Review: Nordost QX4 AC filter


Category: Accessories

Here is a funny one...a phenomenal piece of equipment and really hard to describe. But i thought i would share this one because the Nordost QX4 would not necessarily jump out on many people's 'must have' lists. but it has been on mine since i first heard it, and now i am glad to say i own one.

i would not think of trying to enter into a debate on the technical merits of the technology that sits behind this. i know what i hear...that is all i am sharing. and frankly, that is what i care most about.

The Nordost Thor (QX1 inside) and this QX4 (which has 4 units inside) basically makes it much, much, much easier to understand musical passages. To my ear, this is not primarily due to greater clarity, or soundstaging, or detail retreival or lower noise floor...there are many products which DO actually perform these important things. And possibly better than the Qx4 which does do each of these things but it is not these things which makes the qx4 stand out in my mind.

What the QX4 DOES do is take multiple themes within any given piece...and suddenly when listening to them...you understand it all much better.

Example: you find it easier to listen to the words in a song. normally, even without qx4 if you try, you can hear every word clearly...but normally you never bothered. With the Qx4, now suddenly, you could be typing emails...and it seems so easy to follow the words in the back of your mind without even trying.

Another example: take whisper-quiet taps or rhythms...whereas before they were just that...taps. With the Qx4, it becomes obvious that the composer was creating a secondary rhythm in the music.

Another example: say a violin is playing 1,3,5,7,9...and a piano is playing 2,4,6,8,10. Without Qx4 it sounds fine...2 instruments each playing their own thing. WITH the Qx4, it suddenly becomes obvious that the music is actually 1,2,3,4,5,6,7,8,9,10...just played by 2 instruments in a contrapuntal ensemble.

Somehow, this component delivers a greater understanding of musical patterns...musicality...naturalness and ease to listening to music through an approach that i have not come across ever before. again, i could find lower noise floors, or better detail retrieval elsewhere...but i have never found something which makes music more intelligible and enjoyable. weird.

Is it expensive? hey...such is a hobby like this one where the pursuit of music is endless.

Is it worth it? to me, totally...it is one of the few things you probably never see me sell/trade in. And i am blessed to have some pretty good components which i have managed to buy second hand.

Many thanks to Roy Gregory who first played one for me and who has been exceptionally responsive. And thanks to Arif at KJ West One who ordered and secured one for me...in 24 hours and 2 days before Christmas!!! Talk about service!

Hope that is useful to someone who is interested in reading about this product.

Associated gear
Wilson Grand Slamm
CJ ACT 2
Gryphon Antileon
Zanden DAC
Velodyne DD-18
Transparent Ref Power Conditioner
Transparent Ref IC/SC
PAD Dominus/Ann Contego PC

Similar products
PS Audio Powerplant Premier
PS Audio Quintet
Nordost Thor
Transparent Reference Power Conditioner
lloydelee21
I have just bought my unit and I have to agree with everything you said. My niggle is the cost. In fact, I waited to get one of the rare second hand units that come. The fact they don't come up much, attests to their benefit.

I am afraid I really can't get my head round the retail cost. You are in the UK too and it's what, £1750 new. The origonal QRT units were a few hundred dollars, before Nordost bought them out. Now I know there are 4 QXT units in each QX4, but still, I think the cost is ridiculous, much though I admit how good it is. Sorry to moan about it, but there do tend to be so many things we have to pay through the nose for. I suppose this is symptomatic for the High End being a small and probably shrinking market
Hi David,

Yes, the cost of Audio has risen dramatically in certain cases (not all). And for many of us where the market is tough...that does not help.

I am glad the Nordost is working out for you...it really is one of those pieces that does something to a system i've not found any other component to do...and so the QRT technology is staying! Enjoy your great system!
Hello Sir,
I too am running the Thor , how have you connected the QX4 ,veering away from the topic, I see that you have heard the Metronome Kalista, would you be having any experience with the new Calypso reference transport

Cheers!
Hi Boeing,

I run the QX4 from wall into the power conditioner, and also place the QX4 on top of the power conditioner (Transp Ref Isolation). I admit...i did not experiment a lot...i liked what i heard and left it, based on recommendation from manufacturer.

As for Kalista Ref transport...i have not heard the new Calypso. If i do, i will post...pls do same if you hear it! The Kalista Ref is quite different from the regular Kalista...the main benefit that i could hear was the 2-inch thick slab of methacrylate/clear base...really helped smooth things out. impressive.
Thanks Lloydelee .... Would you say that the PC attaching the QX4 , to the wall has any bearing on sound quality.

Also how would you compare active power conditioning like the Transparent to a passive unit like the Thor ?

Regards,

Boeing