[MCM_Fan]

Since my first TPA3116 build has been up and running for about two and a half weeks, and I started my second one today, I thought it was about time to share a couple photos.

This one uses the blue/black board, with Bourns inductors, Panasonic power supply caps and Radio Shack input caps.  It has an on/off switch, but no volume pot/knob.  It will be a dedicated amp for streaming through an Airport Express.  The gain is set at the standard 26dB and volume control is through software. 

It is mounted in the Context Engineering 3008 enclosure from San Jose Scientific.  It's a bit of a tight fit, both getting all the connectors/jacks on the back panel and getting everything in the case.  But it fits and makes a very small, clean looking amp.

Guts shot:


The back panel:


I should have the second build done in a day or two.  The only difference will be the enclosure and a little green power indicator LED on the front panel.

Wow, it's been over two weeks now and I still don't have my second board installed in its enclosure.  But, there's a reason...

Installing the second board in it's enclosure will be much more challenging.  The new enclosure is wider, but not as deep and not as tall.  It will require some mechanical modifications to both the board and enclosure just to get it to fit, but the real challenge will be getting everything hooked up (without excessively long wires) and buttoning it up.  The new enclosure is a two-piece design with a removable bottom.  Much more challenging than the four-piece Context Engineering case shown above, with a removable top and removable front and back end panels (much easier to drill the holes for the jacks and connectors and hook up the wires).  But, I've figured out how to do it.  Not rocket science, but time consuming, will require slow, meticulous work and a steady hand.  I don't want to be taking the board in and out of the case for mods once I get it installed.  I want to install it in the enclosure once, and only once.

That final sentence is the reason for the delay.  Up until this morning, I just wasn't satisfied with the sound quality I was getting out of my first TPA3116 amp (the one shown in the photos above), and I didn't want to go to through the mechanical challenges of installing the second board in its enclosure (I'll include some photos once I actually get to that point) until I worked out the sound quality issues.

Keep in mind, these sound quality issues are a function of: the other equipment I am using, the source material, the application, the end users, and personal preference.  So, what I am about to share is specific to my requirements and may not coincide with what others have experienced and shared.

First, the end users and application:  These first two amps are to be gifts for my daughter on her 15th birthday and my girlfriend.  Neither girl are what you'd call serious audiophiles, but both love music and enjoy the systems I have given them previously.  They both will be streaming their music (iTunes, Spotify, Pandora, iHeart Radio, etc.) through an Airport Express and listening through bookshelf speakers I have given them previously (Monitor Audio Bronze B1 for my daughter and modified Polk RTi28 for my girlfriend).  These little amps are designed to replace the vintage receivers I'd previously given them (Sansui 221 for the daughter, NAD 7120 for the GF).  Although both like the sound of their current system, neither want, nor need a big, old, power hungry receiver for their intended (and only) use.

I am a more critical listener than either of these ladies and I want both systems to sound as good as possible.  Until this morning, I have been dissatisfied with the sound I was getting out of these amps, compared to both current systems and compared to my own bedroom system (NAD 7150 integrated amp, Pioneer SP-BS22-LR with Definitive Technology ProSub 800 and a variety of high quality sources).

The first thing I noticed is the flat, somewhat lifeless highs and upper mids.  This isn't really a fault of the TPA3116, it's more a function of the compressed source material and the limitations of the Airport Express.  The music just didn't sound as "musical" as what I'm used to.  It lacked that warmth and presence I am used to with my vintage analog gear.

It also lacked deep, full bass.  Keep in mind, I have modified these boards (as shown in the photos above).  The Bourns inductors made the biggest difference.  The bass is very tight, but lacks fullness.

The first thing I did was insert a FiiO D03K DAC between the Airport Express and the TPA3116.  This immediately fixed the mids and highs.  It REALLY opened things up.  The highs are very warm and pleasant, with absolutely no listening fatigue.  Most of all, the music now has an amazing soundstage - amazing stereo image and three dimensional depth to it.  Amazing what a difference this inexpensive little DAC can make.

But, it even further reduced the bass.  I even tried adding a couple different powered subwoofers and was beginning to consider giving both gals subwoofers to go with their new systems, which would have defeated the purpose of something small and unobtrusive that uses very little power.  Besides, even with the subwoofers, I could just not get things to sound the way I wanted them to.  So, I went back to just the Airport Express and no DAC as a slightly better, but not really acceptable (to me) overall compromise and began to look at ways to fix the bass issue.

The first thing I noticed is I had a wiring error in the photos above.  I had the speaker connections wired out of phase (surprised no one else noticed that).  I was hopeful that this would solve my bass issue.  It did not.  Even when properly in phase, the bass still lacked the fullness I am accustomed to.

