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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
smrex13
645 posts
 
I had a very similar issue. My Sphinx buzzed from the left speaker more loudly than the right, and when I turned the balance all the way to the left, the right speaker buzzed louder. I didn't keep the unit, and I've been hesitant to explore Rogue products since. To be fair, it was only one unit, but your experience gives me further pause.

Scott
big_katydid OP
50 posts
 
Smrex.

Interesting that you seemed to have ha a similar issue too. Did your unit hum also? Did you have Rogue inspect that unit?
lowrider57's avatar
lowrider57
5,417 posts
 
The hum coming from inside the amp is likely coming from the transformer. Noise or distortion on the AC line from light dimmers, small appliances, refrigerator can cause this. The only way to know in this case is to remove your amp from a shared AC line. Or it's possible that the factory transformer may be mounted in such a way that it produces noise; (a common occurrence). When playing your system, you don't hear the hum because the music is louder than the hum.

Transformer hum can not be heard thru the speakers. However, your balance control hum may be the same problem I experienced with my Perseus Magnum. After about a year of ownership, a hum developed thru the right speaker. When I panned the balance control left/right I could cause the hum to vary in volume.

I sent it to Rogue and it turned out to be a bad VC. It was replaced and no problems since then.
big_katydid OP
50 posts
 
Thanks to all for suggestions and information. I will try the amp at a friends house to see if that changes anything as the first step to finding the issue.
wolf_garcia
6,708 posts
 
I am a "humaphobe" and will not tolerate hum in hifi gear. I have 2 amps (tube and SS) plugged into a PS Audio Humbuster III (mostly for transformer hum in the SS amp...used rarely only for outdoor deck speakers), and my tube amp (Jolida jd502p) is extremely quiet anyway...you can stick your ear on the tweeter and barely detect it's on. Any issues remotely like the ones described here would drive me nuts, so my sympathies.
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