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Reviews For: MFJ-4125

Category: Power Supplies

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Review Summary For : MFJ-4125
Reviews: 75MSRP: 100.
Description:
MFJ-4125 13.8 volts 25 amp switching power supply
Product is in production
More Info: http://www.mfjenterprises.com/products.php?prodid=MFJ-4125
# last 180 days Avg. Rating last 180 days Total reviews Avg. overall rating
15754.2
WK0G Rating: 2008-04-03
Good product Time Owned: 0 to 3 months.
I recently purchased the 4125P. The delivery from MFJ was fast, the Powerpole connectors were installed per the ad hoc standard and worked with all of my cables. There are a total of 4 connectors on the unit, two on the back, two 5 way binding posts and to sets of Powerpole connectors on the front.The unit seems to exhibit little RF noise on my FT-817. The fan is a little noisy for my tastes and I will probably slow it down ( I don't believe I have one MFJ product that I have not "improved" to meet my needs in some way). It was a choice between the 4125 and another unit reviewed in QST last fall that while smaller exhibited broadband RF noise and I went with the 4125.
GM0ELP Rating: 2008-01-03
UK/USA Small Footprint Time Owned: 0 to 3 months.
Bought this wee SM PSU in the states and used it to power my FT857. It has a switch on the rear for different mains input voltage ranges and it's small size and weight means it's great for travelling. It ran cool with a 100W out from the rig during long periods of operation and I have detected no QRM from it so far in the UK or US. It was small/light enough to fit into the family suitcase without complaint from my wife (I've always had to go QRP before). I took it home to the UK and am still using it when size and weight of equipment are restricted. The fan is loud (reason for 4 out of 5 rating) so sitting it next to the rig without headphones is annoying and therefore limits its usefullness. When travelling or on holiday I tend to wear headphones (family requirement) and with the PSU on the floor I was blissfully unaware of any fan noise.
I also have an Alinco DM-330MW (no fan noise) but it's much larger and heavier and doesn't have input voltage selection switch and has been banned from the suitcase for those reasons. Thanks to MFJ I can now go anywhere with 100W out!
K3NG Rating: 2007-11-30
Fan waaaayyyy too noisy Time Owned: 0 to 3 months.
Electrically this unit is great. No RF noise that I can hear and the voltage regulation is reasonable. The fan is very noisy. Even with it under the desk it was way to loud. I removed the fan from inside the unit and mounted it on the outside with spacers which reduced the noise to some extent, but it's still objectionable. I may end up replacing the fan or removing the metal that obstructs the fan in hopes of reducing the noise. Electrically this unit is a 5. With the fan noise it's a 3. Because MFJ advertised this fan as "wisper quiet" I'm rating this a 2 as I consider it false advertising. This fan isn't wisper quiet unless you're sitting next to a 747 engine trottling up.
WA2LNC Rating: 2007-10-25
Fan Too Noisy Time Owned: 0 to 3 months.
I just purchased the 4125p which has power pole connectors on the front. More about that later.

I just returned the unit today. I loved the size and weight, but the noise from the fan could wake the dead. It actually could not be used in any near proximity to where I was talking. It sounded like a jet engine. MFJ advertises it as a "whisper fan." I will make the assumption that the fan was bad. I sent it back for repair. However, if they tell me it's normal, then they can keep it. As far as I'm concerned it's non-usable in a communications environment.

As far as the power poles, they were mounted on the panel incorrectly. The red/black jacks were on the wrong side of each other and did not follow the standard convention. This was a minor point for me since you can easily make a patch cord to get around this. I shared that information with them as well.

If the unit gets returned with a quieter fan I will report back. If not, they better supply ear muffs.
N0SA Rating: 2007-09-25
VERY NOISY FAN Time Owned: 0 to 3 months.
I just received my 4125 power supply. It does put out the rated voltage, that is the good part but the fan is very noisy. I read previous reviews and either my unit is a piece of **** or my hearing is way too good. My hearing is bad so you figure it out. I'll have to put the power supply in my desk drawer and line it with carpet to use this power supply. Can't for the life of me figure out why anyone would sell an item like this to guys that are sitting next to it trying to listen to a radio.
N2DY Rating: 2006-11-21
Excellent small supply Time Owned: 6 to 12 months.
I am very impressed with this unit. It has no RF hash, just as advertised. On mine, the fan noise is quite minimal. Others have complained about loud fans. Perhaps MFJ has fixed that issue on newer units. I have been running a Kenwood TS-2000 on it for quite a while and it loafs along without any strain. It makes a great supply when traveling. MFJ has a winner here.
N7QAX Rating: 2006-10-24
It handled the desert. Time Owned: more than 12 months.
I bought the power supply to use with my FT-100D while deployed to Kuwait. I pick this one from the others due to the fact that it could be switched between 120V and 220V. I ran Phone and PSK31 with no problems at all. The other guys in my tent never complained about the fan noise. After returning home, I have used it with many different pieces of gear, still runs great
KI1U Rating: 2006-07-19
Does the job Time Owned: more than 12 months.
I've been using this supply for about 5 years now. After thousands of contacts and plenty of field use it is still going strong. In 5 years not a single problem. The fan might be a bit noisy but can't really tell with headphones on hi hi.
W7IFJ Rating: 2006-06-08
Nice little unit! Time Owned: more than 12 months.
My home QTH is in Utah in the US. I'm in New Zealand for two years and brought my IC706MKIIG along. I operate 100 Watt CW in the evenings. When I bought this supply I was concerned that it might not hold up like the Astrons I have used for many years. I needed small size and the ability to operate on 220 Volts which the Astron didn't provide. I have been perfectly satisfied with it's operation. I do wish the 25 Amp power connector came out the back, but that's a small price to pay for excellent performance. Besides the price of the unit makes it very affordable
73, ZL3KSM (N7KM)
W0PPK Rating: 2006-02-19
No problems! Time Owned: more than 12 months.
Had it for over four years in use every day without any problems. Runs flawlessly.

73's Bob