Why are you worried about that? It states it will run at +/-60-80V and it doesn't indicate there is any under-voltage protection, which would be your only concern by under-powering their suggested +/-75V?
I can't speak to it's quality, but I have a amp using similar boards and it sounds good.
How about sharing the schematic of your changes with us? This is a DIY forum after all.
Got the amp from aliexpress
It worked great around 17 days sound was good
but dont know what happened, initially sound used to break in between for less than one second at high volume and later gradually distortion started and it stayed with it, sounding very bad now
what could be the reason IC failure?? please help
It worked great around 17 days sound was good
but dont know what happened, initially sound used to break in between for less than one second at high volume and later gradually distortion started and it stayed with it, sounding very bad now
what could be the reason IC failure?? please help
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Recently I purchased several Chinese class D modules to see how they went in comparison to all the analogue power amps we had built or had experience with over the years. The smallest had a 26 v single rail and was meant to do 100 watts but only produced 57 watts into 4 ohms but at least it was stable. The other 3 all produced a lot of RFI on the scoped sine wave and in my opinion would not have been saleable or even legal. I would think that the RF is residual carrier and due to poor output filter design. Has anyone else experienced this and come up with a workable solution? I would be very grateful for any help with this before we try and build them ourselves. They are so cheap it makes far more sense to buy them built up. They are also very well made.
Anyone have a recommended power supply to operate the L30D? I'm looking at this unit
:
New 70V 5 7A 400W DC Regulated Switching LED Power Supply CNC with CE | eBay
I'd like to maximize the power output of the l30d as much as possible.
Thanks!
:
New 70V 5 7A 400W DC Regulated Switching LED Power Supply CNC with CE | eBay
I'd like to maximize the power output of the l30d as much as possible.
Thanks!
Can't be 100% by the eBay pics (don't show a clear connection pic), but that type of PSU you will need 2 of them. One wired for +70V DC and another one wired for -70V DC. You might be better off buying a transformer and capacitor bank, by the time you buy two of these units. Not to mention the space they will take up in your case.
Edit - yes it will supply +/-70V DC, but with only 5.7A and 400W, you will more than likely be current limited in this application.
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I would plan to run 2 of the L30's with a pair of 8 ohm loudspeakers.
In that case, the l30 would be outputting a max of 300w per channel. So that would mean 600w max for the pair. I wouldn't expect to see that power level on a continuous basis.
In that case, the l30 would be outputting a max of 300w per channel. So that would mean 600w max for the pair. I wouldn't expect to see that power level on a continuous basis.
we are interested in building powered speakers around this amplifier. a few questions for the group: which is the best design? -+75VDC seems to be the sweet spot on the power supply; is there a SMPS that can deliver what this amp needs? thanks - HJP
If you are expecting high continuous output from this board at 75v rails you will need fan cooling for the heatsink and output inductor. this may be problematic inside a speaker enclosure. also my l30d boards exhibit turn on and off pops, this was cured with speaker protection/delay board with a relay.
Greg
SMPS for LD30
thanks for the reply. do you have a suggestion for SMPS for this board type? is there a better way? (Class A/B??) thx
thanks for the reply. do you have a suggestion for SMPS for this board type? is there a better way? (Class A/B??) thx
Class ab will generate even more heat than class d. class d is ideal for powered speakers, maybe look for a better designed board with the option for a bigger heatsink and speaker muting onboard. search abletec for smps this may work. Greg
Hello LJM, I just received L30D PCB from ebay, why is oscillating frequency so low: 178 khz only at idling, is it normal ?
Greg 32, did you have any problems when increased oscillating frequency to 285 khz? I have seen chinese irfb4227 desings at 500 khz, without additional transistor totem pole (irs2092 directly to transistors) and working without any problems. I do not see what is the reason of so low frequency here, maybe ferrite is not good for that frequency ?
Greg 32, did you have any problems when increased oscillating frequency to 285 khz? I have seen chinese irfb4227 desings at 500 khz, without additional transistor totem pole (irs2092 directly to transistors) and working without any problems. I do not see what is the reason of so low frequency here, maybe ferrite is not good for that frequency ?
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I have been using the l30d for a while now and have seen no issues with the osc freq at 285khz. if anything the sound is more natural in the high frequency. and inductor runs cooler. i used 430r timing resistor for 285khz. also what is your supply voltage? Greg
my supply is about 78-/+ V
I plan to use this boards in BTL for 8 ohm speaker.
iraudamp9 is 300 khz and has 2,2 uF cap ..
what is the reason ljm use so low switching frequency, with so low freq thd cant be good.
iraudamp9 is designed specifically for 2r loads, I think that is why the output filter uses 2.2uf. Maybe ljm can explain why the low osc freq.
According to your examinations, how ot behaves at 300 khz, ferrite itself should be hotter, is it ?
I'm thinking of buying a few L30D amplifier boards, but have a question.
This board is designed for a 2R load, is it capable of handling 4R or 8R loads as well? I couldn't find this info in the iraudamp9 document.
This board is designed for a 2R load, is it capable of handling 4R or 8R loads as well? I couldn't find this info in the iraudamp9 document.
I was just checking L30D gate driving design and it is lets say identical principle as in iraduamp9.
IRS2092 gets VERY HOT: What could be the problem:
Check here iraudamp 9 , page 29 .
Why there is NO totem pole base resistor: irs2092 IC outs goes directly to totem pole without any resistor.
Thats is the readon why IRS2092 gets very hot. "base -emitter" of totem pole gets conductive and current goes directly from IRS2092 across base -emitter to mosfet gate capacitance. In this case totem pole driver has no direct benefit on reduction of IRS2092 output current.
Why is this neglected even in iraudamp official design ?
IRS2092 gets VERY HOT: What could be the problem:
Check here iraudamp 9 , page 29 .
Why there is NO totem pole base resistor: irs2092 IC outs goes directly to totem pole without any resistor.
Thats is the readon why IRS2092 gets very hot. "base -emitter" of totem pole gets conductive and current goes directly from IRS2092 across base -emitter to mosfet gate capacitance. In this case totem pole driver has no direct benefit on reduction of IRS2092 output current.
Why is this neglected even in iraudamp official design ?