Hi,
I have a 3 year old transformer with two secondary windings, 17V 3A and 7V 5A. It was used in a DIY linear power supply for a DAC and a Raspberry PI. I have moved away from that setup so I have this large transformer laying around....
Please give me ideas of what should I used it for. I was thinking about PSU for a cheap class-D board but the voltage is quite low (7V) and it is almost impossible to create dual rails for class AB amps at 15V. Also, it would be ideal if I can use the two secondaries or if I left one open, it probably waste of energy.
Best,
AP
I have a 3 year old transformer with two secondary windings, 17V 3A and 7V 5A. It was used in a DIY linear power supply for a DAC and a Raspberry PI. I have moved away from that setup so I have this large transformer laying around....
Please give me ideas of what should I used it for. I was thinking about PSU for a cheap class-D board but the voltage is quite low (7V) and it is almost impossible to create dual rails for class AB amps at 15V. Also, it would be ideal if I can use the two secondaries or if I left one open, it probably waste of energy.
Best,
AP
I am sorry I do not have any answer for your question, but I am interested to know how you DIY the linear PSU for the DAC. Did it improve the sound quality?
I just bought a used Network Player and I am thinking if sound quality would improve drastically by having a separate linear PSU for the left and right analogue channels.
I think the board circled in red is the main switching power supply which feed a few sub power supplies unit for the digital and analogue section
I suspect the part circled in yellow are the voltage regulators for the analogue circuits.
The Burr Brown 1792 is circled in purple.
Thank you.
I just bought a used Network Player and I am thinking if sound quality would improve drastically by having a separate linear PSU for the left and right analogue channels.
I think the board circled in red is the main switching power supply which feed a few sub power supplies unit for the digital and analogue section
I suspect the part circled in yellow are the voltage regulators for the analogue circuits.
The Burr Brown 1792 is circled in purple.
Thank you.
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Yes, I tried to improve and add warmness to the DAC and ability to drive more demanding plannar headphone, as it is a DAC+Headphone amp combo. Original PSU is a small brick with 15V 1A switching PSU. So, I tried building a simple linear PSU based on dual LT1083s. I was working fine but to be frankly, I believe I heard subtle different but it could be all in my head. The 7V is used for 5V supply for Raspberry Pi for streaming. This is before I moved to new home and has acquire new network player, not to improve sound, but for usability and convenience (mainly for other family members).
I think you are correct about your network player PSU config.
AP
I think you are correct about your network player PSU config.
AP
Any safety precaution I have to take for connecting them in series? Also, if I left one open, will it consumes energy?
AP
Here (Thailand) is 220-240V, it should be 220V but practically, it is closer to 230V in most places. So I usually ended up with higher voltage on the secondary.
By connecting the secondary in series, you can get 24VAC and about 3.5A max. The secondaries must be in phase for the voltages to add. So you connect the end of the first and the beginning of the second secondary and measure the AC voltage. If it's not 24VAC (it will be a little more at idle) then you've phased them wrong, so replace the connection but only on one secondary until you get 24VAC or more. After rectification, you will have over 30VDC (aprox. 36 at idle). After that you should put some SMPS DC-DC regulator (24V and 8-10A) to get stable 24VDC for say TPA3116 stereo amplifier. The transformer is about 86VA, so it is realistic to power a D class amplifier 2x40WRMS at 8ohm with it. Since the music is not pure sine wave, the average power is below 20% of the maximum, you will have more power in the peaks.
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Thanks everyone for the ideas. I guess I'll go with with series them up for a new class-D project.