Manager - NA4M
Manager Notes

Reviews For: MFJ-4225MV

Category: Power Supplies

eMail Subscription

Registered users are allowed to subscribe to specific review topics and receive eMail notifications when new reviews are posted.
Review Summary For : MFJ-4225MV
Reviews: 38MSRP: 149.00
25A Continuous (32A peak) Switching Power supply with variable voltage output.
Product is in production
More Info:
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
KI4ZX Rating: 2016-07-09
Nice! (When Modified) Time Owned: 0 to 3 months.
I purchased a new MFJ 4225MV in June 2016 and, after powering it up, was immediately disappointed by the loud fan noise and was surprised by the very brightly lit meters (where are my sunglasses?). After a few days of unsuccessfully trying to LIKE the power supply, I decided to take action. I verified that KM4QLB was exactly right – the noise is generated as the fan tries to force air out the small holes on the side of the box (a very high turbulence zone!). Remove the cover and it’s suddenly quiet. So I cut a large 3-inch opening and installed a wire fan grill (an 80mm black wire Computer Fan Grill off Ebay for $3.29). I also installed a 47ohm, 2W resistor in the fan lead. Although that slowed the fan down, I believe that the air flow is essentially the same since the inefficient exhaust opening is now fixed. Next, I installed 82 ohm, ½ W resistors in the leads going to the two front panel meter lights. That reduced the light by half – just right in my opinion – and also extended the life of the meter bulbs well beyond the life of the power supply. Even though I was 99% happy with the noise reduction, I decided – just out of curiosity – to drill out all the many holes at the other side of the casing (air inlet) with a drill press and a 3/16” bit. The result of that was a further small decrease in noise but, more importantly, the pitch of the noise seems to be lower (more pleasant) and the air flow is undoubtedly further improved. Now I like my MFJ 4225MV a lot!!!
K8DAD Rating: 2016-05-24
7 years, then Ka-Boom Time Owned: more than 12 months.
For the first 7 years it worked just fine, only used 5-10A max, then last week, it shutoff by itself, showed 2 volts on the meter and no current. Off-on cycle, then came on 2 seconds and blew the 5A fuse. Then with no load at all on the unit, I replaced the 5A fuse again, and charcoal. Total failure. Probably will cost me >$100 to fix it, so maybe just trash it instead. The only beef, other than last weeks complete smoke bomb, is that is it very sensitive to RF near it. A portable running 1 watt with a mobile antenna near it will shut it down. So finicky about stray RF. The fan is obscenely loud. Binding posts and cigarette lighter plug are too low on the supply- they should have been placed higher up. Bye-Bye.
KM4QLB Rating: 2016-03-10
Loud Fan and Shoddy Design Time Owned: 0 to 3 months.
I really wanted, and expected, to like this after my very good experience with the small, modern, quiet, and powerful MFJ-4230MVP. But this had nothing in common with that beyond the brand name.

1. Large, easy to read meters simultaneously display current and voltage.
2. Automotive-style power outlet.
3. Owner's manual includes schematic (unlike the owner's manuals for many other MFJ power supplies).

1. The fan noise is obnoxiously loud despite being advertised on the MFJ website as "whisper quiet."
2. The meters are illuminated by incandescent bulbs (1975 called; it wants its meters back).
3. There is no regulated DC for the fan or meter illumination, so reducing the output voltage slows the fan and dims the meters.
4. The automotive-style power outlet is labeled "Lighter," a term which is incorrect and has ugly connotations for many non-smokers.


I'm probably selling mine.

The problem with the fan noise is due to the restrictive little holes punched in the case through which the fan blows air. Take out the 8 screws (three on each side and two on the front at the top) and pull the cover off. You will be amazed at how much quieter the fan is when it isn't blowing through those little holes.

