Max speaker wattage?

[BudM1930]

HELLO
I have a Hi Fi system that includes two JBL speakers in excellent condition.
Unfortunately my Preamp and two Power Amplifiers have failed.
QUESTION: What is the MAX wattage my speakers can safely handle?
Current amplifiers (EICO Model HF35) were 130 watt consumption
with 35 watt output constant and 70 watt output peak.


Speaker #1 was purchased 10/ 1/1956 Model C34 B with D130 speaker
Speaker #2 was purchased 8/30/1958 Model C34 Korina with D130 speaker

Any suggestions for make and model for new equipment for preamp and Amplifiers
(or an integrated amplifier) would be most welcome.

Thank You
Bud M

[Chris Brown]

There won't be a simple answer to this question, as there are many variables. For one, each driver in the system has it's own power handling limitations. The D130 for example, can handle only 75watts, has less than one millimeter of Xmax, and a FS of 40Hz. If you are playing bass-heavy content, you will surpass the abilities of the woofer very quickly. If you are playing content with very little low-end however (or have a subwoofer and use the crossover with your speakers), I have no doubt that the speaker could safely handle considerably more power.

Also understand that there is nothing wrong with having amps that are considerably more powerful than what your speakers can handle. Your amp only puts out as much power as the volume control dictates, and weaker amps can still put out much more power than they are rated for - they simply do it while clipping, which is bad. Most speakers can also easily handle peaks far beyond the average max wattage that they are rated for.

[grumpy]

I think a better question is what power range would be useful?

One watt into those quite efficient speakers would likely be quite loud.

Accounting for likely musical peaks, etc... I expect you never got even
close to clipping those 35w amps. If using tube amps, you probably
had them on 16 ohm taps... if you went solid-state instead (unless
a McIntosh with autoformer), the rating on the amp for a nominal
8 ohms would need to be halved when using a 16 ohm speaker system.

I'm sure there are those with other opinions, but I'd think a nice 35-50w
tube amp would be a fun/vintage-like match.

[BudM1930]

I thought the 16 ohm for the D130 was established when I found a piece of literature in my file stating it was 16 ohm.

Did some searching of past posts in this JBL thread looking for more info on the D130. Was surprised by a posting dated 1/28/12 by claytushaywood entitled JBL D130 Impedance and cone question.

In that post, three responders replies would indicate that the D130’s prior to 1966 ( era of my two speakers) were really 8 ohms. If that is true, my amplifier wattage problem is resolved. Comments would be most welcome.

Thanks
BudM

[grumpy]

Impedance can be stated as 'nominal', minimum... or shown as a plot vs frequency such as



Which was claimed to be a D130 in a ported box, and would tend to support a 'nominal' 8-ohms as reasonable.
For a single speaker (no crossover), and solid state amp, the point is somewhat moot...
a 60w (into 8 ohms) amp should be plenty. If 85w floats your boat for whatever reason, it will not hurt anything
any more than overdriving the 60w amp would (e.g., turning the bass way up and expecting the system to
play subwoofer frequencies).

[BudM1930]

Thanks for the responses.
Can anyone confirm that the speakers are 8 ohm?
Is a spec available?

Regards
BUDM

[Mr. Widget]

Thanks for the responses.
Can anyone confirm that the speakers are 8 ohm?
Is a spec available?

Regards
BUDM

Since both of your speakers are from the late '50s they should be 16 ohm. The same drivers were made for decades and later versions had significantly higher power ratings due to improved glues and other changes. Also later versions were offered in 8 ohms.

Most speakers changed from 16 ohm to 8 or 4 ohms during the later '60s and into the '70s as solid state amplification became the norm and most solid state amplifiers handle these lower impedances better.


Widget

[BudM1930]

Thank you Grumpy

One final question.
I have a new multimeter. One setting is ohms. Searching the web I understand that I may be measuring DC ohms, and that AC ohms may be somewhat higher.

Made several tests on each unconnected speaker at their outside terminals. Left speaker (#2) was constantly at 9.3 ohms. Right speaker (#1) was constantly at 6.2 ohms.

