High Voltage DC-DC Boost Converter 12V to 150V-420V 170V 230V 1.25V-12V 6.3V Filament Adjustable Step Up Power Supply 2-Way PSU DC Regulator Module for Tube Preamp/Nixie Tube

I purchased this for a tube preamp B+ supply that I built. I was only able to get 200 volts output! That was no load! if I loaded it to even a few millamps it would put out even less high voltage an got hot. I tried different diodes in the bucking circuit but it just did not perform as expected. Electronics has been a hobby for more than 60 years.I waited beyond the return window to start my project. My mistake I should have tested it as soon as it arrived. I don't think this thing could perform as advertised, it needs higher rated parts to put out the 400 volts claimed. Meanwhile I wasted $20

I like this. I am using this to power a small vacuum tube amp that I built for my guitar. I can not crank to full voltage but I can get it up to about 200 volts and it runs a little warm but is stable and does not introduce noise into the amp. This works much better than having to have a high voltage transformer etc. You can run this off 12v batteries and get off the grid and play a tube amp without heavy transformers etc.

The resistor by the output has color bands that indicate 30ohms, but the board says 3.3 ohms. which one is it?

I bought this as a general-purpose high-voltage supply. I measured the efficiency at various loads, using a 12.5-volt power supply. The efficiency is about 30%, very low for a switching power supply. It dies with a load less than 5 watts. The supply is based on a 40-year-old design which probably explains its poor performance. Do not buy this unit.

The cheap looking power mosfet died after about 10 minutes. I noticed it getting very hot, so I changed the heat sink. (there was NO thermal compound). With the new heat sink the temp was fine, but it only worked for a few minutes before it died. I replaced the mosfet (IRF840) with a new one from a quality source. It is now working fine.

While the low voltage portion works well and delivers the 6.3 V I need the high voltage side is not functional. The first unit only put out about 160 V with no load and then sagged to under 90 V with a 7 ma load. Second unit was able to be adjusted to the 250 V no load that I needed but sagged to under120 V with the 7 ma load. Completely unusable. Quality wise parts are crooked on the board and look like it was assembled and soldered by someone with no care for the quality of the unit.I ended up going with 2 separate DC-DC converters. One for 6.3 V and another for 250 V.Finally diagnosed the problem with the high voltage side of the supply. The board has a 220uf and a 470uf electrolytic cap. The caps have the values clearly printed on the surface that is facing up. On the board the values are clearly printed at the location they belong which is about 3/4" apart. The 220uf cap was on the 470uf position and the 470uf cap was in the 220uf position. I removed them and soldered them into the correct position and the HV supply is now working fine. Total lack of QC and obviously not tested. Guessing the entire batch was assembled incorrectly.

The media could not be loaded. Has been my favorite for driving multiple tubes simultaneously, which my project requires. Have ordered a second one for another project.

I'm using this to drive a 12AX7 tube circuit. There is a small-amplitude 14 Hz sawtooth on top of the HV, which shows up in the audio output. Bought two of these at the same time and both show this behavior.