Jump to content

Real Review - Lessloss Firewall Filters

Recommended Posts

  • Moderator


LessLoss Firewall Module



Electricity is the life blood of a hifi system.

You would therefore think that people would try to ensure that the quality of the mains they use is the best there is. If no other reason it makes the life of the equipment much easier rather than having to deal with problems like DC, RF noise etc.  For me that meant installing a separate mains spur for my hifi equipment. It was cheap to do and I now have 2x6 sockets on the far wall. This got rid of those annoying clicks and pops that happen whenever the fridge, freezer or central heating switched on or off. And it worked.

So I ventured further with mains filters, purifiers and regenerators. At this point it started to become one step forward, three back. I still have a big heavy box of tricks that filtered the mains with inductors and capacitors and they certainly reduced the noise. But they also reduced the dynamics in the music. I tried a range of them but every time there was this dampening of dynamics. The dynamics make the music sound alive and this was too great a loss. When John Bonham lets rip and the whole musical track takes off I do not want the system to dampen it down. Led Zep are about rawk not roll off. So I gave up.

Now along comes an unusual company, Lessloss, from Lithuania. They offer a range of mains filters, vibration isolators, mains cables and an unusual DAC. Through the post from Elite Audio www.eliteaudiouk.com/ came two mains filters. They are certainly unusual in that they consist of a nice oak wooden box (yes wood). At one end of the wooden box is a very high quality mains socket and at the other end a mains cable with a high-quality IEC plug. It is really simple to use. Plug the mains in one end and plug the other end into the mains socket on your equipment. I was sent two filters one with a plain box and the other had a nice 5x carved on the outside of the box. The normal box has one filter in it. The 5x, surprise, surprise, has 5 filters.

How does it work? Have a look at their web page http://www.lessloss.com/firewall-module-p-216.html for a description. I can’t say I accept this description but what does it do for the audio?


The first puzzle was, which component should I plug the filters into? I thought I would use my top system consisting of an Audionote CDT zero, a borrowed AN DAC4.1x, an AN M6 preamp, 2x AN Conquest Silvers mono-blocks and a pair of Audionote E/HE Silvers. Cables were from Cut Loose and Audionote. I looked on the Lessloss web page and on other web pages to get some advice about where the filters would be most effective. There was no clear view but a few mentioned that digital switching components benefited the most. I plugged the filter into the AN DAC and listened.

On goes the new Imelda May album, Life, Love, Flesh Blood. This is quite different to her last album Tribal, which went along at a great pace most of the time. The new album is far more solemn. Imelda has just gone through a difficult divorce and this album is a collection of songs about her experience. Call me is a sad, sad song about waiting by the phone. With the filter in circuit the background noise is significantly reduced and the decay of notes on the guitar are much easier to hear. The soundstage (as it is) was enhanced. Oddly enough the tonal colours also seemed enhanced. The drum kit was not some amorphous thudding but stretched skins being hit gently. I did not quite believe what I was hearing. I took the filter out of circuit. God this album is compressed to hell. And her voice is shouty. Put the filters back in circuit and the sound goes back to what I heard before far more musical.

OK try Black Tears the next track with the filter in. This is another soft ballad. Near the end of the track there is some really distant guitar playing that sounds to be from next door. Also, the song has outbursts of anger even though the loudness of her voice does not change hugely. Take the filter out. God this album is compressed to hell. And her voice is shouty.

Forget that album, it is compressed let’s try something a lot more dynamic…..you’ll hate this guys. Diana Krall with the track Temptations. Filter out. This is nicely recorded and although the singing is not very emotional it is good. Everyone talks about the bass (which is good) but the guitar is sublime, well timed and just a little back from the voice. OK filter back in.  All the musicians here, the playing sublime and the details on the guitar show how well played and controlled the playing is from Anthony Wilson. The voice had a lot more emotion and although it is slightly sibilant it did not smear. The 3D soundstage was much bigger and made it easier to differentiate who was doing what.

I then blinked. My notes for the music without the filter were hifi comments, with the filter I was commenting on the music. That can’t be bad. Yes, but does it dampen dynamics?

