Ok Eva
Are you seated?
Let me say this loud and clear for the last time:
I don’t hate switching mode electronics!!!
Concerning your comments about your EX4000.
The PowerLight model as roughly the some topology but weights half due to switched PSU.
However their behaviour is exactly the same you describe:
They are no difference. I have investigated further and the SMPS looks like transferring the ripple from secondary to primary.
As simple as that.
Considering also that the audio loudspeaker circuit is closed in the secondary capacitors, is not a surprise that the sound in bass frequencies is a “little strange”. (I know that it is not very scientific statement and you could ignore it)
http://www.qscaudio.com/support/library/schems/Current/PowerLight Series/pl40.pdf page 2 only 3x470uF per rail.
Yes I know that the capacitors are charged 200K times per second, but don’t forget that they also pass the audio power signal…
I know, I know… is just a matter of increase the size of primary and secondary capacitors and this amplifier probably will sound as your bigger one…
Are you seated?
Let me say this loud and clear for the last time:
I don’t hate switching mode electronics!!!
Concerning your comments about your EX4000.
The PowerLight model as roughly the some topology but weights half due to switched PSU.
However their behaviour is exactly the same you describe:
Eva said:
They are no difference. I have investigated further and the SMPS looks like transferring the ripple from secondary to primary.
As simple as that.
Considering also that the audio loudspeaker circuit is closed in the secondary capacitors, is not a surprise that the sound in bass frequencies is a “little strange”. (I know that it is not very scientific statement and you could ignore it)
http://www.qscaudio.com/support/library/schems/Current/PowerLight Series/pl40.pdf page 2 only 3x470uF per rail.
Yes I know that the capacitors are charged 200K times per second, but don’t forget that they also pass the audio power signal…
I know, I know… is just a matter of increase the size of primary and secondary capacitors and this amplifier probably will sound as your bigger one…
I don't like those first generation QSC SMPS at all, they barely replaced the 50Hz iron by 50Khz ferrite, but without improving performance or reliability. My preferred SMPS topology is regulated with plenty of secondary side storage capacitance and continuous (stable) current limiting, not sized to supply the full rated power, but capable of reducing the output voltage in case of overload so that the thing continues happily working.
For example I have developed a high power PFC stage that works that way, you can overload it as much as you want but the transistors, diodes and coils are inherently protected and will never pass more than 35A peak. It can work continuously into current limiting without problem, which is the main advantage of switching mode. It outpus 416V DC pseudo-regulated, 4.8KW with 230V AC input before starting to fold back... still 2.5KW at 120V AC. Efficiency is 96% or so...
Screwdriver load may be considered normal working conditions for any well engineered SMPS
For example I have developed a high power PFC stage that works that way, you can overload it as much as you want but the transistors, diodes and coils are inherently protected and will never pass more than 35A peak. It can work continuously into current limiting without problem, which is the main advantage of switching mode. It outpus 416V DC pseudo-regulated, 4.8KW with 230V AC input before starting to fold back... still 2.5KW at 120V AC. Efficiency is 96% or so...
Screwdriver load may be considered normal working conditions for any well engineered SMPS
The people who think that for driving Subwoofers one must have HEAVIER amplifiers are nothing less than Non-Sense creatures crawling on the face of earth.....[A general view only]
Here are some new lightweight amps
8KW Class-D by QSC
http://www.qscaudio.com/products/amps/powerlight3/powerlight3_feature.htm
http://www.qscaudio.com/products/amps/powerlight3/powerlight3.htm
6.8KW Class-D by Ecler[reverse engineered by my friend]
http://www.ecler.es/EN/product.asp?ProductID=45
6.4KW Class-D by Hotsound Pro
http://www.hotsound.com.br/digilite64_modelos.asp?menu=Série Digilite
There's an exception exists....
here is a link to 4KW Class-AB 3U rack space 34Kg "Weighted" amp
http://www.ecler.es/EN/product.asp?ProductID=66
EVITA, Your smps looks damn sexy!
Are you a Superwoman..
Here are some new lightweight amps
8KW Class-D by QSC
http://www.qscaudio.com/products/amps/powerlight3/powerlight3_feature.htm
http://www.qscaudio.com/products/amps/powerlight3/powerlight3.htm
6.8KW Class-D by Ecler[reverse engineered by my friend]
http://www.ecler.es/EN/product.asp?ProductID=45
6.4KW Class-D by Hotsound Pro
http://www.hotsound.com.br/digilite64_modelos.asp?menu=Série Digilite
There's an exception exists....
here is a link to 4KW Class-AB 3U rack space 34Kg "Weighted" amp
http://www.ecler.es/EN/product.asp?ProductID=66
EVITA, Your smps looks damn sexy!
Are you a Superwoman..
one more smps
An externally hosted image should be here but it was not working when we last tested it.
Workhorse
The picture you have posted show enough details to conclude that this is one of the kind of above posts.
As an ignorant, it seems to me that the solution will be “active ripple filtering” in primary and bigger capacitors on secondary.
Something thing like Eva’s PFC in front-end, followed by that thing.
With the actual component size, it will be much bigger than the today commercial proposals in the market.
Eva
I have tried hard but I couldn’t found you…
Could you show it on a smaller scale?...
TOINO said:
Workhorse
The picture you have posted show enough details to conclude that this is one of the kind of above posts.
As an ignorant, it seems to me that the solution will be “active ripple filtering” in primary and bigger capacitors on secondary.
Something thing like Eva’s PFC in front-end, followed by that thing.
With the actual component size, it will be much bigger than the today commercial proposals in the market.
You want to start a new pro-smps revolution Toino, GO GO GO!
I have seen various commercial amps with PFC frontend + Quasi resonant mode smps...but in case of QSC their Discontinuous resonant mode always failed on poor Gensets...
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