Vera-Fi Audio LLC
Main Stream - Master Class Dynamic Parallel AC Line Conditioner
Main Stream - Master Class Dynamic Parallel AC Line Conditioner
Couldn't load pickup availability
Product Description
Product Description
Now Shipping!
Note: Shipping times for Main Stream can take 5 to 7 days.
Master Class Dynamic Parallel AC Line Conditioner
Main Stream is designed to improve the performance of your high-end audio or video system by reducing the amount of AC Mains-based interference travelling on the wires within your home. This interference is created not only by other components in the system, but also appliances and other electrical equipment elsewhere in the house. Sometimes even emanating from outside your home!
Of course, this interference is mostly in the RF range, but things like refrigerators, air conditioners and heaters, washers and dryers; anything with a big motor and put a pulse of energy onty your home AC line and it will be "felt" by other equipment within the home. The energy imposed on the line is absorbed or filtered in different ways, depending on the frequency band involved. Part of Mainstream's effectiveness is due to the multiple frequency bands it effects while utilizing a simple topology comprising a minimum number of parts.
Line interference can cause many undesirable effects; hum, hiss, hash, or buzzing sounds from your speakers, a slight vibration that can be felt through the chassis of your components or on the motor of your turntable, and on video displays as random lines, moving bars or fuzzy images.
These effects can be experienced individually or in combinations. It is interesting to note that oftentimes the effect (hum, for instance) is apparently reduced, but our bands of interest do not include these very low frequencies. We are reducing energy in a band that infers these types of noise reductions.
Main Stream is called a “parallel” line conditioner because you do not plug your component INTO it, but rather plug it into the Mains socket closest to the component. In this way the MainStream is never restricting the flow of current to your components, simply removing the interference it encounters on the line as the current flows by. And there is no limit to how many MainStreams you can use; a large system may best be served by several.
As you probably know, the other type of line conditioning is called "series". There are many (maybe most?) products out there which plug into the wall and then your component(s) plug into it. With these, the current must pass through the various filter parts on their way to your audio component, necessitating the internal parts being of both high enough voltage and current to support the power demands of the attached product(s). This makes these conditioners both larger and more expensive than a parallel type, and they are often designed to serve somewhat different needs, or sometimes one of just distribution and surge protection.
Mainstream uses a combination of reactive elements to create tuned filters designed to specifically reduce the levels of noise specifically known to interfere with your audio enjoyment. Our topology excludes the use of any type of resonant transformer as a wave shaping device, and rather only removes unwanted frequencies.
• Capable of reducing system background noise to vanishingly low levels.
• Reasonably priced,
• Milled extruded aluminum case
• Designed for a long life of continuous service
• A faint blue glow shows it is working
• Laboratory tests prove the effectiveness of MainStream via Fast Fourier Transform graphs





