Simple power strips/conditioners?

[mansr]

1 hour ago, marce said:

Curious as to why no MOV's?

It is believed that they ruin the sound quality. Don't ask me how.

[marce]

I did wonder. I know they can be considered a fire hazard under certain fault conditions unless other precautions have been taken. But choosing a power strip with the relevant safety approvals should mitigate this (UL).

I would be interested in any documentation as to why it is thought they ruin the sound quality, especially when on the mains input, with PSU's and filtering following...

[mansr]

2 minutes ago, marce said:

I would be interested in any documentation as to why it is thought they ruin the sound quality,

Some figure of authoritah said so. Or maybe it was Cartman.

[Jud]

12 minutes ago, marce said:

I know they can be considered a fire hazard under certain fault conditions unless other precautions have been taken.

This. They also lose effectiveness over time and don’t provide an indication of that.

[lucretius]

On 1/26/2020 at 8:48 PM, Kimo said:

This one is a long time favorite of Naim fans and priced decently.

 

https://www.amazon.com/Wiremold-L10320-Power-Strip-outlets/dp/B00DWIL16O

 

The original legendary Wiremold power strip discovered by Naim Audio North America’s Chris Koster for use in a Naim system. Suited to both Naim’s passive and active systems as well as other high quality component systems due to the close spacing, size and number of outlets. As a result the power outlet connections for all system components are in almost identical electrical, magnetic and acoustic planes even at high frequencies.

 

This and its successor, the AV Options LLC SuperWiremold Deep-Cryo Power Strip, do not appear to provide any surge protection (or EMI/RFI filter) whatsoever. Their purpose appears to be keeping noise low by avoiding using parts that add noise, for e.g. "performance robbing circuit breaker, noisefilter, light, or switch".

 

 

 

 

[Speedskater]

8 hours ago, Mike Rubin said:

Jud, that’s the part they don’t tell you about solar.

In the USA, the SolarEdge residential solar panels are a big source of interference.

[Miska]

For analog gear I'm using 16A version of this:

http://www.jenving.com/products/view/surge-protected-3024000733

 

In addition to digital gear attached to APC's filter/surge protection blocks:

https://www.apc.com/shop/fi/en/products/APC-Essential-SurgeArrest-8-outlets-230V-Germany/P-PM8-GR

And also some analog gear attached to another block of same type. In general I keep SMPS and LPS gear on separate blocks.

 

[marce]

5 hours ago, Jud said:

This. They also lose effectiveness over time and don’t provide an indication of that.

Dependent on the number of strikes they have to cater for, for most domestic this would be quite a while.

[Ralf11]

I 'believe' that protections belong near the panel.

 

OTOH, I doubt that MOVs will really affect SQ very much.

 

OTOOH, why not just cheaply and easily eliminate that as a possibility?

 

Yet again, if you desire to MOVe along* on the distal protection front, that is fine by me.  I do suggest you hand paint each one mauve.

 

 

As you can see, I can go both ways on the MOV thing.

 

 

 

*Or just MOV beyond the x86 instruction set.

[Mike Rubin]

5 hours ago, Speedskater said:

In the USA, the SolarEdge residential solar panels are a big source of interference.

Our panels are branded LG.  I don’t know who OEMs what in solar, though, so mine may or may not be equally noisy.

[Jud]

2 hours ago, marce said:

Dependent on the number of strikes they have to cater for, for most domestic this would be quite a while.

 

Not just lightning strikes, though. Surges also. Don't forget CA has adopted rolling blackouts as a fire avoidance strategy; wondering about surges when the power comes back on.

[sandyk]

51 minutes ago, Jud said:

 

Not just lightning strikes, though. Surges also. Don't forget CA has adopted rolling blackouts as a fire avoidance strategy; wondering about surges when the power comes back on.

 Surges at power reconnection shouldn't be a problem. What can be a problem though is massive momentary overvoltage due to an external fault condition, which I have seen as a massive flare up in brightness from lights .

 In this case a MOV could prevent massive equipment damage while sacrificing itself.

 In storm prone areas they should be replace occasionally, and in any event should always be used in conjunction with a suitably rated fuse or circuit breaker.

[sandyk]

9 hours ago, mansr said:

It is believed that they ruin the sound quality. Don't ask me how.

 

They have several hundred pF of capacitance, but that shouldn't bother any properly designed equipment .

[Jud]

41 minutes ago, sandyk said:

 Surges at power reconnection shouldn't be a problem. What can be a problem though is massive momentary overvoltage due to an external fault condition, which I have seen as a massive flare up in brightness from lights .

 In this case a MOV could prevent massive equipment damage while sacrificing itself.

 In storm prone areas they should be replace occasionally, and in any event should always be used in conjunction with a suitably rated fuse or circuit breaker.

