What Amp specs do I need?

Question

Hi,
I have come into ownership of 2x Jamo D-130 speakers (anyone know them? They have 3 speakers, crossover circuit & rear port on each unit), the casing is pretty rotten but the electrics & speakers are sound, so I will be building new enclosures with dimensions & speaker siting to match the original.
I'm stumped however on what matching Amp I need; the only spec info on the Jamo speakers I can find is off a label from the back of the speakers; Rated Power = 80W, Music Power = 130W, IEC = 35W, Impedance = 4 - 8 Ohms.
When looking at Amps they all quote output in Watts RMS, ie one I've been looking at = 60W RMS, but I don't know how to equate that to the specs off the speaker label.
Is IEC the same as RMS, if so would 60W RMS be oK to match with 2x 35W IEC?
Any help?

Answer 1

Hi.The important match for amplifiers and speakers is their impedance.Ideally, the Amplifier's output impedance should be as close as possible to the speakers nominal input impedance.The term "nominal" means average, because the speaker's impedance varies with its frequency range.A variation as wide as 3 to 40 ohms is possible.The amount of variation,in addition to how low or high the range,determines how difficult the speaker is to drive .The Amplifier must be able to deal with these impedance variations,producing the amount of power necessary to drive the speaker at any frequency. If the Amplifier is not capable of dealing with the impedance swings,audible distortion occurs.

The IEC power rating is the continuous rating of the speaker and the only true meaningful power rating. So if the speakers are 35 watts/channel continuous,then ,ideally the Amplifier should have about twice the power that the speaker can handel.So 70 watts continuous(or rms) per channel will be satisfactory for the speakers.It is always better to have more power than the speakers can handel so the amplifier does not run out of steam. Distortion from a low powered Amplifier is more likely to cause damage to the speaker and amp. than distortion from too much current.Just be careful with the volume control. Most good speakers can handle a bit more power than they should.

EDIT.....I looked at the Jamo Speaker Products link.and could not find any speaker with D-130 .even in the discontinued section.The only Speaker designated D130 belongs to JBL. Very strange.!!!

Answer 2

Based on your description of your speakers (ported enclosure) these are probably efficient (high sensitivity) speakers that do not require a lot of amplifier power. Your 60W amplifier is probably more than adequate. You do not have to match the power ratings, but you don't want the amp to put out more power than the speaker can handle. A 60W amp is a good match for speakers rated at 80W. (The speaker wattage is a maximum capability rating.)

4 - 8 ohms is a wide range for speaker impedance; make sure your amp can handle a 4-ohm load.