OK to use "hot only" mains power switch for AKSA amps?

PSP · « **on:** 10 Apr 2007, 02:59 pm »

Hi Hugh,
I've got my Orions playing now, they sound very nice, and there is much optimization work remaining (positioning, level setting, etc.).

Because I have three amps to turn on and off and especially as we approach summer with thunder storms and power outages, I have been looking for a switch that would handle on/off switching for all three amps and which would prevent the amps from coming back on when power is restored. In many cases, when power is restored it's on for a few seconds, then off, then back on, stutter, stutter, on and on... I do not want to expose my amps or drivers to all of that excitement. Rather, I want to wait until I decide it's safe, then punch the amp power switch and go back to my music. Someone on the Orion board suggested the following switch
http://www.grizzly.com/products/G8990 . It works well, but in testing on my bench, it only has SPST function (in contrast to the DPST power switch you recommend in the AKSA instructions).

So, the question: Will the amp and drivers be happy if I apply power via a SPST switch across the hot side of the mains?

Many thanks, and take care,
Peter

TomS · « **Reply #1 on:** 10 Apr 2007, 04:52 pm »

Peter,

I know this question was directed to Hugh, but I thought I'd chime in with a suggestion.

You might just consider an outlet strip that provides delays. I use the Belkin PF-60 on my HT setup and it has 6 outlets with individually programmable delays. I bought it for about $140 on ecost.com and it works great for that purpose.

Tom

Oz_Audio · « **Reply #2 on:** 10 Apr 2007, 10:50 pm »

Have a look at these guys as well

http://www.selectronic.fr/dcx2496_US.asp

at the bottom of the page is a sequencial mains switch kit.

Mark

AKSA · « **Reply #3 on:** 11 Apr 2007, 06:57 am »

Hi Peter,

Good point. It really is good to have both active and neutral terminals switched on any powered appliance. The reason is that in the event of electrical failure of the transformer insulation (or a mains earth disconnection), it is possible that even with the amp switched off using an SPST switch they could still be powered. If you were working on the primary connections, you might be exposed to electrocution risk, and this very remote probability is the reason most well designed appliances switch both terminations.

Another consideration is that frequently active and neutral are juxtaposed in house wiring. With switching on both wires, active is never alive in the appliance if the switch is off.

In countries with 220-240Vac mains where electrocution is much more likely than with the US 115Vac mains these are worthy considerations.

The suggestions from Tom and Mark are good ones, I feel. Thanks Guys!

Cheers,

Hugh

Occam · « **Reply #4 on:** 11 Apr 2007, 12:42 pm »

And for the economically challenged -
http://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=9362
this is a 4pst toggle switch rated 15A @120vac and 10A @240vac
As they're 4 pole, if you gang 2 terminals together you've go effectively a dpst switch of 30A @120vac and 20A @ 240vac
Sooooo, for $1.99 all you need to do is drill a 1/2" hole, you can switch both line and neutral, and Bob's yer uncle.
Same price for 4pdt center off switches-
http://www.bgmicro.com/index.asp?PageAction=VIEWPROD&ProdID=9360
(same rating), so iff you fuse before the switch (or you fuse BOTH lines), you can do the same, but with the ability to reverse line and neutral for whatever objective and subjective benefits, with a single switch; the center position being 'off'.

FWIW

AKSA · « **Reply #5 on:** 11 Apr 2007, 11:32 pm »

Thanks Paul!!

This is wonderful advice, the product is excellent!!

Back from vacation already?

Hugh

PSP · « **Reply #6 on:** 12 Apr 2007, 12:03 am »

Thanks,
I'm considering two options:

Tom, I like the PF-60. Any downsides? I see that there are two high-power outlets for power amps. Can you hear any loss in dynamics vs. plugging the amps straight into the wall? Secondly, if I set a power on sequence for my components, do I get the reverse sequence for power off? Or, are the power-on and power off sequences separately programmable?

Another approach would be to use my SPST magnetic on-off switch to control a SPDT relay that opens/closes both hot and neutral to the amps.

Thoughts?

Thanks for your help,
Peter

ps.. Hugh, yours is the sorriest ISP tale I've ever heard. I'll buy you a bunch of drinks in Denver to help you drown your sorrows (let's hope the problems are faintly remembered by October...).

AKSA · « **Reply #7 on:** 12 Apr 2007, 08:29 am »

Peter,

I most earnestly look forward to that drink in October, I will remember it for life, I'm sure.

Thank you for your digital commiserations, much appreciated. I have written them a nasty missive, it will be interesting to see if they reply.....

