DIY progress report
- Thread starter Nelson Pass
- Start date
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 ?
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 ?
you can, but better to use 24V - 0 - 24V , which is value of original rails
besides that, some switcher PSU are not liking to see excessive capacitance amount afterwards, so you must try it .......
besides that, some switcher PSU are not liking to see excessive capacitance amount afterwards, so you must try it .......
most of them are having internal protection
in worst case, it'll refuse to start
if needed, you can solve that inserting some small resistance or inductor , between SMPS and cap bank
in worst case, it'll refuse to start
if needed, you can solve that inserting some small resistance or inductor , between SMPS and cap bank
any recommendations for dual rail (+/-) SMPS . I don't think MeanWell make them, although 2 can be hooked up that way apparently....
I do not have any experience in practice, but this seems promising.
CONNEX SMPS300RE Switched-Mode Power Supply Module US Version 300W +/-24V 120V - Audiophonics
CONNEX SMPS300RE Switched-Mode Power Supply Module US Version 300W +/-24V 120V - Audiophonics
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.
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.
Meanwell RID-125-2448?
MicroAudio
SMPS500-CLA – MicroAudio
Neurochrome offers a pcb to combine two meanwells for +/-
Mean Well Control: Power Your Audio Amp with Mean Well EPP or RPS SMPS – Neurochrome
SMPS500-CLA – MicroAudio
Neurochrome offers a pcb to combine two meanwells for +/-
Mean Well Control: Power Your Audio Amp with Mean Well EPP or RPS SMPS – Neurochrome
I have found the “ MW HRP-200-24 smps , 200W, 24V/8,4A” interesting. It does not have the popular hiccup mode (that does not like a capacitor), but current limiting.
That implies it will just give the max current until the cap bank is full.
I used two Meanwell 24 VDC units before. Use inrush limiters (CL-60 maybe) to hide the big caps from the SMPS. Works like a charm.
Use a "cheap" SMPS that has fixed switching frequency in order to avoid modulation of the switching noise with/by the audio signal.
Use a "cheap" SMPS that has fixed switching frequency in order to avoid modulation of the switching noise with/by the audio signal.
diyAudio member Cresnet has dual-rail (+/- voltage) SMPS designed for Class A.
You can send him a PM or visit his online store:
https://micro-audio.com/store/
That, or if you have a 48V SMPS you can build a virtual ground. I have tried this schematic and it works great. Note that in such an amp the ground will be floating, so unless you have a floating supply then you'll have to be creative with for example transformers for the input signal.
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.
Here is my 30v 6A Class A PSU from Sami:
Sami even provides for free, a blank cap bank PCB for you to load extra cap filtering after the SMPS.
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
F2?
