It seem quite a classic and not very hi-tech Class-D amp (P/N mosfets, etc), but has anyone had a look at the power supply? It seems to use the 117VAC input to produce +/-51V rails, with no transformer!!!
For apps. where the user can't touch any terminal, such as active speakers, etc, where safety is not a problem (this supply is not galvanically isolated!), it can be useful.
Mmm, I wonder if that design can be modified for 230VAC mains and any output voltage with proper component values... I will have a deeper look at it but it is, at least, interesting.
For apps. where the user can't touch any terminal, such as active speakers, etc, where safety is not a problem (this supply is not galvanically isolated!), it can be useful.
Mmm, I wonder if that design can be modified for 230VAC mains and any output voltage with proper component values... I will have a deeper look at it but it is, at least, interesting.
Huh?
I don't get it. You rectify 117AC and you get +/- 81V (not including diode losses)
How do they get 51V?? Is my math wrong??
I don't get it. You rectify 117AC and you get +/- 81V (not including diode losses)
How do they get 51V?? Is my math wrong??
The triac cuts the output during a variable time, depending on the output voltage, that is sensed and compared to a reference. This way the caps are charged to the correct voltage. It is similar to a lamp dimmer, but I hadn't seen something like this, operating from a _rectified_ mains and then filtered to get DC.
the center point (GND) is obtained by a voltage divider made by caps. I don't know how stable this will be...
the center point (GND) is obtained by a voltage divider made by caps. I don't know how stable this will be...
Not very high-tech is not right word, stone-age low-tech is proper for this!
Triac "regulated" power supply. TL074 used as a comparator. Not isolated from mains. 50khz modulation frequency. No output coils/chokes. Collection of ideas how not to do d-class. 😱 😱 😱 😱 😱
Yes, Class-D has been improved a little bit since them, hasn't it?
But you cannot say that the supply is not, at least, original and worths the pain being studied a bit more...
But you cannot say that the supply is not, at least, original and worths the pain being studied a bit more...
class d amp articles
I have only put these here because they work but know they are old and can be improved.Class d is still not as easy to build for the diy as gainclone chip amps,also there are not many schematics around.Both of these circuits could use a vco or maybe a tl494 as the osc and also use a high/low mosfet driver chip to drive better fets or maybe IGBTs.Sometimes the best thing to do is use something that works and make it better
I have only put these here because they work but know they are old and can be improved.Class d is still not as easy to build for the diy as gainclone chip amps,also there are not many schematics around.Both of these circuits could use a vco or maybe a tl494 as the osc and also use a high/low mosfet driver chip to drive better fets or maybe IGBTs.Sometimes the best thing to do is use something that works and make it better
class d schematics
I would not recommend using the power supply circuit,very dangerous,better off with standard transformer setup.
I would not recommend using the power supply circuit,very dangerous,better off with standard transformer setup.
class d schematics
I would welcome anyone who has schematics for class d amps to post them here maybe we all can pitch in and redesign something or get a better understanding of what can be built in the diy community
I would welcome anyone who has schematics for class d amps to post them here maybe we all can pitch in and redesign something or get a better understanding of what can be built in the diy community
Re: class d amp article
I for one greatly enjoy seeing these relics you post, I also agree with your vision. However you can shorten the process by a decade or so by first studying amps that have done it right and already solved common problems, perhaps then taking it from there?
Regards,
Chris
steven344 said:
I for one greatly enjoy seeing these relics you post, I also agree with your vision. However you can shorten the process by a decade or so by first studying amps that have done it right and already solved common problems, perhaps then taking it from there?
Regards,
Chris
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