Suggestions for low/medium power audio amplifier ICS?  - Page 1
Forum section: electronics / projects

author: cdev
author_rank: Super Contributor
timestamp: February 07, 2022, 05:09:35 pm
content: I want to put a small audio amp on the underside of my desk to drive two bookshelf speakers at my computer desk. The speakers will be driven by my computer, which has an optical audio out, which Ive never used. I dont need to use it, if that adds a lot to the price. Anyway, this is the first upgrade to my computers audio in years so I'd like to use the best fairly inexpensive audio amplifier module I can find within a modest price range.I dont play music super loud but I like a good dynamic range. What are the best ones to look at value wise. I have 12 volt and 5 volt power supplies I can use. I am probably going to buy a pair of fairly decent bookshelf speakers so I can leave the ones that are currently on my stereo there.Does anybody have any thoughts on the choice of amplifier module??It doesnt have to be pretty as its going to be totally out of sight (screwed to the bottom of a wooden table)

author: bob91343
author_rank: Super Contributor
timestamp: February 07, 2022, 06:26:06 pm
content: Do a search on AliExpress and you will find a plethora of cheap little amplifiers. Or search IC manufacturers' catalogs. There are many and these things are cheap so don't waste a lot of time designing one.

author: cdev
author_rank: Super Contributor
timestamp: February 07, 2022, 07:17:25 pm
content: I have and I've seen a lot of recommendations. What 'd like is some peoples real world experience using them and their favorites. That is better than just guessing which one to buy based on price or whatever. I do like good robust sound but I am not an "audiophool"

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 08, 2022, 02:00:49 am
content: Look up "class D board", particularly the ones based on TI chips. I would suggest the TPA3255, but that needs at least 20V and ideally 40-50V.

author: David Hess
author_rank: Super Contributor
timestamp: February 08, 2022, 02:33:27 am
content: I have been very happy with aFosi Audio BT30D2.1 channel amplifier for my PC. I have thought about getting theirAudio Q4DAC so I can use the optical output on my PC but I have not had any hum or noise problems with the direct analog connection.Last year when I upgraded my PC, I accidentally killed the power supply for my ancient powered speakers and subwoofer. So besides the above amplifier, I picked up a pair of Edifier P12 passive bookshelf speakers and built aDayton Audio 6-1/2" passive mini subwoofer kit, shown below, which worked out excellently. (1) I initially tried using the old subwoofer as a passive one, but its performance was just horrible. The Edifier P12 speakers have really low efficiency which is to be expected for such small enclosures, but the power of the BT30d makes that acceptable.If I did it again, I might build some kit base-reflex bookshelf speakers from Dayton but convert them to forward firing.(1) There is a forum discussion where I asked about low frequency AC response of multimeters because the subwoofer required measurements for tuning below that were most of my multimeters worked, but I got it worked out without too much trouble.

author: MarkF
author_rank: Super Contributor
timestamp: February 08, 2022, 10:16:43 am
content: Funny this subject appeared at this time.I have been considering theFosi Audio BT20A Bluetooth 5.0 Amplifiermyself.Does anyone have any thoughts on the BT20A?

author: Haenk
author_rank: Super Contributor
timestamp: February 08, 2022, 02:43:44 pm
content: Quote from: MarkF on February 08, 2022, 10:16:43 am"no audible noise when Bluetooth connection is established"That's actually a great feature. I tested several of the cheaper BT amplifiers - and they all come with an annoying and very loud "connected" signal. Made me absolutely mad, who thought that was a good idea?!?

author: David Hess
author_rank: Super Contributor
timestamp: February 08, 2022, 04:50:35 pm
content: Quote from: Haenk on February 08, 2022, 02:43:44 pmI tried out the Bluetooth support on my BT30D and found the latency to be completely unacceptable. There might be a USB to Bluetooth dongle which would allow negotiating a low latency connection, but I was unable to find one short of testing them all.

author: MarkF
author_rank: Super Contributor
timestamp: February 08, 2022, 07:35:04 pm
content: Quote from: Haenk on February 08, 2022, 02:43:44 pmThanks,I was actually looking for a wired connection from my tv.These do not sound like something I should get.I have a pair of Polk Model 9 towers and my Pioneer 1010 receiver from the 80s finally died.

