Speaker buzz from AC 30

[planet10]

If the 2 drivers are used together in the same box, they need to be the same sensitivity at least.

dave

 

[Galu]

If the 2 drivers are used together in the same box, they need to be the same sensitivity at least.

Some suggest that the complementary tones of mixed speakers outweighs any problem with unmatched sensitivity levels.

Celestion advises mixing together speakers with a sensitivity difference of no greater than 3dB. This minimises the likelihood of hearing significant differences in loudness, while obtaining the full benefit of each speaker's characteristics.

Sensitivity - What Does it Mean?

 

[JMFahey]

Rather than replace the blue alnico w the same, I was thinking of going w something a little less bright. I will still have the one blue. Any suggestions? This amp has a Brilliant, Normal, and EF86 circuit. Thanks in advance for all the help thus far.

Buy a Greenback.
It will mix and match very well with your Blue.
Not surprisingly, it´s "the other" speaker usually found in AC30.

Remember you will NOT find, say, V30 there, although they are the "premium" option in 4 x 12 "marshallish" cabinets, or G12H, G100, G12T75, etc. , and there´s a (sonic) reason for that.

 

[inboil]

Thank you all for the replies, and the sensitivity link. I think the Greenback will be a nice mix. More warmth to take the edge of the brightness.

 

[inboil]

So, here's something odd. These g12 Blue alnicos are rated @ 8 ohms each. They are wired in series, and I get a reading over 3.2 at each speaker. The leg out of the amp is marked 8 ohms or 15, and the speakers are connected to the 8. Remember, one is blown. I thought series wiring doubled the impedance? Until my replacement arrives, I am going to take the one speaker out, and run one speaker on the 8 ohm leg. Will there be an issue?
Thanks in advance. Pray for my poor country tomorrow.

 

[Galu]

Make sure the speakers are unplugged from the amp in order to get accurate DC resistance measurements (which are always less than the nominal impedance values - 8 ohm impedance may measure as 6 ohm DC resistance).

You did not supply photos as requested, so I have to assume you mean there is an 8 ohm output jack socket to which you intend to connect the single 8 ohm speaker.

If so, there will be no danger of damaging the amp.

And, yes, series wiring will double the impedance while parallel wiring will half the impedance.

 

[inboil]

Can't seem to load image. Puled speaker and one of the crescent-shaped mounting pads had come unglued and was resting on the cone. I think this is the culprit.

 

[Galu]

You mean the speaker gasket has come loose?

That would definitely explain the buzzing!

 

[Galu]

You must mean a speaker sealing gasket section like one of these - Yes?

I'm surprised it has taken you so long to demount the loudspeaker!

 

[inboil]

Yes. The gasket. I don't know why I couldn't find the proper nomenclature. My brain is fried from the election. I only had double stick tape but I was able to secure it in place until I can get some contact adhesive. I'm pretty sure this was it. Many thanks for the help. Very happy not to spend 300$.