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resistor power rating

84.28.34.74

Posted on May 20, 2012 at 10:26:25
horny
Audiophile

Posts: 657
Location: holland
Joined: October 17, 2003
Hello
I will order some carbon resistors
and i can choose 0,25 0.5 1 2 and 5 Watt
how much must i over rate the power?
say a cathode resistor desipate 1 Watt is 2 Watt then enough or better 5 watt?
And is there a preference soundwise for smaller or bigger carbon resistors
or is this not affecting the sound.

 

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RE: resistor power rating , posted on May 20, 2012 at 10:31:08
Neff


 
I derate 50% minimum. Safety bleeders on power supplies derated to 25%.

 

RE: resistor power rating , posted on May 20, 2012 at 13:18:36
TimFox
Audiophile

Posts: 670
Location: Chicago
Joined: January 14, 2006
I am very conservative, after I once burned a finger on a power resistor running close to rating.
I usually derate by x4 from a "reasonable" power value, and by x2 if I am sure it is a worst-case or higher-than=possible power value.

 

RE: resistor power rating , posted on May 20, 2012 at 13:36:39
zacster
Audiophile

Posts: 942
Location: NYC
Joined: November 22, 2003
I say go overboard and go with a 5w for a theoretical 1w use. I've had cathode resistors start smoking myself and they were over spec too.

 

RE: resistor power rating , posted on May 20, 2012 at 14:11:24
horny
Audiophile

Posts: 657
Location: holland
Joined: October 17, 2003
thanks
and what about the sonic influence agains the power

 

RE: resistor power rating , posted on May 20, 2012 at 14:33:01
danlaudionut
Audiophile

Posts: 5122
Location: Schenectady
Joined: June 6, 2002
Horny

Go with the 5 watt.
Lower noise
Lower thermal drift

DanL



 

RE: resistor power rating , posted on May 21, 2012 at 15:29:23
horny
Audiophile

Posts: 657
Location: holland
Joined: October 17, 2003
Thanks Dan
Is a higher power carbon resistor always better for the sound then a smaller one?

 

Except when a resistor is a fuse -- especially cathode resistors, posted on May 21, 2012 at 15:56:32
jedrider
Audiophile

Posts: 10406
Location: No. California
Joined: December 26, 2003
on power tubes. They must be non-flaming, don't forget that detail ;-)

Replace with exactly what the unit was spec'ed with.

 

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