Paul.Ruby
Active member
I do see some smaller components on yours that do not match the fake board. Maybe yours is real?!
TPA3118 60W Power Amp Module
- Thread starter falzhobel
- Start date
That was just a pic I got off the web. My actual build is this one:
Paul.Ruby
Active member
That's a fake one for sure. Matches this exactly. Having tested these, they are roughly equivalent to the real TPA3118 in power output. The real ones deliver much more power and the heat sink is bolted on. (Too much for a pedal board amp, IMO.)
So what's powering that?
Paul.Ruby
Active member
Just powered my fake one. No hiss (unlike the fake 3118s, which hiss pretty badly). But, certainly not 100W. With a sine wave input, it's distorting badly once the output voltage is beyond +/-1V. It's really low wattage for clean output. The real one is not distorting at all, at much higher output. From what I remember, these fakes sounded OK with a guitar. But they are garbage compared to the real ones.
That's my experience too. They work, but just not what you would expect as far as volume goes.
There's no such thing as too much power!
Paul.Ruby
Active member
Trying to find that out now. Long ago I got real ones from here and just ordered more yesterday. Will report back.
JamieJ
Well-known member
When wiring up a TPA3118 module, has anyone experimented with pot value to make the volume more controllable?
The image above uses a B50k wired before the module. I’d assume a A50k would be better. I have a tube preamp build in the works that I want to use this with as a power amp for a 1x12.
temol
Well-known member
The image uses A50k. Log = A
Paul.Ruby
Active member
I put in some effort into some measurements of real and fake 3116 for comparison. My fake 3116 is a small 16 pin chip, not the chipstar 8683. I've already compared by ear and found that the fakes are considerably lower volume with similar volume to a real 3118 and sound OK. Real 3118 and 3116 both sound better. The 3116 can be VERY loud and too much power for a pedal board, IMO, but has a lot of headroom and punch if you want that. Now the engineering results...
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TLDR:
Real 3116 is very low low THD up to 31W with headroom all the way to 50W with degraded THD into 8-ohm and very power efficient.
The real 3116 has some audible hiss at low volume. Well below that of a 50W tube amp but audible. Acceptable.
Fake 3116 has poor THD at all power output levels up to 29W and completely caps output at 31W and is much less power efficient.
My fake 3116 is the tiny 16 pin garbage. More recent fakes use chipstar 8683, which I do not have for testing.
This fake 3116 at least has no hiss at low volume. Even less than the real 3116.
If I get a fake 3116 of the chipstar 8683 variant, I'll test that too. Buying boards is a total crap shoot. So many lousy china chips trying to replace the already great and cheap TI chips. Pointless and frustrating.
The fake 3118 out-performs the fake 3116 in THD and power output (reaches 40W into 8-ohm) but lots of hiss.
The hiss is unacceptable in the fake 3118.
Real 3118 has smoothly degrading THD as power goes up all the way to 46W into 8-ohm with NO hiss at low volume.
This is the king of pedal amp boards, IMO. No hiss. Plenty of volume and headroom.
Sounds great with the right preamp at 30W with lots of headroom.
The real 3116 is lower THD and more power, but larger and with some audible hiss.
Would love a board with TPA3250 to compare, which would likely be the new king.
Also tested my IRS2092S-250W amp for comparison. Very clean, low noise, high power... Really nice. But ain't a pedal amp.
--------------------------------------------------------------------------------
The real 3116...
THD is low all the way up to 31W output into 8-ohm load.
THD degrades abruptly at about 36W but remains roughly constant up to peak output of 50W into 8ohm.
So this is delivering exactly as expected. Keep the average power at or below about 31W and it's very low distortion but has headroom to hit 50W with degraded THD.
When delivering 36W into 8-ohm, power draw is 1.6A at 24VDC... 38W. Pretty good.
Here's a picture of THD at 36W output into 8 ohms. Yellow is input signal. Green is output signal.
The large spike is the 3khz sine wave (the desired spike). The other green spikes are distortion harmonics.
----------------------------------------------------------------------------------------------------------
Now the fake 3116 (16 pin variant, not chipstar 8683).
This has significant distortion at all power levels and totally craps out beyond 29W output.
Baseline THD remains constant up to about 29W output then begins to really crap out.
Peak output is 31W, so it will not push beyond 29W. No headroom if playing loud.
Power draw at 29W output is 1.4A at 24VDC: 34W, so clearly less efficient and the barely-glued-on heat sink and PCB got pretty hot.
Here's the picture of baseline THD. Lots of weird harmonics at 1khz increments. This tuns to total garbage if pushed beyond 29W.
The baseline THD is a bit worse than the degraded THD of the real 3116 at 36W.
So, there is no headroom and must keep the average power considerably lower than 29W, probably at or below 20W, to have any punch or dynamics.
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Fake 3118.
By ear, these have noticeable hiss compare to real 3118.
These have a baseline THD worse than real 3116 but not as bad as the fake 3116.
At the onset of bad THD beyond baseline:
Output: 14.5Vrms into 8-ohm
Power supply: 1.2A draw at 24VDC (29W). Reasonable.
