Wasn't sure where to post this but here goes. I'm trying to use an SMPS made for tube applications. Specs-
(Input voltage: 12VDC
Output high voltage: 150V-420VDC, 1.25V-12V DC filament voltage regulator is adjustable. (Chip voltage regulation, there is a little pressure drop.)
When I connect to preamp,(load), it drops to ~170VDC after being set to output 240VDC. The low voltage 6.3VDC is fine. Attached is pictures of setup:
I'm using an 12VDC/800mA wall wart for SMPS input. Have never used an SMPS before so hoping for an idea as to why?
(Input voltage: 12VDC
Output high voltage: 150V-420VDC, 1.25V-12V DC filament voltage regulator is adjustable. (Chip voltage regulation, there is a little pressure drop.)
When I connect to preamp,(load), it drops to ~170VDC after being set to output 240VDC. The low voltage 6.3VDC is fine. Attached is pictures of setup:
I'm using an 12VDC/800mA wall wart for SMPS input. Have never used an SMPS before so hoping for an idea as to why?
Attachments
I take it the wallwart doesn't drop below 12VDC when under load ---correct ?
IF and I mean IF that is correct then your SMPS is either inefficient or its being presented with a higher current drain than it was designed to cope with ,check with your meter at the wallwart output and current drawn by the audio circuit.
IF and I mean IF that is correct then your SMPS is either inefficient or its being presented with a higher current drain than it was designed to cope with ,check with your meter at the wallwart output and current drawn by the audio circuit.
You need a bigger wallwart. The IR drop is because the 12v @800ma is way to small to handle the PEAK CURRENTS of the SMPS. Try a 12 volt car battery and is should be good. If you have a scope look @ the output voltage of your wallwart.
Well for now I found a 12VDC/3A wall wart and it still drops to 180VDC. Can I measure SMPS output current by putting my meter in line with the + out?
New development, when I test each side individually, neither side sags. Stays at 240VDC.
New development, when I test each side individually, neither side sags. Stays at 240VDC.
Last edited:
When you say -quote- "when I test each side INDIVIDUALLY,neither side sags "-end quote-- lets qualify that do you mean -
A--when ONE side is under load ?
B--or when BOTH sides are under load ?
If --A then the SMPS is lacking efficiency /power .
If--B then the reference you are using as an "earth"/negative point is wrong or the negative connection isn't connected correctly .
Which one is it ?
A--when ONE side is under load ?
B--or when BOTH sides are under load ?
If --A then the SMPS is lacking efficiency /power .
If--B then the reference you are using as an "earth"/negative point is wrong or the negative connection isn't connected correctly .
Which one is it ?