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Re: [Amps] 47 Ohm 5 watt

To: Bryan Swadener <>, "" <>
Subject: Re: [Amps] 47 Ohm 5 watt
From: Joe <>
Date: Sat, 11 Aug 2018 11:46:39 -0500
List-post: <>
Yeah temp would be an issue, these will  be replacing these in a SB-220 amp.

The Original Rolling Ball Clock
Idle Tyme
On 8/9/2018 12:54 PM, Bryan Swadener via Amps wrote:
Be careful of the temperature derating. The datasheet says they start to derate at 25°C and derate to zero at 
155°C. Caddock and others produce similar power resistors.  Kanthal/Globar produces suitable single units 
but, I've not heard of a source for small quantities.  However, a coupla 100Ω/2W carbon composition resistors 
can be used in parallel. Ebay seller 'bigsmythe74' has new old stock Allen-Bradley but, he wants $4/each. Sorting by price, I 
see he has 91Ω/2W available for $1.25 each ( Add $3.50/order shipping to USA.
vy 73,  Bryan WA7PRC


Date: Wed, 08 Aug 2018 16:50:37 +0000
From: Manfred Mornhinweg <>
Subject: Re: [Amps] 47 Ohm 5 watt


I hope someone has in their parts box. (2) 5 Watt 47 ohm non inductive
Actually I do have a few, apparently metal oxide, but shipping them to
you would cost more and take much longer than if you buy them...

Maybe you can use this one:

It's 10W, but still small enough and not too expensive. You can either
bolt it to the chassis, or on a little aluminium sheet that acts as
heatsink, shaped and bent to fit the space you have. These resistors
have lower inductance than old-style "non-inductive" ones, due to their
smaller size. Of course you destroy that advantage if you have to use
long wires to connect them...

Or you can assemble them from several 2W film resistors of properly
chosen values, combined in parallel. Those are very common and
inexpensive. Or use a bunch of even smaller resistors.


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