You can operate 4-ohm speakers with an 8-ohm amplifier if you use caution and understand how impedance works. This is because two 8 ohm speakers in parallel makes the total load impedance 4 ohms. The actual output impedance of your amp, by design, is actually a tiny fraction of an ohm -- effectively a voltage source -- so don't have any concern about it being 'mismatched' for your speakers. You must be sure that each speaker is rated for the demand that it will be expected to dissipate. Yes an amplifier will get slightly warmer when driving a lower load at high volume levels but that is simple ohms law. This has to do with the inductive reactance nature of loudspeaker systems. You could continue this string for as many speakers that you have available, however, it may not be very practical.
When the current in the primary is driven to be discontinuous, you get inductive kickback from the leakage inductances in the form of a voltage spike. Hi Sheldon, You have discovered that connecting speakers in series does not work well when the speakers are of different impedance and you want the same power to each speaker. This in turn generates less heat since the amp isn't driven as hard. That is, both the phase angle and magnitude are presented. Sorry if I appear thick headed, I am sure my use of terminology may be confusing things. Higher efficiency does not necessarily mean it's a better speaker.
And the surge suppression of the Line Conditioner is related to voltage surges not current surges. They say the speakers are rated as 4 Ohm and the Marantz amp speaker outputs are 8-16 Ohm. I am sure its not ideal, but i doubt it will kill anything. Worse, if you have an intermittent contact in the path to the speaker, you will introduce transients that are sharper and hence cause higher voltages. When I connected up the new amp, I was really annoyed at the muddy sound produced. If your amp is not specified for 4 ohms some are 6 ohms or 8 ohms minimum , then you should consider wiring your two speakers in series.
You hire a tech to put them in and taking the easy way out, he wires them in parallel. Emphasis added to sort-of-important parts, but it's all worth a read. Tiamat, Actually, the phase of the current varies with frequency. Once they're set you should be good to go. If the amp could safely take 4 ohm speakers, then the manufacturer would certainly state this somewhere in the specification, because it is an additional selling point.
The protection circuitry may reset if there's no internal damage within the receiver. Base on your response, I guess it is quite likely that I damaged the 'old' amp as speaker wiring was traditional. And, it you want to protect you equipment, you will use a good power line conditioner that has a degree of reserver power. Likewise, speakers C and D make up a series network equal to 16ohms. That's easy enough, now we have back emf as the voice coil moves through the environmental magnetic field. Keep in mind that changing the total load impedance of an amplifier will increase or decrease the power output of the amplifier.
Lastly, only a foolish man leaves his equipment naked to the whims of the power lines. These speakers can be difficult to drive. An 8 ohm amplifier is called such because typically it performs very well with an eight ohm load attached to it. I didnt mean to suggest that anyone should run their amp outside the manufacturers specifications; I certainly dont, at least intentionally with my own gear. In real speaker systems, it's not uncommon to see impedances starting at 6 to 7 O, peaking at 20 to 100 O at woofer resonance back to 7 O after resonance and wondering up and down with rising freq as the next driver's impedance and the crossover's influence begin. Tube Amps: On the other hand, most tube amplifiers need a load to avoid transformer or tube socket damage. The 8ohm cab solution it will be more helpful if you have a powerful amp but you need to use a small cab for a small-medium gig, so you can just pick a any of the smaller cab out on the market now, like a 110, 112 or 210.
Anyway, my apologies to anyone else who somehow misinterpreted my post as an endorsement of running mismatched loads on tube amps. You are ignoring any examples of disasters related to it. Speaker A and B are each rated at 25 watts. To start viewing messages, select the forum that you want to visit from the selection below. We'll use the same example as before, but this time the speakers are wired in parallel. Thanks Tiamat and lhwidget for the interesting responses.
Nelson Pass's site is good for amp design also. It will be fun to learn and very helpful to prevent blowing up a set of speakers. Q: How do I connect a set of four ohm speakers safely to an eight ohm system? Because you can cite two examples of not damaging a tube amp from mismatched cabinets doesn't negate the designers' recommendation not to mismatch impedances. Changing speaker wire or inserting resistance in the line will not change the ratio as everything is still in series. Also, with woofers all drivers actually, but it is more pronounced in large drivers , the impedance increases at higher frequencies, reducing the impact of making small 1 to 5 O changes in the circuit. The 8ohms speaker will be asked to dissipate about 16 watts, while the 4ohm speaker will need to dissipate only 33 watts or so. But anyone could give me advice i would love to hear it as i would hate to see him fry a reciever he just bought.
If you string three 8 ohm speakers in series the net impedance will be 3X8 24 ohms. Its still fine, original trannies still at stock spec. The kind that make up 99% of commercial 8 ohm amplifiers. It's not real noticeable but I do notice it. That means he took the speaker wire pair + and - , went into the first speaker and then jumped from that speaker straight to the next speaker, then to the next and so on. May as well give an example speaker gain vs frequency plot I like Bode and evoke the maximum power transfer theorem while we're at it.