One of the issues is both gals listen at low to moderate levels.  So, both have the loudness buttons on their vintage receivers permanently engaged.  I do the same with my bedroom system.  So, I was really looking for something that would give me the warm highs, fantastic sound stage of my vintage analog gear, combined with the fullness of bass provided by the loudness button on these old receivers.

Well, with digital sources, it makes sense to use the built-in EQ settings to tailor the sound.  Unfortunately, the iPhone and iPad have limited fixed EQ "modes".  The first one I tried was, of course, "Loudness".  It helped the bass, but over-boosted the highs and made them very harsh sounding with severe listening fatigue.  I tried a few other EQ settings until I ended up with "Bass Booster" on.  Much better, but a little boomy.  I was getting close.

Next was reinserting the DAC in the chain to get back the warm, lush highs and fantastic soundstage.  That did it.  The DAC, combined with "Bass Booster" on gave me the sound I was looking for.  The DAC seems to also tame the boominess of the "Bass Booster" setting.  I finally had the sound I was after.  It gives me the warm, lush highs and three dimensional sound stage I wanted, but also full, impactful, but not boomy bass.  In some ways, the sound is even better than the old analog gear it will be replacing.  The TPA3116 definitely has less background noise than the old receivers it is replacing, and the soundstage is incredible.

I spent the morning listening to several different tracks, from my daughter's, my GF's and my own playlists.  The sound is really very pleasing to my ears.  Cymbals and bells are crisp, without any hint of harshness.  Strings and acoustic guitars sound very much like live instruments.  Piano and vocals, especially female vocals, are very lush and full sounding.  I am pleased.  Now, I just need to button up everything and deliver my gifts (daughter's 15th birthday is 1 week from today).

I realize that the sound I was seeking could have been achieved by other means - quite possibly one of the little 3-tube preamps others hve recommended in this thread.  But, the goal here was specific to the end users and their specific application.  They both want something small, unobtrusive and low power that integrates well, and looks good with their iPhones and iPads and allows better sound quality for their iTunes libraries and internet radio apps.

I'll post final photos and eventually a complete BOM for these builds in another week, or two.  For now, I just wanted to share my listening impressions and the path I followed to get the sound I desired out of these little, inexpensive TPA3116 boards.

[matt_garman]

Wow, it's been over two weeks now and I still don't have my second board installed in its enclosure.  But, there's a reason...
[ ... trim for brevity ... ]

Thanks for that detailed write-up, very interesting.

Sounds like you've already got the problem solved, but something else you might want to consider: MiniDSP.  I don't own one, but keep seeing it mentioned in related threads.  I believe you can buy the MiniDSP in "naked" PCB form, and (with the right case), roll it into your tpa3116 build... pretty sure someone over on diyAudio did exactly this.  I can think of at least a couple uses for such a device in my own setup; seems pretty versatile.

I know you're running short on time to get these done, but also on the diyAudio thread, some folks mentioned a bass increase with bigger input signal (dc de-coupling) caps (bigger than 1uF) and/or changing the gain setting... I don't remember the details, and that thread has become a beast, but I do think it was discussed fairly recently, so maybe look at the most recent month's worth of postings?

Anyway, just throwing out more ideas for anyone else who might be wrestling with similar issues.

[MCM_Fan]

Sounds like you've already got the problem solved, but something else you might want to consider: MiniDSP.  I don't own one, but keep seeing it mentioned in related threads.  I believe you can buy the MiniDSP in "naked" PCB form, and (with the right case), roll it into your tpa3116 build... pretty sure someone over on diyAudio did exactly this.  I can think of at least a couple uses for such a device in my own setup; seems pretty versatile.

Interesting option.  I may consider adding a miniDSP for the larger TPA3116 amp I plan to build for myself.  But, for these little cheap and cheerful dedicated Airport Express set ups, I'm very happy with the sound I'm getting and the Fiio D3 DAC is a lot less expensive than the miniDSP.  Certainly not as versatile as the miniDSP, but simple, cheap and does the desired job.

I know you're running short on time to get these done, but also on the diyAudio thread, some folks mentioned a bass increase with bigger input signal (dc de-coupling) caps (bigger than 1uF) and/or changing the gain setting... I don't remember the details, and that thread has become a beast, but I do think it was discussed fairly recently, so maybe look at the most recent month's worth of postings?

I've been following that thread.  There is a LOT of information there.  From what I can gather, the larger caps aren't nearly as effective as the inductor swap (which I've already done on all my TPA3116 boards) for improving the bass.  Also, some posters are actually decreasing the gain down to 20dB to better match the 3-tube 6N3 based preamps.  So many options, so little time.

