quiet hiss in backround?

i have a quiet hissing from speakers when no music is playing and i am sure it is there when music is on but hard to hear. it drives me crazy! i always attributed it to normal noise from my amplifier but i wonder what you folks think? is it a power issue? the amp is a krell fpb600c, dedicated line, no power conditioning (a small quiet line by audio prism (parallel power line filter) is all. is this normal?
I do get a slight white noise from my speakers,but you have to put your ear to the tweeter to hear it..I would assume that is normal..But if yours is audible from more than a couple inches away from the tweeter something isn't right..Did you try removing the Audio Prism???
yes. i think it is a bit louder without it which seems to suggest power issue.
My system is dead quiet even when I press my ear to the speaker. I personally couldn't live with any noise at all. I did recently have an issue on an amp I bought and the manufacturer explained the difference between a hiss and a hum. He said a hum usually comes from a ground loop issue which is easy to diagnose by lifting the ground using a 3 to 2 adapter plug from the hardware store. He said a hiss is usually a gain issue from the amplifier and can often be user adjusted. If the amplifier gain is set very high it may hiss audibly. In the end my problem was an errant single ended/balanced switch at the amp input.
it does bother me. i would describe it as a hiss, not a hum so by your post it is a gain issue? i don't see how i could adjust gain on this amplifier...
No I can't say it's a gain issue definitively but it might be. Gain may be adjustable internally which is the case with mine. Call Krell and ask them if they have any insight and if the gain is adjustable and try it.

I would be asking myself a few additional questions: Has it always done this? Did my old equipment hiss? When did I first notice it? Did anything change that might have caused it? Is it definitely the amp (i.e. turn everything else off, try different cables, single ended, balanced, speakers, etc.- borrow them from a store or a friend)? If it is definitely the amp and it's not affected by cables or speakers then I'd be talking to Krell.
thanks mike. it has always done this and i remember a few years ago i discussed it with some guys who are much more knowledgeable than i (they worked in a high end shop here) they said it was normal. i sort of let it go but as i started thinking about it again, i figured this would be a good topic. almost certain it is the amp as i have had different cables on both and it has always been there. i do think it is worth an email to krell.
If that is the case another amp may be in the cards for you.
not on my current budget! the flip side mike, my stuff really sounds outstanding. it really troubles me that i often want better because it truly is amazing what my setup will do. i recently dove into sacd and it showed me once more how it will perform if fed properly. just special and gives me much gratitude...

thanks again for jumping in my thread and helping out.
You bet. One final note I don't think you have to spend more and may not even have to change from Krell. Contact them I bet they'll be able to help. If not there are other manufacturers out there that may solve your issue w/o increasing your costs or compromising quality.

BTW I agree with your SACD comments. A good SACD can be incredible.
thanks mike.

surprised no one else has experienced this or knows what it may be...?
Me too. However there are probably 1-2 hiss/hum questions a day so maybe everyone is burnt out. You could try re-posting with a more grabbing title. Put Krell in the question and pose the title as a challenge. Like "My Krell hisses, help diagnose & suggest silent comparable amps". That will get a big group of people reading it.
true and kind of funny! people here love to hate on krell. not sure why that is although i suspect it is the size of the company and how long they have been around. time tends to bring out haters....they also love to hate on wilson and funny how i ended up with both!
mike i also have no intention of replacing it. i love the sound of it and would live with the subtle hiss before i moved to another amp. i do hate the size and weight and hope to never pick it up again.
It's easier to hate than love. Anything SS will immediately garner haters from tube lovers, and Krell seems to embody everything they hate about SS. I think that's because it is so SS. Krell just doesn't make any effort to take the edge off and appeal to people in the middle like Ayre, Rowland, Levinson. etc. They simply don't care and instead are intent on exploring what SS can do and do well.

Wilson garners hate because they are expensive, well known, popular, and specifically engineered to sound good at the expense of what some people feel is a sacrifice in realism. Did you ever hear anyone in High school refer to the hottest girl like this: "She's hot, but .....". That's because they're jealous and they know she won't go out with them, so they make themselves feel better by bringing her down.

For me I see the merits of it all. Tubes and SS both do different things well. It doesn't mean one has to be better than the other. Speakers are the same. Wilsons do sound good. So do others and they're all different.

