Identifying Speaker

[Augustin187]

I have this very same Airline 9013-A amp
It’s 15w

I know I can tell the resistance of the speaker with a multi meter. But is there a way to tell the power rating of the speaker?

 

[JustABluesGuy]

That’s a CTS Alnico. I wouldn’t push it much at all, especially considering it’s age.

 

[W.L.Weller]

I know I can tell the resistance of the speaker with a multi meter. But is there a way to tell the power rating of the speaker?

Just drive bigger and bigger amps through it until it breaks. Then measure the last amp and recone the speaker.

In short, no.

Considering that the speaker has an alnico magnet and is 60 or 70 years old, I wouldn't want to subject it to much more than 10 or 15 watts. Go easy on the square wave fuzzes, too.

 

[JustABluesGuy]

Just drive bigger and bigger amps through it until it breaks. Then measure the last amp and recone the speaker.

In short, no.

Considering that the speaker has an alnico magnet and is 60 or 70 years old, I wouldn't want to subject it to much more than 10 or 15 watts. Go easy on the square wave fuzzes, too.

This.

 

[Augustin187]

Would testing a head - any old head not just this one - testing it with a multimeter for residence work?

 

[68goldtop]

Hi!

... is there a way to tell the power rating of the speaker?

Yes, it looks like a ´64 CTS AlNiCo-speaker!
The amp looks like it´s a dual 6V6-amp, so, if the speaker has survived for 60 years by now, my guess is that it easily takes 20 watts on a good day

To be a bit more "earnest"
It really depends.
Some materials (paper, glue...) get old, and they will eventually fail with time.
Hitting them hard (and over long periods of time) won´t help in this regard.
But I (generally) found speakers to be a lot more reliable than I thought they would be.

Having said that - I´ve NEVER blown a vintage speaker (in 30+ years).
I did blow some brand-new ones, straight from the factory, used well within the recommended specs, though.
And yes, I was a bit puzzled, too

cheers - 68.

 

[Dacious]

The amp probably isn't a real 15wrms unit. So if used in this amp given they've been together so long. I wouldn't run it with a modern 15 watt amp like Blues Jnr or Vox AC15. If you showed a front pic we could estimate based on voicecoil diameter a power rating. By the magnet loop probably 20 watts.

 

[uriah1]

Ya, I would say a CTS of low wattage looking at the thin metal basket which looks like an organ pull.
15-20 tops.

 

[W.L.Weller]

Would testing a head - any old head not just this one - testing it with a multimeter for residence work?

Not sure exactly what you're asking here. There are a lot of measurements you can take on an amplifier with a multi meter, what information are you looking to learn? The output impedance of a given output transformer, in ohms? The power output of a given amp, in watts?

There are usually other ways to get this information, also. Like many schematics show the speaker impedance that the amp was designed for. And the output wattage can be estimated to a reasonable degree of accuracy with some information about the plate voltages on the power tubes and the specific type of power tube being used.

 

[Augustin187]

Not sure exactly what you're asking here. There are a lot of measurements you can take on an amplifier with a multi meter, what information are you looking to learn? The output impedance of a given output transformer, in ohms? The power output of a given amp, in watts?

There are usually other ways to get this information, also. Like many schematics show the speaker impedance that the amp was designed for. And the output wattage can be estimated to a reasonable degree of accuracy with some information about the plate voltages on the power tubes and the specific type of power tube being used.

Sorry I’m asking here basically how to tell what the amp wants to see regarding resistance.

The speaker when checked with a multi meter while disconnected from the amp read 5.5 ohms.

Sor of between 4 and 8 ohms.

1 - I wonder what other speakers I can try with the amp 8 or 4 ohm

2 - can I try my fender champ (4 ohm / 5 watt) with this speaker?

And by “can” I guess I mean where would I be in terms of matching the resistances?

I like to match things…. Keeps the option paralysis to 1 less parameter

 

[uriah1]

If you only want amp ohms. I imagine there are a lot airline spec sheets out there.

 

[W.L.Weller]

5.5 Ω is the right DC resistance range for an 8 Ω speaker. The 8 Ω is the nominal impedance. But impedance depends on the frequency of the AC signal (the frequencies you're playing and the amp is amplifying) among other things.



(What's worse, no schematic or one that's a little too blurry to read?)

I would have assumed that your 9013A had the original speaker and that the amp expected an 8 Ω speaker load, but this schematic looks like it says 3.2 Ω VC (voice coil).

So your Champ speaker would be an impedance-matched alternative. What model speaker is in the Champ?

And I wouldn't necessarily worry about the impedance mismatch, if I'm right that the OT secondary is 3.2 Ω and the speaker is 8 Ω. As long as you keep operating conditions the same, as far as overall volume and duration of playing, you're not going to melt anything.

If you can't find a cleaner schematic, it is possible to test the turns ratio of an output transformer and then calculate the values for the primary and secondary impedances but it requires working safely with live power.

 

[Augustin187]

I’m gonna reread this and see if I can get it

My champ is a new reissue modded by Carl with a Webber Alnico in there 4 ohm

 

[W.L.Weller]

Yes, you can plug your Airline into the Weber speaker in your Champ. Do you know how to solder? It looks like the Airline just has wire soldered to the OT (output transformer) and speaker.

You'd need to unsolder the speaker currently in the Airline, disconnect the Weber speaker from the Champ OT and then connect the Airline to the Weber speaker. Sorry if all that was obvious.

 

[Augustin187]

No it’s ok the obvious is always helpful to me. Yeah I’ve already added jacks to both of them!

Thanks so much for your help.

In the end we are now unsure if the Airline itself is looking for 4 or 8? Is there a way for me to open it up and tell?

 

[W.L.Weller]

In the end we are now unsure if the Airline itself is looking for 4 or 8? Is there a way for me to open it up and tell?

That blurry schematic looks like it says the amp came with a 3.2 ohm speaker.

There is a way to test the Airline's output transformer to calculate the turns ratio, which you could then use to calculate the primary (power tube side) and secondary (speaker side) impedances. But it's done by connecting a known voltage to the primary side and measuring the resulting AC voltage on the secondary side. If you're not comfortable working with live power, don't try this.

What I was trying to get across in post #12 is that the amp will probably be fine with a 4 or 8 ohm speaker impedance, as long as you aren't setting all the knobs on 10 and using a boost pedal. Since the amp has an 8 ohm speaker now and you've been using it for however long without breaking it.

 

[Augustin187]

Awesome thanks
Amazing to hear how different it sounds from the champ speaker. Very cool.