Speaker hiss with XPA-5

[darien87]

I didn't see it mentioned but what are you using for a processor? I definitely noticed a difference when I went from a Yamaha receiver to my UMC-1. I had a slight hiss with the Yamaha which went away when I got the UMC-1. I would think it's your source introducing the hiss, not the amp.

Edit: I see you're using a Marantz receiver. Try disconnecting the amp from the receiver and see if the hiss is still there.

 

[ski2xblack]

ADTG, I'm sure you're good to go. "Turb" just means "turrible" in the Charles Barclay idiom. Your audio reproduction limits are a lack of dedicated rooms for your outrageous (and awesome!) collection of speakers. Get crackin' on the mansion already!

 

[jp_over]

+1 My 1803 is silent even with my ear to the tweeter - of course, this may not be indicative of all the 1800 series.

Really?

My AT3005, AT3002, & AT2004 are absolutely dead silent with my ear pressed against the speakers and the Denon AVR master volume all the way up (w/o source playing).

I've heard from other members that the AT1800 & other models are also dead silent. But apparently not all cases then.

 

[AcuDefTechGuy]

+1 My 1803 is silent even with my ear to the tweeter - of course, this may not be indicative of all the 1800 series.

Yes, I've heard from many people that their AT600s, 1200s, 1800s, 2000s, and 3000s were all dead silent as well....but anyway.

I used to own the Emotiva MPS-2 and all the speakers had some hiss sound from them, but never THAT loud as to be heard from more than 3ft away.

I know the Crown XLS 2500 produces hiss if the ear is pressed against the speakers, but totally not audible from more than 12 inches away.

 

[slipperybidness]

I agree, it's a design flaw most consumer amps have. On my Velodyne sub they put input level controls on the single-ended inputs but not the balanced inputs, so my pre-amp causes an overload at levels necessary to drive the ATI amp, which is why I needed discrete attenuators. The sub is designed like the Emotiva to work with low signal levels (dumb, IMO, in a $5000 sub, but most of Velodyne's subs are very mainstream products). The high-end world got obsessed with removing potentiometers from the signal path, even switches, so we're all suffering from a trend started by a line of bogus minimalist thinking.

Absolutely correct on the bogus reasoning.

How many switches, knobs, pots, did the signal go through when it was being recorded and mastered? Do you really think that a couple more in the signal path at playback will be a drop in the bucket as compared to what the signal has already been through?

 

[Rblaster85]

Eliminated hiss from RS-52. Cheap RCA cable was the problem. Now the weird thing is my rear speakers are basically dead silent but the fronts and centers have a slight hiss and hum, cannot hear them from my seat so I guess its a moot point, but I wonder why the rears have nothing coming out and the fronts you can hear a hiss? I replaced the RCA I was using with a newer "Shielded" one but no dice.

What I figured out was the with no RCA cables connected to the amp the speakers hissed. But when I connected a crapy RCA cable I got HUM and hiss. Now with a good RCA cable its just silence .

 

[MidnightSensi2]

I agree, it's a design flaw most consumer amps have. On my Velodyne sub they put input level controls on the single-ended inputs but not the balanced inputs, so my pre-amp causes an overload at levels necessary to drive the ATI amp, which is why I needed discrete attenuators. The sub is designed like the Emotiva to work with low signal levels (dumb, IMO, in a $5000 sub, but most of Velodyne's subs are very mainstream products). The high-end world got obsessed with removing potentiometers from the signal path, even switches, so we're all suffering from a trend started by a line of bogus minimalist thinking.

Well, amplifiers are by design a fixed gain device. So, they have to make them have a gain that 'makes sense' for their intended application. The ATI sounds like it doesn't have a lot of gain (not bad or good, just depends on the intended application). For the Velodyne, no level controls on the balanced inputs is probably because of an expectation that in that price range someone will be using external bass management or multiple subs, where, it's easier to have all the sub levels set the same and then control the the levels instead from whatever is handling the bass management (or system dsp as a whole). It's not right or wrong, it's just a choice. Also, try using the UNBALANACED inputs...if Velodyne has set theirs up similar to other manufacturers, you won't need attentuators.

