Kanged switching power supply for a tube amp.

It uses an ATX power supply (or a 12V battery/car) to heat the heaters and drive boost converters for HV, including one that boosts 12V to 13.5V to get 440V from a 380V supply.

I use an EVGA 750W G2 supply: EVGA - Products - EVGA SuperNOVA 750 G2, 80+ GOLD 750W, Fully Modular, EVGA ECO Mode, 10 Year Warranty, Includes FREE Power On Self Tester Power Supply 220-G2-0750-XR - 220-G2-0750-XR

into the following:

This module gives the boost from the LV supply: 1200W 20A DC Converter Boost Car Step-up Power Supply Module 8-60V to 12-83V | eBay

This module gives me 280V for the preamp/buffer/headphone amp: DC-AC Converter 12V to 110V 200V 220V 280V 150W Inverter Boost Board Transformer | eBay

This module gives me the 440V for the power stage after boosting the input to 13.5V: MINI DC-AC Inverter 12V to 18V220V/380V 500W Boost Step UP Power Module New Hot | eBay

This works far better, and for less money than a conventional linear supply.

It powers an integrated amp with 20 tubes.
 

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I admire your solution...even if some of the most linear minded DIYists would have a serious issue with it :)
Also your amp looks nice!

Would you like to elaborate on how it works better than a linear PSU?

Also thanks for sharing the links.
When I need a boost converter I might also buy one of those :)
 

PRR

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..how it works better than a linear PSU?...

I'm seeing $55 total cost.(*) Aint no way I could assemble that much high voltage power linearly and have change from a $100 bill.

And I assume it is regulated, or at least not as saggy as a low-buck iron supply.

(*) I count the ATX supply as "free". In a past life I had them stacked to the rafters. ATX supplies fail, but not as often as the rest of the PC, and failed PCs came to me. Even retired, I could find another in the house; or buy one in town 6 days a week. I'd put loose cash in extra $13 modules, because IMHO some of this stuff does not last. I put $6 e-meters on my power line, and one had a minor failure in a year, so I rushed to buy two more exact same type (to minimize change-over pain). No objection to Koda buying a very nice ATX supply, of course.
 
Totally agree with the cost thing, kodabmx also mentioned that in the first post.

I think the 12V output is the "most regulated" one on an ATX PSU.
From the 3 links I am pretty sure that the first boost converter (12 to 13.5V) is regulated and the rest are not.

I guess the reason for having 380V is so that you can modulate a 230Vrms sine wave and have some required margin in you HF type DC to mains inverter. Hence it does not need to be regulated in its intended use.

I would be a bit concerned about high frequency noise from the converters, but if it sounds and works good then you have saved money in the right place :)
 
There is only 15mV of ripple on the 12V line. Correct. Only the first boost converter is regulated. The 380V becomes 440V by running it at 13.5V instead of 12V. That is the B+ for the power amp. The switching frequency is about 20kHz on the 500W inverter, and 37kHz on the 150W. Because of the high frequency a good filter can be made with a 1R/1000u. The 500W inverter has about a 20V drop from no load to load, which is fine since it's configured as a tetrode amp with regulated screens. There is no audiable noise, either. Especially 120Hz (I hate hum).
 
With the 500 watt inverter board, what are you doing for rectification? I would think run of the mill diodes would overheat due to the 20kHz output and the diodes recovery time.

Some eBay feedback suggests that 17-20 VDC input is needed to realize the full rated output with these. Are you able to vary the output voltage by varying the input voltage?
 
Hi Koda!

The DC-AC Converter 12V to 110V 200V 220V 280V 150W Inverter is not clear to me. It says the "Output Wave Form: high frequency square wave or DC(un-filtered)" Has it 280Vac and 280Vdc or 280x1.41=394Vdc??

Another question: they recommend to use the DC Output. ( because normal electric units are using normal rectifier. If connected to the "High Frequency AC Output", rectifier will heat up fast and damaged, diode will be destroyed.) Do you use the DC output?

greets:
Tyimo
 
No. It's square wave. 280VDC = 280AC because of 50% duty cycle.

I use either. What they really mean is "This switches at 37kHz, and will burn out standard rectifiers used for 60Hz." I use UF or HER series diodes when I use the AC output, and that is only when I use it as a voltage doubled output (220x2=440V because it's square wave).
 
I wonder if this works fine for my purpose.

70W DC 12V 24V to 200-450V 380V High Voltage Boost Converter Step Up Converter | eBay

I'm about to test a tube gain stage for Mofo (FET follower amp with 24V 10A SMPS, popular amp in Pass labs forum). I would like to try different tubes before buying a real power transformer, so variable voltage is a big advantage for me. I also wonder about HV converter compared to conventional linear supply, in terms of sound, noise and safety. I'm hoping HV converter will work fine, and I don't have to build separate linear PSU for tube stage.
 
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I wouldn't even use a choke at all... If you do, realize this switches at 40kHz or so, and you'll need a choke like 10mH instead of 10H like for 60Hz... I just use an RC filter... Say 620R/47u or so if I remember correctly.

Thank you. I'll check the 40KHz noise filter performance with LTSPICE.

One question. Output of this converter is PWM wave, or already smoothed out with some ripple?
 
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I have no idea actually... Maybe you could ask the vendor or someone with more power supply knowledge here can weigh in?

I do know that the frequency of the oscillation (whine) i hear changes with load and voltage it's set to... I try and drop 30V-40V in the first RC filter which seems to help it stabilse.