puratube - ac fILTERS
High end AC line purification!
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 was connected to the circuit it would fall to below 50mV. Note that the Pteros V2 power bar used at the show had filters inside (DC blocker, EMI and RFI). The addition of the Puratube worked in unison to lower the high level of EMI present. Simuler results can be achieved with multiple Puratubes as described further below.
The EMI tool used 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 that features a visual presentation & sound of AC line noise.
How to rate line noise with EMI tool?
Compared with 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 such as time of day, shops that use motors, heat pumps, fridges, freezers, etc.. Even your neighbors use of electricity affects the line noise in your home. Unless you are alone on the transformer power line you are getting infected by the others that are connected to this power line. Knowing this our goal is to get to a "Very good <100mV" or better results which is achievable with multiple units.
Some will say that the noise is above the audio band and thus should not affect the sound. True the noise is mostly above the audio band but the problem lies in the produced harmonics of this noise that finds its way on the audio signal. Lowering this noise is just beneficial with no draw backs like certain commercial filters that are in series with the load (CD player, preamplifier, amplifiers...). The Puratube filters are parallel units and as such cannot limit current and have some power factor correction which offer a more efficient power delivery to your devices.
The EMI tool used 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 that features a visual presentation & sound of AC line noise.
How to rate line noise with EMI tool?
- <50mV Excellent
- <100mV Very Good
- <800mV Good
- <1000mV Average
- >1500mV Poor
Compared with 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 such as time of day, shops that use motors, heat pumps, fridges, freezers, etc.. Even your neighbors use of electricity affects the line noise in your home. Unless you are alone on the transformer power line you are getting infected by the others that are connected to this power line. Knowing this our goal is to get to a "Very good <100mV" or better results which is achievable with multiple units.
Some will say that the noise is above the audio band and thus should not affect the sound. True the noise is mostly above the audio band but the problem lies in the produced harmonics of this noise that finds its way on the audio signal. Lowering this noise is just beneficial with no draw backs like certain commercial filters that are in series with the load (CD player, preamplifier, amplifiers...). The Puratube filters are parallel units and as such cannot limit current and have some power factor correction which offer a more efficient power delivery to your devices.
Testing filters with an EMI meter
From left to right:
- First photo: No Puratube - 672mV
- Second photo: Puratube added in same socket - 194mV
- Third photo: Puratube added near the breaker box - 119mV
- Fourth photo: Puratube added at audio system receptacle which is across the room - 92mV
Puratube Pictures
Description:
These Puratubes are effective in reducing AC line noise and include Enhanced Ground Tech. The Puratubes 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 your living environment.
*Perceived performance gains are different from one system to the next and also the electrical noise that is present.
*Perceived performance gains are different from one system to the next and also the electrical noise that is present.
Specifications and features
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What to expect
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The perceived performance gains will vary from system to system / environment. The gains vary from " That made a difference" to "WOW that is just incredible". In all cases once experienced it is is hard to do without.
how many should I buy?
The minimum number of recommended units is two for a significant reduction in noise. The more units you add the better the results.
Price for 120V Volts AC:
1 X 285.00$ each
2 X 570.00$ Set
3 X 855.00$-25$ = 830.00$
4 x 1140.00$-50$ = 1090.00$
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$
For 220-240V AC 375.00CAD each - contact us here or use the information below.
For sales or questions: [email protected] or 438-338-0218.
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.
1 X 285.00$ each
2 X 570.00$ Set
3 X 855.00$-25$ = 830.00$
4 x 1140.00$-50$ = 1090.00$
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$
For 220-240V AC 375.00CAD each - contact us here or use the information below.
For sales or questions: [email protected] or 438-338-0218.
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:
- 1 Puratube : Install at the receptacle of the audio system.
- 2 Puratubes: Install one at the receptacle of the audio system and the other across the room.
- 3 Puratubes: Same as above but add the third near the main breaker box of the house.
- 4 Puratubes: Two in listening room and two in the breaker box room at both ends of each room respectively.
- 5 or 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 the human body until it is gone.
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.
FAQ
I have a power bar / conditioner / isolation transformer.... what will happen if I add a Puratube?
If you have a power filter / conditioner / isolation transformer you may surprised once measured with the EMI tool that many such products actually add noise to your AC line which is very strange as most advertise the contrary (measured with the EMI tool before the power bar / filter /conditioner and the output of these devices). By adding a Puratube before and after these conditioners will improve their performance immensely. You may want to try and bypass your beloved conditioner and use the Puratubes only. You could be impressed at the gains in sonic performance when the Puratubes alone are used. As they say your mileage may vary so test away.
Will the Puratube reduce noise introduced by certain light dimmers?
No. You will need to change / upgrade your dimmers to fix this problem. There are also some LED strips that have very noisy switching power supplies. You should consider a better switching or linear supply for these LED strips to fix the noise problem introduced by these.
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 (see 220-240 VAC version for higher voltages)
- 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 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.
- As a general safety precaution verification of proper receptacle wiring should be confirmed with a tool similar to the one below that is available at most hardware stores.
An example of an outlet circuit analyzer that we use (Gardner Bender GFI-3501).
That said, enjoy this great product!
More tests using an oscilloscope
Here are oscilloscope screen shots at different bandwidths without a Puratube and with a Puratube plugged into the AC line. Read the lower pictures in a vertical fashion.
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#1 Without Puratube
#1 With Puratube
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#2 Without Puratube
#2 With Puratube
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In these before and after shots we are using just one Puratube filter on the same receptacle that the scope is connected to. As demonstrated by these measurements the noise is significantly reduced. By using more Puratube filters the results just get better.