There are two dedicated lines supplying power to my stereo. Each line has a Core Technologies power conditioner. I added a Main Stream to one line and a Snubway to the other. After two weeks of burn -in I can say with confidence that the results are positive and pronounced. There is more space around instruments and voices. The sound stage is deeper and wider. Most importantly to me is the entire presentation is more clear and focused. Best $600 I've spent on this rig!
Improvements were immediately noticeable. I haven't paid enough attention to whether they improved further in time.
What the mainstream did: a feeling of more power behind everything, especially noticeable in the bass and impact of drums. It feels correct and better, not just different, and the improvement is pretty significant.
What the snubway did: a more subtle improvement. First thing I noticed is a more accurate location of sounds. In general there's more subtle detail.
For context, I do have a computer with a switching power supply on the same group that I use to play music. Other than that it's only audio devices with lineair power supplies. I use the snubway to protect those, and use the mainstream for everthing. I did a few tests with positioning and this seems to work best. Mainstream: directly in a wall socket. Snubway: in the power distributor for audio devices.
I’ve had unit installed about 4 weeks now and really happy.
They are as effective in lowering noise and revealing detail as the many I have tried in the past. However, they are making a little additional magic that no other plug-ins could provide. Music flows with ease and smoothness, but it is more than that. The PRaT was at its best playing from all my sources, and the music became more engaging. I also noticed the soundstage and instrument separation turned better and became more believable.
Didn't think the Main Stream would make a positive difference since I live in the boonies, with no neighbors. My home has a dedicated transformer on the utility pole. I was wrong. The Main Stream improved detail and the instruments have more color. Thankfully it doesn't decrease dynamics. Highly recommended.
The delivery was done a long time ago, but due to the internet line at home being down, I was only able to set it up and test it today. It’s truly impressive. It feels like the sound has come alive. I can’t believe how much of a difference this one thing can make.
Back in my audio years (70's 80's and 90's) no one talked about AC line filtering. We sold a "power conditioner" from Monster Cable but all it really did was compress the music! I don't think anyone really knew anything about what was on the AC line and how it affected a system's sound quality. But back then, customers balked when we suggested that they upgrade to a 12 gauge power cord for an extra $45!
I have auditioned a few of your competitor's products and while they did "something" none of them made as big a difference as your two filters. You have every right to be proud of your products as they really make a significant difference. I wish you every success in marketing your filters in a field that is crowded with voodoo clones some of which selling at stupidly high prices!
Using it in 2 systems, paired with the Snubway. In both systems, a 2.1 and an 11.2 Home Theatre, I’m getting more dynamic music and soundtracks, with dead silent backgrounds. Brighter, cleaner, and immensely enjoyable.
I used this in conjunction with the snub way noise defender. Bass is fuller, treble is sweeter and instrument separation is enhanced. Overall a noticeable improvement in all aspects of sound quality. My system is: Zu Audio DW6 superfly speakers, HiFi Rose RA 280 amp, Denon DCD1700 ne CD player, Eversolo DMP A6 streamer, Schitt Jotunheim II headphone amp and Audio Technica ath WP-900 headphones. Cables/interconnects are Zu Audio Mission II's.
After I installed Vera-Fi's Main Stream, SnubWay and the Swiss Digital Fuse Box, my patient wife asked me if I was happy with my latest upgrade to my power tube sound system. I answered in the affirmative, I'm thrilled! She knows how hard I am to please when it comes to what my ears hear. I'm always trying to get that last percentile of quality out of my stereo. And right now I couldn't be happier. In closing, CroTone Tubes are the best sounding tubes made in the USA.
Main Stream Reviews on YouTube

Audio Pursuit
Audio Pursuit gives Main Stream the Tesla award alongside SnubWay

TONE Audio
Vera-Fi Main Stream Quick Overview

Audio Pursuit
Budget-Friendly Power Conditioners: Snubway & Main Stream
Articles about Main Stream

Positive Feedback
Tom Gibbs awards Main Stream and SnubWay for 2024 Writers' Choice Award

Headphone Guru
Main Stream wins 2024 Accessory of the Year awarded by Headphone Guru

Positive Feedback
Main Stream provide the kind of overall improvements you'd expect to pay through the nose for.

Tone Publications
The Main Stream will make a similar contribution to your system just like fine-tuning your speakers for optimum placement and turntable setup.

Stereo Times
The Main Stream brought me ever closer to the music while providing a more nuanced performance.

Headphone Guru
The Main Stream is an incredible value and an extremely simple way to improve your audio system without introducing any negative effects.

Audiogon Forums
I can’t think of any other product that improves recorded music as dramatically as Main Stream.

Positive Feedback
Main Stream has worked wonders in my all-analog system.
Frequently Asked Questions (FAQs)
What does the Main Stream Master Class Dynamic Parallel AC Line Conditioner do?
The Main Stream reduces a broad spectrum of AC noise, allowing your system to achieve ultimate performance.
How is the Main Stream different from other power conditioners?
The Main Stream is a plug-in filter that increases the blackness of one's audio system, enhancing sound quality without introducing any negative effects. It concentrates its effects mostly between 10kHz and 20kHz where problems with AC Mains tend to show themselves.
Is the Main Stream easy to install?
Yes, simply plug the Main Stream into an outlet on the same circuit as your audio equipment. Main Stream is fine in Power Conditioners as well. Main Stream is also a parallel type filter so can be plugged into any available free power socket in your system.
Can I use the Main Stream with other power conditioning devices?
Yes, it can be used alongside other power conditioning devices like SnubWay or other products like Puron etc.
What kind of improvements can I expect in my audio system?
Experts and users have reported a darker background, revealing more detail and ambient cues, expanded soundstage, and tighter, deeper bass.
Where can I find Vera-Fi Audio warranty information?
You may find information about warranty here.
Follow Us!
Subscribe to our mailing list for insider news, product launches, and more.
- Choosing a selection results in a full page refresh.
- Opens in a new window.

