Den_hr,
Very nice setup you made. Those enclosures for the Sanwu's look great - obviously way oversized but makes it look substantial. If people saw how small the amp actually was, they might have a different perception and opinion. Those Sanwu 3118 PBTL's are one of the best sounding stock amps I have tried. So not surprising that your audience was impressed.
Very nice setup you made. Those enclosures for the Sanwu's look great - obviously way oversized but makes it look substantial. If people saw how small the amp actually was, they might have a different perception and opinion. Those Sanwu 3118 PBTL's are one of the best sounding stock amps I have tried. So not surprising that your audience was impressed.
The enclosures look bigger in the photos than they actually are: the outside dimension of the square "pipe" is 80x80mm, and the walls are 4mm thick, so there is not that much space inside when you add the wiring, connectors, etc...
But yes, the enclosures could easily be smaller. I did several smaller enclosures for some other amps that I made, but then there's a practical problem: all of the buyers complained about the difficult cable connections (they usually use some "monster" oversized cables, with diameters easily reaching 22-26mm - about an inch and more). So, I need a bit larger enclosure for the buyer to be able to connect the speaker and interconnect cables without too much trouble
Hello,
I connected TPA3118 Sanwu amp today and it is not working.
It is giving a tumb sound every second
What could be wrong?
Bostjan
What kind of power supply do you use?
Did you power the amp up without a load connected?
That sounds like it is going through self protect reset each second. There is either a short somewhere or a bad major component like a bad input cap or bad bootstrap cap. Use an ohm meter and probe those caps to make sure they are not internally shorted. Is the red LED lighting up continuously?
The led is on. Amp was powered without load
I asked that, because that way i ripped a fully modded 3116 board.
It showed the same symptome as yours.
My guess is that your amp is finished.
BTL = Bridge Tied Load (aka "bridge mode"). Two amps driving the load between their positive outputs. Gives you twice the voltage swing of a single amp.
PBTL = Parallel Bridge Tied Load. Four amps in Parallel+Bridge configuration. Gives you twice the voltage swing and twice the current capability of a single amp.
/U.
PBTL = Parallel Bridge Tied Load. Four amps in Parallel+Bridge configuration. Gives you twice the voltage swing and twice the current capability of a single amp.
/U.
I'm thinking about using one of the sanwu pbtl boards in a small portable speaker build. Wondering if anyone has tried powering this amp with a 7.4V li ion battery and measured output?
I'm thinking about a 2.5" driver that has very broad frequency response and fairly low qts that should give me nice bass response in a very small package. However, the sensitivity of this driver is quite low.
Lots of SPL is not my goal for this speaker, but want to get an idea of just how much volume I might be able to get out of this amp with this speaker at 7.4V. Then I'll decide if it'll be loud enough as is or if I want to move up to an 11.1v battery or to a higher sensitivity driver.
The specs for the chip say 2x15W into 8ohm at 15V (and I'm guessing this is at 10%THD+N). So if it's in PBTL mode at 7.4V into 8ohm is it unreasonable to expect somewhere around 6W somewhat clean?
I'm thinking about a 2.5" driver that has very broad frequency response and fairly low qts that should give me nice bass response in a very small package. However, the sensitivity of this driver is quite low.
Lots of SPL is not my goal for this speaker, but want to get an idea of just how much volume I might be able to get out of this amp with this speaker at 7.4V. Then I'll decide if it'll be loud enough as is or if I want to move up to an 11.1v battery or to a higher sensitivity driver.
The specs for the chip say 2x15W into 8ohm at 15V (and I'm guessing this is at 10%THD+N). So if it's in PBTL mode at 7.4V into 8ohm is it unreasonable to expect somewhere around 6W somewhat clean?
Damaged outputcapacitors most times do allow music played, but with evenly timed pop, a damaged bootstrap would prevent normal startup. If voltage rating capacitors is high enough they survive I think, but I also managed to damage one 63V outputfilm once, checking sound one channel very briefly (no balance knob available then), like 20 seconds, not a good idea.
Nice bass + small enclosure = doesn't work. You will always have to trade Bass for SPL.
So this leads into:
Bass + small enclosure = low SPL
Bass + high SPL = big enclosure
high SPL + big enclosure = Bass
Something like so.
I didn't know this was a rule, but I was beginning to see this pattern as I searched through the small full range drivers available at parts express. Iwas looking for small, efficient drivers with low Qts and low Fs. But as you say, they don't really exist.
I think if I have to make that tradeoff for this particular build I'm happy to give up volume/efficiency in order to keep the enclosure as small as possible and still have a somewhat full-sounding low end.
There are lots of tiny powered speakers available, but the ones I've heard all seem designed to make as much noise as possible on as little power as possible. I want to try to make something that doesn't sound so awful and squawky in as small a package as I can even if it's not able to make a great deal of volume.
Looks rather too optimistic to me. Since power scales as the square of voltage, you're looking more at 3-4W. There's a plot in the DS, page 10 which shows the max output vs supply for BTL. Running PBTL only nudges this up very slightly for an 8ohm load.
Thanks for pointing that out. I missed that figure. 3w might just do it. If not, a 3s battery will give me more than enough spl.
You can't reach rail voltage so assume 90% of 7.4 and assume 8ohm load is max 5.5 watts. It should be clean though. Small drivers can only get deep bass in small enclosures when specially designed with a passive radiator as all the major BT speaker companies do to reach 50Hz with a 2.5in driver in a box the size of small loaf of pound cake. Another way to do it is to fool your brain into thinking there is bass by playing the 2nd harmonic of a 50Hz kick drum well with boost. So design a sealed box with appropriate volume to force a high Q bass peak overshoot at 100Hz. This can be done easily with a driver and small enclosure. It will sound quite nice actually and if you high pass the speaker at say 90Hz with a BW2 filter, you can get more power into it without hitting excursion limits and still fool your brain into thinking you hear bass.
I have been lucky as I often leave my amps powered on with no load connected and haven't had a problem frying a cap yet. This is on Ybdz amp which is essentially on all the time and I connect and disconnect speakers, sometimes leave it running for months with one channel unconnected.
I have been lucky as I often leave my amps powered on with no load connected and haven't had a problem frying a cap yet. This is on Ybdz amp which is essentially on all the time and I connect and disconnect speakers, sometimes leave it running for months with one channel unconnected.
The enclosures look bigger in the photos than they actually are: the outside dimension of the square "pipe" is 80x80mm, and the walls are 4mm thick, so there is not that much space inside when you add the wiring, connectors, etc...
But yes, the enclosures could easily be smaller. I did several smaller enclosures for some other amps that I made, but then there's a practical problem: all of the buyers complained about the difficult cable connections (they usually use some "monster" oversized cables, with diameters easily reaching 22-26mm - about an inch and more). So, I need a bit larger enclosure for the buyer to be able to connect the speaker and interconnect cables without too much trouble
I mounted mine on a wall plate
Now I can put them on almost anything, wood, metal, plastic box. Even wall mount, or I might put then in speaker stands. They will fit a standard electrical wall box or mount with 2 screws onto a chassis.
