[pauly]

I'm just about finished my AKSA100n.  Just wondering if it is necessary to use a dpst switch or if a spst switch is OK across the active mains lead?


thanks anyone who can advise








Paul

[AKSA]

Hi Pauly,

A spst is OK as long as the switching function is performed on the active line.  However, in most AC systems it is difficult to guarantee this;  in consequence the toroid can be active even when switched off.

Therefore a DPDT is preferred;  and for the 100W you really need a minimum 10A 110/120Vac rating and for 240V I suggest around 7.5A.

You want a switch which is rated for inductive loading, such as an electric motor.  The reason is that such switches resist the arcing produced when the amp is switched off;  this is created by the dying gasp of the toroids as they close down, in precisely the same way as a spark is produced by an ignition coil as the primary current is interrupted by the breaker points as they open.  

Cheers,

Hugh

[andyr]

Hi Pauly,

A spst is OK as long as the switching function is performed on the active line.  However, in most AC systems it is difficult to guarantee this;  in consequence the toroid can be active even when switched off.

Therefore a DPDT is preferred...

Hugh,

Sorry, but don't U really mean "Therefore a Double Pole SINGLE Throw is preferred"?  It's the Double Pole which is important (to make sure the neutral AC wire is switched off too - in case the AC circuit has bin wired incorrectly by the bloody sparkie) ... Double Pole is only relevant if you want to play the trick (in the US) of swapping active and neutral around.

Regards,

Andy

[Carlman]

Double Pole is only relevant if you want to play the trick (in the US) of swapping active and neutral around.

I have this.. it's the Arco switch Hugh recommended.  But, I don't really hear much of a difference flicking it up or down from the off position.  I'm not sure which way is 'correct'.

-C

[kyrill]

Well

I thought i read it somewhere in this forum, that it would not harm the amp to put it on 24 hrs a day. Actually ( except from a couple of dollars a yrs on electricity costs extra) it woul lengthen the lifetime of the amp.
Is this true in case of the AKSA?

[AKSA]

Andy is right.  It should be double pole single throw.  Bloody things always confuse me, particularly late at night........

Andy, one day I'm going to correct you!!  

Carl, the Arco switch gives you the option of Active to Toroid primary 1, Neutral to Toroid primary 2, and vice versa.  Some Golden Eared critics insist they can hear a difference.  I'm skeptical too, but it was mooted as desireable, so I incorporated the idea.  It's certainly no more expensive!

Kyrill, yes, you certainly can leave the AKSA power amps on, I do this as well as they draw only a couple of watts and it costs almost nothing in electricity.  Life of the filter caps is enhanced, since they don't have to contend with huge inrush charge currents too much.  This gives them a slightly longer life......

Cheers,

Hugh

[pauly]

Thanks to you andy and hugh for your help.
I found a dpst 10A switch  locally here in Victoria Canada. It was the last one on the rack at the only electronics shop in town.  
Glad I didn't have to order one from a far away place. ...........Again.
Sourcing stuff here is impossible .   If it wasn't for the www, my house would be half empty




One more cup of coffee and is time for final testing .

Paul

[Bert]

Hi,

To switch my amps on and off, I used a pulse relay from General Electric together with a simple pushbutton. I don't know if "pulse relay" is the correct term. But it is the device used in large buildings or factories to switch the lights on or off. The advantage of a pulse relay is that the coil of the relay is only powered as long as the pushbutton is pushed, because of that, it will not introduce hum or any other form of polution to the signal. A standard relay is capable of switching 16Amps, which is more than enough, even for the 100W AKSA. Pictures can be found here.

[kyrill]

nice pictures Bert
As I am in the "start blocks' of building an AKSA 55N, yr pictures helped me, especially the coloured pcb pictures plus parts from "behind" as opposed to the colured pcb and parts pictures on the website.

But you did not bother to take a picture of the finished amp, including the power supply board (this is also true for the AKSA 100 amp)

Where did you buy the relais on/off switch?

[Malcolm Fear]

Be careful where you mount your transformers, from a balance point of view.
You may end up thinking about isolation supports, and AKSA's sitting on shelves (of Corian) sitting on half inflated innertubes. Berts layout doesn't lend itself to that form of isolation.
I've mounted my transformers on each side of the box. There is no hum.

