Old Jensen speakers watt rating

[slidincharlie (Carlo P)]

How much power do old Jensen speakers handle?
I have a mid-60's ceramic C12Q installed in my sf Deluxe Reverb and a 1958 alnico P12Q with a just repaired (rebuilt?) voice coil waiting to be used.
May I use it safely in the Deluxe Reverb (22W)?
I want to try it in my 1482 Silvertone also (around 12-15W).
What is the watt rating difference between P and Q series in vintage Jensens?

[pdf64]

Angela.com used to have a early 60s leaflet with this info, but it seems to have been taken down now.
I remember that my P12R was 12 watts.
So if you halve the modern Jensen reissue ratings, it shouldn't be too far wrong.

[olddawg]

The point is really kind of moot. I have a ratty old 1960 Ampeg Jet that had the original Jensen in it. It worked fine until I used an OD pedal with the amp and I killed it inside of a week. I now have an Eminence in it which holds up well and sounds as good. If I had been thinking I would have shelved the original speaker before I destroyed it not after. Even if it exceeds the RMS output of the amp the old Jensen will probably blow if you push it.

[slidincharlie (Carlo P)]

Even if it exceeds the RMS output of the amp the old Jensen will probably blow if you push it.

You mean that there is no strict relationship between the "theoretical" watt rating of a speaker and the amp output power and you're never safe if you think in terms of rating? Or you're saying that an OLD speaker is weak and can blow easily if pushed?
Which is the weaker part in a speaker? The paper cone or the voice coil? I ask because my P12Q has the original cone but a new voice coil.

[olddawg]

You mean that there is no strict relationship between the "theoretical" watt rating of a speaker and the amp output power and you're never safe if you think in terms of rating? Or you're saying that an OLD speaker is weak and can blow easily if pushed?
Which is the weaker part in a speaker? The paper cone or the voice coil? I ask because my P12Q has the original cone but a new voice coil.

The voice coil melts. The amp rating is based on a clean signal at 1Khz. If you saturate the amp you are hitting the speaker with a clipped signal with a lot of harmonics and lower frequencies. It has more apparent power and a more grueling duty cycle. The voice coils in these old speakers are small and tend to smoke when you use them for more than they were intended to do.

[MWJB]

"I ask because my P12Q has the original cone but a new voice coil." Ask the guy who did the recone what the wattage rating of the new voice coil is, it's not uncommon for modern voice coils to have a much higher rating than the original coils.

[olddawg]

"I ask because my P12Q has the original cone but a new voice coil." Ask the guy who did the recone what the wattage rating of the new voice coil is, it's not uncommon for modern voice coils to have a much higher rating than the original coils.

There has to be room for a beefier coil. You can't get something for nothing, and if you do, you change the characteristics and it is a different animal.

[MWJB]

Yes, that's the risk you take when you recone a speaker. For instance, a guy round our way has reconed old Jensens & claims the coils that he uses are rated at more like 40W. No doubt using parts closer to the original will be closer to original W rating, just pointing out that one reconed Jensen may be rated differently to another... & may sound different too.

[olddawg]

Yes, that's the risk you take when you recone a speaker. For instance, a guy round our way has reconed old Jensens & claims the coils that he uses are rated at more like 40W. No doubt using parts closer to the original will be closer to original W rating, just pointing out that one reconed Jensen may be rated differently to another... & may sound different too.

Which goes back to a point I made in a similar post that you need someone that has reconed a lot of speakers for a long time, knows what works with what, and what the results are. There is more to "restoring" a speaker. Usually you will want the magnet re-guassed and the cone broken in if the cone is replaced. Truthfully, local reconers seem to come and go and tend to do a half assed job IMH. That half assed job is good enough for many people, especially if it is a someone just wanting to fix something to sell. There are good reconers out there that you can ship to if you are not close. Weber was great. You have to do your homework. If someone does manage to fit a modern mylar voice coil in a vintage speaker it may increase the power handling capacity. What else did it do? Maybe nothing. Maybe a lot. You might ask? Theres a lot to consider.

[Sweetfinger]

If you've ever seen the instruction manual that came with old Fender amps, they warned you that turning up the amp would blow the speaker(s). They never expected that players would turn their amps way up until the sound DISTORTED! Voice coil technology is more advanced now- so even a close to vintage construction recone will still handle more power than a vintage speaker due to heat resistant glue, etc. In most cases, the old Fender amplifiers could deliver more power than the speakers were rated for so plan accordingly.

[slidincharlie (Carlo P)]

hmmm... I'll email the reconer (which is one of the most trusted here in Italy, btw) and ask details about the voice coil he used.
Thanks.