There are a couple of qualities of these subwoofers that I would like to comment on favorably. First, the coverage of the midbass frequencies, and in fact the musicality of the subwoofers, is remarkable for the price. In my room, the frequencies between 65 and 125 are suppressed by the room. The Caldara subwoofers compensate for this very nicely. Second, the visual appearance of the units is very nice.
Wow, I miss the ultra low frequencies that my old but no longer functional REL subwoofers provided, my music room does not really allow for reproduction of the frequencies between 20 and 40 Hz. The trade-off of musicality is therefore significant compensation.
I appreciated Mark’s generous offer to substitute the Caldera for the smaller model which was out of stock. If I can make one suggestion for future Caldera models, it would be to have speaker level inputs in addition to the RCA inputs.

Wow - I honestly wasn't sure if I was even a "bass guy" before purchasing 2x Caldera 12"s, and my Wharfedale Linton's even had already solid bass response, but in the endless quest for the "wow" factor, I was pointed towards Vera-Fi's subwoofer offerings.
Let me just say, I am absolutely blown away. I can't stop listening to my system -- it just sounds too good. I also have not experienced such remarkably good customer service from a company in quite some time. Thank you to Mark and the team for making such a reasonably priced product that punches far into much higher price points.

The Line Noise BlackHole (LNBH) sets the new industry standard for AC line noise elimination. In both my systems, the LNBH in combination with the Snub Station Zero easily bested the AudioQuest Niagara equipment that occupied both systems. If you can manage with a combined amperage total of less than 10 amps (that's much easier than most might imagine), these devices will shock you with the goodness they bring to your listening sessions. Yes, they eliminate AC-borne line noise, but the opens an entirely new listening experience, with incredible transparency and clarity, whether you listen to analog or digital sources. Very highly recommended, and maybe the most important product launch from Vera-Fi Audio yet!

I have two in my systems, both used in combination with the Line Noise BlackHole. The one in my all-analog system connects my PS Audio Stellar phono preamp, ProJect Classic EVO turntable, and my PrimaLuna EVO 300 tube integrated amplifier, which also has a Swiss Digital Fuse Box between the amp and SSZ's high-current, soft-start AC outlet. I'd been slightly troubled by a slight "buzz" in the system, which I attributed to either the Ortofon Quintet Bronze MC cartridge, the phono preamp, or the tube amplifier. After inserting the new VeraFi power conditioning equipment, the buzz was completely gone, and in its place is complete silence! The combination has replaced an AudioQuest Niagara 1200, which is a good unit, but not in the same class as the VeraFi LNBH, SSZ, and SDFB -- I have been totally shocked by the improvement, which stretches across every possible metric of analog playback.
The same setup is in my digital source system, except with an Infinity Fuse unit replacing the Swiss Digital Fuse Box. In this case, a new Boyuurange A50 Mk III SET 300B tube amp is plugged into the Infinity Fuse, then into the SSZ's soft-start outlet. My Aurender A1000 music server/network player is also connected to the SSZ, as well as my S.M.S.L. VMV D2R DAC. The soft-start outlet is perfect for extending 300b tube life, and the overall system sound is astonishingly good! I'm playing through a pair of vintage Klipsch RB3 Reference monitors (94 dB/watt, 3.8 ohms) and the room synergy is now beyond perfect with the VeraFi Equipment!

