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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
big_katydid OP
24 posts
 
I think what is perplexing about the hum is just how asymmetric it is: turn the volume up and it rises (slightly) on the right, reduces on the left, if you then turn the balance to the left the hum becomes much louder on the right but unchanged at the left. The hum from the right speaker in that instance really is audible from several feet away but in practice I can think of no instance where I would listen to the left channel only.

Anyway something for potential sphinx buyers to test when they audition the model.
big_katydid OP
24 posts
 
further to my last post, I have a rega brio in the TV room and the noise consists only of typical 'hiss', noticeable through the tweeter, little deeper in the mid unit and barely perceptible in the bass unit.

If I turn up the volume knob to maximum (no signal) there is no change that I can detect in the level of hiss and to the nature of the sound, it really does demonstrate to me how noisy the sphinx is, unacceptable by comparison.
big_katydid OP
24 posts
 
Reynolds853.

the transformer hum you described in the perseus, did that give any noise through the speakers also? Or was it only the hum from the unit itself? I do wonder if my 'variable hum' is related to that which I hear from the unit.
donjr
1,311 posts
 
I have a Rogue Cronus Magnum and have had it for years. It's been a perfect amplifier. I've been in contact with Rogue several times with questions and their customer service has been excellent. Devil boy's comments are the first negative comments I've ever read about Rogue anywhere.
big_katydid OP
24 posts
 
I'll agree with Donjr, the customer service response is excellent.

Mark O'Brien did email me this morning. He suggests that the grounding for tubes and class D to be tricky and that in different environments there may be noise at the balance. He reckons that any sphinx in my set up would do the same. Perhaps its not ideal but as long as my unit is operating to spec then I can be assured that at least at future upgrade I can say it's working to spec.

On the topic of rogue I did also home demo the cronus magnum but I found it quite mushy sounding compared to the sphinx, maybe I'm not destined to be a full tube fan. I was actually surprised just how much softer the cronus was compared to the sphinx, still it made a street harp players recording sound incredibly seductive instead of biting.....and it made thinner or bright recordings much more manageable, but overall I prefer the more 'direct' sound of the sphinx.

I think being so used to SS that I'm used to the extra detail, plus im not sure I'm ready for hot 60lb metal and glass in my house!!
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