[FS UK]: Some really tiny 50W+50W amps for portable speakers (All gone) - Page 1
Forum section: electronics / general

author: IO390
author_rank: Regular Contributor
timestamp: November 13, 2014, 02:49:21 pm
content: 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.

author: TheBay
author_rank: Unknown
timestamp: November 13, 2014, 03:03:19 pm
content: 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?

author: IO390
author_rank: Regular Contributor
timestamp: November 13, 2014, 03:19:59 pm
content: Quote from: TheBay on November 13, 2014, 03:03:19 pmWith 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.

author: TheBay
author_rank: Unknown
timestamp: November 14, 2014, 08:26:37 am
content: Quote from: IO390 on November 13, 2014, 03:19:59 pmIt'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 theseSo 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?

author: IO390
author_rank: Regular Contributor
timestamp: November 14, 2014, 11:50:18 am
content: Quote from: TheBay on November 14, 2014, 08:26:37 amYou 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:

author: TheBay
author_rank: Unknown
timestamp: November 14, 2014, 11:52:04 am
content: Quote from: IO390 on November 14, 2014, 11:50:18 amYes it's amazing, lot's of uses and a great price! someone should snap these up

author: IO390
author_rank: Regular Contributor
timestamp: November 14, 2014, 12:52:53 pm
content: Got 2 sold today from this forum, so 2 left. Gonna have to build another batch.Quote from: 3roomlab on November 14, 2014, 12:03:46 pmYes, 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

author: TheBay
author_rank: Unknown
timestamp: November 14, 2014, 01:07:24 pm
content: Quote from: IO390 on November 14, 2014, 12:52:53 pmSell some as kit form

author: IO390
author_rank: Regular Contributor
timestamp: November 14, 2014, 01:20:53 pm
content: Quote from: TheBay on November 14, 2014, 01:07:24 pmI 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.

author: wraper
author_rank: Unknown
timestamp: November 14, 2014, 01:40:47 pm
content: Where did you get that they are 50W on 4 ohms? What I see in the datasheet is 42W peakhttp://www.ti.com/lit/ds/slos841a/slos841a.pdf

author: Refrigerator
author_rank: Super Contributor
timestamp: November 14, 2014, 01:50:32 pm
content: Quote from: wraper on November 14, 2014, 01:40:47 pm+1^Exactly what i've thought. Right off the bat it looked like that chip was too small to handle 50W/ch.

author: IO390
author_rank: Regular Contributor
timestamp: November 14, 2014, 02:22:47 pm
content: 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).

author: IO390
author_rank: Regular Contributor
timestamp: November 14, 2014, 02:24:19 pm
content: Bear in mind that this chip has identical performance as the TPA3116 but in a different package (one or two less features though).

author: Refrigerator
author_rank: Super Contributor
timestamp: November 14, 2014, 02:27:32 pm
content: Still a nice little amp, really compact, i have a vintage 50W/ch amp and it's enourmously huge compared to this one.

author: TheBay
author_rank: Unknown
timestamp: November 14, 2014, 07:23:47 pm
content: 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.

author: Richard Crowley
author_rank: Super Contributor
timestamp: November 14, 2014, 09:22:19 pm
content: 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.

author: IO390
author_rank: Regular Contributor
timestamp: November 14, 2014, 09:51:23 pm
content: Quote from: Richard Crowley on November 14, 2014, 09:22:19 pmAll 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.

author: SNGLinks
author_rank: Regular Contributor
timestamp: November 15, 2014, 11:11:58 am
content: Received mine this morning! Well packed and came with a useful instruction leaflet.Well done.Ashley

author: IO390
author_rank: Regular Contributor
timestamp: November 15, 2014, 11:36:57 am
content: Quote from: SNGLinks on November 15, 2014, 11:11:58 amGood to hear it arrived quickly.Have you tested it yet?

author: SNGLinks
author_rank: Regular Contributor
timestamp: November 15, 2014, 01:00:12 pm
content: Not yet - rather busy!

author: doctormord
author_rank: Regular Contributor
timestamp: November 15, 2014, 01:28:44 pm
content: 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

author: IO390
author_rank: Regular Contributor
timestamp: November 15, 2014, 03:01:10 pm
content: Quote from: doctormord on November 15, 2014, 01:28:44 pmI'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.