Or you could use the ZeroSurge or similar and not have to worry about remembering to replace something with sacrificial elements.

[fas42]

28 minutes ago, sandyk said:

 

They have several hundred pF of capacitance, but that shouldn't bother any properly designed equipment .

 

The problem is, that there are hardly any such animals ... 😜.

 

I've played a bit with using devices with MOVs, either as part of the gear, or added on - to do filtering. Their capacitance has been deliberately relied upon to modify what happens with high frequency noise on the line - and has delivered audible benefit.

 

A finger in the wind test I use is to simply add a retail surge buster to a socket that audio gear is plugged into - this is almost guaranteed to change the sound, meaning the component needs better isolation from mains waveform variation; something the manufacturer should have "well sorted", before putting it on the market,😀.

[sandyk]

25 minutes ago, fas42 said:

I've played a bit with using devices with MOVs, either as part of the gear, or added on - to do filtering. Their capacitance has been deliberately relied upon to modify what happens with high frequency noise on the line - and has delivered audible benefit

 

 That has also been my experience with several devices, including the Linear PSUs for my P.C's DIY DAC PSU (Musical Fidelity X-DAC V3) , and Headphone Amplifier PSU, where the main heavy duty DIY Power Board filter for the PC etc. also has MOVs.

The MOV can be seen at the far top left next to the shrouded fuse socket, as well as a snubber R and C at the input to the PSU PCB (transformer secondary)

The added PW5 resistor is to even out the load on both + and - output rails where the +VE rail is much more heavily loaded in the DAC than the -VE rail ,  which only supplies the -VE rail for the analogue I.C.s in the DAC

 

Both of these items are on a separate A.C feed at the rear of the P.C.

 

This isn't a storm prone area though.

[sandyk]

51 minutes ago, Jud said:

Or you could use the ZeroSurge or similar and not have to worry about remembering to replace something with sacrificial elements.

 Hi Jud

Do you have any technical info on how Zero Surge works ?

 Ideally, we should not have to use even more expensive items to protect our gear, including heavy duty filtering ,

as most of us already seem to need way too many additional devices to obtain decent SQ. My MOVs continue to work well after many years due to the ratings of the MOV's used and suitable series fusing, however. as I said I do not live in a storm prone area.

 

Regards

Alex

[Speedskater]

11 hours ago, mansr said:

It is believed that they ruin the sound quality. Don't ask me how.

a] Point of Use Surge Protectors with MOV's dump the noise into the Safety Ground/Protective Earth.

b] while Whole Home MOV Surge Protectors don't have this problem.

c] Brick Wall, ZeroSurge & SurgeX Point of Use Surge Protectors don't use MOV's.

d] they are very nice, but very, very expensive Point of Use Surge Protectors.

e] most of us don't need them.

f] a Whole Home Surge Protector is the way to go.

[mansr]

4 minutes ago, Speedskater said:

a] Point of Use Surge Protectors with MOV's dump the noise into the Safety Ground/Protective Earth.

Why is that a problem? Most of my audio equipment doesn't even have a ground connection.

 

Quote

f] a Whole Home Surge Protector is the way to go.

Difficult if you're renting.

[Jud]

3 hours ago, Speedskater said:

f] a Whole Home Surge Protector is the way to go.

However, these also have the problem of wearing out over time, though they do give some indication (if in the form of AFCI/GFCI breakers) of this by beginning to trip with irritating frequency.

 

The breaker for our coffeemaker tripped all the time. Returned coffeemaker for a new one, same problem. Electrician who wired the house replaced it with another (which he noted had a sequential serial number, so if the original was part of a bad batch...). He also tested to make sure there weren’t unexpected surges when the coffeemaker operated. There weren’t. Same problem. I went out and bought a new AFCI/GFCI breaker of the same brand (Square D) and spec at Home Depot, and no problem since.

 

I’m just a little happier with point of use surge protection for my AV system that doesn’t deteriorate over time by design.

[sandyk]

40 minutes ago, Jud said:

 I went out and bought a new AFCI/GFCI breaker of the same brand (Square D) and spec at Home Depot, and no problem

 These items are not mandatory in 230VAC countries due to the lower current requirements

 

https://en.wikipedia.org/wiki/Arc-fault_circuit_interrupter

Limitations[edit]

 

This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed.
Find sources: "Arc-fault circuit interrupter" – news · newspapers · books · scholar · JSTOR (July 2010) (Learn how and when to remove this template message)