I bought a high quality dolly, and some furniture dollies so I don't have to pick stuff up. That way I can keep trying different things though I do admit to leaning to smaller pieces when given the opportunity. I don't want to find that forever piece because I'm having too much fun. I do admit to being slightly jealous when I find someone who has. :)
although i say i wouldn't replace it...part is love but part is money and apathy as well. over time, it rises and falls in the scope of priority and we get those moments where we realize it all sounds good and we are just playing like kids in a sandbox. if i was making as much money as i had been 5 or 6 years ago i may be hanging out at the shops a bit more and taking it more seriously but, as many others have, i am simplifying life a bit and unfortunately the hobby was impacted. i suppose that is what led to some of the realization that it does sound amazing so just enjoy the music! there are also very few places to listen here (2) and they have not carried a wide variety of interesting manufacturers. for example, i have never listened to rowland although i always wanted too. all i have read is rave and they are beautiful pieces. ariels also. your stuff looks great and i assume sounds great but i have never listened. of all that i have heard and a change i do think about, i still have a lust for the revel salon's, yet another well known speaker!

i have a dolly also but my amp is hanging from my ceiling on a commercial hvac rack so it would be a chore to get it down. most on here would probably crucify me for the way it is configured but it sounds no different from when it was on an amp stand in my living room. i think you could put an amp of that size anywhere and it would sound the same. never understood that part of the obsession.
I can understand your reluctance. It is a pain. The Salons are great. I also think you should have a quiet amp. That kind of thing drives me nuts!

As for limited retail outlets I've all but quit looking at stuff in stores anyway. You lose 50% from retail to used so just buy used smartly, try it for a while, and move it on. It's funny but I wish I'd had $100,000 (or more for that matter) in used audio gear in 2008. Then it wouldn't have lost 40% of it value.

BTW if you ever want a non biased opinion on something you're thinking of trying feel free to email. I've not heard as much as some, but I have heard a lot.
i agree re used stuff. most of mine was purchased on here but i did know the guys really well at one shop so we used to play around with stuff quite a bit.

so what would you do to maximize what i have (value) and get some better sound...don't include the hiss in your assessment! one thing i have considered is selling the watch center and surrounds as i think i could pull some $ to use for improvement and replace with something that would fill nicely for less. i know some updates, change would improve but i suppose i am a bit scared to start playing with it...

wish i would have used this forum years ago. it is amazing how good people like yourself are so quick to help. gives me hope for the human race!
Well for starters I think 2 channel is the place to focus your attention if you are looking for great music reproduction. I keep my 2 channel and home theater separate. For HT I have a nice system comprised of Denon and B&W for home theater. Probably totaling about the cost of just your center channel speaker.

The WP7's are terrific speakers. If you like the Wilson sound then there's no need to change that but I know you are tempted by Revel. The Salon 2's would be a stright across move for you cost wise. Since I know you like the Krell sound I think you'll like the Salons better than the WP7's. More refined and detailed, less balance and overall smoothness.

As for combination if you keep the WP7's, which is what I recommend, I definitely think you should consider other options. The Krell is not the first amp I'd suggest for WP7's. The nice thing is the WP7's work well with lots of components. I figure your Krell is worth $5000-$6000 or so used.

I personally think the WP7's would mate the best with tubes. Lamm is supposed to be an out of this world match, and I suspect BAT would be great too. There is an interesting snippet from the latest CES about a BAT VK55se amp and WP8's that Dave Wilson thought was as good as anything else he's heard http://blog.stereophile.com/ces2009/ . I also think Wilson uses Audio Research to voice their speakers so that's an obvious choice. Depending on the $ you spent you could get a Wilson sub or keep the Thiel to augment any drop off in bass response you suffer.

