My RPi + Allo Boss DAC + TPA3116D2 Amp

[jls001]

but, if we come out of imagination, it is still crappy for "for hi-fi music listening"

i would consider TDA8922 over this if i have to go for a medium power class D chip

I've done shootouts of TPA3118 PBTL amp with a well regarded AB power amp (factory made), a factory made class A power amp, a factory made tube integrated amp, and a DIY-ed LM3886-based MyRef Rev C AB chipamp. Each had their strengths, and of course they all had their weaknesses, but overall the differences in these amps (including the TPA3118) were minor.

Personally, I like the TPA3118 enough that it has displaced the above mentioned class A and DIY-ed AB amps from my rack for day to day listening. I must mention that my TPA3118 is tweaked quite a bit and is no longer the stock Rs 640 (per) board.

Do tell more about the TDA8922. It looks like an interesting option.

 

[rikhav]

Hi
I have also happen to listen the mentioned TPA boards of JLS001 quiet a few times and I totally agree with him
When we compare it with the amps he has mentioned the tpa boards perform tremendously well, specially considering it's price and it's not at all easy to distinguish which amp is playing
Of course when you listen critically to compare one can make out small differences in sound signatures between the amps but the point here is it mixes well with well regarded factory made amps which quiet a lot of exotic parts as well

JLS001 speakers are not so power hungry so it might perform differently with speaker's which need lot of power

 

[SanjeevM]

Hi
I have also happen to listen the mentioned TPA boards of JLS001 quiet a few times and I totally agree with him
When we compare it with the amps he has mentioned the tpa boards perform tremendously well, specially considering it's price and it's not at all easy to distinguish which amp is playing
Of course when you listen critically to compare one can make out small differences in sound signatures between the amps but the point here is it mixes well with well regarded factory made amps which quiet a lot of exotic parts as well

JLS001 speakers are not so power hungry so it might perform differently with speaker's which need lot of power

I have connected the TPA3116D2 to my friend's Harbeth P3ESR. It comes out as pretty resolving.

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[Aniket]

Aniket, what are the THD% and SNR figures for the TPA8922C chip? I could only see talk of voltages and protection circuits in the spec sheet.

For 3116 they are 0.02% and 102dB respectively.

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Do tell more about the TDA8922. It looks like an interesting option.

Sanjeev,

0.02% and 102dB ???
1. at what power output
2. at what frequency/ies
3. at what power supply
4. at what load

For TDA8922 its,

0.07% @ 1W pc, 22Hz to 20kHz, Vp= +/-26V, Rl=8ohms
0.5% @ 32W pc, 22Hz to 20kHz, Vp= +/-26V, Rl=8ohms


for TPA3116D2

0.1% @ 25W pc, 1kHz, Vcc=21V, Rl=4ohms

all found in the datasheet.

rest there are graphs for TPA which shows THD>0.5% at anything above 6kHz at power exceeding 10W.

I wont prefer any class D chip for HiFi music listening, but TDA is better than TI's class D on paper, and another good thing is, it works with symmetrical power supply, so you get better power supply ripple rejection and lower noise and eliminate any chance of supply pumping, which TPA may suffer,
so TDA will outperform.
good results can be achieved if you use a solid power supply and make a proper layout and use ample local decoupling as close as possible to the chip.

Also one more very important thing which we neglect is, using any input buffer with class D chips. there will be good sonic improvement.
its pretty simple, with a simple opamp one can build, any low noise opamp like NJM2068, NE5532, NJM4580 would work great, forget about Burr Brown/TI's OPA series, they have terrible noise and THD figures, go for LM4562 for real hifi.

I wont say anything on sound quality as its very subjective, any amp may sound best for one person and worst for other, so build one which sound's good to you.
for me any amp which produce least distortion and induce least noise is HiFi, but sadly, for many people amp which reproduce distorted and sonically altered sound is perceived as hifi

Regards,
Aniket

 

[SanjeevM]

Aniket, the THD+N of 3116 @1Wpc is 0.06%

Even at rated power its thd is lower.