Cheers,

Hugh

andyr · « **Reply #8 on:** 19 Apr 2007, 03:20 am »

Quote from: Occam on 11 Apr 2007, 12:42 pm

so iff you fuse before the switch (or you fuse BOTH lines), you can do the same, but with the ability to reverse line and neutral for whatever objective and subjective benefits, with a single switch; the center position being 'off'.

FWIW

Hi Paul,

I use those mains switches you procured for Hugh (DPDT) and I do put the fuse between the IEC "socket" and the switch ... so I can have the "up" position for straight-through mains (A-to-A/N-to-N) and the "down" position for reversed mains (A-to-N/N-to-A) ... so I can make sure my power transformers are correctly oriented relative to the mains.

I'm curious to know why anyone would fuse N as well as A? As IME, fuses are a "necessary evil" - why would you want to have two of them in the mains circuit when you really only need one?

Regards,

Andy

AKSA · « **Reply #9 on:** 19 Apr 2007, 11:17 pm »

Andy,

You can never be too thin, too clever, or have too many fuses........

Cheers,

Hugh

ginger · « **Reply #10 on:** 9 May 2007, 03:56 am »

Fusing the neutral and indeed using a double pole mains switch to switch both active and neutral is mainly ro cover the possibility that the electrician was having a bad day when he wired your house and the power point in the wall may have active and neutral transposed. It also covers the condition where the neutral to ground link in your meter/fuse box is not up to standard or has become detached in which case the neutral can drift quite some volts above ground and present both personal and equipment safety and fire risks.

My house was built in 1949 and despite having beed rewired in around 1987 I treat the wiring with suspicion and always fuse and switch both active and neutral.

To be sure this is partly a "hang over" from the fact that my electronics training was done in a major hospital and double pole mains switching (active and neutral) AND fuses in both active and neutral is REQUIRED by medical equipment standards. Seems a small incremental cost for added personal and equipment protection so I just continue to do it even though its not strictly required for domestic appliances.

If it only ever saves your life once .....!!!

Cheers,
Ian

andyr · « **Reply #11 on:** 9 May 2007, 09:01 am »

Quote from: ginger on 9 May 2007, 03:56 am

Fusing the neutral and indeed using a double pole mains switch to switch both active and neutral is mainly ro cover the possibility that the electrician was having a bad day when he wired your house and the power point in the wall may have active and neutral transposed.

If it only ever saves your life once .....!!!

Cheers,
Ian

Sure Ian, but as having a fuse degrades the sound compared to not having one (but is advisable for safety reasons) why always have to suffer the degradation of having a second fuse on 'Neutral' ... instead of paying some money to hire a competent electrician to come in, test every power point and rewire the ones that the original Neanderthal had wired up wrong?

Doing this also makes the house safer and removes the possibility that, after you sell the place and someone gets electrocuted, you get sued for 'DIY electrics'?

Or, if you want to save money, buy one of the "wired right way round" testers that the electricians use and test all the PPTs yourself - and switch the wiring round on any that you find have been wired incorrectly (after first switching off that circuit at the fuse box/circuit breaker box, of course!

)

Regards,

Andy

stvnharr · « **Reply #12 on:** 9 May 2007, 11:29 pm »

Andy is most correct in that it is best to ensure that the wiring is correct!

House wiring is Australia and the US is both the same, but also different. In Australia, the power points are generally individually wired from a box, and have on/off switches on them. And with color coded wires it takes a real slacker to install incorrectly.
In the US, the outlets are generally wired in a parallel string, which can more easily have an "incorrect" hookup, though the power will still work fine. The outlets are not switched, though they can be installed with a separate switch.

That all being said, I use double pole on/off switches. My previous amp, BAT VK-60, just had a single pole "hot" switch.

I think that if one is in doubt about the wiring, checking for correctness is the safest course. And this goes way beyond anything pertaining to audio!

DSK · « **Reply #13 on:** 10 May 2007, 01:10 am »

The concept of reversing polarity (or is it phase?) of the conductors in a power cable, and whether it has any impact on the sound of our systems, is an interesting one.

Several years ago I purchased some 'hifi' AC cords with US plugs on them. I placed US to AUS adaptors on them at the wall sockets. What I didn't realise at that point was that positioning of the hot and neutral pins in the US is the opposite of what we have here. Consequently, I fitted the adaptors upside down, thus reversing the polarity. When I found out about the mistake I reversed the three adaptors to maintain correct polarity. Though I can't recall the exact nature of the difference, I did hear a difference ...from memory it was a little more relaxed and a slight hardness to the sound was gone. The adaptors have an earth socket at the top of the adaptor and one at the bottom of the adaptor, allowing you to align the earth pin of the US cord with the earth pin of the Aus side of the adaptor (reverse polarity), or reverse it 180 degrees so the US cord's earth pin is nearest the ceiling and polarity is maintained. When I first got the cords, I temporarily replaced the US plug and adaptor with a quality Aus plug. I heard no difference whatsoever and refitted the US plug as it was a better design for holding the large gauge conductors in place.

