I put together the 2 TPA3118 modules on piece of MDF together with the power supply and a potmeter for some level of volume control. Forgot to order 2 pair of speaker terminals, so those are the orange wires for now (some spare wire I had laying around, to test)
Unfortunately the line-in picks up a LOAD of hum like this, together with some high pitched sound like Aliens are talking to me. Also saw that I did not connect the potmeter (10k log stereo) to ground on the remaining pin, so it does not do all that much at the moment.
Will try again with the other pin of the pot connected to ground (RCA outer tab ok for each channel? If that does not improve things, take a step back and connect some RCA directly to the input of the amps. If I power them up as shown on the photo (nothing connected to the RCA plugs) it still has a lot of hum.
With the input disconnected from the board there is still some white noise, but I read that that might be because of the high gain inside these things, and can always be altered later on. Also moving my hand towards the white wires increases it, so that is my first direction to look at.
Unfortunately the line-in picks up a LOAD of hum like this, together with some high pitched sound like Aliens are talking to me. Also saw that I did not connect the potmeter (10k log stereo) to ground on the remaining pin, so it does not do all that much at the moment.
Will try again with the other pin of the pot connected to ground (RCA outer tab ok for each channel? If that does not improve things, take a step back and connect some RCA directly to the input of the amps. If I power them up as shown on the photo (nothing connected to the RCA plugs) it still has a lot of hum.
With the input disconnected from the board there is still some white noise, but I read that that might be because of the high gain inside these things, and can always be altered later on. Also moving my hand towards the white wires increases it, so that is my first direction to look at.
You need shielded wire for the inputs and, if I am not mistaking, your input RCA connectors are connected to the L profile which is made from metal (so that is a kind of short circuit for GND). You will need isolated input connectors and route the shielded wire to the potentiometer. The potentiometer definitely needs GND to function correctly. Amp boards should be mounted with M3 standoffs to the chassis..
Last edited:
Will try with shielded cable, some COAX perhaps?
The profiles are plastic, bought that on purpose to prevent any issues with it 😉
The profiles are plastic, bought that on purpose to prevent any issues with it 😉
I would use a thin flexible shielded cable. Coax is often quite sturdy. Microphone cable is nice for this purpose.
Please remove the "spijkers" (nails) as these have no place in electronic stuff as they can come loose and cause shorts.
Please remove the "spijkers" (nails) as these have no place in electronic stuff as they can come loose and cause shorts.
Considerations for multiple monoboards with single PSU?
I'm planning on using three of the Sanwu TPA3118 mono boards in a single case to power L + R + Center for my TV. I plan to power them externally from a single good quality 19 or 24V laptop brick.
Short of running each board off its own PSU, as some have done, what should I do to avoid problems with interactions between the amp modules through the power bus?
Also, more generally, when powering a class D module (such as the red Sanwu 2x50w TPA3116) from a laptop or general purpose SMPS, are there any accommodations that should be made for bus pumping, additional decoupling, filtering, etc?
Thanks!
I'm planning on using three of the Sanwu TPA3118 mono boards in a single case to power L + R + Center for my TV. I plan to power them externally from a single good quality 19 or 24V laptop brick.
Short of running each board off its own PSU, as some have done, what should I do to avoid problems with interactions between the amp modules through the power bus?
Also, more generally, when powering a class D module (such as the red Sanwu 2x50w TPA3116) from a laptop or general purpose SMPS, are there any accommodations that should be made for bus pumping, additional decoupling, filtering, etc?
Thanks!
My Thinkpad PSUs have a large ferrite core on the DC output. So that and/or do the same for each feed to each amp?
I would say an LC filter (inductor+ strong capacitors) would eliminate many power supply interferences. Depending on power needs, a forward diode also would keep some interferences from power supply power lines.
I guess, using 3 PSU can be cheaper, simpler and efficient process.
I guess, using 3 PSU can be cheaper, simpler and efficient process.
Blamm, turning the psu 90 deg and let both power inputs of the amp boards face the psu should allow for a smaller enclosure and for shorter cables.
Jean-Paul the nails are VERY temporary as I had no standoffs or screws that fitter the small holes and wanted to secure them in place for testing
Will get them with my next order. Together with some microphone cable, thanks for that tip! Unfortunately no shops nearby that carry those
Buehgemeiste will take a look at that, looks like a good suggestion
Will get them with my next order. Together with some microphone cable, thanks for that tip! Unfortunately no shops nearby that carry those
Buehgemeiste will take a look at that, looks like a good suggestion
Thanks for the suggestion(s).