AFCIs are designed to protect against fires caused by electrical arc faults. While the sensitivity of the AFCIs helps in the detection of arc faults,
these breakers can also indicate false positives by identifying normal circuit behaviors as arc faults. For instance,
 lightning strikes provide voltage and current profiles that resemble arc faults, and vacuum cleaners and some laser printers trip AFCIs.
 This nuisance tripping reduces the overall effectiveness of AFCIs. Research into advancements in this area is being pursued.[9]

Also, AFCIs provide no specific protection against glowing connections also known as a High Resistance Connection, high line voltages or low line voltages.
 AFCI circuit breakers include a standard inverse-time circuit breaker. Glowing connections occur when relatively high current exists in a relatively large resistance object.
 Heat comes from power dissipation. This energy, when dissipated in a small junction area, can generate temperatures above 1000 °C (1800 °F) and can ignite most flammable materials.[10]

Bad wiring junctions can occur in utilization equipment, cords, or in-situ wiring and especially in a defective switch, socket, plug, wiring connection and even at the circuit breaker or fuse panels. Terminal screws loosened by vibration, improper tightening or other causes offer increased resistance to the current, with consequent heating and potential thermal creep, which will cause the termination to loosen further and exacerbate the heating effect. In North America, high resistance junctions are sometimes observed at the terminations of aluminium wire circuits, where oxidation has caused increased resistance, resulting in thermal creep. No technology located in a circuit breaker or fuse panel could detect a high-resistance wiring fault as no measurable characteristic exists that differentiates a glow fault from normal branch circuit operation. Power Fault Circuit Interrupters (PFCI) located in receptacles are designed to prevent fires caused by glowing connections in wiring or panels.[citation needed] From the receptacle a PFCI can detect the voltage drop when high current exists in a high resistance junction. In a properly designed and maintained circuit,
substantial voltage drops should never occur.[citation needed] Proper wire terminations inside utilization equipment, such as appliances, and cords prevent high-resistance connections  that could lead to fires.

An AFCI does not detect high line voltage due to an open neutral in a multiwire branch circuit. A multiwire branch circuit has both energized wires of a 120-240 V split phase service.
 If the neutral is broken, devices connected from a 120 V leg to the neutral may experience excess voltage, up to twice normal.

AFCIs do not detect low line voltage. Low line voltage can cause electromechanical relays to repeatedly turn off and on. If current is flowing through the load contacts it causes arcing across the contacts as they open. The arcing can oxidize, pit and melt the contacts. This process can increase the contact resistance, superheat the relay and lead to fires.
Power fault circuit interrupters are designed to prevent fires from low voltage across loads.[citation needed]

AFCIs are also known to be sensitive (false tripping) to the presence of radio frequency energy, especially within the so-called high frequency spectrum (3-30 MHz)  which include legitimate Citizens Band and Amateur Radio operations. Sensitivities and mitigation have been known since 2013.[11]

 

 

 

[marce]

11 hours ago, Jud said:

Or you could use the ZeroSurge or similar and not have to worry about remembering to replace something with sacrificial elements.

All the high end stuff I see uses MOV's (not audio, mission/life critical electronics), all the commercial stuff uses MOV's. Proven technology especially for high current...

And for serious stuff gas discharge.

[Jud]

5 hours ago, marce said:

All the high end stuff I see uses MOV's (not audio, mission/life critical electronics), all the commercial stuff uses MOV's. Proven technology especially for high current...

And for serious stuff gas discharge.

 

And all that stuff hopefully is on maintenance schedules. I just want less to remember and be concerned about, that's all.

[marce]

2 hours ago, Jud said:

 

And all that stuff hopefully is on maintenance schedules. I just want less to remember and be concerned about, that's all.

To be quite honest for domestic, unless you have major surges you don't need to worry that much, to play say you could always replace the strip every two years...

https://www.littelfuse.com/~/media/electronics/trainings/littelfuse_varistor_mov_products_training.pdf.pdf

Page 15 shows the current through a MOV and its lifetime. The mains should be reasonably stable so lifetime should not be an issue. 

[Jud]

1 hour ago, marce said:

To be quite honest for domestic, unless you have major surges you don't need to worry that much, to play say you could always replace the strip every two years...

https://www.littelfuse.com/~/media/electronics/trainings/littelfuse_varistor_mov_products_training.pdf.pdf

Page 15 shows the current through a MOV and its lifetime. The mains should be reasonably stable so lifetime should not be an issue. 

 

That's certainly a very viable way to do things. I just prefer in many cases buying something and never having to worry about its function again, even just once every two years. So I paid for solar and don't have to worry about monthly utility bills. (At least not for electricity usage. Still pay a little less than $8 a month in various taxes.) Designed the home with everything wheelchair-accessible so it won't need retrofitting if that eventuality ever occurs. That sort of thing. So (hopefully) never having to think about or replace the ZeroSurge appealed to me, even at the price.