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Ohm Readings.
Posted: Wed Aug 11, 2010 2:07 am
by Halfstacker
I have an SA112OL with a 122918 Fane. When measuring the resistance using an old, simple meter I have, touching the 1/4" plug, I read 11 ohms. So I tried my SE4122 cab through the 1/4" jack and read 11 ohms. I tested a cab I have that has two 8 ohm Carvin speakers in series off the jack and read 16 ohms. I tested another 4 ohm cab off the 1/4" jack and it was 4 ohm.
Out of curiousity, I had a tech measure both the SA112OL and SE4122 cab with a quality meter. He got 11 ohms on both.
Is this normal for Fanes? Should I set my amp for 8 or 16 ohms?
Re: Ohm Readings.
Posted: Wed Aug 11, 2010 3:57 am
by OldSchoolDave
Halfstacker wrote:He got 11 ohms on both. ... Is this normal for Fanes?
It's normal for ALL speakers...
What your and your tech's meters were reading was DC Resistance. Speakers loads are rated in impedance. The two are not the same, but they usually track fairly predictably. Impedance will shift with frequency, but that's a topic for another day.
A 16 ohm (impedance) speaker will typically measure 11 - 12 ohms DCR
An 8 ohm speaker will typically measure between 5 - 6 ohms DCR
Not sure what happened with the Carvin cab. That should have read near 11 ohms DCR as well.
By the way, is your Fane a cast or stamped frame model? My SA112 has a cast frame 122918 dated 9/80. That's the latest cast frame (of that era) Fane I'm aware of. Is there any other info on your Fane (flux density, power rating, etc.)?
Dave
Re: Ohm Readings.
Posted: Thu Aug 12, 2010 2:42 am
by Halfstacker
OldSchoolDave wrote:By the way, is your Fane a cast or stamped frame model? My SA112 has a cast frame 122918 dated 9/80. That's the latest cast frame (of that era) Fane I'm aware of. Is there any other info on your Fane (flux density, power rating, etc.)?
Dave
Thanks for the info on the ohm readings. As for the frame on the 122918, I think it is stamped. Its a black frame, but has that gritty feel to it like cast aluminum sometimes has, but that could be the paint. There is no info on it other than "14583", which it the date code, right? It has the plastic black cap on the magnet, but no label. Do you have any idea what the specs might be?
Re: Ohm Readings.
Posted: Thu Aug 12, 2010 4:14 am
by OldSchoolDave
Halfstacker wrote:There is no info on it other than "14583", which it the date code, right? It has the plastic black cap on the magnet, but no label. Do you have any idea what the specs might be?
Not certain - still gathering intel at this point. The Fane date codes got strange during that era, but I'd venture a guess to say your speaker was made in the 45th week of 1983. Does that jive with component dates in the amp?
My 122918 has a heavy magnet. Since there's just one speaker in that 50+ watt amp, I'd hope it's rated at 75 watts or higher. I'll show you mine, if you show me yours
:
You can check the thickness on the frame legs to see if they're cast or stamped (cast are thicker). Also, if you have a refrigerator magnet handy, try sticking it to a frame leg. If it sticks, it's stamped steel.
Dave
Re: Ohm Readings.
Posted: Fri Aug 13, 2010 2:42 am
by Halfstacker
OldSchoolDave wrote: I'll show you mine, if you show me yours
:
Also, if you have a refrigerator magnet handy, try sticking it to a frame leg. If it sticks, it's stamped steel.
I don't have any photos to post. Maybe in the future as I'm thinking of changing the grill cloth to the salt and pepper (I will save the old cloth just in case).
I forgot about the magnet trick. Good idea. I tested it and it stuck - it's stamped steel.