DIY progress report

Hi amigos,

I am in the process of assembling a new Pass A3 Amplifier. I come from Class D world....
I would like to avoid to use a Toroidal PSU for my modules, so question for experts :

Can I plug a SMPS Dual rail 28-0-28V VDC instead of the required Todoidal PSU 20-0-20 VAC for this module that already includes a rectifier ? (20 VAC = 28 VDC)

I guess I would only risk a Diod loss and nothing else ?


HTB1YazPjgfH8KJjy1zcq6ATzpXaZ.jpg
 
If you look up dual smps there are some triple output models with .+5, -24, +24.

Not high current but enough for any line level circuits.

Just smooth off the 50-12mv of ripple with a two or three stage CR network and you are done. Ideal for constant current dual supply loads. If you want better with regulation then consider the Silent Switcher.
 
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any recommendations for dual rail (+/-) SMPS . I don't think MeanWell make them, although 2 can be hooked up that way apparently....
Micro-Audio (Sami) makes excellent SMPS that have a topology where they don’t mind massive cap banks at the PSU output. Very low noise and designed for audio hobbyists ease of use or for OEM applications. I have used many of Sami’s supplies and they are excellent. They don’t have startup hiccup issues. Sami is also very customer service oriented. You are basically getting a custom PSU. You can specify exact voltage, what regulated auxiliary voltages you need (+12v, +5v always on and +/-15v switches are typical). The auxiliary outputs are linear regulated.

You can see he uses top quality name brand components. Here is an example that Vunce is using with a small Noctua fan to help keep it cool for continuous Class A operation.

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Here is my 30v 6A Class A PSU from Sami:
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Sami even provides for free, a blank cap bank PCB for you to load extra cap filtering after the SMPS.
 
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I don't personally use SMPS's (so far), but from an engineering standpoint, I like the CONNEX approach which uses quasi-resonant switching. This greatly reduces noise and RFI. It was pioneered by Tektronix and used in their 7000 series mainframes. Obviously, in a high-end oscilloscope, low noise is a must-have. You can buy direct at https://connexelectronic.com/
 
I don't personally use SMPS's (so far), but from an engineering standpoint, I like the CONNEX approach which uses quasi-resonant switching. This greatly reduces noise and RFI. It was pioneered by Tektronix and used in their 7000 series mainframes. Obviously, in a high-end oscilloscope, low noise is a must-have. You can buy direct at https://connexelectronic.com/
Half Bridge resonant
for a single V LLC Resonant topology plus Synchronous Rectification