Eaton 9PX VS. P20

I do not mean to be a jerk in here. Just sharing my feelings. I feel the Eaton sounds better than the P20 and it does not spec as good. However it is not really necessary for such low THD IMO. I did put a better power cord on it but made little to no difference. For most people I would still say a power plant. Eaton, every 5-7 years change heavy $300 battery is the downside. I cannot quantify in words how exactly it sounds better to me but I like it. Nonetheless I am still using my P20’s. Just because I paid a lot for them and feel like putting that money to use. A used Eaton is very cheap. A new one is not the price of a P20 either. It handles the worlds infrastructure which is much more sensitive than a stereo. Of course that does not equate to how it sounds but I did feel it sounded better anyways. Another problem is that on the larger ones the fan is very loud but you can fix that and I did so as well. Just relating my feelings. I would still highly recommend power plants. The difference is not night and day but there is a difference. Running off of batteries has been discussed here. If you do want to run off of batteries this is probably the best way to do so. The Yeti is but a toy IMO. You cannot set voltage or anything on that. Also the powerplants offer much more on their screen readouts. You can trust the Eaton is doing it’s job though so long as it is a functional unit.


Hi 2chan,
A while back, I was researching the Eaton 9PX.
It was it’s size and the fan noise that killed that option for me.
I’ve read of people installing better fans in them.
I just didn’t have the space for the Eaton.
Eaton is pretty decent equipment though.

You son of a bitch! I found someone selling three Eaton 9PX 2000 RT (2000VA version) as a set on eBay (1 used and two unopened new) for $1050 total ($350ea) to my door. After your review I couldn’t pass up the opportunity to try them out at such a reasonable price.

Which version do you use in your set-up?

Any tips on fan replacement parts to make it quieter?

Do you run off the battery every now and then so that its life is prolonged?

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Hi Tod,
I think it was an Audiogon forum post; where I was reading about the fan/fans getting swapped for much quieter fan/fans on the Eaton 9PX.

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The impedance of the Eaton should be/is FAR higher than the P20, perhaps you prefer the sound impact of increased impedance?

I would think increased impedance would primarily result in a reduction in dynamics - sometimes too great a dynamic swing can be tiring to listen

Why do you think you’re being a jerk to post this?

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Yeah but my system has dynamics galore. So it can stand to lose some. I am just using the 1000VA model on my bedroom system. The fan is less than 40Db but I replaced it with a 15DB one. Just look around at 60MM fans. You want about 1500RPM. Enough to keep it cool and not harm it. The 2000VA is much, much louder. Will certainly need a fan upgrade. It is very easy to replace the fan but be very careful! There are things in there that can kill you even unplugged and batteries disconnected. I like it in this system. don’t get me wrong. My reference system is still running off of 2 P20’s. I just point this out as a budget option. As you see, they are for nothing used. Just make sure it has a good battery in it. Or cost you $$. I do not have to “run it on battery” It is Always running on battery. Hence online. similar to the Power plants it converts AC to DC and back to Ac. It uses the batteries as a huge capacitor instead of an amplifier circuit in the powerplants. You will find large capacitors in many “filtering” passive devices such as Shunyata. This is just a bargain basement option that is not bad at all. Just in the scenario someone cannot afford a powerplant. Although it actually sounded better than my P12 upstairs here. That is odd enough. YMMV big time on this. Nothing to lose though really, you all see how cheap they are used.

Oh, I just thought it was kind of a jerk move to sort of undermine a company in their own forum. I hope no one took it that way though. There is a company that makes an “audiophile” UPS. It is a slightly modified 9PX. It is 20 Grand! I think that alone might speak for itself LOL. As I said I put on a better power cord but it made little to no difference. I would not even bother with that in retrospect. Their power cord is surprisingly good. It is not fancy OCC I put on but it works just fine. It is but one option among many. Albeit a very cheap one. Beware the 2000VA unit needs a 20 amp branch circuit. It will not even plug into a 15A outlet. Do not use a cheater plug! This by it’s design is likely to overheat before your breaker trips. Just don’t try that with it. It needs true 20A dedicated branch. I hope I gave enough info.