Hi there, Mark.
Hope you & yours are doing well. I had told you previously that the Mainstream, simply plugged into a wall outlet on the same circuit as most of my equipment, was revelatory the moment I plugged it in. Basically everything was clearer and the soundstage opened up with a new, blacker background. I have since added a Snubway on a dual plug with the Mainstream and plugged the cord from my Nagara 1200 into the same outlet. Since I did this concomitantly with adding two LNBH’s running off the Niagara (one powering the Pass INT-60 integrated and the other leading to my CD player and DAC) it's difficult to say what is doing what, but every tme I’ve added something here the results have been almost immediately perceptible. The bottom line is that it’s like havng a new system, which is interesting because I thought things were pretty good before! The individual instruments are clearer and more pin-point located, the highs are where they weren’t before (cymbals are a good indicator) and the bass is deeper and more well-defined. The soundstage has gotten deeper and more lateral. You can hear the wood in a cello. Female vocals, especially, are shockingly present. This is almost like the first tme I can say, like other people do, that’s it is like having the players in the room with you. Of course, this is not going to happen with a full symphony orchestra, but with a small group it’s close, and it wasn’t like this before. I will say, however, that positioning the LNBH’s was complicated, both by finding space on my racks and by the fact that, as light as they are, heavy power cords tend to flip them around. It made me wish I still had those old wooden/steel blocks I used to use to minimize vibration on equipment. I left those in Tennessee when I moved to Texas last summer. Isoblocks, I think they were called back in the 80’s. I’m gonna send a couple photos of my setup where you can see one LNBH atop the Niagara on the middle stand under the amp and one on the bottom of the right rack. The Mainstream/Snubway is plugged into the wall behind the right KEF speaker.
Since all that got plugged in together, it was hard to tell what the Snubway was doing, but I got another one to use in the living room where the TV (and the wireless modem) are hooked up. I plugged it into the wall about 6-8 feet away from the outlet (on the same circuit) those other things were hooked up to. I didn’t see much difference in picture quality, but the next evenng I came back and discovered my 15 yr-old OLED TV had somehow been replaced by a new one with deeper, more vibrant colors and blacker backgrounds. I’m not a big video guy, but I’m imjpressed at that result, especially since I didn’t want to pull everything out from the wall and move all the furniture there to get to the power strip.
Thank you, Mark!! The whole shebang was about $1100. It’s amazng to find value like this, and no way am I going to describe the results as “tweaks”!
Best wishes

I installed these in my lake house with an old pair of B&W DM601s. They sound fantastic. Great job guys and gals.

Vera-Fi Audio staff and owner are truly world-class - knowledgeable and kind! I can't ask for better experience. Thank you!!

As a late-comer to the fuse-upgrade culture, I'm glad that I finally stepped into the realm of SDFBs. I currently use a pair of Dutch and Dutch 8Cs sourced by Grimm Audio Mu2 as reference. I replaced all three fuses with SDFB and Graphene Sluggos. On my 8Cs, not only it opened up the soundstage, it did so without any sacrifice, the soundstage is more defined and the presentation is embodied with better clarity and even better focused - large orchestral passages become more layered, the tonality more visceral and congested sections more relaxed without sounding "loose". The additional graphene added to my Grimm Mu2 tightened the overall focus even more and further enhanced the overall realism of my system. This upgrade to me is fundamental and astounding. It ranked among the best upgrades that I'd ever experienced!

The Caldera 10s blend nicely with my Wharfedale EVO4.2s (big bookshelf speakers). The 10s were initially a little boomy in my small room, but blocking the vents yields pleasingly crisp bass. I plugged my integrated amp & the 10s into a "smart power strip" - so that switching on the amplifier energizes the outlets for the 10s. I'm really pleased with my purchase, and I'm relistening to my whole collection to hear the improvement.

I have 2 Caldera 12 subs. My wife think they look great and I love the sound of them. They blend so seamlessly with my Spatial Audio open baffle speakers. My only issue is with the auto on/ off…. It cuts off too quickly when no signal is present while the music is playing and then it cuts back on when signal is present while the music is playing… the problem is the switching on/off is audible. It distracts from the illusion of musicians playing in front of me. Of course I just leave them on now for a work around. Other than that it is a great piece of equipment that I am proud to own… to say nothing of its price/ value and quality. It sets it apart from a lot of budget subs and on par with the best