2. amps-preamps
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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
djverne
77 posts
 
Had this amp, had this same problem, and returned it. The noise increases when you turn the volume up or down right?
big_katydid OP
50 posts
 
I have yet to purchase a replacement amplifier, for the time being I am using some pro equipment to run my speakers.

Jspively, apparently the original version sphinx does have this noise issue, some may not object but in comparison to say a NAD 365BEE that I auditioned it is very noisy, the NAD is almost dead quiet even with an ear to the speaker (at least with my ears). The sphinx does run very cool though which is a plus.

When I audition an amplifier now I check it for practicality first: noise, good use of the volume rotation (I hate sensitive designs that jump to full power almost immediately with loud CD's), heat.
big_katydid OP
50 posts
 
To go a bit further.

I did feel a bit burned with the noise issue on the amp, Rogue suggested it was a product of implementing valves and class D, unfortunately my dealer had a no return policy after home demonstrations, I did not notice it until the unit was purchased (I did not at that point check amps for noise on demo) I probably could have got a refund/exchange had I argued the noise issue but stayed with it as in practice during use it was not noticeable when sitting away from the speakers.

I accepted that amps will make some noise, until checking out the aforementioned NAD, it was easily the quietest amp i've (not) heard. My old naim nait 3 by comparison gives a slight audible hiss.

Hopefully sphinx V2 has fixed the hum/buzz and it is perhaps telling that V2 comes so very quickly after the release of the original model. I'm surprised such an obvious flew was not picked up prior to release of the original. It is disappointing as had the sphinx been quiet I would no doubt still own it.
andrewko
1 posts
 
anyone with V2 sphinx can give any input regarding the noise issue ?

thanks.
adriel
1 posts
 
Yes, Sphinx V2. It is not my main amplifier, but used on my computer workstation with Magnepan MMG that are 4 feet behind my desk. I can hear a hissing noise that is present all the time, and when increasing the volume knob the hissing noise takes on a higher frequency overtone. The tubes are new production, low noise and microphonics selected.

My previous class d on the workstation was a Peachtree Nova 220SE, which was quiet, but lacked emotional involvement, and with 33 months of usage the power input relay died so it cannot turn on.

My main system has Magnepan MG12 with two ampflification options. AES Sixpacs, or class d Channel Islands D200 with a Primaluna tube preamp. No hissing noise in either case there with class d and tubes, as they are separate chassis.

In every class d amplifier, I’ve always used adhesive ERS sheets on the interior of the chassis. As the adhesive version fullsheet is hard to find these days, I have not been able to apply it to the Sphinx V2 yet to see if it makes a difference.
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