3a Power Handling

[Guest pbda]

I recently bought a Marantz 2385 receiver (vintage 1977) and plan to use it to power my 3as. The 2385 is rated at 185 wpc RMS @ 8 ohms (and somewhere north of 225 @ 4 ohms).

Question: in using a receiver with this power level have I overmatched my ~30 year old pair of 3as?

[ninohernes]

Not at all, as long as the receiver can provide clean, undistorded power.

[soundminded]

Congratulations on buying this outstanding receiver. It should be able to extract every last bit of performance AR3a has built into it.

[Guest Nigel]

You have about the right amount of power for the 3a speakers, depending on listening level and room absorbtion. A bit more power would not hurt .

The woofer will handle just about any amplifier, the tweeter will be damaged by clipping with lower powered amplifiers. Classic AR speakers were/are rarely damaged by too much power, but often damaged by insufficient power.

[tysontom]

>You have about the right amount of power for the 3a speakers,

>depending on listening level and room absorbtion. A bit more

>power would not hurt .

>

>The woofer will handle just about any amplifier, the tweeter

>will be damaged by clipping with lower powered amplifiers.

>Classic AR speakers were/are rarely damaged by too much power,

>but often damaged by insufficient power.

Nigel,

Well put, and that just about sums it up. I think the AR-3a can handle (without difficulty) short-term peaks of probably close to 400-500 watts, but it is usually the insufficiently powered amps that damage them. Of course, five or ten watts, long-term average power, at a single frequency is sure to burn out a tweeter voice coil. Playing synthesized or rock music with too much power can also cause problems, of course, because average-power ratings can get so high.

In my experience I've had several amps fail, but I have never burned out a driver in any AR speaker I've owned, and I am quite lucky because I tend to put big amplifiers behind anything I own. I think, too, that you can begin to sense when an AR speaker is being stressed and you know when to "let up." Because of these speaker's inherently low distortion and clean response, distortion rises quickly when you get close to the limit.

--Tom Tyson

[Steve F]

In 1973, my cousin bought a Phase Linear 400 amplifier to use with his 3a's. It was a terrific combination, and the big reserves of undistorted power really let the 3a's shine. The "Phase 4" and "Phase 7," as they were informally known in audiophile circles back then, were often paired with 3a's and LST's, with excellent results.

I'd exercise a little caution and a good deal of common sense about driving your 3a's too hard today, however. Remember, the adhesives, driver leads, and all the other delicate parts of your speakers are now more than 30-plus years old, and it's quite likely that they won't stand the same degree of abuse that they would have shrugged off in 1968 or 1973. With factory-original parts being tougher and tougher to come by, I'd be less likely to show off "what these babies can do" to my friends, and far more likely to treat them as the rare gems that they are.

Play them, enjoy them, but don't mistreat them.

Steve F.

[tysontom]

>In 1973, my cousin bought a Phase Linear 400 amplifier to use

>with his 3a's. It was a terrific combination, and the big

>reserves of undistorted power really let the 3a's shine. The

>"Phase 4" and "Phase 7," as they were informally known in

>audiophile circles back then, were often paired with 3a's and

>LST's, with excellent results.

>

>I'd exercise a little caution and a good deal of common sense

>about driving your 3a's too hard today, however. Remember, the

>adhesives, driver leads, and all the other delicate parts of

>your speakers are now more than 30-plus years old, and it's

>quite likely that they won't stand the same degree of abuse

>that they would have shrugged off in 1968 or 1973. With

>factory-original parts being tougher and tougher to come by,

>I'd be less likely to show off "what these babies can do" to

>my friends, and far more likely to treat them as the rare gems

>that they are.

>

>Play them, enjoy them, but don't mistreat them.

>

SteveF's reply is very appropriate, and I really forgot to mention that caution should certainly be exercized with speakers this old. For example, during Christmas in the 1960s, Acoustic Research placed two AR-3s up on the "roof" of the AR Music Room in Grand Central Terminal in New York. Christmas music was played continuously for days at high-acoustic levels to provide music for the terminal (at least in the main GCT lobby area), and to my knowledge no damage resulted to the AR-3s even though the amplifiers, Dynaco MKIIIs, were driven close to the limit the whole time. This could not be done today as these 40-year-old speakers just simply could not sustain this kind of power without something breaking or popping loose. The glues have become brittle, and the tinsel leads and connections and papers and so forth have changed through the years, and problems could result from too much power to these vintage speakers.

--Tom Tyson