Thanks to all for the help and advice! So now the amp is in place and hooked up enough to test. Driven by my ipod with Rush 2112 cranking the 4050 module is if my math is correct 31 peak volts squared / 4 ohms for an output of 240.25 watts rms. The 4048xi 's are peaking at 41.2 volts into 16 ohms for an output of 105.06 watts rms. The meter is a Fluke true rms scopemeter. I am guessing that the 4050 wont last long at that output but my normal listening level is much lower,if i lock down the volume on my ipod to 28 volts rms (196 watts) will it live?? Anyone have any experience driving 4 ohm loads at levels not exceeding 200 watts with these chips?? The sound quality in the open air of the screen porch is excellent with clean crisp highs solid midrange and a tight low end.thanks again for all your advice!! WE ARE ROCKING NOW!!
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Measure the maximum voltage into four different resistive test loads.
16r0, 8r0, 4r0, 2r0.
Calculate the dBV for each loading.
Compare how much dBV falls for each incremental lowering of load resistance.
A really good amplifier will lose <=0.8dBV for a halving of test load.
A really bad amplifier will lose >=1.5dBV for a halving of test load.
If you cannot bring your self to test for maximum power into a 2r0 resistive load, then you should not be considering the much more severe loading of a 4ohm speaker.
If the 16r0 to 8r0 dBV is <=-0.7dBv then proceed with next test.
If the 8ro to 4r0 dBV is ~-1dBV then you should probably not test into 2r0.
16r0, 8r0, 4r0, 2r0.
Calculate the dBV for each loading.
Compare how much dBV falls for each incremental lowering of load resistance.
A really good amplifier will lose <=0.8dBV for a halving of test load.
A really bad amplifier will lose >=1.5dBV for a halving of test load.
If you cannot bring your self to test for maximum power into a 2r0 resistive load, then you should not be considering the much more severe loading of a 4ohm speaker.
If the 16r0 to 8r0 dBV is <=-0.7dBv then proceed with next test.
If the 8ro to 4r0 dBV is ~-1dBV then you should probably not test into 2r0.
Thanks for your replies. As for testing my main concern is not cooking the 4050 chip, i do have a 1 khz 1volt signal injector but to test the sub amp suppose i need more like a 80-100hz signal i suppose this would be more accurate than capturing a peak music signal? I don'y have any resistive loads so the speaker will have to do. I think that volt amp reactance will screw up things but unsure how to calculate. the heat sink is pretty good and runs only slightly warm after an hour or so at 80% (approx.) also not sure how to test for dBV what calculations are needed?
Hi Jimmy, is very complicated put a 4 ohms load with this supply levels, you have to know that STK4050 work as single amplifier but it have four output transistors, working as two pairs in parallel mode and recommended
load is 8 Ohms for continuous 200W rms at +/-66V, For less impedance loads the module will overhead also with large heatsink.
Thanks, ive seen that, but i dont know what the ratings of an MG250 transformer are, tried googling it and i cant find anything. Would a 55-0-55 transformer at 300va be fine for a single chhannel? I used 55-0-55 so that at full load there will be atleast +- 66v and unloaded there will be 77V
Can the STK 4050 handle a 4R0 load? on the datasheets ive looked at it doesnt say? Oh, and are you using any sort of soft start circuit or does it work fine without one?
I used a 47-0-47 xformer and am getting 60volts after the bridge rectifier thats enough voltage to get 238 watts into 4r0 with my input configuration. the 4050 is not rated for 4r0 loads but i have about 200 hrs run time into 4r0 with no problems yet. I am using the 4050 as a sub amp so its peaking at 238 all the time. I do have a massive heat sink 11lbs of aluminum and it gets warm after about an hour of full crank jamming...time will tell but i suspect it will fry eventually! if not....cool.if so i will replace sub with 8r0 sub and throw a new 4050 in. I will report my findings either way. also instead of 500r0 i used 3.3k 3 watt in series with a standard 20ma led to bleed the caps i installed after the dc fuses in each side of the power supply gives you a visual indication of dc output and fuse condition. 300va should be fine for one channel
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if you expect the amplifier to handle a reactive 8ohm speaker load then it's not even breaking a sweat to power a 4r0 resistor to maximum for a few seconds. That should be one of the tests you carry out to prove to yourself you have built an 8ohm capable amplifier.
But that was not the point of my comment. I showed two sets of data, 4r0 and 8r0 from 40Vac transformer.
A 45Vac transformer should meet the 200W into 8r0 target without difficulty and still be able to power a 4r0 load in the short term as a test of capability.
plz send me this PCB layout email me for this power amp. kukayron03@yahoo.com tnx im a newbie i build stk4048 and its very nice and good quality sound.., and i want to build syk4050 plz help me
any one here have a stk4050 pcb layout? i am planning to build this power amp. i appreciate if you send to this add. joeyt6415@yahoo.com thank you very much
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