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: February 08, 2022, 08:50:14 pm
content: Check out TPA6021A4. 20 pin DIP package stereo amplifier capable of up to 2W per channel. Works with a single ended power supply.

author: MarkF
author_rank: Super Contributor
timestamp: February 08, 2022, 09:24:41 pm
content: I was thinking more like 50W per channel. The Polk speakers don't require a lot of power for floor speakers. I choose them instead of the Bose 901 which cost twice as much and sounded basically the same.The Pioneer 1010 was 100W per channel. I really should take it apart and check it out.It runs okay for a few minutes and then the safety relays kick out and all the switches need cleaned.The only time I use it any more is to listen to a music program on the tv.

author: ve7xen
author_rank: Super Contributor
timestamp: February 08, 2022, 09:36:45 pm
content: I've been using a TDA8950 board to drive myOvernight Sensationsfor quite a few years now. The filtering on the board is definitely insufficient both for power handling and for EMI, but it sounds fine and has served me well. It won't run on 5V or 12V though (needs 25V min). Should give about 80-90W of relatively clean power from a 70V supply. I can't remember what supply voltage I'm running it from, I think it might be a +/-22V toroid, but it has more than enough oomph for these speakers.

author: free_electron
author_rank: Super Contributor
timestamp: February 08, 2022, 09:53:57 pm
content: icepower modules.

author: MarkF
author_rank: Super Contributor
timestamp: February 08, 2022, 10:09:35 pm
content: Sorry, I didn't mean to hijack this thread.Thanks for the suggestions. But...I'mnotlooking for modules or a DIY project.I consider the Fosi Audio BT20A a minimum solution.Ideally, I would like to have my Pioneer receiver repaired.Note: The Polk 9 speakers are NOT bookshelf speakers.They are large floor standing speakers.

author: SilverSolder
author_rank: Super Contributor
timestamp: February 08, 2022, 10:50:26 pm
content: Quote from: cdev on February 07, 2022, 05:09:35 pmI get good results with these cheap'n'cheerful Class D amps for computer use. Don't look for massive power output, but they sound decent enough.https://www.amazon.com/Lepy-LP-2020A-Class-D-Digital-Amplifier/dp/B01FZKA28Y

author: coppercone2
author_rank: Super Contributor
timestamp: February 09, 2022, 12:38:33 am
content: the specifications on all the amplifier IC modules are lame IMO.THD level under the commonly accepted mass manufacture audio systems specifications go against the party theoretic, worker.

author: tooki
author_rank: Super Contributor
timestamp: February 10, 2022, 12:07:12 am
content: Try a module based on the TPA3126d2 (or its older version the TPA3116), the slightly less powerful TPA3128 (or older TP3118), and or another in the TPA31xx series (there are numerous models, with the ‘26, ‘28, and ‘56 being the most powerful IIRC).

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 10, 2022, 12:58:43 am
content: Quote from: tooki on February 10, 2022, 12:07:12 amThe TPA3255 is currently the best. Considering a board with it is available for as little as $30, there's not too much reason to go for something lower.

author: themadhippy
author_rank: Super Contributor
timestamp: February 10, 2022, 01:20:36 am
content: How about the sta540,https://www.st.com/en/audio-ics/sta540.html.There cheap,very few additional parts needed , they sound perfectly acceptable to my ears and go loud enough to let my neighbors listen in

author: tooki
author_rank: Super Contributor
timestamp: February 10, 2022, 09:20:53 am
content: Quote from: NiHaoMike on February 10, 2022, 12:58:43 amThe TPA3255 is far more powerful than the OP asked for, and requires a minimum supply voltage higher than what the OP said they have available. The TPA31xx series works within the OP’s requirements.

author: NiHaoMike
author_rank: Super Contributor
timestamp: February 10, 2022, 01:45:50 pm
content: Quote from: tooki on February 10, 2022, 09:20:53 am50W on 8 ohms is not going to happen from a 12V supply. Need at least 30V for that, which the TPA3255 would be happy to operate from.

author: tooki
author_rank: Super Contributor
timestamp: February 11, 2022, 09:01:59 am
content: Quote from: NiHaoMike on February 10, 2022, 01:45:50 pmThe OP didn’t specify any power rating whatsoever.

author: David Hess
author_rank: Super Contributor
timestamp: February 11, 2022, 04:53:09 pm
content: Quote from: coppercone2 on February 09, 2022, 12:38:33 amSpeakers generate several times more distortion than even a consumer grade audio amplifier, so characteristics other than distortion are more important as long as the distortion is low enough.Like the cobbler's children go without shoes, I am the one using a consumer grade audio amplifier.Quote from: MarkF on February 08, 2022, 10:09:35 pmLike I said, I am very happy with the Fosi Audio BT30D, which as far as I can tell is a BT20A plus the controls and third channel for a subwoofer. The Bluetooth functionality seems pretty useless to me but I think that is more of a problem on the source side; I am sure some people like it for connecting to their phone.The power supply is external which is annoying but I have found it acceptable, and since that is the part most likely to wear out, that makes it easy to replace.

