So I am working with some of these guys here:
I just started some of my testing of this module.
I already did the R13 resistor replacement (mine was 100R, replaced with 3.3K) to bring the gain down. Did this before even hooking up to bench test.
I got this running from by bench power supplies (so I could limit current if anything went wrong) at +/- 64 volts exactly. I actually have TWO of these little modules running.
But I noticed: even idle, they run a bit warm. It was late and I did not break out a temp probe or the temp gun, but not only are the heat sinks warm - but the entire PCB is rather warm on the backside. If I had to guess, I would say the PCB backside is upwards of 100-115 degrees F.
Class D amps are supposed to run cool, no? lol...
Next thing I noticed is this: one amp seems to idle warmer than the other one by at least 10-15 degrees F. They are literally both connected to the same power supply. Should I be concerned?
Final thing I noticed: one amp has a bit more hiss than the other. Again, not that this will matter much: these are destined for subwoofer duty - so not gonna hear much hiss from a 10" sub anyway.
Finally... regarding that heat. I am thinking of picking up some heat sink stock, see here: https://articulo.mercadolibre.com.m...lor-aluminio-negro-76cm-ancho-12-mt-largo-_JM
That heatsink is about 3 inches wide, 3/4 inch thick and 4 foot long. I was thinking of removing the MOSFETS from the top side and carefully rotating them to the backside (180 degrees), mounting them w/ mica insulators directly to the heatsink and then mounting the PCB to the heatsink with nylon standoffs. My plan was to cut off two 12 inch long sections of that heatsink and so each of the two amps would have a dedicated 3" x .75" x 12" chunk of heatsink. The big question here is: would this be enough for passive cooling?
Last question - the IRS2092 chip itself. I noticed it has a small aluminum chunk that bridges it to the heat sink currently. As I understand, this chip also generates some heat. Since I would be re-locating the primary heat sink to the back-side, the IRS2092 chip will need some heat sinking as well. I have some small self-adhesive (.5" x .5" x .25") mini heat sinks I often use for low-power LM317 applications. Would one of those stuck to each IRS2092 chip be enough? Or would something larger be required?
Each of these amplifier modules will only be driving an 8 ohm load, so nothing too crazy.
-Dean
I just started some of my testing of this module.
I already did the R13 resistor replacement (mine was 100R, replaced with 3.3K) to bring the gain down. Did this before even hooking up to bench test.
I got this running from by bench power supplies (so I could limit current if anything went wrong) at +/- 64 volts exactly. I actually have TWO of these little modules running.
But I noticed: even idle, they run a bit warm. It was late and I did not break out a temp probe or the temp gun, but not only are the heat sinks warm - but the entire PCB is rather warm on the backside. If I had to guess, I would say the PCB backside is upwards of 100-115 degrees F.
Class D amps are supposed to run cool, no? lol...
Next thing I noticed is this: one amp seems to idle warmer than the other one by at least 10-15 degrees F. They are literally both connected to the same power supply. Should I be concerned?
Final thing I noticed: one amp has a bit more hiss than the other. Again, not that this will matter much: these are destined for subwoofer duty - so not gonna hear much hiss from a 10" sub anyway.
Finally... regarding that heat. I am thinking of picking up some heat sink stock, see here: https://articulo.mercadolibre.com.m...lor-aluminio-negro-76cm-ancho-12-mt-largo-_JM
That heatsink is about 3 inches wide, 3/4 inch thick and 4 foot long. I was thinking of removing the MOSFETS from the top side and carefully rotating them to the backside (180 degrees), mounting them w/ mica insulators directly to the heatsink and then mounting the PCB to the heatsink with nylon standoffs. My plan was to cut off two 12 inch long sections of that heatsink and so each of the two amps would have a dedicated 3" x .75" x 12" chunk of heatsink. The big question here is: would this be enough for passive cooling?
Last question - the IRS2092 chip itself. I noticed it has a small aluminum chunk that bridges it to the heat sink currently. As I understand, this chip also generates some heat. Since I would be re-locating the primary heat sink to the back-side, the IRS2092 chip will need some heat sinking as well. I have some small self-adhesive (.5" x .5" x .25") mini heat sinks I often use for low-power LM317 applications. Would one of those stuck to each IRS2092 chip be enough? Or would something larger be required?
Each of these amplifier modules will only be driving an 8 ohm load, so nothing too crazy.
-Dean
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I will add to my observations... the one with more white noise / hiss (at idle) is also the one that generates just slightly more heat.
Again, not that this will be a big deal - I will likely not hear ANY of this noise come through a 10 inch subwoofer.
I am gonna take a couple of the other examples I have out of their packaging and compare the performance as well I suppose.
Also going to get the heatsink ordered out Wed.
Again, not that this will be a big deal - I will likely not hear ANY of this noise come through a 10 inch subwoofer.