Thanks you did! I have a dedicated 20A line so no issues there. I also have had P20s in my listening room but had to return them due to incompatibility/quality control issues. It will be interesting to see if I favor the P9X as you did.

Good point brett.

Tod, did you get them yet? If so, what do you think? You will certainly need a fan on the 2000VA.

They just arrived this afternoon. I am currently at work and looking forward to getting at them. Give me a few days with them and I will report back.

Man, I am really enjoying the Eaton 9PX in my system! If you recall, I previously had two P20s but PS Audio couldn’t get them to play nice with my large monoblocks (the P20 would make their transformer hum loudly). It has been a bit over two months since I had the P20s in my room but to my ears everything I loved about the P20s (dynamics + clarity) have been replicated by the Eaton 9PX. The crazy thing is I was able to get three 2000VA 9PXs on eBay as a lot (1 used + 2 new/unopened) for $1050 total to my door!

I guess everything happens for a reason and although my poor experience with PS Audio regenerators was frustrating at the time, it saved me almost $19,000. I am back to the audio bliss I experienced with the P20s, without the nasty hum the P20s caused in my system and I saved a ton of money.

Anyone interested in a regenerator do yourself a favor and take PS Audio up on their in-home trial and compare their line to an Eaton 9PX, you will be happy you did.

Is it just a plain 9px or something else there are quite a few different kinds on ebay

Just like PS Audio has a P3, P12, P15, and P20 there are tons of variants of the Eaton 9PX. The equivalent of the P20 is the Eaton 9PX 2000RT. Any model number with an ‘N’ at the end is set-up for network control but is more expensive.

Here is a good deal on eBay $600 to your door, new open box:

Just keep in mind that you will have to replace the fans as 2Chan mentioned, the stock ones are really noisy as these are intended to be used in a server room.

Thanks! That is very helpful.

Just buy a P20 and be done with it…

I have one! But I got a new amp for a center channel and it is spiking my p20 to 70-75% !!!

I may just throw the center straight to the wall or buy a Shunyata thingy for it and I got a smashing deal on a Hegel h590 that will need some juice too. I really think two p20s would be amazing but a bit out of budget at the moment.

I had four, they all went back to PS Audio because they induced DC into my system. I would advise the exact opposite, especially when a $600 solution IMO competes toe to toe with the P20.

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Four?? You bought four P20’s? Wow!

I originally bought two. The P20 caused mechanical hum in my monoblock amplifiers’ transformer. Keep in mind no hum was present when the amplifiers were plugged directly into the wall- the P20 was doing something to cause this issue. PS Audio replaced those with two more that were supposed to absolutely fix the issue, they did not.

At this point I can’t remember how many I had in my home, it may have been 5 total because one of the first P20s I received was DOA. If only we as consumers could bill manufacturers for our time spent on their defective products, I probably could have made a few grand off this ordeal with PS Audio alone.

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Beste mensen van het PS Audio Form.
Ik schrijf het in het Nederlands maar ook een regenerator is geen perfecte machine en ik geef toe dat een dedicated line zonder een regenerator soms beter klinkt dan bijvoorbeeld een Torus Balanced Power transformer!
Ik heb twee Balanced Power Transformers van Kemp elektroniks Nederland my home land en voor mij klinkt het soms schoner dan de P5 met de outlets de gekoppelde B.I.S. van Kemp.
waarom weet ik niet?

Google Translate:

Dear people of the PS Audio Form.
I write it in Dutch but also a regenerator is not a perfect machine and I admit that a dedicated line without a regenerator sometimes sounds better than a Torus Balanced Power transformer for example!
I have two Balanced Power Transformers from Kemp electronics Netherlands my home land and to me it sometimes sounds cleaner than the P5 with the outlets the linked B.I.S. van Kemp.
I do not know why?