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How quiet is your Rogue Sphinx?

I have a new Rogue sphinx, I don't recall the unit I demoed to be especially noisy but I do find my unit to have some noise despite other owners describing the model as 'dead quiet'.

In both 'standby' and 'on' there is a quiet though audible hum coming from the right hand half of the unit (maybe I can hear it through the vent on the top). You need to put your ears pretty close to the unit though.

There is also a similar hum to be heard through the mid/bass unit, audible about 2 feet away. This is aside from the more common 'hiss' that is also present. Oddly if I turn my balance control left all the way, the hum becomes much louder through the right speaker only and can be heard about 10 feet away. If I turn the balance to the right the original hum in the left speaker actually decreases in volume!

I am used to speakers having a hiss but the question I ask is do any other sphinx owners notice this extra layer of hum/buzz that varies with the balance control in this way? Is your actual amplifier unit dead quiet or does it have a faint hum also?

Just trying to figure out if my unit operates typically or otherwise.

Thanks in advance.
big_katydid
bojack
652 posts
 
Yep, don't convince yourself the speaker hum is acceptable, as your pre should never have left the manufacturer exhibiting hum. Gear is just too expensive not to work perfectly, and that means no hum.
big_katydid OP
50 posts
 
I've emailed Rogue again and as both units demonstrated the various noise I have asked if they think this warrants a return, I guess the ball is in their court so to speak, there is plainly an audible hum and the odd unequal hum from the speakers, if that is enough to convince Rogue their is an issue then so be it and I could send the unit to be checked/repaired, part of me does think that maybe that is just the design of the unit, admittedly that's not optimal but I'm currently not willing to start playing around with retail returns over something that doesn't actually affect my listening, I do however understand how some would not find it acceptable, $1500 is not crazy money but you still expect a quiet unit, there are plenty of cheap amps that are silent.
lowrider57's avatar
lowrider57
5,417 posts
 
My final thoughts on the matter...the transformer hum seems to be in the design and it's not a deal breaker. You'll only hear it when the amp is idle and maybe not at all from your listening position.

However, no amp especially new and in spec should deliver hum thru the speakers. We know definitively that it is coming from the amp since you have repeated the problem when using the balance control. (I hope you have tested this by swapping cables).

I have read many threads regarding the Sphinx and nobody has ever mentioned hum and my suggestion is that instead of asking Rogue, you tell them you are sending it back for service. If you don't have the unit repaired, you will never in good faith be able to sell this amp if you decide to upgrade.
reynolds853
386 posts
 
Big_katydid,

I had a transformer hum issue with one of my M180 amps. I sent the amp back to Rogue and they replaced the transformer. After that the amp was fine for the entire time I had that system.

Rogue said too that they'd apparently had some bad transformers make it into some amps. Regardless of whether the other amp in the store was noisy, I'd send the unit to Rogue for inspection or repair.
big_katydid OP
50 posts
 
lowrider57/Reynolds853.

interesting that your two issues cover both of my units observations and both were repaired. (The testing was thorough, cables/speakers were switched, even different power cords used.

I'll see how Rogue responds next.

Thanks.
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