I am gonna take a couple of the other examples I have out of their packaging and compare the performance as well I suppose.
Also going to get the heatsink ordered out Wed.
Seems that "adjusting" the deadtime is not that simple - involves replacing SMD parts.
Also - how would I even measure this without affecting the capacitance of the mosfets (and the deadtime itself)? 300-500khz is getting up there in frequency, no?
I got a proper Rigol dual channel. But this may be getting a bit out of my confort zone.
Once I am back from work, I will test a couple of the others. I may just hunger games this 5h1t: Coolest running out-of-the-bag wins. They only cost like $5 each on AliExpress.
Also - how would I even measure this without affecting the capacitance of the mosfets (and the deadtime itself)? 300-500khz is getting up there in frequency, no?
I got a proper Rigol dual channel. But this may be getting a bit out of my confort zone.
Once I am back from work, I will test a couple of the others. I may just hunger games this 5h1t: Coolest running out-of-the-bag wins. They only cost like $5 each on AliExpress.
One other item:
So I assume the majority of the heat generated is purely from the MOSFETS?
Man... 300khz (or more) is kind of overkill for an amp that will never see more than 200hz input signal, no? I would imagine that cranking this down (I assume is possible w/ the IRS2092) would not only reduce the demand and heat on the chip but also run the mosfets cooler and let the entire thing more reliable, no?
So I assume the majority of the heat generated is purely from the MOSFETS?
Man... 300khz (or more) is kind of overkill for an amp that will never see more than 200hz input signal, no? I would imagine that cranking this down (I assume is possible w/ the IRS2092) would not only reduce the demand and heat on the chip but also run the mosfets cooler and let the entire thing more reliable, no?
Yes, the IRS2092 just provides the gate of the MOSFETs, it doesn't actually contribute anything to the power of the amp.
The IRS2092 actually works with a PWM frequency of 800kHz. I don't know if you actually can reduce it because the IRS2092 is self-oscillating.
Gotcha. I have very little experience w/ DIY class D stuff. I was reading over posts online talking about dead times and switching frequencies. I likely mis-read the info I saw.
Damn... 800k is just crazy for something that is FAR from HiFi IMO. This thing sounds kinda crappy compared to the TDA3255 amps I often employ. Even the build quality is lacking compared to current pre-built 3255 boards I am buying from Ali Express.
Then again, this is not exactly HiFi - this is for subwoofer duty. 20hz - 200hz. Nothing more.
I usually don't build my amps from scratch, I'm lazy and the TPA3255 boards are much cheaper than to do it yourself. And for the most part, it's 'good enough' for the actual use or can be modified.
Many IRS2092 amps often perform better in the bass than others from the same time (i.e. TDA7498E), so it's still viable for subs IMO since you can get them so cheap and it's often easier to modify. I can't say if the TPA3255 is better in the bass (I have no IRS2092 amps to compare anymore) but they are a lot better above the bass, likely better on the bass too.
Many IRS2092 amps often perform better in the bass than others from the same time (i.e. TDA7498E), so it's still viable for subs IMO since you can get them so cheap and it's often easier to modify. I can't say if the TPA3255 is better in the bass (I have no IRS2092 amps to compare anymore) but they are a lot better above the bass, likely better on the bass too.
I recently did a pair of "portable" powered speakers: 3 way design w/ 10 inch sub driver in each one. The 10" is a dual-4-ohm VC. I originally had each 4-ohm coil in parallel to a 3116D2 mono amp and was barely squeezing out 100 watts at 24 volts. I since upgraded THAT speaker to a 3255 [stereo] amp board running at 36 volts and easily get over 150 watts to each 4 ohm VC now (300 watts total to the sub). Each speaker has one of these 2-channel 3255 board amps just for the 220hz-down frequencies and I must say: it will vibrate any mid sized room pretty violently.
And at 4 ohms, the 3255 seems to handle itself pretty well (so far) at these lower frequencies. Have never compared 1:1 against something else in the subwoofer department but this latest application I tested in is certainly did pretty good.
And at 4 ohms, the 3255 seems to handle itself pretty well (so far) at these lower frequencies. Have never compared 1:1 against something else in the subwoofer department but this latest application I tested in is certainly did pretty good.
I just posted a new thread regarding THAT build here:
https://www.diyaudio.com/community/threads/my-custom-portable-hifi-loudspeaker-lots-of-pics.415703/
https://www.diyaudio.com/community/threads/my-custom-portable-hifi-loudspeaker-lots-of-pics.415703/
If you aren't satisfied with the sound, you could still use it for a subwoofer or active speaker in the bass. I don't know what you paid for it, I've bought one for a friend quite a while ago for under 10€. If you still don't have any use for it, you can salvage it for parts, heatsink and fan, the terminals, capacitors and choke are more expensive if you buy them in the western world. Or just sell it on here.