This appears to indicate that both the speakers are 8 ohm, and not 16 ohms. Comments would be appreciated.

Thanks
BudM

[Mr. Widget]

A digital multimeter will typically only measure DC resistance. The DC resistance of a speaker is almost always significantly lower than the nominal impedance. A DC resistance measurement of 9 ohms is typical of a 16 ohm woofer, The 6.3 ohm woofer may very well be an 8 ohm woofer, in any case if you are not planning on adding tweeters and you're just going to run these woofers as they are, I really wouldn't worry about it. It just won't matter what the impedance is. You may need to adjust the channel balance between the two as the one with lower impedance will play louder at the same setting.


Widget

[BudM1930]

Thank you for the 16 ohm info.
I was ready to purchase a Yamaha integrated amplifier Model A-S301 having 60 watts/channel, but note that it states 6&8 ohm for the speakers.
The higher wattage Yamaha units A-S501 states 85 watts/channel for 6 &8 Ohm and
The A-S701 states 100 watts/channel for 6&8 ohms.

DO I need a higher wattage unit because I have 16 ohm speakers or do I need to find a new amplifier manufacturer that has a product that will handle the 16 ohm JBL speakers I have?
Thanks for your help
BudM

[BMWCCA]

Why not look inside your cabinets at the rear of the speakers and see what the JBL label says as to 16 or 8 ohm? I'd be likely to bet they're 16, but why not check?

Better question would be how do you know they're D130 if you haven't seen the backs already? And are they simply D130 or do they include a crossover on the back with maybe an 075 as a tweeter?

I've run my 16-ohm D130/075 JBLs for over 60 years starting with Pilot mono tube amp, then Kenwood receiver, then Fischer SA1000, but for the past 50-years I've run Crown amps rated 75 to 90 watts-per-channel, often playing them outside at fairly ridiculous volume levels with no issues.

When I "rescued" the first one from my Dad (he was giving it the Goodwill when he went stereo) I played it from the earphone jack of a tiny ChannelMaster transistor radio. Believe or not, it played very well!

Got any photos of your vintage JBLs you can share?

[BudM1930]

Hello again

My new amplifier has been installed.
It was a good choice.
Only issue is volume. Range on dial is from 7:00 to 4:00.
Above 10:00 sound is so loud you can not stand it.
So, I will need to watch the volume control carefully.
Everything else is above expectations.

Thanks to all that helped me through this need.
I will be enjoying my great JBL speakers for years to come.

Regards
BudM

[grumpy]

Glad you found something that will work and let you listen.

[JeffW]

Thank you for the 16 ohm info.
I was ready to purchase a Yamaha integrated amplifier Model A-S301 having 60 watts/channel, but note that it states 6&8 ohm for the speakers.
The higher wattage Yamaha units A-S501 states 85 watts/channel for 6 &8 Ohm and
The A-S701 states 100 watts/channel for 6&8 ohms.

DO I need a higher wattage unit because I have 16 ohm speakers or do I need to find a new amplifier manufacturer that has a product that will handle the 16 ohm JBL speakers I have?
Thanks for your help
BudM

Generally speaking, running higher impedance speakers is less of a strain on the amplifier than running lower impedance - your amp will be happier running into a 16 ohm load than it would be if it was a 4 ohm load.

[BudM1930]

Decision time:
Have decided to go with integrated amplifier model A-S301 by Yamaha.

1) Has slightly more power than my failed amplifiers
2) While connecting posts are not marked on my speakers I am assuming black wires are ground and colored wires are Positive. So on my speakers that would be left contact is ground and right contact is positive.
3) While it is still not clear if my two JBL D130 speakers are 8 or 16 ohm, and this amplifier’s max is 8 ohms - so I am going to assume the extra amplifier power is more than enough.
4) I am not planning to add any additional speakers at this time.

I will advise how it turns out after I get it all up and running.
Thanks to all for your comments and patience.

Regards
BudM