author: doctormord
author_rank: Regular Contributor
timestamp: November 15, 2014, 05:36:13 pm
content: 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

author: IO390
author_rank: Regular Contributor
timestamp: November 15, 2014, 05:57:21 pm
content: Quote from: doctormord on November 15, 2014, 05:36:13 pmI 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.

author: doctormord
author_rank: Regular Contributor
timestamp: November 15, 2014, 06:06:31 pm
content: 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

author: IO390
author_rank: Regular Contributor
timestamp: November 15, 2014, 06:19:15 pm
content: Quote from: doctormord on November 15, 2014, 06:06:31 pmYes, it's made on 1oz copper. Your board (which is very nice by the way) has over double the area of mine so you have much more room for cooling. Also do you have output filtering of any kind? If not, have you had any issues with EMI? This TPA amp can be run without any filtering, although I preferred to use ferrite beads and snubbers to keep crap out of the FM band. The next version of my board will be using full LC output filters, whether the sound quality will improve/worsen I'm not sure yet, but it will ensure clean outputs.Also, what are your thoughts on Elecrow? I've only been using itead up until now, I've had two orders with them in the last couple months. Really quick, (boards always received in 1.5 weeks from ordering, with cheap shipping) and very pleased with them. Elecrow offer much cheaper ENIG, so if they can match the speed of itead I'll give them a try.Edit: I'm looking at the MAX9709 datasheet and it has far more features than the TPA3132. The package is a fair bit bigger though. Also the separate power inputs are close together, they are on opposite sides of the board on TPA3132. So one needs power traces coming in from each side, which gets very annoying. How does the MAX9709 sound?

author: doctormord
author_rank: Regular Contributor
timestamp: November 15, 2014, 10:48:56 pm
content: Please have a look at my website, there are measurement documentations as well. Sound depends a bit on gain setting. Lower gain sounds a bit warmer, but all in all it's super clean sound, not every one likes. (An amplifier should amplify, not alter the sound)Elecrow is cheap but quality isn't as good as itead or seeed. I like the seeed PCB service most.Problems at elecrow were bad alignment and "fat" HASL. I had to rerun a batch already in the past. To much solder to my needs. Haven't tested Enig there.I always do teardroping the vias, giving the manufacturer more "safe margin".For quality comparison please look here:http://www.mikrocontroller.net/topic/319266

author: IO390
author_rank: Regular Contributor
timestamp: November 15, 2014, 11:17:16 pm
content: Quote from: doctormord on November 15, 2014, 10:48:56 pmYes, I looked through your measurements. Impressive figures - this TPA amp has similar distortion levels, yet begins to rise earlier on with power output (that's with my crappy built in motherboard ADC though so not really to be trusted). I set the gain of these amps to 32dB as the plan is for use with portable speakers, so 32dB better matches the output of phones/ipods. Reducing the gain to 20dB sounds a little better but requires a higher input level. It's a matter of changing one resistor though so not much of a worry - and I see you did it with DIP switches, good idea when there's room.I agree - I like to hear detail in music, so the lower the distortion the better. I really don't like tube amps. My LM3886 composite amp has a THD of 0.002% and is better than any tube amp I've listened to (IMO). My only personal preference here is to over compensate the amp ever so slightly as the warmer sound is less tiring to listen to on some songs. That said, unless I properly sit down and listen, I often find it hard to distinguish between a THD of 0.002% and 0.1%.And thanks for the info. I think I'll stick with itead, ENIG isn't at all necessary for this and itead have been great so far.

author: doctormord
author_rank: Regular Contributor
timestamp: November 16, 2014, 10:13:12 am
content: Well, i guess the difference between 0.002% and 0.1% can hardly be heard when a normal speaker has 10x the distortion by design + listening room.

author: Richard Crowley
author_rank: Super Contributor
timestamp: November 16, 2014, 03:04:03 pm
content: Quote from: doctormord on November 16, 2014, 10:13:12 amOh, PLEASE don't say that! You will make the Audiophools' heads explode. And that may damage their Golden Ears!

