Furman PM PRO Power Conditioner Internals and Repair

I had to replace some blown MOVs and fuses inside a Furman PM PRO power conditioner, so took a few minutes to talk about the internals of these devices. I find manufacturers often over-glorify what these devices actually are. Nothing super technical here, but may be interesting if you have never seen inside of one of these basic versions before or have read into the marketing hype.

[@buildstoys]

Thanks for the look inside, wondered what set them apart from being just a regular surge protector.

[@shanklecpa]

Very interesting. Thanks for taking it apart and pointing out the innerworkings.

[@alexlassabeatmaker]

Thank you so much for this teardown. I have a rack power strip witch i modded to add EMI filters to each outlet but now i see i need a little more complex circuit with varistors.

[@BayAreaCinema]

Thank you. I’m looking to see what’s wrong with my Furman line conditioner/sequencer and I saw your video. So now I’m going to open it up and see what I have.

[@bhamadicharef]

These Furman are expensive but now we know what they really do ! Thanks

[@mb2776]

That was a really interessting video!!

[@Executioner213]

DUUUUDE! This is actually pretty amazing. I have an old Fuhrman power conditioner thats been collecting dust for years. It pretty much just powers on in protection mode anymore, which means no power to the outlets. I was in a band years ago and the place we practiced was powered from the house next door through extension cords, and my rack started popping more and more until the unit just wouldn't come out of protection anymore. I asked a guy once and he basically described the MOV's like you did (eventually take too many hits to work anymore, etc). Since then, I've gotten to where I can start fixing some things and was thinking of looking at this unit again after so many years. This video was very enlightening. I will ask, just as a secondary opinion for input, if you think that scenario I gave sounds like its a MOV issue? I look forward to hearing your thought. Thanks for doing this!

[@malibustacy3606]

That is the exact same unit I had years ago, I got mine shortly after the 20 amp Pro Series was introduced, I had two over the years and both worked well but it was the first one I got that was surprising as it came with a 15 amp plug on the end of it, that would change by the time I got the second one and the 20 amp plug had to be cut off and a 15 amp plug installed.....power conditioners are good "peace of mind" investments.

[@bhamadicharef]

Really interesting video ... learning too.

[@rogeriozx1]

Very good your video. I bought one exactly like this one and when I plugged it in the protection, ground and ampere consumption lights do not work. I think your video will help me solve this.

[@nickanthony4979]

Can u comment on power condition aspect of these units? I always thought that was a bit of ‘snake oil’ but don’t know the science. A lot of guitarists use furman rackmounts. I wonder if the power conditioner aspect of this or the more expensive units would help minimize unwanted noise and interference in a high gain guitar amp? I’ve found one video that tested emi on a similarly priced furman and it reduced emi a little but not a lot. Great video. Thanks!

[@illestofdemall13]

For most residential homes, there is only 1 phase that feeds the transformer and then the secondary side is center tapped to create two lines of 120V and a neutral, but it is not called split phase. It is referred to as single phase.

[@bluesteelbass]

Always wondered the line filtering going on in these units. Might as well do the same thing they did by purchasing a nice filtering unit and cramming it in a surge protector. At least the one I get will have both common and differential noise mitigation.

[@DJBonRich]

Good day thanks so much for the interesting video. My Furman PL PRO DMC just caught a spike. Do you do repairs on them still?

[@dlopez61]

Hello I watched your video today. Thank you for a great review. I have a question to see if you can help me answer it. Had a power outage in my home today for a split second, when I went into the room to turn my equipment on, I realized that my Furman p.m. pro-was completely dead (no lights). Would you happen to know what might've happened? I will be checking for the circuit breaker button in case it does have one in the back but will get to it when my friend can help me access it (I am disabled and cannot do it myself). I would appreciate any help. thanks in advance

[@santiagomoreno696]

Hi, do you happen to have a schematic for this unit? I have one and the ammeter works but the voltmeter doesn't.

[@oriole8789]

Interesting video, thanks! That's pretty low effort but acceptable for the price. These are better than super cheap generic rebranded Chinese units, though that's not saying much. Because of all the space, you could always improve on the filtering if you wanted to. There's enough space to put in a higher inductance common mode choke in series. You could even use this as a base for a more accurate system that would respond instantly to overvoltage etc. The most "interesting" power conditioner I've seen in terms of design is Accuphase's PS-1230. It's about 70% efficient (it just seems like a regular high power audio amp with fewer stages if you look at the PDF..). Maybe its one advantage is lack of fans for the available power, the disadvantage being absurd audiophile price. In the end, some AC > DC > AC > Filter solution (aka on-line UPS units) seem like a better deal if you want guaranteed clean power haha.