[Markvdv]

Some are reducing gain to 20dB without even considering the tube preamp.

[rhing]

I've been doing some extensive listening with my Yuan Jing TPA3116 2.0 blue amp modified with the following:

• Panasonic OSCON SEPF 330uF/25V organic semiconductor capacitors as power supply decoupling caps
• TDK X7R 220nF/250V ceramic capacitors as bootstrap capacitors

This combination sounds great and really improved the sound quality in terms of:

• Improved frequency response--deeper, more punchy bass, and airy highs
• Smoother presentation with a warmer tone
• Greater detail
• Better separation and a more focused image
• More dynamic range with a significant improvement in attack and decay

I decided to do the same Panasonic OSCON mod to my Sure Electronics TPA3110 amp as well, and obtained the same improvements.





I used a magnet to check if the leads and caps were magnetic and they are not. In fact, both the TDK and Panasonic OSCON caps have tinned Copper leads. Better yet, the OSCONs do not contain a liquid electrolyte that will slowly evaporate over time.

My next step is to install the Coilcraft SER2915L 10uH shielded inductors in my Yuan Jing TPA3116 2.0 blue amp. After that, I will install a quad of NOS Wima MKP10 3.3uF/160V metallized Polypropylene film caps on the inputs.

[Folsom]

I hate that the oscons don't go to 35v...

Rhing, a quad per channel, or two per channel? I ask because it'd be correct with 2 per channel, but 4 per channel would require larger caps for proper corner frequency. Unless you change the gain.

Are people at DIYaudio using the TDK? Just curious how you came to them.

[rhing]

I hate that the oscons don't go to 35v...

Rhing, a quad per channel, or two per channel? I ask because it'd be correct with 2 per channel, but 4 per channel would require larger caps for proper corner frequency. Unless you change the gain.

Are people at DIYaudio using the TDK? Just curious how you came to them.

The OSCONs are mostly used in digital circuits and high frequency applications. I would be surprised to see anything in larger voltages. If you want low ESR, Panasonic FM and Nichicon HE electrolytically are good performers.

As for the Wima's, it would be two per channel, so for a 2-channel amp, it would be four total or a quad. 3.3uF is recommended per the TI data sheet for 26dB gain. This yields an input impedance of 30kohm, which is fine for my system.

Wushuliu mentioned in an earlier post on this thread that he used the TDK X7R ceramic caps for the bootstraps and the Panasonic low ESR hybrid caps, which got me thinking about trying the OSCONs. I would expect the Panasonic hybrid caps to be very good for power supply decoupling in this amp too.

[Markvdv]

I hate that the oscons don't go to 35v...

Rhing, a quad per channel, or two per channel? I ask because it'd be correct with 2 per channel, but 4 per channel would require larger caps for proper corner frequency. Unless you change the gain.

Are people at DIYaudio using the TDK? Just curious how you came to them.

For 3116 25v is enough I think? Most capacitors can handle a little more for short period, don't know about oscons, but the hybrids can handle +30% surge voltage. I also don't think tpa3116 protection allows more, which can start switching off at 24.3v (27v-10%) so a 24.3v<27v powersupply can work on some but not all produced chips I read somewhere. Some are experiencing heat with 24v powersupplies, so I guess that is not unexpected/strange. SQ gets better going down to 21v some experienced long time ago with variable bench supplies.

edit: nichicons (blue marked) do go to 35v, don't know if they are equal, worse or better:)

[matt_garman]

Hey Rhing, great-looking clean work as always.  I'm curious, how many tpa311x amps have now passed through your hands?

[rhing]

Hey Rhing, great-looking clean work as always.  I'm curious, how many tpa311x amps have now passed through your hands?

Thanks Matt. Seven total. I built a couple for people who asked me to build amps for them. I built one using a donated ChengZhi TPA3118 amp from shadowlight for the amp tour, and the others are in my possession. I have other SS and tube amps I've built or restored and modified.

[Poultrygeist]

Green board with top cover removed is up and running. Excellent sound with the 3 tube preamp but less than spectacular with the solid state TC preamp.

No annoying on/off pop with this one. Can't say at this point if it's better or worse than the blue/black.

Having sampled all colors, they're all winners. 

[dboy]

Hi all,

I just got a few days ago a YJ blue/black board after stumbling on the discussion here. I rigged it up in temporary setup with stepped attenuator on input for listening prior to modding. Sounds promising so far, apart from a really bothersome hiss coming through the speakers. At the moment this makes the amp a disappointment to me - impossible to use nearfield on computer, but can still hear the hiss seated about 15ft away. Using 87db-ish full range 4 inch speakers (DIY).

