Ohmage calculation thread

[Jack]

58 minutes ago, la bam said:

So - what load am I using, using a 6ohm cab bridged? 

6 ohms.

[Count Bassy]

2 hours ago, Bill Fitzmaurice said:

There's no reason to sell the amp. Bridged it will handle a minimum load of 4 ohms. Minimum means that's the lowest value you may use, not the highest, nor the exact load you may use. Perhaps this will help:

https://billfitzmaurice.info/forum/viewtopic.php?f=10&t=19292

BTW, there's no such term as ohmage. The term you should be using is impedance. Ohmage is the made up word used by those unaware that ohms are use not only to measure impedance but also its components, resistance, capacitive reactance and inductive reactance, either separately or in combination.

Bill, I'm very relucant to question the master, but surely it's the the other way round?  i.e. impedance that covers the combination of factors that you mention, and resistance which is used for passive resistance. Hence a coax cable having an impedance that is independent of it's length (at Radio frequencies at least)?

 

[Bill Fitzmaurice]

Cable characteristic impedance is a completely different topic, having no relation to speakers. When you see that a cable is 75 ohm it doesn't mean it measures 75 ohms end to end. The characteristic impedance of a coaxial cable is determined by the dielectric constant of the inner insulator and the radii of the inner and outer conductors. Since those factors are unaffected by cable length neither is the cable characteristic impedance.

[xgsjx]

 

[Count Bassy]

15 hours ago, Bill Fitzmaurice said:

Cable characteristic impedance is a completely different topic, having no relation to speakers. When you see that a cable is 75 ohm it doesn't mean it measures 75 ohms end to end. The characteristic impedance of a coaxial cable is determined by the dielectric constant of the inner insulator and the radii of the inner and outer conductors. Since those factors are unaffected by cable length neither is the cable characteristic impedance.

Yes, I knew that Bill, hence my point about impedance being the complicated one & resistance being the simpler one.

From the net (other sources are available😞

impedance

/ɪmˈpiːd(ə)ns/

noun

noun: impedance; plural noun: impedances

1. the effective resistance of an electric circuit or component to alternating current, arising from the combined effects of ohmic resistance and reactance.

    

Edited November 25, 2018 by Count Bassy