author: kxenos
author_rank: Frequent Contributor
timestamp: November 16, 2014, 03:36:26 pm
content: There is this appnotewww.ti.com/lit/an/snva419c/snva419c.pdfabout thermal calculations for smd devices

author: IO390
author_rank: Regular Contributor
timestamp: November 16, 2014, 03:52:42 pm
content: Quote from: doctormord on November 16, 2014, 10:13:12 amYes, exactlyQuote from: kxenos on November 16, 2014, 03:36:26 pmThanks, that looks very helpful. I'll do my best to implement some of this into the new board.

author: rr100
author_rank: Frequent Contributor
timestamp: November 17, 2014, 02:43:05 pm
content: Quote from: IO390 on November 13, 2014, 02:49:21 pmAny idea for some decent "off-the-shelf" portable speakers we could use for this? I always wanted a boominator (maybe something a bit smaller but not much) but I'm just not that good with manufacturing "real" stuff.

author: TheBay
author_rank: Unknown
timestamp: November 17, 2014, 03:25:09 pm
content: Quote from: rr100 on November 17, 2014, 02:43:05 pmJust get some car speakers? Focal do some cracking speakers for the money.

author: IO390
author_rank: Regular Contributor
timestamp: November 17, 2014, 03:29:21 pm
content: Quote from: rr100 on November 17, 2014, 02:43:05 pmI'm not really an expert on speaker selection. It depends on what you want to use this amp for really, and how much you want to spend. I'd suggest you do your own research on this, as it comes down to personal preference mostly.If you want to use them outside, then power is the main thing. A friend of mine has been using the previous version of this board with some cheap speakers he got second hand (I think they were rated for 50 or 100 watts) strapped together, running from a 3s LiPo. Works well if you want something small to take around with you but not hugely powerful. Two of these, each one bridged (mono config) and stuck to the back of a decent size bookshelf speaker would also be a good choice. Or go cheap and get some car speakers and stick them in a box (probably a good idea actually).I have a full workshop here, and could build a mini boominator for you if you want. Could only do it if you're in the UK though, but postage might still be expensive.

author: rr100
author_rank: Frequent Contributor
timestamp: November 17, 2014, 04:07:24 pm
content: Trouble is as I'm sure you know (I think I spotted you on at least one other forum...) for Boominator if you're concerned with efficiency there are only a very few speakers you can chose from. I really don't want to bother with it (and not to bother somebody else for that matter) but if there would be somewhere an off-the-shelf product - I don't say similar but at least somewhere in between normal speakers and boominator - I would be very interested to find out. There can't be so many.Speaking of power, how strict are those 22V? I have some e-bike 7S batteries but those are when full ~7x4.15(=29)V.

author: IO390
author_rank: Regular Contributor
timestamp: November 17, 2014, 04:13:24 pm
content: Quote from: rr100 on November 17, 2014, 04:07:24 pmYeah, I'm also on DIYAudio. Can't say I really like it there though and interestingly enough I've had a far better response here than on the dedicated audio forum. Go figure. I'll look around for some speakers for you, I sorta need something similar too anyway.The limit on the chip is 26V, so I suppose a safe max is 24V, if going by battery ratings. Unfortunately I screwed up on my Farnell order and ordered 25V electrolytics by mistake - so hence the 22V limit, but the caps can be replaced. Next version is going to use 35V caps so it's not a worry. You could always use your bike batteries with a few diodes in series.

author: doctormord
author_rank: Regular Contributor
timestamp: November 18, 2014, 08:02:04 am
content: I would rather go for a buck converter with output set to 20V.With diodes, let's say 0.7V drop per diode, you'll need ~8 in series. At an average output of 50w combined on both channels, ~14W gets wasted at the diodes.

author: IO390
author_rank: Regular Contributor
timestamp: November 18, 2014, 01:13:24 pm
content: Quote from: doctormord on November 18, 2014, 08:02:04 amYes, that would be the proper way of doing it. Diodes would just be a quick and easy fix, but not efficient.

author: doctormord
author_rank: Regular Contributor
timestamp: November 19, 2014, 09:33:26 am
content: Testing the TPA3132D2 in KiCAD, actually 37x25mm.

