Kanged switching power supply for a tube amp

[plasnu]

Here's a picture of my latest kanged power supply.

Great. What is the output configuration of the large board? RCRC? What value?

 

[kodabmx]

CRC... 470ux2 -> 5R -> 470u. There is a stepped soft start using the resistors that look like a C in an RCRC filter though. The noise if any is all common mode rejected in the OPTs...

 

[plasnu]

hmm, I think my supply's MosFET has to be replaced. Connected to 6800u -500ohm - 6800u and ripple is close to 300mV/20KHz with Fluke multimeter...

 

[plasnu]

I start thinking this can be a grounding issue. Do you isolate the output from input?

 

[kodabmx]

No. The 12V ground and the B+ ground are connected at the PSU.

 

[plasnu]

My bad, it was a grounding issue. Now, ripple can't be detected (0.000V) even just with 6800uF cap (no choke, no resistor).

Thank you so much, kodabmx. This converter is awesome.

 

[plasnu]

And no sag. The voltage is as it should be. 18.9V input 220V tap output = 346V with 200mA load, very accurate. This is a great converter with adjustable voltage SMPS (MEANWELL)!

 

[kodabmx]

You're welcome, plasnu!

It might not be as pretty to look, but it works well and it's relatively cheaper 🙂

 

[plasnu]

I got the converter yesterday. I haven't had the time to hook it up, but I find some inconsistencies. The spec and title of the listing on Amazon says DC12V/24V to AC 0-220V..... My board has a 16 volt 4700 uF electrolytic across the input. It's not going to like 24 volts.

I forgot to change 16 volt cap and it exploded with 20V input. 😀

The board stopped working now, No blue light. It's not related to capacitor. It was constantly feeding 100mA/350V without FET heatsink, so I guess FET is dead, but it's not clear that this board actually can handle 24V input (440V from 220V tap)...

 

[kodabmx]

The controller and MOSFETs can handle the voltage, the transformer might not be happy about it
though.

I've had a few MOSFET failures (DX3205 and YP1906) and I replace them with IRF3205 and all is well again 🙂

 

[plasnu]

Good information, I'll get the same. 🙂
I check transformer.

 

[Marco audio]

Hello,
Did someone tried this?
€ 21,73 | Transformateur de carte d'alimentation de commutateur d'amplificateur de Tube 60W pour l'entrée de AC95V-260V d'ampli de Radio de Tube de préamplificateur Audio H252
Tube Amplifier Switch Power Supply Board Transformer 60W For Audio Amplifier Preamplifier Tube Radio AMP AC95V 260V input H252|Amplifier| - AliExpress
I want to use it for my tube phono preamp.
How far from tubes should i mount it ?
How should be the way of the transformer ?
Please
In coments and feedbacks someone have builded one phono unit,but impossible to ask any question.
Regards

 

[madmarcus]

Did you try that 60W power supply?

 

[Marco audio]

Did you try that 60W power supply?

Hello,
I didn't try it with my phono preamp because i didn't finish my project.
But voltage are 294v and 6,2v.
Regards

 

[madmarcus]

Thanks. I'd hoped to hear about it's reliability over time but I certainly understand having projects that get pushed to the back and never finished.

 

[Marco audio]

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Perhaps i will finish it soon.

 

[kodabmx]

For those of you trying a DC boost module using a SG3525... Pin 8 IS your friend.

Changing 1uF to 22uF will allow most SMPS to start this into a large capacitance.

 

[therling]

Hi, a lot of good information here.

I know this is a rather old thread but if possible, could you provide a block diagram of the finished power supply? I think that would sum up the work you’ve done on this project in one place and helpful to people who want to emulate your design. A graphic such as that would likely show up in a Google image search and would draw more readers. I know providing links for each module may be a lot of work, and perhaps too much to ask, so even just a model number or other identifying information would be welcome.

Thanks.

 

[kodabmx]

There's not really a finished version - it's just as simple as taking 12V, getting DC-DC boost and kanging them together.

This one works well for preamp/phono/headphone/low power amplifier: DC AC Converter 12V to 110V 200V 220V 280V AC 150W Inverter Boost Board Transformer Power(6.5)|dc-ac converter 12v|dc-ac converterinverter boost board - AliExpress
This one works well for mid/high power ~50W-100W per channel 500W DC12V To AC 18V 0~160V~220V~380V DC To AC Inverter Pre amplifier Boost Converter Module|boost inverter|inverter acac boost converter - AliExpress
There was a 1000W unit, but it's not available now.

 

[dgta]

Did any of you guys find a boost module that puts out 60-80V negative? Since none of them are isolated, you can't use the regular ones for a (negative) bias supply.