I read that reducing the gain to 20db might help (which I will do) but wondered if anyone could comment on other solutions and whether my board is perhaps worse than the average or if this is just a factor with this chip? Is it an issue that originates with the power supply? All input greatly appreciated to help me hear the magic happen.

[Folsom]

As for the Wima's, it would be two per channel, so for a 2-channel amp, it would be four total or a quad. 3.3uF is recommended per the TI data sheet for 26dB gain. This yields an input impedance of 30kohm, which is fine for my system.

You need two 6.6uf two yield 3.3uf , when paralleling caps. Two 3.3uf will be seen as 1.65uf to the circuit as fas as corner freqjuency goes. That's how that works.

[Poultrygeist]

Hi all,

I just got a few days ago a YJ blue/black board after stumbling on the discussion here. I rigged it up in temporary setup with stepped attenuator on input for listening prior to modding. Sounds promising so far, apart from a really bothersome hiss coming through the speakers. At the moment this makes the amp a disappointment to me - impossible to use nearfield on computer, but can still hear the hiss seated about 15ft away. Using 87db-ish full range 4 inch speakers (DIY).

I read that reducing the gain to 20db might help (which I will do) but wondered if anyone could comment on other solutions and whether my board is perhaps worse than the average or if this is just a factor with this chip? Is it an issue that originates with the power supply? All input greatly appreciated to help me hear the magic happen.

Somethings amiss. All my TPA's are silent even with HE speakers.

[rhing]

You need two 6.6uf two yield 3.3uf , when paralleling caps. Two 3.3uf will be seen as 1.65uf to the circuit as fas as corner freqjuency goes. That's how that works.

The TPA31xx amps have differential inputs, positive and negative, per channel. Referring to the Texas Instruments data sheet, I am using a single 3.3 cap on each input to establish a cut-off frequency of 1.6Hz for 26dB gain.

Hi all,

I just got a few days ago a YJ blue/black board after stumbling on the discussion here. I rigged it up in temporary setup with stepped attenuator on input for listening prior to modding. Sounds promising so far, apart from a really bothersome hiss coming through the speakers. At the moment this makes the amp a disappointment to me - impossible to use nearfield on computer, but can still hear the hiss seated about 15ft away. Using 87db-ish full range 4 inch speakers (DIY).

I read that reducing the gain to 20db might help (which I will do) but wondered if anyone could comment on other solutions and whether my board is perhaps worse than the average or if this is just a factor with this chip? Is it an issue that originates with the power supply? All input greatly appreciated to help me hear the magic happen.

Can you post a photo of your setup? Like Poultrygeist mentioned, something must be amiss for you to experience RFI.

[dboy]

Sure, photo below. Please don't judge too harshly, like I said this was only so I could have a listen prior to changing caps, etc.

The hiss is not massive, but clearly audible and distracting over quiet passages of music. I heard mention of hiss a few times here and at Diyaudio, without anyone saying it was a much of a big deal. I guess I just got a duff board. I had a Sure TA2024 board once that hissed like crazy. I put it down to the implementation and moved on to TA2020 which I preferred. I've ordered an Audiobah board too, so hopefully that will be better when it arrives.

[rhing]

Sometimes touching up the solder joints on the thru-hole components helps. It may not make a difference, but tidying up the wiring might help too. Class D amps can emit RF energy, and the hope is that the LC filter on the outputs will suppress it.

[dboy]

Thanks - I'll give it a go. Cheers for taking the trouble to reply Rhing & Poultrygeist.

[matt_garman]

I just got a few days ago a YJ blue/black board after stumbling on the discussion here. I rigged it up in temporary setup with stepped attenuator on input for listening prior to modding. Sounds promising so far, apart from a really bothersome hiss coming through the speakers. At the moment this makes the amp a disappointment to me - impossible to use nearfield on computer, but can still hear the hiss seated about 15ft away. Using 87db-ish full range 4 inch speakers (DIY).

I get this, but only when my source is disconnected (or connected but powered down).  If the source is connected and powered on (even if no sound is playing), there is no hiss that I can discern.  This isn't a big deal to me, I just can't leave the amp powered on without the source being powered on as well.  Better for my power bill that way. 

Have you tested that attenuator on another device?  Or, tried your 3116 without it?  Maybe it has some wacky issue(s)?

[dboy]

I took the attenuator off an old gainclone that I haven't used for a couple of years, but that always worked fine. I'm fairly sure it isn't that.

I've tried 2 different 12v power supplies so far. I've got some spare parts with which I can knock up a 15v linear unregulated supply so will try that next. I reckon it will probably be a fault on the board though - I guess for the price you can expect a few duff ones.

By the way, I checked and the hiss is fairly constant with or without a source connected and/or playing.