Last week I was pottering about testing for the cause of a little hum coming from my speakers. Whilst doing this I also swapped the positions of a couple of my AC cords to see whether I could find even better synergy. In order to make one of the swaps I needed to buy an Aus to US adaptor. This adaptor aligned the power cord earth pin with the earth pin on the other side of the adaptor (ie. reversed polarity) and didn't have a second earth pin socket to allow correct phase. I didn't think it would make any difference, but I was wrong. The front to back layering of the soundstage totally collapsed into a narrow band between the speakers, and the excitement and magic of the music was gone. I removed the adaptor and replaced the short cord with a longer cord of the same type (that already had a US plug and didn't need the adaptor) and everything returned to normal. I guess you could argue that it was the change from Aus plug and adaptor to US plug an no adaptor that caused the change. But, due to the fact that I previously heard no difference when replacing a US plug and adaptor with an Aus plug, I don't think so.

I know that the 'power cords make no difference' proponents will be rolling around on the floor absolutely p!ssing themselves over this one.....

andyr · « **Reply #14 on:** 10 May 2007, 03:47 am »

Quote from: DSK on 10 May 2007, 01:10 am

The concept of reversing polarity (or is it phase?) of the conductors in a power cable, and whether it has any impact on the sound of our systems, is an interesting one.

Last week I was pottering about testing for the cause of a little hum coming from my speakers. Whilst doing this I also swapped the positions of a couple of my AC cords to see whether I could find even better synergy. In order to make one of the swaps I needed to buy an Aus to US adaptor. This adaptor aligned the power cord earth pin with the earth pin on the other side of the adaptor (ie. reversed polarity) and didn't have a second earth pin socket to allow correct phase. I didn't think it would make any difference, but I was wrong. The front to back layering of the soundstage totally collapsed into a narrow band between the speakers, and the excitement and magic of the music was gone. I removed the adaptor and replaced the short cord with a longer cord of the same type (that already had a US plug and didn't need the adaptor) and everything returned to normal.

I know that the 'power cords make no difference' proponents will be rolling around on the floor absolutely p!ssing themselves over this one.....

Let them piss themselves, bro!

You and I have heard the difference (I must remember to use the secret "AC afficionado" handshake next time we meet up!!

)!!

This an essential article, IMO:
www.boundforsound.com/tweak.htm

In fact the effect has nothing to do with the AC mains, per se ... simply whether the "right" side of the power trannie is connected to active.

Regards,

Andy

DSK · « **Reply #15 on:** 10 May 2007, 06:08 am »

Quote from: andyr on 10 May 2007, 03:47 am

Let them piss themselves, bro! You and I have heard the difference (I must remember to use the secret "AC afficionado" handshake next time we meet up!! )!!

This an essential article, IMO:
www.boundforsound.com/tweak.htm

In fact the effect has nothing to do with the AC mains, per se ... simply whether the "right" side of the power trannie is connected to active.

Regards,

Andy

Thankyou Andy, in all my reading somehow I had missed this one. MGD is obviously very passionate about this area and I find myself agreeing with him on some points and disagreeing on others. The last update was 1997 and it would be interesting to know what he would change if he were to update it today.

Common sense seems to suggest that power cords, plugs, and dedicated lines should make no difference to the sound of our systems ... so long as the system is fed with sufficient current, secure connections and no other contaminating electrical appliances on the same line. But, from my own testing, I know that such things can make an audible difference. Despite auditioning a number of interconnects and speaker cables over the years, some of them costing several thousand, the two times I heard the largest changes when swapping cables both involved the change of a single power cord. Both equated to a major component upgrade. Interestingly, both occasions (a few years apart) involved the Synergistic Master Coupler AC cord that MGD mentions, the first one adding it and the later one replacing it with the Eichmann AC cord.

Like MGD, I have found AC cords to have a more profound effect on power amps than front end gear. And my experience with AC conditioners echoes his too, some do some good things but are a step backwards overall, others are better overall and a worthwhile addition. And, while some have a positive effect on front end gear, few are actually an overall improvement on power amps.

However, unlike MGD, I'm not about to go squirting oil onto the prongs of my AC cords or seeking some super cheapie wall outlets ...

stvnharr · « **Reply #16 on:** 10 May 2007, 11:17 am »

Quote from: DSK on 10 May 2007, 01:10 am

The concept of reversing polarity (or is it phase?) of the conductors in a power cable, and whether it has any impact on the sound of our systems, is an interesting one.