I don't think 3 PSUs will be cheaper or simpler by my criteria. The power bricks will be a messy tangle. If I spend some time, I can probably find them for cheap or free if I spend a bunch of time looking, but for a quick source of used, they are ~$5/each. PSU modules are $10 each, and will require a significantly larger and more expensive case.
On the other hand characterizing the noise before specifying the filter will take me some time. I guess the output filters provide a starting point for consideration, does that make sense?
Does anyone have a known-good power input filter design for running multiple Sanwu monoboards off the same PSU?
Very good question. I would like to know as well. Power input device to clean it up and eliminate noise?
Some time ago I got recommended, in the 3116 thread, that I should look at the Sanwu 3118 mono boards.
I tried bying these:
Free shippingTPA3118 PBTL mono digital amplifier board 1X60W 12V 24V POWER AMP 1PCS-in Sensors from Electronic Components & Supplies on Aliexpress.com | Alibaba Group
They sound VERY good. WAY to high gain, though! R1 is 39k and R2 is 100k equal 32dB in Master. I read in here that I could remove R2, and leave R1 at "wrong value" which will result in 20dB. I removed R2 and left it open. Gain is now MUCH lower, and hiss almost went away. (yeah, I'm really really sensetive)
I use 4 of them to power 2 floorstanding speakers (bi-amp)
No SANWU on backside?
The front side did not have print like other Sanwu boards. I found on here that 3rd last resistor=R27=R2=104. 2nd last resistor=R28=R1=393. So I removed 3rd last resistor. Leaving R1 at 39k
I tried bying these:
Free shippingTPA3118 PBTL mono digital amplifier board 1X60W 12V 24V POWER AMP 1PCS-in Sensors from Electronic Components & Supplies on Aliexpress.com | Alibaba Group
They sound VERY good. WAY to high gain, though! R1 is 39k and R2 is 100k equal 32dB in Master. I read in here that I could remove R2, and leave R1 at "wrong value" which will result in 20dB. I removed R2 and left it open. Gain is now MUCH lower, and hiss almost went away. (yeah, I'm really really sensetive)
I use 4 of them to power 2 floorstanding speakers (bi-amp)
No SANWU on backside?
The front side did not have print like other Sanwu boards. I found on here that 3rd last resistor=R27=R2=104. 2nd last resistor=R28=R1=393. So I removed 3rd last resistor. Leaving R1 at 39k
please scale those images down! 😉
I got some noname ones from ebay, too. when I went with the lowest price HK dealer, I got those 2 that did not look as good as sanwu and did not have the name below it.
there are many grades of 'good' in chinese ebay; even if you buy from the same seller, he could get some other grey grade goods from a diff supplier next week. and parts can be all kinds of quality. its not just 'good/real' or 'junk/fake' but many levels in between. very frustrating to deal with people who do things like that.
I got some noname ones from ebay, too. when I went with the lowest price HK dealer, I got those 2 that did not look as good as sanwu and did not have the name below it.
there are many grades of 'good' in chinese ebay; even if you buy from the same seller, he could get some other grey grade goods from a diff supplier next week. and parts can be all kinds of quality. its not just 'good/real' or 'junk/fake' but many levels in between. very frustrating to deal with people who do things like that.
Very frustrating indeed. I have been through couple of the 3116 boards now, and I found them having hiss and being badly configured. Finally got lucky though. Watching movies I dont really hear the big difference between these and my half-ton power-thirsty Onkyo. So the Onkyo hit the shelf, and I now pocket the power savings :-D
FWIW, I have an ebay seller I've had good luck with for Sanwu boards.
I ordered and received two of the Red/Orange Sanwu TPA3116 boards from them, a couple of weeks apart. Both had the metallic Sanwu logo on the board and were sealed in antistat bags with a SanWu "anti-counterfiting" sticker affixed (near as I can tell, it just takes you to a broken/obsolete WeChat URL or profile). When I ordered the second TPA3116 board I also ordered two of the mono TPA3118. They weren't in sealed bags, but do have the silver Sanwu logo.
I just took a closer look comparing the Sanwu TPA3118 with the knockoff TPA3118 boards I got from "Mega" on AliExpress. Save RVT caps. Same shielded inductors without the blue goop in the gap between the shield and core as shown in a lot of product photos for both the genuine, and the knockoffs. Without a magnifier, the quality of the placement and soldering looks similar, with no badly askew components. One thing I noticed is that the vias under the chip on the sanwu boards are bare tin, while the clones are covered with blue solder mask.
