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B&W Nautilus 802, JRDG 112


First let me say that I truly enjoy my 802s, that isn't my problem. My situation is this, I was playing Bali Run by Fourplay ( Warner Bros. 9 26656-2) through my Jeff Rowland 112, and to my disbelief, the amp clipped. (left channel) I couldn't believe it. I reset the amp, played the same piece at the same level and half way through it silence had fallen upon me once again. This time it was the right channel. My friend and I were jamming at the time with the music levels a little higher than your normal listening levels. The piece that was playing was full and lively with a bottom end that was full and robust. The 112 was warm to the touch, not hot at all so what gives. I really like the way the 112 sounds and hate to give it up. Do I need more power? Am I to believe that the 112 rated at 150 watts per channel @ 8ohms can't drive the 802s with demanding music at a volume that was on a scale of 1-10 a 6 or 7. Did anyone ever experience this with the 112?
dannyv
onhwy61's avatar
onhwy61
5,216 posts
 
Contact JRDG. A moderate amount of clipping should not cause the amp to shut down. I have a 112 and have not encountered this problem (driving Martin Logans).
mdorsam
58 posts
 
The JRDG should not have shut down. The N802 has a 3ohm load on the woofer, which should have allowed the JRDG plenty of power (I believe it doubles into 4 ohms), at this point, the N802 should not have pulled too much.

The Martin Logans (wonderful speakers) are probably much more difficult to drive than the N802s.
dannyv OP
21 posts
 

Well, I've spoken to a rep. at Jeff Rowland and his reply was that the "breakers are set very conservatively" to protect any speakers and the amplifier from harm. He further elaborated that I can send back the amp and have them install a larger circuit breaker to allow the amp the ability to provide the speakers the power it needs without setting off the breakers. I know that speakers don't use all the power from an amplifier all the time but my concern was whether this change in the breakers would cause any damage to my speakers. He assured me it would not. Does this sound right to you?
dan2112
144 posts
 
With regard to the 802's impedance it's a basically a 4 ohm speaker. I have measured mine and I think DB Keele did a review of the 802 in Audio where shows the impedance as well. Basically the speakers are a fairly demanding load between 60 and 500 Hz where it averages to about 4 ohms. At it's lowest it's just under 3 (about 2.7 ohms). So if you are playing material that has a lot of these frequencies you are essentially driving a 4 ohm speaker. The 802 demands current - lots of it. With that in mind I think 112 should be able to drive them. I have an Accuphase A-50V and it's drives them very well indeed.

- Dan
dannyv OP
21 posts
 

Just a follow up.

I did something that was totally my mistake. Due to my negligence to pay attention to detail.

It sounds amazing.

Dan
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