[@davesmith2233]

This actually isn't that much better than a cheap unit off Aliexpress, and certainly nowhere near as good, if "good" is a term you can use here, for some of the bit-more-than-bare-bones units on Ali. This really is the absolute minimum you can do and still meet your technical claims, and certainly there's no special design or magic tech here, it's just a bunch of conventional off-the-shelf stuff bolted together with a flashy-light display to make it look good. I'd say it'd be around the two-hundred-dollar mark on Ali... what's the cost of this one?

[@cameronwarrenmusic]

Hey. I purchased an furman ar117 and it provides power to all outlets. The only thing is that it has a gun to it now. Do you know if that is something that Could easily be fixed and where the problem may lie and if this could be potentially dangerous to things that I have plugged in?

[@MaxiMovier]

yo thank U for great stuff, i have checked my furman why this protection ok diode is not going on and also those protectors, they looks good but at the diode i have 60VAC :) do U think this is normal? Do someone know how to check those protectors if they looks good? ThankU

[@dreamin2x]

i want my furman pl-pro dmc e repaired.. "protection ok" won't lit on..do you able to do the service?

[@alejandrosperanza9786]

Hi Brad! thanks for the info! we've been scratching our heads over at the music studio as to what unit is the right one for cleaning power, and how much is a power regenerator necessary? Do you have any videos on that or could you shine some light on the matter? would a transformer based power conditioner like the Monster 2500 pro line do the trick? thanks A

[@ASH-ou4cg]

Nice watch, thanks for sharing. I have a very old Furman power conditioner in my rack, from 2001. The PL-8. I am wondering if designs have gotten better over the years and whether it is worth me 'upgrading' for a new version, or will it be more or less the same and nothing has really changed much, in all this time? My unit has never taken any 'hits' as far as I know and still works just fine. Just curious what else is being offered out there and whether I should be looking into getting a more modern unit?

[@bloothedog4443]

I've heard ceramic fuses should be used because the filament oscillates creating noise in a regular glass fuse. ..and Hey Brad, can you point us to some reasonably priced units that do the same or better?

[@rstroud2623]

*Hey do you ever open up Audioquest units? Are they worth the money. Are they built better then other companies?*

[@bloothedog4443]

AQ takes over-hyping to an extreme (and makes money from gullability).

[@alphabeets]

Ya know, ya know, ya know.

[@stevew4910]

Surprised to see plain glass fuses in open-frame fuseholders in a (relatively) high-current device. My understanding is that sand-filled fuses are favoured anywhere a very high fault current *might* need to be broken. If v high fault current fuse wire can vaporise - rather than just break; fuse then explodes, depositing mist of conductive metal vapour in vicinity, potentially leading to secondary shorts and worse. Sand prevents this (as would an enclosed fuseholder). Main breaker should be providing this protection, I suppose but probably good practice anyway. Unit in vid looks like it's from mid-'90s, anyone know whether current-production units have plain glass or sand-filled (or whether this is now standard/required practice)?

[@bradthx]

The fuses here are only to break paths to the MOVs in the even they fail closed, outlets in the back do not pass through them. The circuit breaker offers protection for that case here as you mentioned. Thanks for watching!

[@stevew4910]

@@bradthx Thanks Brad! Keep 'em coming :)

[@doylesheppard9056]

22

[@dennyfarrell4388]

Thank you. Are fake Furmans on the market? I have one and just looked inside and looks nothing like yours. 8 WITH A FUSE BREAKER THAT IS IT. iNTERESTING

[@bradthx]

Maybe, counterfeit anything wouldn't surprise me at all. In this case it may just be a more basic model. The really base units are nothing more than a fancy power strip. Thank you for watching!

[@robertw1871]

It’s $500 worth of air in a pretty box…

[@toranarama1]

A whole lot of nothing in there really. just spike and surge protection. These things have no filtering, isolation or power conditioning. there is nothing in here than can improve you Hifi equipment sound

[@nickanthony4979]

Can u comment on power condition aspect of these units? I always thought that was a bit of ‘snake oil’ but don’t know the science. A lot of guitarists use furman rackmounts. I wonder if the power conditioner aspect of this or the more expensive units would help minimize unwanted noise and interference in a high gain guitar amp? I’ve found one video that tested emi on a similarly priced furman and it reduced emi a little but not a lot. Great video. Thanks!