[kyrill]

Be careful where you mount your transformers, from a balance point of view.. . .

yep, good tip    wouldn't have thought of it

[tg3]

You want a switch which is rated for inductive loading, such as an electric motor. The reason is that such switches resist the arcing produced when the amp is switched off...

Do snubber caps across the power switch help?

[AKSA]

Yes,

Tony, snubbers help, and with the 100W I include a 220nF X2 rated cap for just that purpose.

Cheers,

Hugh

[gonefishin]

Hi guys

   I've been scouring the internet for a power switch for my low voltage AKSA55.  Because I want the AKSA55 to match another amp (possibly AKSA100) I would like to have a rating of minimum 10Amps.  

   The above should be easy enough...but I'm looking for a rotary switch to accomplish this.  While I only need two positions...I could still make due with more positions and an adjustable stop.  Two poles and either double deck (for two separate A/C cords) or I could buy two single decks.

   I've done a large number of searches.  I don't know if the wording I'm using is limiting my searches or what...but I've come up with a couple manufacturers.  But none of these companies sell to the public...I also couldn't find anyone who carries their line.  I suppose I could go with a toggle...but I really wanted to match the "look" that I have on my Bent Audio NOH preamp...but instead of large knobs for selector or volume knobs...I would use them for a rotary power switch.

  Help,   (thanks)
    dan

[SamL]

Hay Dan,

Have you look at local electrical supply shop that sell to electrician? A lot of the office/factory main power board switch are rotary and they are rated 10A or higher. I was interest at rotary switch a while ago and found them at the electrical supply shop. However, they are expensive, not too nice looking and big in size. You really need to replace the knob to make it appealing.
As for me, I end up getting 2 toggle switch from Hugh for my aksa100n.

Have fun,
Sam

[MattCassidy]

I have been on a vain search for a nice switch also. I am having a real hard time getting a nice switch that is rated correctly and is double pole. Is it absolutely necessary to have the double pole? I have found a suitable single pole switch made by Arco and available at Farnell. I am based in brisbane so if anyone has any ideas for me please let me know. I actually got an expensive switch from RS only to discover that it had a momentary action only!!! It looked damn good though.

Cheers
Matt

[andyr]

I have been on a vain search for a nice switch also. I am having a real hard time getting a nice switch that is rated correctly and is double pole. Is it absolutely necessary to have the double pole? I have found a suitable single pole switch made by Arco and available at Farnell. I am based in brisbane so if anyone has any ideas for me please let me know. I actually got an expensive switch from RS only to discover that it had a momentary action only!!! It looked damn good though.

Cheers
Matt

Matt,

On my AKSAs I have used DPST switches from RS Components.  I seem to remember they're 10 amp rating.  They have a silver toggle and you see the locking nut - so they don't actually look the best but I believe switches belong on the back panel, near the IEC plug and fuse holder, so their looks are not an issue.

Yes, double pole is good from a cable routing pov ... particularly if you place the switch on the back panel.  They could certainly be single throw, though!!

Regards,

Andy

[PSP]

I've used a 10amp DPST NKK black rocker switch, silver over brass contacts (NKK JWM21RAA) on my AKSA amps.  They have a matte-black, no nonsense look to them, a nice feel, and have worked flawlessly for several years now.

Digikey requires a minimum order of 50 switches, but you can get one for $6.25 at Mouser:  
http://www.mouser.com/index.cfm?&handler=data.listcategory&D=*JWM21RAA*&terms=JWM21RAA&Ntt=*JWM21RAA*&Dk=1&N=0&crc=true

Good luck,
Peter

[gonefishin]

Well guys...I think my search for a 10amp dual pole rotary is over.  With no luck.  The only two pole/one or two deck rotary I could find was big$$...close to a hundred bucks.  I'm thinking that's not the switch I need to have    Maybe they should put "audiophile grade" in the name and they could sell couple   <---- ducking!

   Anyway, instead of mounting the rotary on the front I think I'll just have to go with toggles in the rear...with perhaps maybe a single led showing in the front.  The case I'm putting it in right now is going to be temporary anyway...so I suppose if I don't get everything looking the way I want it isn't as big of a deal.  But I will keep my eyes open for one in the future.

  thanks for the suggestions guys


 dan