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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
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.
auxinput
2,920 posts
 
The attenuator will basically reduce the entire signal level (which does include the hiss).  The result is that you will have to turn up the volume control higher than normal on your preamp equipment to get the same amount of sound out.  As long as you are able to get enough loudness out of your speakers to make you happy, this is a great solution.
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.
auxinput
2,920 posts
 
In a lot of preamps, the "amount of gain" is fixed and is not really affected by the volume control.  The volume control is a potentiometer or a resistor ladder circuit that lowers the signal level.  The the signal is sent through a resistor circuit which drops the signal level again (this could be a large amount like 100 db).  The it gets sent through the "gain circuit" which re-amplifies the signal and provides current to drive the output to the amplifier.  On some preamps, there is a very large amount of gain in this analog circuit.  When you combine it with a very effecient speaker, you will get a lot of hiss.

It's weird that it would occur on your Focal speakers since they are a more conventional speaker, but maybe something is happening.  In any event, it looks like you have resolved the problem.
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