Bias? or is that done via component value?, Volume adjustment done at source level with your design, is there a point on the IC to put a pot for volume/pre-level adjustment?

You mean DC bias on the input? The inputs are AC coupled so no if that's what you meant. The chip uses two resistors to set the gain (I've set these to 32dB) but the only way to control the volume would be with the usual potentiometer on the input. There was no room on the board for this so hence why it doesn't use one.

As you can see, for 100W total output, it's pretty dinky:

[TheBay]

So these need no DC Bias? or is that done via component value?, Volume adjustment done at source level with your design, is there a point on the IC to put a pot for volume/pre-level adjustment?

You mean DC bias on the input? The inputs are AC coupled so no if that's what you meant. The chip uses two resistors to set the gain (I've set these to 32dB) but the only way to control the volume would be with the usual potentiometer on the input. There was no room on the board for this so hence why it doesn't use one.

As you can see, for 100W total output, it's pretty dinky:

Yes it's amazing, lot's of uses and a great price! someone should snap these up 

[IO390]

Got 2 sold today from this forum, so 2 left. Gonna have to build another batch.

wow ... im def in the mountain for too long ... so tiny ... why do they not require heatsinks? PWM based?

Yes, they are class D. The audio signal is PWMed so they have very high efficiency. This one is about 90%, so it barely heats up.

Edit: Oh looky, post #100

[TheBay]

Got 2 sold today from this forum, so 2 left. Gonna have to build another batch.

wow ... im def in the mountain for too long ... so tiny ... why do they not require heatsinks? PWM based?

Yes, they are class D. The audio signal is PWMed so they have very high efficiency. This one is about 90%, so it barely heats up.

Edit: Oh looky, post #100

Sell some as kit form

[IO390]

Sell some as kit form

I wanted to, but this thing is really inconvenient without a stencil... Which are £13 each (which reminds me, smtstencil.co.uk are great). If you're good with a syringe, then you'll have to be good with 0603 components too. 0603s get easily lost so I'd have to supply extras, which increases cost. Also the QFN might not be ideal for some.

I suppose I could do some as kits on special request but for now I'd rather assemble them myself.

It's about time for another batch. I've redesigned it with full inductor output filters and some other minor changes. Only problem is they are more expensive to build, so final price will be £25 and there is no longer space for terminals, so they will have to be replaced with pin headers.

OR I could do them as they are for £18 still. The new design won't have to have short speaker wires though.

[wraper]

Where did you get that they are 50W on 4 ohms? What I see in the datasheet is 42W peak http://www.ti.com/lit/ds/slos841a/slos841a.pdf

[Refrigerator]

Where did you get that they are 50W on 4 ohms? What I see in the datasheet is 42W peak http://www.ti.com/lit/ds/slos841a/slos841a.pdf

+1^
Exactly what i've thought. Right off the bat it looked like that chip was too small to handle 50W/ch.

[IO390]

The datasheet specifies 42W/channel into 4 ohms at 19V. At a supply voltage of 25V (the max, I wouldn't run it this high normally) I measured 48W, but it draws a load of current and gets a bit warm. Still manageable, but I wouldn't want to listen to it at that output power as the THD rises right up (as seen in the datasheet).

[IO390]

Bear in mind that this chip has identical performance as the TPA3116 but in a different package (one or two less features though).

[Refrigerator]

Still a nice little amp, really compact, i have a vintage 50W/ch amp and it's enourmously huge compared to this one.

[TheBay]

I'm fascinated by this little thing, might have to try one.
A slightly bigger board and a TI PCM2704, this little Class D amp IC would make an awesome AMP/DAC combo, plug in a ARM based pogoplug and multi room audio!
Should drive some nice speakers.

Or would be great with bookshelf speakers for a PC as monitors.

[Richard Crowley]

I would be interested in buying 2 or 3 of them. The new version would be my preference, but the current version looks great, too.

[IO390]

I would be interested in buying 2 or 3 of them. The new version would be my preference, but the current version looks great, too.

All of these have been claimed, so I'm sorting out the next version. Price for the new one will be £20-22 as the output inductors are a little pricey. If you want I can reserve you a couple of the new batch? No obligation to buy them of course, so if you change your mind no problem. I should add that postage to the US is £3.80 for this small package using the 5-7 day service. Anything quicker is a bit (lot) more expensive.

That goes for anyone else, if you are going to be interested in one let me know.

[SNGLinks]

Received mine this morning! Well packed and came with a useful instruction leaflet.

Well done.

Ashley

[IO390]

Received mine this morning! Well packed and came with a useful instruction leaflet.

Well done.

Ashley

Good to hear it arrived quickly.

Have you tested it yet?

[SNGLinks]

Not yet - rather busy!

[doctormord]

Have you tested this layout at full power for a subwoofer-amp? I wonder, if it will go into thermal-shutdown while putting out full power at 100Hz in a non vented enclosure.

The MAX9709 will do in this 50x50mm Layout at 25+25W or 50W bridged:

http://www.360customs.de/en/2013/12/max9709-25w50w-class-d-version-3/

Using much of the copper the keep it cool.

Anyway, nice Layout. Whats your desired -3dB lower cutoff?

Regards,

doc

[IO390]

Have you tested this layout at full power for a subwoofer-amp? I wonder, if it will go into thermal-shutdown while putting out full power at 100Hz in a non vented enclosure.

The MAX9709 will do in this 50x50mm Layout at 25+25W or 50W bridged:

http://www.360customs.de/en/2013/12/max9709-25w50w-class-d-version-3/

Using much of the copper the keep it cool.

Anyway, nice Layout. Whats your desired -3dB lower cutoff?

Regards,

doc

I've not no. I don't have any large woofers to test it on. However, running at max voltage, at max power into a 2 ohm resistor it gets fairly hot (still touchable) but doesn't shut down.

This chip can be bridged. In fact one guy who bought one asked about it, so I just tested it a moment ago (simple job of removing a couple caps and grounding 2 pads) and it works nicely. This uses both outputs of either channel tied together. The two tied channels then go into one load. In this config, the output power will be nearly 100W at 24V input, but will sound like crap at that level.

The -3db cutoff is at 20Hz.

[doctormord]

Nice, i will do some thermal calculations later when I'm back home. Would you tell me, how big your ground plane is? (Combined cooling copper)

Regards,

Doc

[IO390]

Nice, i will do some thermal calculations later when I'm back home. Would you tell me, how big your ground plane is? (Combined cooling copper)

Regards,

Doc

I played with it some more today, and for a few minutes at max power into a 2 ohm load it gets very hot, but no shutdown. It is touchable for a few seconds. I'll attach a thermometer to it next time.

What's important is that in all usable conditions (absolute max output has 10% THD) the chip doesn't heat up.

The ground plane covers both sides of the board and is split into two. The smaller one is for the input end and the larger one for the output. It has a star ground which meets at the pad on the chip, with a trace running from the pad to the power input terminal, so the return path for the whole thing is through one point. Probably a bit overkill but it sounds better than a previous board I designed (same chip) with everything on one ground plane that was connected directly to the terminal.

Effective area of copper for cooling is probably about a total of an inch square. The ground plane has lots of holes in it, sadly this is unavoidable on such a small board.

[doctormord]

Thanks, I guess it's made up on 1oz. copper?

My boards got way more effective cooling area than yours, but to knowledge, the output-stage of the TPA is more effective because of lower RDS_on.

The thermal flag output is connected to the mute and shutdown inputs to disconnect load while in thermal shutdown. At 24V and ~2*20W output (dub step), the boards temperature is about 54°C.

Regards,

Doc