I was also looking at this one, but I discarded because it has not enough power for heaters, and is almost 3 times the price:
GZLOZONE GZLOZONE High power LLC Switching Power Supply KT88 300B Tube Amp Power Supply L14 10|Amplifier| - AliExpress
"GZLOZONE GZLOZONE High-power LLC Switching Power Supply KT88 300B Tube Amp Power Supply L14-10"
Interesting. But a curious comment :
"This power supply has been encrypted, and the R&D reference value is low. It is for use only."
I guess it's lost in translation
That's probably it, especially the "low R&D value". Is silly, there is a zillion of schematics, tutorials, application notes etc out there, no neet to copy that thing.
I ended up buying one "HIFI 250W Switch Power Supply DC300V@0.6A +12.6V@4A +6.3V4A", it has a great built quality, but the performance is way below par:
High voltage output with no load: 350v
75mA load: 282V
150mA load: 275V.
Thats way below the 300V/600mA advertised. Asking for a refund, but not holding my breath.
You get way you pay for.
High voltage output with no load: 350v
75mA load: 282V
150mA load: 275V.
Thats way below the 300V/600mA advertised. Asking for a refund, but not holding my breath.
You get way you pay for.
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Did you get your money?
On a side note: I used this SMPS for a 6F12P/6P43P Little Miracle amp (6 tubes total) and I get 12.6V and 292V from it. I'm "burning" it in right now.
My trick was to tack a 33k resistor across the timing resistor for the 555 so the HV only delays 1/2 seconds instead of 30. There is no capacitor on the HV for output tubes, and RC of 10k/50uF per channel for the VA/PI stage. It hummed like a bastard on the bench, but it's quiet in the rack.
On a side note: I used this SMPS for a 6F12P/6P43P Little Miracle amp (6 tubes total) and I get 12.6V and 292V from it. I'm "burning" it in right now.
My trick was to tack a 33k resistor across the timing resistor for the 555 so the HV only delays 1/2 seconds instead of 30. There is no capacitor on the HV for output tubes, and RC of 10k/50uF per channel for the VA/PI stage. It hummed like a bastard on the bench, but it's quiet in the rack.
After checking how much I'd have to pay to send it back by tracked delivery I decided to keep it. I also was explained that I need to load the 12V output to get the maximum HV voltage. I got around 295, I can live with that.
I use mainly for experiments, seems to be relatively quiet.
😂
The transformer gets really hot, even at relatively low loads on the HV. I don't feel like trusting it for a real amp.
Big scary "if"
On another slightly related subject, I got the same inverter you purchased 12-to-110...280, with the black heatsinks. Works quite well, although I would not use it without a fan for long term use at 100W. You mention that you use it with a doubler, what kind of capacitors you use? The unit I bought works at 60Khz.
I have seen variants of the SM power supplies in Aliexpress, sometimes the vendor even explains what they changed, but is a hit an miss. Quite often the seller has no idea what are they selling, you ask a question and sometimes it takes weeks to get the right answer from a technical guy.
Basically, one has to manage expectations, and accept the risk of purchasing some crap. The savings are big, enough to warrant throwing something away or fixing it yourself.
Generally, I use 22uF or 47uF for the caps in the doubler, and HER108 for the diodes UF4007 will do, too. When I double to 400V, I draw 50mA. When I double to 560V, I need to draw 30mA. Well under 100W so I don't use a fan. In fact, I'm running them and the PSU mentioned here in an non-ventilated box. The B+ of the 6P15P amp I'm powering with one of the boosters is still only 48W draw. It's in a ventless case, too.Big scary "if"
On another slightly related subject, I got the same inverter you purchased 12-to-110...280, with the black heatsinks. Works quite well, although I would not use it without a fan for long term use at 100W. You mention that you use it with a doubler, what kind of capacitors you use? The unit I bought works at 60Khz.
I'm going to use the diodes on the board, they seem fine. Thinking about using electrolytic with 0.22uf poliester in parallel seems to clean the supply a lot.