ohms of the 1960 Ampeg Jet (Speaker swap)

[BADFISH]

Any one know the OHMS of a 1960 Ampeg Jet???
I just found the amp, it sounds really good. Its a little on the Dark side. It has a 45 year old Jensen P12S on it. I'm thinking of dropping in a Weber , maybe a 12A125 .

My questions are
1. Ohms
2. Will this speaker Fit in this little Jet.
3. any other speaker recomendations?

Thanks for any and all info.

[Jimmy Somma]

It's probably 8 ohms...as where most single speaker Ampeg amps.

You can check the existing speaker with an ohm meter. An 8 ohm speaker will read about 7.5 ohms, unless of corse it's blown.

[Reeek]

Originally posted by Jimmy Somma
It's probably 8 ohms...as where most single speaker Ampeg amps.

You can check the existing speaker with an ohm meter. An 8 ohm speaker will read about 7.5 ohms, unless of corse it's blown.

What Jimmy somma said. The reading across the speaker tabs should be in the "ballpark" of the original impedance but a tad less. The rule of thumb I use is to multiply the actual reading by 1.3 but it will seldom hit 8 Ohms (in the case of an 8 Ohm speaker) exactly. An 8 Ohm speaker will read anywhere between 6 and 7 most likely, with the low to mid 6's being the norm in my experience. Unless the speaker's impedance has drifted dramatically for whatever reason, the impedance is easy to determine by settng the DMM to Ohms and simply reading across the speaker leads.

8 Ohm speakers will read between 6 and 6.5 usually if the speaker is not damaged (minus voice coil rub)

4 Ohm will read in the 3ish range

16 Ohm will read around 12ish

As you can see, the readings are typically too far apart from each other to mix them up.

Good luck!

[DanR]

I also have a '60 Ampeg Jet. The stock speaker is a Jensen P12S and it's 8 ohms.


DanR