Slowing the fan down, and reducing cooling in the process, is not how I would reduce the fan noise. Instead, I would cut out the section of cover with the tiny air holes and put a wire finger guard over the fan. To further improve things, I'd do the same to the opposite side of the case.
K6RWM Rating: 2015-04-15
Nice, light power supply Time Owned: 0 to 3 months.
Just got this installed a week ago to power a Yaesu FT-857D, purchased together at R&L Electronics. The size and weight of the unit is very nice. I do not detect any hash at all from the device. The two meters are brightly lit and provide the needed information. I do like the detent on the voltage knob that is set at 13.8 vdc. The display on the FT-857D indicates 13.6 volts which is close enough for ham work. Curiously, the fan runs continuously, not sure why it has a fan indicator light as it is always on, and is not temperature controlled. There is some fan noise but it is not objectionable.

I will continue to use it and will see how it holds up and report back.

73 -- K6RWM
KK5DR Rating: 2014-09-22
Good for ten years Time Owned: more than 12 months.
I have had mine for nearly 20 years. When I first got it, I measured the DC ouput voltage, which was In error when my Fluke 179 told me the panel meter was off by about half a volt, but that might be nit picking.
Then after ten solid years of no trouble it now has an intermittent problem wherein it will not power on from time to time. I'll have to fix that soon. I replaced it with a 4125. No problems with that one.
AA2SM Rating: 2014-03-09
Can't be beat for the money Time Owned: 3 to 6 months.
Had one of these power supplies for many years until it got damaged while moving around items in my shack. Replaced it with a 4245 and found that to slowly get a loud hum, loud fan and complaints from other hams that my rig was buzzing. Well I decided to get another 4225MV. Its a real nice power supply, super quiet and you don't even know its turned on. I love the size also. Tried Astrons, and various other supplies in the past. This one is consistent with its quiet and reliable performance. A great product. Could afford one ten times more expensive but why mess with success.
KF7ZSF Rating: 2014-02-21
Fan noise, yet another approach Time Owned: more than 12 months.
I've owned this unit for about a year. It's dedicated to powering my Yaesu FT-7900R (which I mounted on top of the 4225 by flipping the vehicle mount bracket upside down, and using quake putty to hold it in place, it looks really good and its as solid as screws!) so it's not being pushed real hard and sits in a climate controlled living room next to my LazyBoy.

Solid fit and finish, it's been flawless with daily use.

The fan noise is annoying and surprisingly loud. To fix this I installed a small SPST toggle switch in the fan circuit. The front panel just didn't have enough real estate behind it, so I mounted it on the back panel, right above the fuse holder. The switch I used has a 1/4" mounting post. It fit perfectly and works/looks great.

I flip the fan on when I'm really chewin the extended rag even though it's probably not necessary as the chassis remains room temp throughout. Of course, that yellow fan light on the front goes off when you flip the fan off, so there is a visual reminder as well. It's when it's quiet and you're just listening that you'll really appreciate the fan being off.

The 12v lighter socket is an interesting extra that I actually use on occasion with a phone charger.

The meters are handy and accurate.

Other than the noise of the blowing fan, this is a solid switching power supply that's well built, dependable, looks good, and is a good value.

KD0PCJ Rating: 2013-12-31
Good unit for the price Time Owned: 0 to 3 months.
I use the MFJ to power an IC-735 and a couple of cooling fans for my Swan 270 and Dentron amp without any problems. The fan noise is for real, but I took the mod one step further by replacing the OEM fan with an Antec 92mm three speed computer fan. Its very quiet, I can control the fan RPM with an external switch, its bigger and still fits in the housing. The DC adjust dial is bit touchy on mine, may replace it in the future. Overall, a decent power supply for the price I paid used.
KJ4VVU Rating: 2013-08-26
Still working after 3 years Time Owned: more than 12 months.
It powers my Alinco Dual band and TYT radio's for the last 3 years. The fan is a litltle noisy and the meter lamps went out....but it is a good power supply.
N7JJK Rating: 2013-02-28
Works great Time Owned: N.A.
I got this power supply shortly after I got my license in 2006. It works very well, and the fan noise is present, but not too loud. I usually wear a headset so it doesn't bother me. Like most MFJ products, it's a good value for the price.