Is there a safe way to hook up JBL e20's (8ohm) to an 4 ohm amp? I know this amps sucks but bare with me, if the amp is 10watts per channel at 4ohms. Can I do this with the JBL's.
400dB could probably d...,
4000 isnt ev...
100,000dB FU...
Post Number: 139 Registered: Dec-06
Posted on
It's not going to hurt anything if you run a higher impedance speaker with an amp rated for lower power. In fact, it uses less power from the amplifier.
The time to be concerned is when you hook up low ohm speakers to an amp designed for higher amperage.
There is no such animal as a "four Ohm amp". Amplifiers are designed to drive a particular load impedance in order to be at their most efficient. If the amplifier is a transistor unit (it more than likely is), the amp would prefer to have an eight Ohm load on its outputs. Since speakers do not stay at a particular impedance and an eight Ohm "nominal", or average, speaker can, at any frequency, be higher or lower than its stated impedance the amplifier is typically designed to allow some lee-way in load impedance. How much lee-way is often a costly affair. Cheap amplifiers usually have little to no lee-way to speak of. Therefore, an amplifier that is meant to drive an eight Ohm load will become stressed when the speaker's impedance goes lower than eight Ohms. This stress becomes a problem of the load trying to draw more current from the amplifier than the amp is designed to allow. When this happens the amplifier first begins to heat up beyond its normal operating temperature. Eventually, if you don't remove the stress from the amplifier, the amplifier will go into thermal overload and stop - as in Blow Up!
Apparently the specification you are quoting indicates the amplifier produces very little power into an eight Ohm load and the manufacturer has quoted the higher four Ohm power rating to look better on paper. Amplifiers with this sort of specification do suck when you try to improve the system. Their distortion is typically very high and their ability to drive any speaker other than the units provided with the amplifier is minimal. A better speaker might, in this case, let you hear just how bad this amplifier really is. No doubt the amplifier will make sound with the JBL, but how well and for how long is questionable. If I were you, I would hold off on new speakers right now and put my money into a better amplifier.
"The time to be concerned is when you hook up low ohm speakers to an amp designed for higher amperage."
If I understand what you're inferring here, you are wrong. Lower impedance loads will draw more amperage from the amplifier while higher impedance loads prefer an amplifier that acts as a voltage source. Therefore, a low impedance load requires an amplifier that can produce substantial amounts of current/amperage over sufficient periods of time.
None of which alters the fact there are no "four Ohm amplifiers". There are amplifiers more capable of driving a low impedance load and there are also amplifiers which produce more "wattage" (see Ohm's law) into a lower impedance load (most solid state amplifiers can manage this feat for at least a short period of time).
There are, however, amplifiers that advertise their ability to drive low impedance, and do so with impunity. The paperwork with my Classe amp has a 2ohm rating(not going to try). Nad regularly states 4 ohm operation, as do a few others. They are also very heavy, hehe.
My speakers run down to 3.2 ohm, the amp is effortless. And hot. Of course, it is hot just sitting doing nothing.