High Voltage DC-DC Boost Converter 12V to 150-420V & 1.5-12V Step Up Power

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.

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.

Works Perfectly ! Coil must be glued by silicon!

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.

I purchased one of these, and the filament voltage side on that one would not adjust down lower than the 12 v input. Output voltage adjusted just fine. Returning items to Amazon is a huge PITA because of my location, so I just ordered a second unit (while willing to suck up the cost of the first one). Second one arrived today, and it has the exact same problem - the filament voltage side will not adjust. It just remains stuck at the input voltage. (Again, the output B+ voltage side adjusts.) This time, with two of these to return, it's now worth the time and money to return both units for refunds. Shop around somewhere else to find one of these types of power units. Clearly these are just a waste of time and money. I'd give this ZERO stars, if that was possible.

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.

Very good

Worked well for a very short time, then failed. Provides 200V under no load, but output drops to near zero volts under even light load (a few 10s of mA.)

Does not function as advertised.