On to something more pacey. Dystopian Overture by Dream Theater. And what a dense track this is. Well the filter certainly allowed all the individual elements to be easily heard without any frequency response changes. The sound was also quite natural for a studio creation. And no dampening of the dynamics. All the advantages of mains filters but no loss of dynamics. OK now some sophisticated rock with the Steve Wilson’s remastered Yes album, Fragile. I prefer this album to the 24/96 version, which shows that mastering is far more important than a fancy bit rate. Same effect. The sound was more 3D and it was easier to hear the individual instruments. Also, the drums had a stronger tonal colour than without the filter.

I stopped analysing and just played tunes that I wanted to hear without having to change the filter. This was good fun. It sounded as though the worse the mix the better the effect. Without the filter mixes that were mixed hot sounded bad, with the filter they just sounded hot but not bad/awful, if that makes sense.

I then decided to try the filter on my preamp to see what effect that had. Again, another surprise. Virtually nothing. There was a difference but it was not that big. I could not try it with the power amps as they are mono-blocks and I did not have two filters.

I then gave the other filter a go, the 1x. On the DAC, there was a difference and I think the numbers are about right, it was a smaller effect maybe by a factor of five. It was definitely worthwhile but the 5x was always there in my head as it had a bigger impact.

I then thought I would try something completely different. I have a headphone set up in the front room. I tried the filter in a system of Logitech Touch, Audionote DAC2.1x, Little Dot headphone amp and a pair of Sennhieser Momentum on ear headphones. The headphone amplifier with the 5x filter did not really have much of an effect. But on the DAC the noise levels were reduced, the 3D effect did not increase as much as on the main system but the tonal colour was much better. The biggest impact was again on the DAC.

Was this a weakness in the Audionote DACs? No. I tried the 5x on my Metrum Octave and I heard a similar effect, less noise, more 3D sound, greater tonal colour.  

Is it possible it only works with NOS DACs? No. Out came my Esoteric DAC with a very similar finding.

One set up left to try and that was with the same AN front end using the 1x filter and a Hattor passive preamp with the 5x filter on a Nord Class D power amplifier. This time there was a difference using the 5x filter on the power amp. The Nord responded positively. The biggest difference was with bright mixes where the ‘truthfulness’ of the Class D could make things a bit fierce. The 5x filter tamed that and all that was left was a bright mix. There are many reports on the web of people recommending mains treatments for Class D amplifiers. I had not tried that as I was concerned about the loss of dynamics. With the Lossless filters there was no real change to the dynamics but the brightness had gone and the tonal colours had increased.     

So, at the end of all this I had to conclude that these filters do work and they do so particularly well with DACs and a Class D amplifier.



The LessLoss 5x firewall filter costs £800 and the 1x cost £300. You can also buy the filters naked as above and wire it up yourself at £190. But please only if you are expert at working with the mains.

But are they worth it? Given what most of the serious mains conditioning units cost and the fact that some do impact the dynamics (not all of them) then my answer is yes. Is the 5x worth the extra? In a high-resolution system, the answer is positive. A really interesting product that is easy to use and does the job without a negative impact on dynamics.   


Equipment Used

Audionote CDT Zero (1&3), Auralic Aries (1&3), Logitech Touch (2)

Audionote DAC4.1x (1&3), Audionote 2.1x (2), Metrum Octave (1), Esoteric D03 DAC (1)

Audionote M6 (1), Little Dot Headphone MkIII Amplifier (2), Hattor Passive (3)

Audionote Conquest Silver Signature, Nord Stereo power amplifier (3)

Audionote E/HE Silver (1&3), Senhiesser Momentum on-ear headphones (2)

Cut Loose digital and interconnects, Audionote Copper speaker cables. (1&3)

Three systems used 1,2,3

A Real Review by George Sallit

For further information on this review or if you would like a REALREVIEW on any of your products please contact the content team on press@hifiwigwam.com


Edited by George 47
  • Upvote 1
Link to comment
Share on other sites

  • Guest locked this topic
This topic is now closed to further replies.

  • Recently Browsing   0 members

    No registered users viewing this page.

  • Create New...