Power output: 26W
This is pretty close in output power at lower THD than the fake 3116.
THD matches the fake 3116 when this is delivering 30W, slightly more than the fake 3116!
Peak power gets all the way to 40W before THD totally falls apart, which is way more headroom than the fake 3116.
The fake 3118, a smaller, cheaper board, is considerably better than the fake 3116 and with better power efficiency. But has more hiss, borderline unacceptable.
Here's the THD at 26W output.
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Real 3118.
At onset of degraded THD: 16.5Vrms, 34W into 8-ohm.
Power draw at onset of degraded THD: 1.5A, 36W. Good efficiency.
Peak at onset of clipping: 19.2Vrms, 46W into 8-ohm.
Plenty of volume and headroom with no hiss at all.
THD is really good at low power and gradually degrades. I chose the power level where the 3rd harmonic at 9khz crossed -25db as my point of degraded THD. This is somewhat arbitrary because it's a gradual degradation. Having no hiss at all with no signal is very important and a shining point of this amp. And, of course, that it sound's great, despite the THD smoothly degrading all the way until clipping. If not for the HISSSSSS, the fake 3118 boards would be reasonable. They approach the power levels of the real thing and are as good with THD. But the HISSS!!! UHG!
Picture at onset of degraded THD.
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IRS2092S 250W
This is not suitable for a pedal amp. I built a traditional amp out of this but including it here for comparison.
Ebay link: https://www.ebay.com/itm/312705869615
But you also need +/-50V power: https://www.ebay.com/itm/112468429497
This gives 25.9V RMS before the noise floor begins to rise. 84W clean power into 8 ohm.
Peak power prior to clipping is 37.7Vrms into 8-ohm. 177W.
This amp uses +/-50V power supply built into the chassis with a preamp, TMB section, balanced output...
All the works for a use as a bass amp or guitar power amp. Sounds fantastic.
Here's the picture of THD. It's really nice compared to the tiny amp boards.
Here's what the amp looks like while I'm testing it...
--------------------------------------------------------------------------------
TLDR:
Real 3116 is very low low THD up to 31W with headroom all the way to 50W with degraded THD into 8-ohm and very power efficient.
The real 3116 has some audible hiss at low volume. Well below that of a 50W tube amp but audible. Acceptable.
Fake 3116 has poor THD at all power output levels up to 29W and completely caps output at 31W and is much less power efficient.
My fake 3116 is the tiny 16 pin garbage. More recent fakes use chipstar 8683, which I do not have for testing.
This fake 3116 at least has no hiss at low volume. Even less than the real 3116.
If I get a fake 3116 of the chipstar 8683 variant, I'll test that too. Buying boards is a total crap shoot. So many lousy china chips trying to replace the already great and cheap TI chips. Pointless and frustrating.
The fake 3118 out-performs the fake 3116 in THD and power output (reaches 40W into 8-ohm) but lots of hiss.
The hiss is unacceptable in the fake 3118.
Real 3118 has smoothly degrading THD as power goes up all the way to 46W into 8-ohm with NO hiss at low volume.
This is the king of pedal amp boards, IMO. No hiss. Plenty of volume and headroom.
Sounds great with the right preamp at 30W with lots of headroom.
The real 3116 is lower THD and more power, but larger and with some audible hiss.
Would love a board with TPA3250 to compare, which would likely be the new king.
Also tested my IRS2092S-250W amp for comparison. Very clean, low noise, high power... Really nice. But ain't a pedal amp.
--------------------------------------------------------------------------------
The real 3116...
THD is low all the way up to 31W output into 8-ohm load.
THD degrades abruptly at about 36W but remains roughly constant up to peak output of 50W into 8ohm.
So this is delivering exactly as expected. Keep the average power at or below about 31W and it's very low distortion but has headroom to hit 50W with degraded THD.
When delivering 36W into 8-ohm, power draw is 1.6A at 24VDC... 38W. Pretty good.
Here's a picture of THD at 36W output into 8 ohms. Yellow is input signal. Green is output signal.
The large spike is the 3khz sine wave (the desired spike). The other green spikes are distortion harmonics.
----------------------------------------------------------------------------------------------------------
Now the fake 3116 (16 pin variant, not chipstar 8683).
This has significant distortion at all power levels and totally craps out beyond 29W output.
Baseline THD remains constant up to about 29W output then begins to really crap out.
Peak output is 31W, so it will not push beyond 29W. No headroom if playing loud.
Power draw at 29W output is 1.4A at 24VDC: 34W, so clearly less efficient and the barely-glued-on heat sink and PCB got pretty hot.
Here's the picture of baseline THD. Lots of weird harmonics at 1khz increments. This tuns to total garbage if pushed beyond 29W.
The baseline THD is a bit worse than the degraded THD of the real 3116 at 36W.
So, there is no headroom and must keep the average power considerably lower than 29W, probably at or below 20W, to have any punch or dynamics.
---------------------------------------------------------------------------------------------------
Fake 3118.
By ear, these have noticeable hiss compare to real 3118.
These have a baseline THD worse than real 3116 but not as bad as the fake 3116.
