These filters are an evolution of 3 years of work. They are usually hidden at shows but at the Montreal audio Fest 2024 we didn't have a choice to expose them as we ran out of receptacles on the rear wall. I never thought that people would ask what those black cylinders were for but once they did I would demo the filter live using the EMI tester. The results were amazing as the Hotel room electricity had a lot of noise when measured with the tool. The average measured noise in this Hotel room was around 1600mV and once the filter connected to the circuit it would fall to below 50mV. Results may vary from circuit to circuit. This EMI tool is not a laboratory testing unit but it can measure from 10KHz-10MHz and is an affordable alternative for consumers wanting to test their electrical environment with the aid of a visual presentation and sound of the line noise.
How to rate line noise with EMI tool?
<50mV Excellent
<100mV Very Good
<800mV Good
<1000mV Average
>1500mV Poor
As seen from the chart above the noise level was in the "Poor" region at the time of testing at the Hotel room. Some homes are quieter than others and the noise level depends on many factors to long to enumerate here. Our goal is to get to a minimum of "Very good <100mV" level that is achievable with multiple units. Still lower numbers give better results.
Testing filters with EMI meter. Click on pictures for closer view.
From left to right:
First photo: No filter - 672mV
Second photo: Filter added in same socket - 194mV
Third photo: Filter added near the breaker box - 119mV
Fourth photo: Filter added at audio system receptacle which is across from where the EMI meter is - 92mV
In total 3 filters were used for this demonstration. For this particular situation we were able to achieve 92mV of noise compared to the 672mv from picture #1. As seen with more filters added we get lower noise and subjectively better audio results.
Puratube Pictures
Description:
These filters are effective in reducing AC line noise and include Enhanced Ground Tech. The filter presented here are upgraded versions of what has been seen on various videos on Youtube. They provide a better low level presentation* and expanded sound stage* compared to the prototype model used at the Montreal 2024 Audio Fest. This is our best filter and is very effective in reducing noise/EMI in your AC electrical network and environment. *Perceived performance gains are different from one system to the next.
Specifications and features
EMI filter to reduce AC line / environment noise
120VAC 50/60Hz (Do not use on 220VAC lines)
UL rated
Pewter Logo
3 prong connector
Approx. cable length: 59CM
Approx. size: 15cm X 7cm
Durable solid construction
Enhanced Ground Tech
Approx. weight: 0.4kg
What to expect and how many should I buy
Reduced noise on power lines
Expanded Sound Stage*
Better Low Level Presentation*
Lowered Noise Floor*
Improved Transparency*
Enhanced Vibrancy and Presence*
Reduced in home EMI emissions
Possible health benefits - better sleep
The minimum number of recommended units is two for a significant reduction in noise. The more units you add the better the results.
Price: 1 X 285.00$ each 2 X 570.00$ Set 3 X 855.00$-25$ = 830.00$ 4 x 1140.00$-50$ = 1190.00$ 5 X 1425.00$-100$ = 1325.00$ 6 X 1710.00$-125.00$ = 1585.00$ 7 X 1995.00$-150.00$ = 1845.00$ 8 X 2280.00$-175.00$ = 2105.00$
All prices do not include shipping/insurance/customs or sales tax if applicable. Please take note that if these units are out of stock we ask for 14 days to turn around for delivery. Depending on our work load times may vary. We strive for the best service and will communicate transparently. *Perceived performance gains are different from one system to the next. Warranty - AC filters : 2 years (transferable) See warranty page for detailed information.
How to use:
I bought 1 Puratube : Install at the receptacle of the audio system.
I bought 2Puratubes: Install one near the main breaker box of the house and one at the receptacle of the audio system.
I bought 3Puratubes: Same as above but add the third one across the listening room of audio system.
I bought 4Puratubes: Two in listening room and two in the breaker box room at both ends of each room respectively.
I bought 5or more Puratubes: Do as above but now spread out the Puratubes on your AC network. Example: You install further out such as, bedrooms, basement, garage, shed etc. The idea is to take care of the noise further out on your home AC network so less noise makes it to the audio system and you lower your overall EMI emissions in the home at the same time.
By installing in a bedroom you may experience better sleep / well being. Studies have shown that some people are more sensitive to EMI than others and at times we may not realize how this noise is affecting them until it is quiet.
These are basic usage instructions but don't be shy to try other combinations. It is next to impossible to go wrong with these filters in any combination.
I scuffed/scratched my Puratube! If ever you scratch or scuff the outer shell you can use a hair dryer in the high heat settings (or heat gun on low) and warm up the damaged area to reduce the visual damage. This mostly makes them look like new again.
Warnings
Do not plug into higher voltages then the recommended: 120AC 50/60Hz receptacles only
Be careful to not touch the the connectors for a few seconds (3 seconds or so) when disconnecting from the wall as there may be residual voltage left and a shock is possible
A precaution of shorting out the prongs (the two flat ones) before touching is recommended
For indoor use only
These Puratube units will resist most AC line transients but there are limits such as lightning strikes or high voltage spikes and as such the units may fail and need replacing. See warranty page for further information.
You should verify your receptacles with a tool available from a hardware store for proper wiring configuration for general safety precautions