author: TheBay
author_rank: Unknown
timestamp: November 19, 2014, 11:00:10 am
content: I could drive a high end pair of Bowers and Wilkins that have poor sensitivity (Need a powerful amp) on a TA2020 @ 12v on a SLA battery, sounded absolutely amazing.I should think these can drive a bit more than the TA2020!

author: IO390
author_rank: Regular Contributor
timestamp: November 19, 2014, 11:32:43 am
content: Quote from: doctormord on November 19, 2014, 09:33:26 amLooks nice! Problem is fitting the terminals on. If I only had pins on this current board it could reduce to 1" square.

author: doctormord
author_rank: Regular Contributor
timestamp: November 19, 2014, 12:13:30 pm
content: Well, yes. Haven't decided for the connectors yet, would think of using SPOX connectors. So it's just bare datasheet minimum.Terminals at your board are an important part of the thermal design.Still wonder if AVCC would need some ferrite bead filtering.

author: IO390
author_rank: Regular Contributor
timestamp: November 19, 2014, 12:38:27 pm
content: Yes, these boards have ferrite beads on AVCC inputs. It was more of an afterthought for various reasons, but it clears up the sound noticeably.

author: doctormord
author_rank: Regular Contributor
timestamp: November 19, 2014, 02:04:10 pm
content: For what frequency did you integrated the ferrite?

author: IO390
author_rank: Regular Contributor
timestamp: November 19, 2014, 02:25:28 pm
content: Quote from: doctormord on November 19, 2014, 02:04:10 pmI didn't. As I say it was an afterthought to replace something else, and I happened to have some 0603 ferrite beads spare to replace the unused component. The new boards use a proper LC filter for avcc.

author: doctormord
author_rank: Regular Contributor
timestamp: November 19, 2014, 05:28:08 pm
content: Yay, but this needs to be calculated. (If really needed at all)Will have to overlook the datasheet for specs of the integrated LDO.(EV-Board does not do filtering)We may open a new thread for this?Regards, doc

author: IanB
author_rank: Super Contributor
timestamp: November 19, 2014, 06:31:23 pm
content: Quote from: rr100 on November 17, 2014, 04:07:24 pmThere are absolutely off-the-shelf products. The market is saturated with them. For instance, this:http://us.creative.com/p/speakers/creative-d100(is quite large)Or this:http://www.ultimateears.com/en-us/boom(is more compact)For either of them, just pair an iPod or other Bluetooth device and away you go. (Or you can plug in an audio patch cord if you don't have or want to use Bluetooth.)

author: IO390
author_rank: Regular Contributor
timestamp: November 19, 2014, 09:03:22 pm
content: Quote from: doctormord on November 19, 2014, 05:28:08 pmThe ripply in the supply is 400KHz, the switching freq of the amp. The LC filter is 10uH and 220nF, so around 100KHz cutoff.And yes, I was going to suggest the same thing. I didn't plan on the thread being more than a page long, now it's cluttering up the buy/sell/wanted section. I'll start a new one in the projects section tomorrow.

author: rr100
author_rank: Frequent Contributor
timestamp: November 19, 2014, 10:52:37 pm
content: Quote from: IanB on November 19, 2014, 06:31:23 pmSorry, we aren't talking about the same thing. I tested quite a bit of those (including both the ones you mentioned), one of the favorite was the Logitech UE Boombox (which is probably double or more the power of the ones you mentioned) but is nothing close to what I have in mind. Those are a very few W/channel, maybe, maybe one order of magnitude above a good mobile phone.IO390 knows for sure what I have in mind, something close to the mini-boominator, something in the tens (or even 10 "good") watts per channel.Sure, I DO know the drill, whatever bookshelf speakers, bigger is better. But I wanted to know if there is something efficient, well designed, with some nice drivers, etc. Not really hi-fi and "4-digit-price-quality", not some cheap crap, something decent audio-wise and preferably with good efficiency.

author: IO390
author_rank: Regular Contributor
timestamp: November 20, 2014, 11:12:50 am
content: Quote from: rr100 on November 19, 2014, 10:52:37 pmhttp://www.ebay.co.uk/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR11.TRC1.A0.H0.Xmission+751&_nkw=mission+751&_sacat=0Those are pretty high sensitivity and there's a few cheaper options on ebay.