Ok, all that said, the seller is ayanhu81. Their prices are good, but rarely the best. They ship quickly and pack well. I use the default shipping option and I think the three orders I've placed so far have all arrived in Seattle within 2 weeks of my order. Two orders were packed in small boxes. One was in a well padded envelope. I think the same seller may also operate some other eBay accounts with similar stock and pricing.
I ordered and received two of the Red/Orange Sanwu TPA3116 boards from them, a couple of weeks apart. Both had the metallic Sanwu logo on the board and were sealed in antistat bags with a SanWu "anti-counterfiting" sticker affixed (near as I can tell, it just takes you to a broken/obsolete WeChat URL or profile). When I ordered the second TPA3116 board I also ordered two of the mono TPA3118. They weren't in sealed bags, but do have the silver Sanwu logo.
I just took a closer look comparing the Sanwu TPA3118 with the knockoff TPA3118 boards I got from "Mega" on AliExpress. Save RVT caps. Same shielded inductors without the blue goop in the gap between the shield and core as shown in a lot of product photos for both the genuine, and the knockoffs. Without a magnifier, the quality of the placement and soldering looks similar, with no badly askew components. One thing I noticed is that the vias under the chip on the sanwu boards are bare tin, while the clones are covered with blue solder mask.
Ok, all that said, the seller is ayanhu81. Their prices are good, but rarely the best. They ship quickly and pack well. I use the default shipping option and I think the three orders I've placed so far have all arrived in Seattle within 2 weeks of my order. Two orders were packed in small boxes. One was in a well padded envelope. I think the same seller may also operate some other eBay accounts with similar stock and pricing.
fwiw, this is also a sanwu board and seem pretty nice for the price:
https://www.amazon.com/gp/product/B01EW4YSCK
I bought 2 of them and they seem to be out of stock for now (sorry). I was surprised to see the sanwu name on it and it did not have any junk on the board (pots, bad connectors) that I had to remove or bypass. very small board for stereo and while not as good as dual mono, the psu is easier (just 1) and the board is so tiny, its really a neat one to do a build with.
https://www.amazon.com/gp/product/B01EW4YSCK
I bought 2 of them and they seem to be out of stock for now (sorry). I was surprised to see the sanwu name on it and it did not have any junk on the board (pots, bad connectors) that I had to remove or bypass. very small board for stereo and while not as good as dual mono, the psu is easier (just 1) and the board is so tiny, its really a neat one to do a build with.
@linuxworks
I agree, the pots on most of the boards are "trouble makers". Just curious, how does this board sounds?
Regards,
I agree, the pots on most of the boards are "trouble makers". Just curious, how does this board sounds?
Regards,
@linuxworks.
Yeah, I like that board. Small, seems well made, and no obvious audio faults to my fussy but relatively untrained ears.
That's the one I got two of from ayanhu81 on ebay. I'm about to turn one into a PBTL board and then integrate the two of them into an evolving 2.1 preamp/amp project. First pass is using an existing 2.1 low-pass pre-amp module. Next step is a custom adjustable crossover. Once that's right, I'll put it all in a case.
How much did you pay through Amazon? The listing you linked to is now showing as "not available" now.
Yeah, I like that board. Small, seems well made, and no obvious audio faults to my fussy but relatively untrained ears.
That's the one I got two of from ayanhu81 on ebay. I'm about to turn one into a PBTL board and then integrate the two of them into an evolving 2.1 preamp/amp project. First pass is using an existing 2.1 low-pass pre-amp module. Next step is a custom adjustable crossover. Once that's right, I'll put it all in a case.
How much did you pay through Amazon? The listing you linked to is now showing as "not available" now.
it was $17 shipped. too cheap to say 'no' to. and so small, too.
was able to put one inside a PGA preamp build and make an 'all in one' system with line in, preamp, spkr-out.
I see that unit on ebay but not by many sellers. have not listened very long, but 'seemed fine' on simple test. I assume its fine, too, but really have not had enough time with it to know for sure.
was able to put one inside a PGA preamp build and make an 'all in one' system with line in, preamp, spkr-out.
I see that unit on ebay but not by many sellers. have not listened very long, but 'seemed fine' on simple test. I assume its fine, too, but really have not had enough time with it to know for sure.