Is some "hiss" from the speakers normal? (1 Viewer)

[JohnKings]

I have a very low level hissing sound eminating from my speakers since I added an amplifier (Parasound 1205A) to my AVR-3802. It is a stable (doesn't get any louder when the volume is raised) white noise type of sound which can only be heard if you are within 1 foot or so of the speaker and only occurs when the amp and the 3802 are on. I am guessing this is the noise floor of my system.

Does this in any way distort the source material?

Thanks in advance for your input.

John

 

[Mike Sloan]

That seems a little excessive to me. I would check all my interconnects...and perhaps unplug one by one until hiss goes away. I had a similiar experience and it was a bad interconnect! Now if you said you had to put your ear 1/2" from the tweeter to hear something...ok...not a foot, however.

 

[John Royster]

what speakers do you have?

If you have klipsch that may be normal, but for other speakers you shouldn't have any hiss whatsoever.

 

[Salvador]

I got a 3802 and 20's and i also hear some hiss when i stick my ear to the 20's. The hiss level is relative to where the volume is in m 3802. So if its +15 then i could definately hear it from about 5 ft away. But i never go beyond -15 so the hiss doesn't bug me.

 

[Kevin C Brown]

I personally would say that hiss at, or less than 1 ft is acceptable. I assume that you can hear absolutely no hint of it at your listening position. Bottom line is, some speakers (high efficiency) and some amps are just more susceptible to this.

 

[James Bergeron]

Salvador, that sounds odd, 5+ feet and you hear hiss? I can crank my denon 4800 to +10db and not hear ANY hiss from about 1 foot away, I can hear hiss if I put my ears really close to the speakers, I have studio 40's. I'm not sure if the 4800 has that much better amps or not though.

 

[Henry_W]

With 3802 (and most power sources) you will hear a hiss within a foot and it will probably vary by source (CD,Tv,DVD,etc) and will be heard on most any speaker. The higher efficiency speakers will let you hear the hiss at a lower power.

As said earlier - this is no problem until it extends past the 1 foot range (and my experience has been that the hiss does increase in volume as you turn up the power). If you listen to high efficiency speakers at outrageously loud levels it may be obvious, however, if you have been doing this for any great length of time your hearing will deteriorate to the point you can't hear the hiss anyway ---problem solved

 

[Salvador]

Salvador, that sounds odd, 5+ feet and you hear hiss? I can crank my denon 4800 to +10db and not hear ANY hiss from about 1 foot away, I can hear hiss if I put my ears really close to the speakers, I have studio 40's. I'm not sure if the 4800 has that much better amps or not though.

It could be my soundcard. I'll try later to disconnect all the wires and see if i could still hear the hiss 5 feet away at +15db. But as i said, it's no biggie for me because the volume knob on my 3802 never goes past -15.

 

[Martin Rendall]

Bottom line: if you can't hear it from your listening position, then don't worry about it.

Hiss is normal. It's always there... just sometimes you can't hear it. It depends on a number of operating conditions, as well as the equipment used.

BTW: do you hear the hiss with just the amp on? If so, try disconnecting the cables to the amp (at the amp end). Still hear hiss? The next step is to short out the inputs, which you may not want to try. If it turns out that this hiss is NOT coming from the amp, you could always get 6dB inline attenuators for plugging between the amp and cables. This would lower your noise floor (by 6dB, obviously), which would probably put the noise as being audible up to 6 inches. You might lose some "sonics" doing this... but I've never noticed any degredation.

Martin.

 

[JohnKings]

I have a feeling this hiss has something to do with the gain placed on out going signals to the amp. I never really noticed any hiss at all when just using the 3802 for both processing and power, but with the amp there is some.

Does anyone have a 3802 connected to an amp? If so are you experiencing this?

By the way, in contradiction to my earlier statement, I have notice that the hiss does increase with volume.

Thanks to all for their help.

John

 

[John Royster]

Yes I have amps hooked up to a 3802.

No hiss with my ear at the tweeter. Try doing your experiment with a digital source to see if its coming from your source or the 3802 itself.

 

[JohnKings]

John:

What amp, speakers and interconnects do you have? If you turn the volume all the way up do you hear anything?

Thanks,

John

 

[John Royster]

amp is aragon 8008bb, speakers are martin logan, don't know about the cables. I'll have to try tonight turning it up to "11", err 15 I mean.

I don't particularily like turning the volume knob to that position as I fear if anything happened my panels would die an atrocious death and high voltage sparks would fill the room.

 

[Salvador]

Just tested it with the cables connected to my soundcard removed. I get the same result. Hiss when at +15 i can hear 5ft away.

Doesn't matter though. I'm not bothered by it. Just as long as it doesn't do it at -15 i'm happy.

 

[CurtisC]

I also have the 3802/1205a w/klipsch rf7.The Denon was dead quiet with its amps.The 1205a did introduce a very minor hiss at few inches, with vol.25%,no signal,this is perfectly normal.If anyone has rf7's with high power amps and no hiss period at a few inches from horn,for less than 2k,please sell it to me.This is not a trade off because the 1205a sounds much better at any volume,low to high,than the 3802's,which is a good pre/pro and runs the rears.I also tried balanced power supply and it lowered the noise floor to almost nothing,must save up for one.

 

[Jason Co]

John,
I have the exact same amp and receiver. The problem I had turned out to be a ground loop from my cable outlet. The feedback I received was that this was a typical occurence with the Parasound amp. I went to Rat Shack and bought a ground loop isolator and connected it from my amp to my receiver....problem solved.

Jason

 

[CurtisC]

If you have a ground loop this will be a hum in larger drivers.

 

[JohnKings]

John:

How did you connect the ground loop isolator? I have seen those things with the rca plugs which is what I believe you are talking about. Did you place it in line on one (or all) of the channels from the 3802 ot the 1205A? How do you have installed exactly?

Also, what level do you have the individual volume knobs on the Parasound set to? Are they at the max level.

Finally, are you getting any hiss at all when you turn up the volume on the receiver (with a source selected and that source powered on) or is it dead quiet?

Thanks alot,

John

 

[RayJK]

The best product to get rid of spurrius hiss that I have found if a balanced power box. Furman, Equitech and BPT make them among others.

 

[Chu Gai]

It's really unclear to me why varied results with respect to his occur when people go the route you did John. Nonetheless, it suggests an issue with the pre/pro-cable-amp combination. Chasing this down is not such an easy thing to do. If the ultimate reason is the amp itself, then you'd be SOL. However allow me to suggest a possible solution. If in some way the problem is due to the entire interface, then 'breaking' the ground between the amp and pre-pro will solve your problem and give you total silence instead of that noise. There are several products out there that'll achieve this. A relatively inexpensive one is available from an outfit called Ebtech. Basically what you'll be doing is running an RCA to XLR cable from your pre/pro to the Ebtech. Then another XLR to RCA cable from the Ebtech to the amp. The box itself I believe utilizes an inexpensive isolation device inside that breaks the ground. You can read more about the unit here. It's available at your local Guitar Center. Those stores are literally all over the country and they can hook you up with 3 boxes and the necessary cables probably for under $150. The actual price will be higher but Guitar Center dickers on price and has, at least to my experience, a no hassle return policy. If it doesn't work, they'll take the stuff back and no foul. For more information, look up the HTF member Philip Hamm as it seems to have solved a problem, different than your, for him.