2. amps-preamps
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Hiss not Hum help

Hi all,

I have been on my "audiophile"  journey for several years and my main goal is to reach great instrumental separation and clear voice with a wide soundstage.

I mixed and matched many brands such as Anthem, Onkyo, Parasound, Emotiva, Furman, APC, Audioquest, Kimber Cable, Oppo, Ifi, and even DIY, and in general, liked the sound of the latest system, however, there is a hiss coming out of any tweeter, and overall for music is fine since I am 10 feet away from my front towers but If I turn on the Home theater the aggregation of all speaker makes the hiss unbearable.

My attempts to solve the "problem"  include replacing receivers and preamps like switching from Onkyo to Oppo network streamer and recently to Anthem AVM60, and also from RCA to XLR cables, which I used basic cheap RCA, to AudioQuest Red, Acoustic Research Master series, and currently Mogami Gold, cables and cable type made no difference.

On the power line, I started with a regular cyber power AC filter, moved to an APC H15 AC filter, then a Furman Elite PF15, and also tried an Emotiva CMX2 and an Ifi AC purifier, all of this made little to no difference.

Does anyone here experience similar hissing, and has any budget suggestions to attempt to solve this issue?

thanks for everyone's help.
badgod86

Showing 6 responses by badgod86

badgod86 OP
11 posts
 
I went ahead and ordered some ground isolators, transformer isolators, and also attenuators, let's see which one works best and I will post results here.
badgod86 OP
11 posts
 
what kind of attenuators any suggestions?
badgod86 OP
11 posts
 
I have two different outlets that are not connected, one has a Furman ac filter, the other has an APC H15.

From the Focal towers, it has KK PR8 cables, to Emotiva or Parasound Amplifiers, that are fed by the Furman, then Mogamy XLR to the Anthem AVM60 fed by the APC H15, on the Anthem I have CD player, Bluray player, Chromecast, and all that.

Changing the Amps, or the outlets does not help but I currently don't have multiple preamp and receivers available to test, but the hiss is noticeable only after a signal from the preamp is plugged into the amplifiers so either it comes from the wall or the preamplifier itself, but either I am super unlucky to get 3 or 4 different ones with some defect of something disturbs all the preamplifiers I had.
badgod86 OP
11 posts
 
I briefly tested today with a noise isolator and a 10db attenuator, and the 10db attenuator worked great, hiss is only audible a few inches from the tweeter, I am going to do additional testing to ensure sound quality was not degraded but I purchased a professional-grade microphone attenuator, it should be at least decent... will update further.
badgod86 OP
11 posts
 
@auxinput, yes I understand the point of attenuators, they attenuate the voltage/amplitude of the entire signal, but I tested this at 0DB and compensated on the preamp by setting the sound to be +10DB, yet it improved and that is why I will do additional testing tonight.

even if it lowers the overall top loudness I never went about -20DB if the sound is decent and hiss is inaudible at 1 foot away at 0DB, I will be happy at most levels.
badgod86 OP
11 posts
 
Hi all, just a quick update, I set my front speakers at +10DB on the preamp, and up to -10 DB on volume, the hiss is barely audible, for whatever reason, the preamp seems to be overdriving the amps, and the attenuator helped easy this connection.

After listening to music the whole afternoon I can say the problem got solved for now.

However, I will try to get "cable art"  and an Anthem service to confirm no other noise source can be removed.
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