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 11, 2022, 05:16:00 pm
content: Quote from: NiHaoMike on February 10, 2022, 01:45:50 pmYep. I suppose we're talking 50W RMS. (As we know, vendors of amplifiers tend to show power figures that mean squat... just saying.)If so, 50W RMS for a "desk" amplifier? That'd be crazy anyway. You certainly don't need that. 10W RMS or below would already be enough to make your ears bleed in loudspeakers 1m away or so.

author: oPossum
author_rank: Super Contributor
timestamp: February 11, 2022, 05:20:51 pm
content: LM3886 or LM4766 if you want a good quality class AB chip amp.

author: David Hess
author_rank: Super Contributor
timestamp: February 11, 2022, 06:45:46 pm
content: Quote from: SiliconWizard on February 11, 2022, 05:16:00 pmBookshelf and smaller speakers can be pretty inefficient in the quest to get a flat frequency response so 50 watts is not that outlandish.

author: tooki
author_rank: Super Contributor
timestamp: February 11, 2022, 07:23:48 pm
content: Uhhhh… even with that, 50W is atonof power. For context, for typical desktop PC speaker use, 3W is enough. 10W is usually enough to annoy the neighbors.

author: SilverSolder
author_rank: Super Contributor
timestamp: February 11, 2022, 11:53:21 pm
content: Yeah, I doubt I get over 1W on the desk. In the car, on the other hand...

author: Gyro
author_rank: Super Contributor
timestamp: February 12, 2022, 10:54:36 am
content: Quote from: oPossum on February 11, 2022, 05:20:51 pmYes, they're supposed to be pretty good quality. You don't have to use the full 50W capability, just use lower supply rails and reduce the heatsinking requirements.

author: 2N3055
author_rank: Super Contributor
timestamp: February 12, 2022, 11:22:59 am
content: LM3886 amps sound really good and it is easy to make them. You can power them with just a toroid transformer, diode bridge with filter caps and two elco capacitors..Only thing is that you will need to heatsink them properly.Some of the new class D amps sound surprisingly good too (Ti for example) and practically need no special thermal considerations...

author: mawyatt
author_rank: Super Contributor
timestamp: February 12, 2022, 01:41:19 pm
content: Agree, the LM3866 is a really good option. Might make a good Hi Power AWG AmpBest

author: tooki
author_rank: Super Contributor
timestamp: February 12, 2022, 02:30:05 pm
content: Are you guys deliberately ignoring what the OP said? They said a low/medium power amp with either a 5V or 12V supply.A 315W amp that requires 18-53V? Not even close. A 68W amp that requires bipolar ±28V? Not even close.OP, again, take a look at the TPA311x series, which will work on 5V or 12V and still have ample power.

author: 2N3055
author_rank: Super Contributor
timestamp: February 12, 2022, 04:08:44 pm
content: Quote from: tooki on February 12, 2022, 02:30:05 pmWell in our defense, discussion was kind of of hijacked along the way...But you have the point.I think a device of the likes of the Fosi Audio BL10C would be more than enough to fit the bill and more...

author: mawyatt
author_rank: Super Contributor
timestamp: February 12, 2022, 04:22:24 pm
content: Guilty as chargedBest,

author: SilverSolder
author_rank: Super Contributor
timestamp: February 12, 2022, 06:34:01 pm
content: The simplest solution is to use an amp that someone else has already made! - I own 3 of these ones, and they perform very well for computer monitors, bedroom music, portable sound, that kind of thing.They are based on the Tripath Class D chip. I wouldn't trust them to give more than about 5W-10W per channel of clean output, but if they are kept under that level, they actually sound good. (Look at the specs: 12V, 3A power supply, but 2x20W rms. Hmmmm....) - but if you ignore the silly spec and just treat it as a 5 - 10W amp, you will be happy.

author: cdev
author_rank: Super Contributor
timestamp: February 12, 2022, 09:32:43 pm
content: This info looks like what I need. Actually my wife was kind enough to lend me her amp and speakers because she as I said never uses them because she uses headphones all the time and also is super busy. But I think Imay still get an amp or build one from some of the parts I have if that is sufficient for my needs, to make an unltrasonic cleaner. (a different thread)Might as well get things that are as flexible as possible.Quote from: tooki on February 10, 2022, 09:20:53 am

author: tooki
author_rank: Super Contributor
timestamp: February 12, 2022, 11:01:38 pm
content: Quote from: SilverSolder on February 12, 2022, 06:34:01 pmNice! That’s based on a chip in the series I suggested, and should do a fine job.

