Carbon Films Flame Proof?

[rp]

Regarding an upcoming Rocket, I can get 5W Kiwames from the UK easier than hunting down MOs. Wondering if they are ok for power string and pt screens? I've been known to smoke things and don't want ugly little bonfires in my amp.

[guitarmike2107]

As long as the power rating is correct and there are no major faults in the amp you should be fine, but don't sell the amp as it won't meet safety testing standards in the EU.... and keep a fire extinguisher handy

[rp]

As long as the power rating is correct and there are no major faults in the amp you should be fine, but don't sell the amp as it won't meet safety testing standards in the EU.... and keep a fire extinguisher handy

This one will be sellable, I desperately need a Lavasciuga
http://www.euronics.it/acquistaonline/g ... 18929.html

Ok so they are not flameproof, now I must do an extra order for 18K & 9.1K MOs from Farnell $

Nothing in my life meets safety standards in the EU, not even me. Even when ratings and faults are all good I've been known to leave heat sinks, bleeder jumpers behind, and have accidentally swapped power tubes and rectifiers. I can smoke anything, and I don't want a buyer doing the last.

[FYL]

I can get 5W Kiwames from the UK easier than hunting down MOs.

The Kiwame are rebranded and overpriced Koa Speer SPR resistors. And yes, they are flame retardant.

http://www.koaspeer.com/products/resist ... stors/spr/

[rooster]

Good question. I am beginning to think that CF resistors might be flame proof even though they are not advertised as such. And I say this because I recently dissected some 1 watt versions I purchased from CEDist. The material inside is not flammable and really not that different from MF versions.

What I see in a CF is a spiral flat metal ribbon wrap with metal end caps around a ceramic core. There's nothing flammable there. And fwiw, have any of you seen a failed CF resistor that behaved as a carbon resistor? I have not. In my experience they just go 'open'.

I also appreciate that while the larger MF resistors typically have a type of pourus powder coating on them, the smaller versions have a coating that looks very similar to a CF resistor, only blue in color, and not the typical beige.

I will also add that the the CF resistors made these days are available in up to 5 watt values only, and in the case of the Kiwame versions, these are listed as flameproof by the manufacturer.

[xtian]

In related news, I've been burning up 100R metal film 1/2 watt resistors in my artificial heater CT. They don't burn, like with a yellow flame, they flash out with a nice blue-white light, the cleansing fire of lightning. Poetically.

[pdf64]

It's beneficial to beef up their power rating, to ensure that the heater chain maintains a solid ground reference even under fault conditions.
Pete

[renshen1957]

It's beneficial to beef up their power rating, to ensure that the heater chain maintains a solid ground reference even under fault conditions.
Pete

+1

What Peter said. I will add don't use the smaller size versions of the resistors, get the full size, better heat dissipation.

As you are not one other Big Four concerned about the bottom line, and there's space, don't be pinching pennies and use something that's merely adequate would be my advice.

Best regards

Steve

[katopan]

In related news, I've been burning up 100R metal film 1/2 watt resistors in my artificial heater CT. They don't burn, like with a yellow flame, they flash out with a nice blue-white light, the cleansing fire of lightning. Poetically.

I've had both - the flash, and the quickly turn black and then burst into actual yellow flame which kept going until I blew it out. Never in a valve amp but on SS stuff.

[rooster]

Xtian - Replace the resistors, use 1/2 watt as they are fine. Then unplug all the tubes. Measure either leg of the filament supply to ground with the amp off, you should read 50 ohms or thereabouts. Start installing your tubes, standby on/off, power tubes first. If the resistors hold, start adding the other tubes one at a time and keep using the standby on/off. Measure the filament supply to ground, one leg at a time as you install each tube, you should read 3.2 VAC off either leg.

If you end up with all the tubes installed and are able to read 3.2 VAC to ground off either leg then you are done - you will not have anymore problems. However, if you read lower on one side, then you have a tube with a unique filament short within the tube. It's either this or you have buggered the filament wiring on a socket. Look carefully.

[xtian]

Thanks, Rooster, but I got it sorted already: http://ampgarage.com/forum/viewtopic.ph ... 2&start=30