 

[Irvrobinson]

Well, amplifiers are by design a fixed gain device. So, they have to make them have a gain that 'makes sense' for their intended application. The ATI sounds like it doesn't have a lot of gain (not bad or good, just depends on the intended application). For the Velodyne, no level controls on the balanced inputs is probably because of an expectation that in that price range someone will be using external bass management or multiple subs, where, it's easier to have all the sub levels set the same and then control the the levels instead from whatever is handling the bass management (or system dsp as a whole). It's not right or wrong, it's just a choice. Also, try using the UNBALANACED inputs...if Velodyne has set theirs up similar to other manufacturers, you won't need attentuators.

Amplifiers are only fixed-gain devices if they don't have potentiometers in the signal path. Like I said, consumer amps often don't because of the irrational fear of switches and potentiometers in high-end audio circles.

While the Velodyne can work with bass management it has numerous features that are for systems without bass management. Obviously, since the Velodyne's single-ended inputs have level controls that would solve the problem without attenuators, but I'm using balanced cables from the pre-amp to the ATI, since they're about 40 feet long. It is simpler to use attenuators than to convert from balanced to single-ended at the amp.

There's no question in my mind, the Velodyne has a design flaw.

 

[MidnightSensi2]

Amplifiers are only fixed-gain devices if they don't have potentiometers in the signal path. Like I said, consumer amps often don't because of the irrational fear of switches and potentiometers in high-end audio circles.

While the Velodyne can work with bass management it has numerous features that are for systems without bass management. Obviously, since the Velodyne's single-ended inputs have level controls that would solve the problem without attenuators, but I'm using balanced cables from the pre-amp to the ATI, since they're about 40 feet long. It is simpler to use attenuators than to convert from balanced to single-ended at the amp.

There's no question in my mind, the Velodyne has a design flaw.

Well, the amplifier is fixed gain because lowering the input attenuator doesn't stop the amplifier from reaching full power. But I see what you mean.

Just making sure he had gain staged, as thats the most common hiss complaint. The cables were not a suggestion, lol.

Lol, yeah, not knocking attenuators.

I think Velodyne maybe used that +26 "standard" that was around a while (still is)....it usually works well with output leves of +10dBu (2.5Vrms and above).... that maybe the case?

Which one do you have?

 

[twylight]

OP - consider replacing cables with bluejeanscable and eliminating the cheap cable thing...monoprice RCAs are too cheap (had 3 pair fall apart on me) or DIY

I fixed a friends system with a bad RCA as well...in the middle of 30k rig that he was ready to throw in the trash over it...I do not think cables make a difference...but poorly built/damaged cables will drive you bonkers

Also if nothing is hooked to the amp (ie no receiver just amp and speakers) and you have some hum or hiss? That a bad sign in an amp with no ground connection (hum) might be a bad amp...hiss is probably normal consider you have a high sensitivity speaker hooked up to a high gain external amp and can be safely ignored

 

[PENG]

They probably did it because of weakling AVR pre-out driver circuits,

I have never experienced such AVR preout limitations, not even my ex Yamaha RX-V657. It is quite possible that some entry level models do have such issues but again, even the 657 did fine. I think in some cases people on forums such as this were confused by the not so good/clear specs published by AVR manufacturers. I remember reading about the 2V or less output specifed by quite a few AVRs but in fact those AVRs can output much more, it is like the power output, nominal impedance thing, no standard ways to specify so the consumers often end up comparing apples and oranges.

 

[slipperybidness]

OP - consider replacing cables with bluejeanscable and eliminating the cheap cable thing...monoprice RCAs are too cheap (had 3 pair fall apart on me) or DIY

I fixed a friends system with a bad RCA as well...in the middle of 30k rig that he was ready to throw in the trash over it...I do not think cables make a difference...but poorly built/damaged cables will drive you bonkers

Also if nothing is hooked to the amp (ie no receiver just amp and speakers) and you have some hum or hiss? That a bad sign in an amp with no ground connection (hum) might be a bad amp...hiss is probably normal consider you have a high sensitivity speaker hooked up to a high gain external amp and can be safely ignored

+1 to the Blue Jeans cables.

They are a little pricey. In the $ range of Monster (Nonster) Cables, but your $ is going to quality, not namebrand and marketing.

However, the quality is top notch, you know that you will never have a need to upgrade, the shielding is excellent, and that is an item that can be permanently marked off the list as "not the problem".