Trainwreck build ?

[leleduke]

What is the ceramic disk 130V MOV on the power switch for and who sells them.

Thanks,

MD

[rfgordon]

It's a Metal Oxide Varistor to protect against wall voltage spikes. Get 'em from Mouser or any other big electronic supplier.

[leleduke]

It's a Metal Oxide Varistor to protect against wall voltage spikes. Get 'em from Mouser or any other big electronic supplier.

1000pF ??

Thanks,

MD

[rooster]

No, not a capacitor for noise filtering like you might be thinking. This is an 'over' voltage protector for your amp - for when you have an electrical storm or the pwr co. sends you too much momentary or prolonged juice. You will find this same device in many pwr strips, BTW. It was KF's way, one of them, to assure long amplifier life. It attaches right across the AC leads at the 'mains' switch which you can see in the build guide...

Sometimes you will also see - on other amps - hi-fi or lo-fi, and typically with transistor amps - a .1uf poly or ceramic cap. This is another thing entirely and not to be confused with the MOV. This is added to some amps to stop a 'pop' that sometimes occurs when you switch the amp on or off.

[leleduke]

Is this it?

Varistor, Circuit Protection; 130VAC; 340V; 4500A; Metal Oxide; 1000pF; Radial
$0.62 (Each)

[rooster]

Hm, yeah, that's kinda it. The one you found has an added feature, the capacitor and yes, there are types that have this added feature. The basic product is a resistor that opens when it passes too much current, the basic varistor. I really don't know what benefit the cap has but I don't think it will hurt your application. Google 'varistor', you should get a grasp of what beneifit the added cap offers.

[M Fowler]

If you are so inclined Radio Shack sells them as well 130v VOM. I have had no luck getting them online so far and back order is May 2009.

Mark

[sst4270]

Try this guys...

In stock and inexpensive.

http://www.mouser.com/Search/ProductDet ... 30Aw%3d%3d

Steve

[M Fowler]

Sure is funny Mouser has never sent my order or emailed me about my backorder status for the MOV.

Mark

[leleduke]

Try this guys...

In stock and inexpensive.

http://www.mouser.com/Search/ProductDet ... 30Aw%3d%3d

Steve

Thanks a million,

MD

[M Fowler]

Right after my previous reply mouser sent me an email that my back order MOV and 5 watt resistors was being shipped. They paid the postage way more than the cost of the parts, nuts.

Mark