The problem with Neon..

Neon mains switches in particular..

When I built my first gssl , i wanted an uncluttered simple front panel , and ditched the 'power on' led in favour of a green neon illuminated mains switch , pretty much identical to the ones Amek use on their 9098 rackmount gear. (R13-73 series ) www.mouser.com/catalog/633/1567.pdf

The gssl has always seemed pretty clean , humm free etc..

I've since found comments to the effect that neon induces noise etc..

In another thread , guru PRR advises that they are generally bad for audio.

This is something that has been bugging me for a while , but i've searched hard without finding much more explanation on this..

Are they just bad ,period , or are they bad in certain applications (mic pres say) ?

In a circuit like the gssl , how much noise might that be introducing ?

Can the psu reservoir caps / regs /filter caps not usually cope with this?


I'm asking this now because I'm in the process of swapping out the gssl innards , to replace with the ultimate ssl circuit , and I figured now would be a good time to ditch the neon mains switch (and drill the panel for a power led) if there is something to be gained by doing so..


Lastly , companies like AMEK and SPL are using these kind of switches.....so how do they get around the pifalls of neon??


Cheers


nEon
(no pun intended!)

I've never heard about this! concerning panel mount bulbs. I think it is reference to lighting in a building that runs off of a switching supply/ballast.
Never noticed a problem in gear with neon bulbs, have you?

Little Neon bulbs are even used as voltage regulators in some tube power supply
like this one by Steve Bench:
http://members.aol.com/sbench101/PowerSupplies/supply2.gif

The long neon lights (like the 'Open' sign at pubs) induce a lot of noise. It's high voltage and high current and a long tube, and it induces a ton of noise everywhere. It gets into guitars from three metres away!

Thanks for the responses , guys!

It's nice to hear some discussion on this , as i've searched and googled everywhere to try and get some clear answer to those questions i have .

I understand that neon on the scales that you descibe is bad , RFI etc...

Here, though , I am just referring to a simple neon mains switch in circuit, and how does it impact electrically (noise) onto the incoming supply to the transformer,and beyond..?

Shabtek , I had never noticed a problem in gear with Neons, either , which is why I used one in the gssl !

Check this thread, about 2/3rds down the page:

http://www.groupdiy.com/index.php?topic=2260&start=0&postdays=0&postorder=asc&highlight=mountain+switch

PRR and OWEL's comments are interesting. This was one of the places that got me thinking about those questions i have .

I guess to a (still) relative newcomer like myself, it's just a case of wanting to be sure I'm not doing something that is fundamentally a "no no"!

..And after searching and finding almost no discussion on this subject , I'm really keen to hear peoples opinions..

Cheers y'all!


nEon....

if PRR says 'tis so than it warrants investigation. I've seen neon bulbs used as a type of zener diode to regulate DC as in the Bench P.S. above, so that diode action may introduce some transient/harmonics with ac going through. Need to av a look with a scope and a listen with a highZ input in proximity to a bulb.
editid amek use neon bulbs? In the meters? I thought they were only led and incandescent

[quote author="dale116dot7"]The long neon lights (like the 'Open' sign at pubs) induce a lot of noise. It's high voltage and high current and a long tube, and it induces a ton of noise everywhere. It gets into guitars from three metres away![/quote]

Isn't the noise source the switching power supply that generates the high voltage, and not the high voltage itself?

-a

A lot of those big neon signs don't have an SMPS driving them, just a big transformer. It's the AC running through it.

Did amek use neon bulbs? In the meters? I thought they were only led and incandescent

Click to expand...

No i don't think they did , but they did use the same green neon power switch which I am talking about.. ( or something very similar )

SCI R13-73 dpdt neon power switch.

Any more thoughts anyone ??....is it a no-no or is it a yes-yes to use this in an audio project?

cheers

nEon

no problem here
http://i5.photobucket.com/albums/y181/josan1/greenpre2042x1019.jpg

or here
http://i5.photobucket.com/albums/y181/josan1/1636.jpg

These are the kind of neon bulbs I was talking about... (or some variation of this).



They connect across your AC lines, and need 110V or 220V to "light up."

As I said, it does generate RFI.

If you look closely at it, it's not lit steadily like an incandescent bulb. It's more like flickering, glowing.

If you want lighted power switches, there are other options that are better. Some switches use LEDs within the switch housing.

Quoted from another website, on how neon lamp works.

At both ends of the tube there are metal electrodes. When you apply a high voltage to the electrodes, the neon gas ionizes, and electrons flow through the gas. These electrons excite the neon atoms and cause them to emit light that we can see.

Click to expand...

If you want that kind of action going on in your audio gear, go for it. I don't because I find the noise finds it's way in your audio circuit.

I'd rather go for a simple LED.

Neon lamps were popular back in the 70s and early 80s.

owel, what do you think about audio gear powered with this:

It is a mains power supply rack from www.thomann.de
(it has a neon illuminated switch)

ok

Thanks again , guys.

Good to hear your further comments there , owel .

My neon switch is smaller than the one in the pic that keefaz posted , and it makes me wonder how much the size of a neon indicator affects how much noise is emitted .
Maybe thats why some pro audio manufacturers get away with using the small ones??

Anyway, I'm gonna ditch mine , as I've found a non-illuminated one which will fit into the existing panel.

This was my first build a few years back , and I went with neon , purely on being safety conscious..

..subsequently I stumbled across the noise issue in comments on a hifi forum....but I wanted to get the full low down on this , after all , those guys would have me clean my ac mains plug pins , right! :roll:

So it's damn good to hear some conversation in a place that I trust!

Cheers y'all

:thumb:

nEon

I think that it depends on the circuit, the Steve Bench power supply that uses 3 neon bulbs (used as zener diode like shabtek said) is supposed to have only 3mV ripple at output and Steve Bench is serious about audio quality, look at various test performed by him at:
http://members.aol.com/sbench101/

The Gssl being a line level circuit, I don't think it is very sensible to RFI like a mike preamp, but I don't know. In any case, I would test GSSL outputs with the illuminated switch and with the non-illuminated to see if there is an improvement by using the non-illuminated one

[edit]
I feel a little concerned because I am building a 3deq right now and plan to use a little illuminated (with neon bulb) switch, I have a non-illuminated as well so I will perform test with both. I will post the results

Hmmm bummer, neon looks so much cooler than LEDs....

neon looks so much cooler than LEDs....

Click to expand...

Agreed! ...especially to a 60s/70s head like me anyway!

Keefaz, please DO post results when you have them.. :thumb:

I just got the mac the scope demo , after good recommendations in another thread , so when I've figured out how to get useable results via my rme interface , I will run tests too...

It can only help...this ain't a very widely discussed issue!

Cheers guys

nEon

[quote author="Dr nEon"]

neon looks so much cooler than LEDs....

Click to expand...

Agreed! ...especially to a 60s/70s head like me anyway! [/quote]
I thought I'd seen some 'fake' lamps recently: they look like say the Fender jewel light but are a LED.

We do like the reliability of LEDs of course, but replacing a neon or a bulb a few times is worth it imho.
If we're talking about an Entwhistle(sp?)-bass it's another story of course :wink:

Canford currently have this all singing all dancing, filtered, studio mains distribution box . . .

http://www.canford.co.uk/techzone/MainsDistributionUnits/MDUSelector.aspx

..and the ON switch is...yep , u guessed !


fender jewels with led behind , I like a lot , but you have to find best led for colour integrity..

Cheers

nEon

I think it is always a  matter of the signal to noise ratio  between the artist and the neon bulb,
Best,
D