Anybody running TPA series Class-D amps? (3116, 3251, etc.)

Hello all,

After searching around the forums for a class D amp board I came across the posts by FauxFrench who recommended a particular TPA3116D2 board, this one.


Heat sink removed to show the resistors under it, after seeing lots of other poorly populated efforts it does look like a proper job.
He explained that it used good components; was very close to the data sheet, did not have any filters or bluetooth and did not need a pre-amp. It's full 'google will find one' description is " KYYSLB DC12-24V TPA3116D2 Amplifier Board XH-M590 " FF went on to explain not to buy the one with two glued on heat sinks but the one with a single heat sink, this is removable with a screw in order to get to the SMD resistors under it.

Mine arrived and I powered it up, it hissed at 1/2 volume, I was advised to remove two 75k (753) resistors (watched a how to on YT) which reduced the gain from 36dB to 20dB, result not even a smidgen of hiss. The lower gain didn't make any difference to volume levels that I noticed.

My speakers are Frugel Horn Mk3's that I made myself from the original drawings in 2011 with Mark Audio CHP-70's which are 4 Ohm, 86dB, 18 Watt. Looking at the data sheet I saw that at 12V I would get 20 Watts.

I was advised to change the 4 caps which are 470uF to 2,200uF which I did, that made it rather 'shouty' in the upper register, I changed those to 1,000uF, still a bit 'shouty' finally going back to the 470uF ones I splashed out a tenner for 4 Nichicon ones, 'shouty' gone.

In amongst that I was also advised to have to caps between the power supply and the amp, I introduced 25,000uF left over from an analog chip amp project. It sounded very nice, smooth and pleasant, but the bottom end sounded woolly and the top truncated, the bits in the middle a little less distinct.

I removed those and got the full force of the amp back, as Mr Hoyt said in the first post here, what I got was "Gain".

I then conducted a test over many days by using two dummy loads, one in the class D and one in my 3886 chip amp. One fed the left and the other the right speaker and the inputs were connected to a DPDT switch so that I could go from one to another instantly from a listening position.

I've done this before and expected that at first there would be very little perceived difference, there wasn't. I'll not bore you with lists of music, the eventual outcome was the 3886 was slightly soft and the 3116 slightly faster and more detailed especially in the upper and lower registers.

I must emphasise that the differences are very small and others may have chosen the smooth and pleasant rather than the fast and detailed.

I use this 12V 8.5 Amp power supply, cost 9GBP


I've just tried a 12v 2.5 Amp plug into the wall socket PS, no difference whatsoever. Looking at the data sheet one can see why "Feedback Power-Stage Architecture With high Power Supply Ripple Rejection reduces PSU requirements".

With the amp at waking the dead volume and a full range wall of electronic music.
I connected an ammeter in series with the +V output it registered between 0.2 and 0.4 Amps.
At 12v = 4.8 Watts divided by 2 = 2.4 Watts less 10% for efficiency wastage = 2.16 Watts or 1/2 that at 0.2 Amps.

Cheers - J
 

MWalt

Active Member
I have the Allo Volt +D with a 24V linear power supply. It sounds really good, but it doesn't have anywhere near 100 watts per channel. It does sound louder than most of the other tripaths I have had.
 

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MWalt

Active Member
I read that article 3 times to make sure I wasn't missing anything. Interesting. The Volt +D is rated at 60x2 watts at 23V. I am using a 24 volt PS that I am guessing generates a clean 15-20 watts RMS by "misleading" audio standards.
 
Hello M.Walt,

If you connect a multimeter in series with the +DC output you will be able to work out the actual power being used.

e.g. from my own test, my speakers are 4 Ohm so the power supply is 12v the amp is a 3116 this one

With the amp at waking the dead volume and a full range wall of electronic music. I connected an ammeter in series with the +DC Volt output it registered between 0.2 to 0.4 Amps. At 12v = 4.8 Watts divided by 2 = 2.4 Watts per speaker less 10% for efficiency wastage = 2.16 Watts or 1/2 that at 0.2 Amps.

Cheers - Jim
 
I have been playing around with some of lower powered versions of these amps (3110,3118 and 3116) for streaming movies or for casual music playback with a computer. I will have to say these amps score very high on the "bang for the buck" scale when paired with modest satellite speakers. The amps are rated for 4 to 8 ohm speakers. Does anyone have experience with these amps using vintage 16 ohm speakers? I know that there will be less watts available for the speakers but the vintage speakers typically have sensitivity ratings in the 95 to 100+ db range which makes their wattage needs pretty modest. I would test the amps on my 604E's but my wife's online math teaching gig happens in the room with the Altecs making them pretty much unavailable :( for a while.

I am asking because I want to set up a server system in my shop with one of these amps and think it would be cool to match it with something from my vintage speaker collection. And an enclosure for the speakers would be a nice shop project too.
 
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