Several years ago I purchased some 'hifi' AC cords with US plugs on them. I placed US to AUS adaptors on them at the wall sockets. What I didn't realise at that point was that positioning of the hot and neutral pins in the US is the opposite of what we have here. Consequently, I fitted the adaptors upside down, thus reversing the polarity. When I found out about the mistake I reversed the three adaptors to maintain correct polarity. Though I can't recall the exact nature of the difference, I did hear a difference ...from memory it was a little more relaxed and a slight hardness to the sound was gone. The adaptors have an earth socket at the top of the adaptor and one at the bottom of the adaptor, allowing you to align the earth pin of the US cord with the earth pin of the Aus side of the adaptor (reverse polarity), or reverse it 180 degrees so the US cord's earth pin is nearest the ceiling and polarity is maintained. When I first got the cords, I temporarily replaced the US plug and adaptor with a quality Aus plug. I heard no difference whatsoever and refitted the US plug as it was a better design for holding the large gauge conductors in place.

Last week I was pottering about testing for the cause of a little hum coming from my speakers. Whilst doing this I also swapped the positions of a couple of my AC cords to see whether I could find even better synergy. In order to make one of the swaps I needed to buy an Aus to US adaptor. This adaptor aligned the power cord earth pin with the earth pin on the other side of the adaptor (ie. reversed polarity) and didn't have a second earth pin socket to allow correct phase. I didn't think it would make any difference, but I was wrong. The front to back layering of the soundstage totally collapsed into a narrow band between the speakers, and the excitement and magic of the music was gone. I removed the adaptor and replaced the short cord with a longer cord of the same type (that already had a US plug and didn't need the adaptor) and everything returned to normal. I guess you could argue that it was the change from Aus plug and adaptor to US plug an no adaptor that caused the change. But, due to the fact that I previously heard no difference when replacing a US plug and adaptor with an Aus plug, I don't think so.

I know that the 'power cords make no difference' proponents will be rolling around on the floor absolutely p!ssing themselves over this one.....

Darren,
It sounds like you need some of these from VH Audio:

http://www.vhaudio.com/images/vhaussie.jpg

They are 19.95 each, and do the job well.

Steve

Speedskater · « **Reply #17 on:** 10 May 2007, 11:31 am »

I would not fuse the neutral line.
99 plus percent of all US circuits are correctly wired.
If the neutral fuse blows, the unit is still hot while you are troubleshooting it.

Kevin

DSK · « **Reply #18 on:** 10 May 2007, 01:25 pm »

Hi Steve, thanks but the US to Aus adaptors I've been using for the last few years are sonically transparent, are available locally and are cheaper than the VH ones. The adaptor that I mentioned that collapsed the soundstage was an Aus to US one (the reverse of the VH plug you linked to and the adaptors I already use) as it was for use on an AC cord with Aus plug going into an AC conditioner with US sockets. It was only for use in a temporary test as I traced some hum and was so bad that it was ripped out and cast across the room to come to rest in a dark corner, never to be used again.

ginger · « **Reply #19 on:** 14 May 2007, 04:30 am »

DSK etc.
I think you should check that the pin arrangement between US and OZ wiring is really opposite. I'm not sure this is actually the case. What you have to watch is the colour (or color in the US) codes.
US use BLACK for active and WHITE for neutral. Back in the days we used red and black for active and neutral respectively this caused no end of problems as folk would wire black to black and the white to the red which is exactly backward of what it should be. Thankfully we have since changed to the international browns hot (active) and blues not (neutral) colour coding which make us think about it a bit more.

I have never been convinced that fusing both sides has any effect on sonics whatsoever.
Technobabble justification:
I did a quick measure of a 5 Amp fuse and its resistance was 0.3 Ohms. Add 0.1 Ohms (worst case) for each end contact - that gives an additional (worst case) 0.5 Ohms in the power transformer primary circuit.
In a 240V to 25-0-25 transformer this reflects into the full secondary as an additional 0.02 Ohms.
In a 110V to 25-0-25 transformer it reflects into the full secondary as an additional 0.1 Ohms.
Either way these are swamped by the actual resistance of the secondary windings.

If you think you can hear a difference and are happier with a single (active) fuse - feel free, BUT I suggest its purely psychosomatic and that you only hear a difference because you had convinced yourself ahead of the actual listening that you were going to.

I could as easily argue (for the sake of arguement) that the tiny increase in total effective secondary resistance will very marginally decrease the peak current flow in the secondary and the reverse recovery transients generated in the rectifier diodes. This would reduce the resultant radiated RF, and reduce the ripple currents in the filter caps, hence relieve them of some stress. From this point of view the additional fuse should make the amp sound better - hows that for a juicy rationalisation?

I the end what sounds best is what you are happiest with. It doesn't have to make sense.

Cheers,
Ian