What is the SNR of the TDA?

I am using a single SMPS with 3116, but there is no on off pops, supply pumping, etc that you mentioned. I am considering a CM circuit to improve the DC.

Also, now 3116 boards on eBay have undergone several iterations and are very stable. So no issues here.

 

[jls001]

I want to see if there is a significant improvement in the quality of sound of the 3116D2 (chiefly, does it make the vocals and highs smoother, and improves the bass punch) when run on a Linear Power supply.

Eightaudio, Hyderabad has some ready-made (linear) PSU boards suitable for 50-60 Watt amps. Do check them out. Of course you'll need a transformer too.

I haven't gone down the linear PSU route, though I certainly believe that a good linear supply will improve my 3118. I thought of "borrowing" the PSU from my MyRef Rev C amp but it's of much higher voltage than the 24V typical for 3116/3118. In keeping with the theme of the very low cost involved in building the 3118, I'm a bit hesitant to spend some multiples of the cost of the board on power supply.

 

[SanjeevM]

Eightaudio, Hyderabad has some ready-made (linear) PSU boards suitable for 50-60 Watt amps. Do check them out. Of course you'll need a transformer too.

I haven't gone down the linear PSU route, though I certainly believe that a good linear supply will improve my 3118. I thought of "borrowing" the PSU from my MyRef Rev C amp but it's of much higher voltage than the 24V typical for 3116/3118. In keeping with the theme of the very low cost involved in building the 3118, I'm a bit hesitant to spend some multiples of the cost of the board on power supply.

I have purchased a "EA - Audio Grade 4700uF 63V X 8nos Dual Rail Power Supply ? 2,100.00 INR" from them, and I am waiting for my trafo to come in. Since I will be using a single secondary coil, I will connect all the caps in parallel to get a decent bank. If later on I gather courage & motivation to make a discrete amp, this bank will also work there.

I found the PCB to be slightly flimsy. Had I made the board, I would have used a thicker glass fiber PCB, considering the weight of the capacitors and the heat sink. Hope the PSU does its job well.

You are right, it is many times the cost of the 3116D2 board. I hope it's worth the money dunked in

 

[Tmr_suresh]

any link to a cheapo wifi adapter that works out the box with Volumio

Rasberry pi3 has built in wifi . so no need for external wifi adaptor. i just bought rpi3 and tried volumio. as per forum members suggestion it worked . i am trying to use a cambridge audio cd 640 v2 as my dac. those interested can downlod the schematic form hifiengine . it is based on wolfson (now cirrus logic) WM8740 . it is dual differential output. the cd player got some problem in pickup unit and i tried to replace it but no luck. then there is mechanical wear in the mechanism and loading tray has become a problem. so i decided to use the dac.

Regards,
R.Suresh.

 

[SanjeevM]

Rasberry pi3 has built in wifi . so no need for external wifi adaptor. i just bought rpi3 and tried volumio. as per forum members suggestion it worked . i am trying to use a cambridge audio cd 640 v2 as my dac. those interested can downlod the schematic form hifiengine . it is based on wolfson (now cirrus logic) WM8740 . it is dual differential output. the cd player got some problem in pickup unit and i tried to replace it but no luck. then there is mechanical wear in the mechanism and loading tray has become a problem. so i decided to use the dac.

Regards,
R.Suresh.

The RPi's wifi adapter is very weak and not practically usable, so one has to use an external wifi adapter.

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[Kannan]

Rasberry pi3 has built in wifi . so no need for external wifi adaptor. i just bought rpi3 and tried volumio. as per forum members suggestion it worked . i am trying to use a cambridge audio cd 640 v2 as my dac. those interested can downlod the schematic form hifiengine . it is based on wolfson (now cirrus logic) WM8740 . it is dual differential output. the cd player got some problem in pickup unit and i tried to replace it but no luck. then there is mechanical wear in the mechanism and loading tray has become a problem. so i decided to use the dac.

Regards,
R.Suresh.