author: cdev
author_rank: Super Contributor
timestamp: February 12, 2022, 11:21:09 pm
content: This is a really decent amp for its price andmost importantly, when there is no signal going into it, its very quiet!''this is a pet peeve of mine. As Ive often described here, I live in a semi urban suburban area with lots of RF noise so its actually quite surprising to me that I lucked out and dont have lots of noise.Usualy when some gain device is hooked up here its all over the place. For example mu UNi-TUT61 DMM when I just put it on its regular V volts and hold the two leads apart would lead one to believe I was surrounded by "free energy tothe point that I could power various misc devices off of it!The reading never holds still and it goes quite high sometimes from one moment to the next!If I was obsessive-compulsive about things, I could see myself "having a field day" with all that electricity.This amp sounds tight and strong, like live performance, with the dayton audio b652s. Its makes a kick ass computer system.

author: SilverSolder
author_rank: Super Contributor
timestamp: February 13, 2022, 12:39:00 pm
content: Quote from: cdev on February 12, 2022, 11:21:09 pmIf you connect an amp to a computer, it can sometimes be difficult to keep the background noise under control due to ground loops between different devices plugged into the PC. In my case, I had issues with a printer plugged in via USB... as soon as the printer was plugged in, there was a background whine! I ended up using a small audio isolation transformer in the audio lead, which made it all nicely quiet again.

author: MarkF
author_rank: Super Contributor
timestamp: February 13, 2022, 01:26:59 pm
content: Quote from: tooki on February 12, 2022, 11:01:38 pmF.Y.I.The Fosi BT20A is based on the TPA3116 chip.

author: David Hess
author_rank: Super Contributor
timestamp: February 16, 2022, 12:34:23 am
content: Quote from: tooki on February 11, 2022, 07:23:48 pmI agree, but we are talking about bookshelf speakers and not typical PC speakers. Bookshelf speakers will be 2-way or 3-way with a built in passive crossover, and are often ported like mine are. In order to get flat and extended low frequency response in a small enclosure, they have to sacrifice efficiency, so higher power is required to get the same sound pressure level. My previous "high end" powered PC speakers were toys in comparison; I only used them because they were free and I had no need for anything better.The specifications of the mentioned BT20A (and BT30D that I have) say that they operate down to 12 volts, at reduced output power of course. But I think FOSI is specifying peak power as twice RMS power so halve the power levels they advertise. The TPA3116 datasheet from Texas Instruments gives a much better idea of available output power.Taking into account the above, my BT30D is a more reasonable 15 watts into 8 ohms.Quote from: SilverSolder on February 13, 2022, 12:39:00 pmGround loops can be a major problem if you do not plan ahead. It helps a lot to make sure that all of the components are plugged into the same outlet strip.I could not hear any noise from my BT30D with a direct analog connection, so ended up not buying an optical DAC, but I was prepared to if there was an issue.

author: tooki
author_rank: Super Contributor
timestamp: February 16, 2022, 06:42:39 am
content: Quote from: David Hess on February 16, 2022, 12:34:23 amMy numbers are from actual measurements using 2-way and 3-way bookshelf speakers.

author: SilverSolder
author_rank: Super Contributor
timestamp: February 16, 2022, 05:04:34 pm
content: Pretty much any speaker should hit 85dB at 1 meter, at 1W? Many will do better than that.I guess it all comes down to what we consider normal listening levels - and whether you want the neighbours to be listening as well!

author: 2N3055
author_rank: Super Contributor
timestamp: February 16, 2022, 07:53:33 pm
content: Quote from: SilverSolder on February 16, 2022, 05:04:34 pmThat is a single one. A pair will be 3dB louder...

author: cdev
author_rank: Super Contributor
timestamp: February 17, 2022, 03:35:48 am
content: Proper listening level is when it pumps your body in the solar plexus,,it gets you right there in trhe center of your chest.moves your ass Google translates that as eMueve tu culo

author: SilverSolder
author_rank: Super Contributor
timestamp: February 17, 2022, 11:12:03 pm
content: Quote from: cdev on February 17, 2022, 03:35:48 amIn my car, I have a system that meets that specification. On the desk, though...

author: David Hess
author_rank: Super Contributor
timestamp: February 18, 2022, 11:54:29 pm
content: Quote from: cdev on February 17, 2022, 03:35:48 amWith the properly tuned 6-1/2 inch subwoofer that I built and tuned, I can rattle the windows without being able to hear it.