At the onset of bad THD beyond baseline:
Output: 14.5Vrms into 8-ohm
Power supply: 1.2A draw at 24VDC (29W). Reasonable.
Power output: 26W
This is pretty close in output power at lower THD than the fake 3116.
THD matches the fake 3116 when this is delivering 30W, slightly more than the fake 3116!
Peak power gets all the way to 40W before THD totally falls apart, which is way more headroom than the fake 3116.
The fake 3118, a smaller, cheaper board, is considerably better than the fake 3116 and with better power efficiency. But has more hiss, borderline unacceptable.
Here's the THD at 26W output.
-------------------------------------------------------------------------------------------
Real 3118.
At onset of degraded THD: 16.5Vrms, 34W into 8-ohm.
Power draw at onset of degraded THD: 1.5A, 36W. Good efficiency.
Peak at onset of clipping: 19.2Vrms, 46W into 8-ohm.
Plenty of volume and headroom with no hiss at all.
THD is really good at low power and gradually degrades. I chose the power level where the 3rd harmonic at 9khz crossed -25db as my point of degraded THD. This is somewhat arbitrary because it's a gradual degradation. Having no hiss at all with no signal is very important and a shining point of this amp. And, of course, that it sound's great, despite the THD smoothly degrading all the way until clipping. If not for the HISSSSSS, the fake 3118 boards would be reasonable. They approach the power levels of the real thing and are as good with THD. But the HISSS!!! UHG!
Picture at onset of degraded THD.
------------------------------------------------------------------------------------------
IRS2092S 250W
This is not suitable for a pedal amp. I built a traditional amp out of this but including it here for comparison.
Ebay link: https://www.ebay.com/itm/312705869615
But you also need +/-50V power: https://www.ebay.com/itm/112468429497
This gives 25.9V RMS before the noise floor begins to rise. 84W clean power into 8 ohm.
Peak power prior to clipping is 37.7Vrms into 8-ohm. 177W.
This amp uses +/-50V power supply built into the chassis with a preamp, TMB section, balanced output...
All the works for a use as a bass amp or guitar power amp. Sounds fantastic.
Here's the picture of THD. It's really nice compared to the tiny amp boards.
Here's what the amp looks like while I'm testing it...
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Paul.Ruby
Active member
The module takes line level. Needs a preamp with volume control ahead of it. I've posted a lot of different options for this in this thread...
Volume-only preamp detailed here: https://forum.pedalpcb.com/threads/tpa3118-60w-power-amp-module.2015/post-105799
Final PCB layout of volume-only here: https://forum.pedalpcb.com/threads/tpa3118-60w-power-amp-module.2015/post-107643
Cold-turkey preamp here: https://forum.pedalpcb.com/threads/tpa3118-60w-power-amp-module.2015/post-106049
Box and All here: https://forum.pedalpcb.com/threads/tpa3118-60w-power-amp-module.2015/post-106330
6-band EQ here: https://forum.pedalpcb.com/threads/tpa3118-60w-power-amp-module.2015/post-106474
Tone Tweq here: https://forum.pedalpcb.com/threads/tpa3118-60w-power-amp-module.2015/post-109615
And please check this post as well: https://forum.pedalpcb.com/threads/tpa3118-60w-power-amp-module.2015/post-110531
Soft-touch stand-by addition here: https://forum.pedalpcb.com/threads/tpa3118-60w-power-amp-module.2015/post-109242
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Paul.Ruby
Active member
I see that some fake 3116 boards have upgraded to the Chipstar 8683. It's possible that's what you have. It's not what I have as a fake. This review on amazon shows it.
Paul.Ruby
Active member
Seems futile to do this unless you have a reliable supply of the original modules. The fakes far outweigh the real ones now. But, the schematic for it is easy. Might be easier to design a full PCB to direct solder the TPA3118 (or it's compatible and better successor TPA3250D2) and maybe convert all the components to through hole, except for the chip. I'm seriously considering doing it myself but I've never done a "real" PCB. I manually layout and make one-off, single-sided boards on my laser machine. I would be happy to help with design work. Would love a PCB with the Marshall TMB, push button toggle bright switch, soft-touch footswitch mute that powers up on mute, 5-second power on delay, power LED and active LED. That is a KILLER little pedal board amp. A bit of a bear to do by hand but possible... This one does not have a bright switch.
This is not a trivial build...
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Paul.Ruby
Active member
4 real 3118 boards just arrived from them.
The remains of 5 nonrefundable fakes that were certainly never going to end up in any project of mine...
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Paul.Ruby
Active member
This is a real 3116 board.
Much more expensive that the previous and needs more effort to make it into a pedal. It's performance is very good. Dead silent with no signal and the volume control maxed out. Very clean all the way to 34W before THD begins to degrade gradually. It has interesting behavior as it approaches maximum output power (of 60W into 8-ohm). It doesn't clip. The sinewave gets closer to a triangle wave with rounded peaks. This has plenty of clean power and tons of headroom without clipping at any power level. This is an interesting amplifier. I'll report more once I've tried it out as a guitar amp.