I have a raspberry pi2 and not 3

 

[omishra]

Try edimax or tplink. If you face any issue then let us know. I tried both with moode media player. Tplink needs latest device driver but i can guide you to simple steps.

 

[Kannan]

Try edimax or tplink. If you face any issue then let us know. I tried both with moode media player. Tplink needs latest device driver but i can guide you to simple steps.

Thanks, I already have a Ralink wifi adapter purchased two years back.
I had successfully installed it at that time using ADB/putty tools after a number of driver searches and some tweaks, but it did not work with the Volumio version of that time, but worked well in Raspbian if I remember right.

I tried it with the current Volumio but is not detected. I have totally forgotten the model number and am just too lazy to go through the whole routine again.

So was looking at an option that would play out of the box with the latest volumio.

cheers
kannan

 

[SanjeevM]

JLS,

My Rs 850 chinese 3116d2 board sings better than an Allo 3118 board with the same 24v SMPS suppy !!!

Also, same source and spkrs.

 

[niccolewis]

JLS,

My Rs 850 chinese 3116d2 board sings better than an Allo 3118 board with the same 24v SMPS suppy !!!

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Could you provide a link for where you picked this board up and the SMPS supply you use? I want to try out these boards as a cheaper alternative for my smaller setup. Thanks!

 

[SanjeevM]

This is the link: www.ebay.in/itm/XH-M189-2-50W-DIGIT...797832?hash=item3ae927b948:g:rlMAAOSwAuZX6krn

I will strongly suggest that u take a 0-18v 6A trafo with tap at 15v and a rectifier ckt for a clean power supply.

You can get power supp unit here: https://www.eightaudio.in/products/ea-audio-grade-4700uf-63v-x-8nos-dual-rail-power-supply

Torotrans Pune is a good source for Trafo.

 

[niccolewis]

Great, thanks for the reply Sanjeev! Do you have a link of a DIY tutorial that shows how to put everything together? This looks like a fun project.

 

[SanjeevM]

Great, thanks for the reply Sanjeev! Do you have a link of a DIY tutorial that shows how to put everything together? This looks like a fun project.

No, I'm afraid.


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[jls001]

JLS,

My Rs 850 chinese 3116d2 board sings better than an Allo 3118 board with the same 24v SMPS suppy !!!

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That's a very interesting observation

 

[SanjeevM]

That's a very interesting observation

Yeah, the chinese board sings with an open throat, the other one sounds clinical.

Maybe the boards are sensitive to the impedance of the speakers; like one board likes my speakers other one does not

I have purchased a "EA - Audio Grade 4700uF 63V X 8nos Dual Rail Power Supply ? 2,100.00 INR" from them, and I am waiting for my trafo to come in. Since I will be using a single secondary coil, I will connect all the caps in parallel to get a decent bank. If later on I gather courage & motivation to make a discrete amp, this bank will also work there.

I found the PCB to be slightly flimsy. Had I made the board, I would have used a thicker glass fiber PCB, considering the weight of the capacitors and the heat sink. Hope the PSU does its job well.

You are right, it is many times the cost of the 3116D2 board. I hope it's worth the money dunked in

I finally got the traffic delivered. It's a 0-15-18-25VDC single secondary 250VA trafo. The VA is high as compared to the needs of 3116d2. I have connected it to the Eight audio PS and it's feeding the 3116 board.

What a difference did it make to the sound !!

... the sound cleaned up,
... it more musical now,
... bass is much better now (maybe bcos of rock steady psu & 18000 mfd)
... since there is no switching noise, the clarity is higher..

The improvement is huge .

This is the trafo.

JLS / Aniket, I am using an unregulated LPS as of now, so if the line voltage goes down or up, the Amp board also gets lower or higher voltages. Can I add a regulator between the rectified supply and the Amp, say, made of two LM338 5A regulators in parallel with a 0.5R 5W resistor in series followed by a large capacitor bank (to get a 10A 24V regulated PS) ?

 

[vizeta]

Can we start Groupbuy for LCD+RPI+DAC+PSU+AMP borad+Traffo? I am interested to use it as Squeezebox player. Let me know your thoughts.