Hello everyone,
I am starting building a 40W 8Ohm chipamp for bookshelf speakers. It will need a 24V power supply (12V/-12V for two-rail operation). So, to build a power supply, I need to get a transformer. I looked up on mouser and found thiese results:
Transformers | Mouser
Digikey results:
Power Transformers | Transformers | DigiKey
Since I hae not built a power supply before, do you think I am looking at the right transformers? Also, what considerations do I need to choose which transformer to buy? Do all transformers upply positive and negative rails?
Thanks!
Mohit
I am starting building a 40W 8Ohm chipamp for bookshelf speakers. It will need a 24V power supply (12V/-12V for two-rail operation). So, to build a power supply, I need to get a transformer. I looked up on mouser and found thiese results:
Transformers | Mouser
Digikey results:
Power Transformers | Transformers | DigiKey
Since I hae not built a power supply before, do you think I am looking at the right transformers? Also, what considerations do I need to choose which transformer to buy? Do all transformers upply positive and negative rails?
Thanks!
Mohit
The Mouser transformers appear to be single-secondary types. For a bipolar supply, you'll want a center-tapped (or dual) secondary. The DigiKey page shows those (dual secondary types).
Do you have a psu schematic you will be using?
The load and the psu circuit itself (for example, ripple filter components, regulated/unregulated output) are the most basic factors involved in transformer selection.
Transformers supply converted and/or isolated AC voltage. The circuitry afterward determines the kind of DC output.
Do you have a psu schematic you will be using?
The load and the psu circuit itself (for example, ripple filter components, regulated/unregulated output) are the most basic factors involved in transformer selection.
Transformers supply converted and/or isolated AC voltage. The circuitry afterward determines the kind of DC output.
Thanks for your tips. I am using the circuit based on this project:
DIY LM3886 Chip Amplifier (Gainclone) Kit
The power supply is in Figure 2.
For the amplifier, I plan to use LM3875, and use the circuit from its datasheet. http://www.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=lm3875&fileType=pdf
Hope the amplifier and psu are compatible
DIY LM3886 Chip Amplifier (Gainclone) Kit
The power supply is in Figure 2.
For the amplifier, I plan to use LM3875, and use the circuit from its datasheet. http://www.ti.com/general/docs/lit/getliterature.tsp?genericPartNumber=lm3875&fileType=pdf
Hope the amplifier and psu are compatible
The power output depends on the powersuply voltage and the speaker resistance. If you
use your proposed + & - 12v supply you will get nothing like 40w. Looking at the data sheet even if you use + & - 28v you only get between 30 and 38w . So your 12v + &- will only give you something in the 5 to 10w range. I would be looking for something like 48v ct transformer at at least 150va. You might look at 2 of the toriods on this page one with dual 24v outputs and another with dual 28.4 outputs ( you can wire the secondaries in seriese for a center tap transformer) miscellaneous.html
use your proposed + & - 12v supply you will get nothing like 40w. Looking at the data sheet even if you use + & - 28v you only get between 30 and 38w . So your 12v + &- will only give you something in the 5 to 10w range. I would be looking for something like 48v ct transformer at at least 150va. You might look at 2 of the toriods on this page one with dual 24v outputs and another with dual 28.4 outputs ( you can wire the secondaries in seriese for a center tap transformer) miscellaneous.html
After a quick search, I didn't find anything on Mouser, but only this one at digikey:
VPT48-1040 Triad Magnetics | 237-1335-ND | DigiKey
Does this sound about right to you?
VPT48-1040 Triad Magnetics | 237-1335-ND | DigiKey
Does this sound about right to you?
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