Figuring you prefer SS over tubes the WP7's just don't need that big burly amplifier you've got. In fact I suspect you're over-driving them. Pass would be my best suggestion. You could get a 250.5 for less $, 350.5 for the same, or a 600.5 monos for $9-$10k or so. As for Rowland I prefer the 300 series stuff. The 201 monos and 501 monos are good and rediculously small but can seem a bit dry. I'd look for a 312 or 302 but they'll both run $8000-$9500. They won't break your back though. Mine is like 65 lbs.
Also there is another member Dave_b: http://forum.audiogon.com/cgi-bin/fr_memb.pl?vevol&1169177163&memb&zzDave_b that is a frequent forum contributor. He has a Krell 400 amp and Sophias. He might be a good person to search out to ask about your background hiss.
I contacted a close friend who used to have the WP7's (I've only listened to WP8's in person). He said the Audio Research Ref 210 was head and shoulders the best combination he ever found for his WP7's. And he is someone who has literally tried everything.
just lost a long response...i hate that...anyway...

that is great stuff, appreciate your thoughts allot! the comments on the bat amp are very strong and i have heard good things about them previously. i have never owned tubes and know little about them to be honest so i have some reading to do. it would also be a smooth change $ wise as well. i have heard some of the audio research stuff but it has been many years. i do remember liking them and found them to be quite warm and detailed but also carried a nice punch. they are a bit more money then the bat but i think a fine suggestion. i really would like to avoid using a sub for 2 channel. i have played around with it and come to the conclusion it really works best with 2. it would be interesting to see how much of a bass dropoff i would have without the krell. you really think it is overdriving them? never heard that before.
i will need to do some figuring on how i could roll my watch center/surrounds into a complete theater but i have actually been looking at that anyway (new blu-ray interest, new panel technology...a long story, another obsession...)
wheels are spinning now....
I know the feeling.

Sorry about that!

Audio Research 110 would be a great match and unbeatable at the $'s.

Yes I do think the Krell is a terrible match. Krell would be great with Revels, not Wilson.

Go for it! You won't be dissapointed.
mike i am going to lose my audiogon privileges for asking these questions...i am really not an audiophile, i just love music and great sound. i know some but not much compared to allot of the guys on here...

how much different are tube amps? do they have the same ability i am used to as far as soundstage (it is huge and i suspect allot is the krell), depth, power etc? are they more delicate? how long do tubes last? are you constantly looking for better tubes or do you just use what comes with the amp? am i going to be banned for asking these ?'s?
On those speakers they'll do more than the Krell. They won't be as highly resolving as you're used to. That is what Krell does well. Soundstage should be just as good if not better.

Tubes last a while but if you leave the amp on all the time they'll wear out. You'll probably want an amp that is self biasing which means balance the voltage at the tubes and some track use time. Every once in a while a tube will go out so you might want a good tube tester and a few extras around. I would guess every other year you'll need to change them all out which is nothing more than screwing out the old ones and screwing in the new ones. Yes they require more work than SS but it's not a lot.
Every once in a while a tube will go out so you might want a good tube tester and a few extras around. I would guess every other year you'll need to change them all out which is nothing more than screwing out the old ones and screwing in the new ones. Yes they require more work than SS but it's not a lot.


My tubes have pins - they aren't threaded.
Thanks for the correction Macrojack. I'm SS these days.

The idea is it's fairly simple. Perhaps you could comment on your experiences?
Sure Mike,

Not much to tell. I have a pair of Audio Mirror 20 watt mono tube amps. They are self-biasing, SET amps and use a quad of output tubes every 2000 hours.

I'm using one of the better horn speakers on the market so my choice of amplifier is somewhat critical, or it would be if I was. Anymore I just turn it on and listen. By the way, I can hear a faint hiss sound in the background even when the preamp is muted. It sounds a little like the rushing sound you hear by holding a seashell up to your ear. Apparently the dbx Drive Rack PA that I use as a crossover/EQ/RTA is meant for pro amps and needs to be stepped down a bit for use with home audio. The tech advisor at dbx suggested Ebtech Line Limiters as a solution. Maybe your preamp is not an ideal match for your amp, Richard.

If you can get $6000 to $7000 for that amp, do it now. There are very satidfactory sounding products available for a fraction of that money. Same goes for the WPs.
thanks macrojack. i'm sure there are better sounding for less but as we were discussing, not sure what direction to go. miss the days of getting stuff to demo, this can be somewhat of a gamble. the more i read, the audio research 110 sounds like a fantastic match though. i do think it would be tough to replace the wp7's and be satisfied at a fraction.
the sound you describe is the same as my hiss. i have to lean toward the watt to hear it but i know it's there. just like the sound of a sea shell.
I have a suggestion that won't cost you anything more than minimal shipping.

Audition a pair of NuForce Ref9V2 SE amplifiers. They are the quietest amps I have ever heard. You can return them for a refund, less shipping.

If you still have a hiss, then you'll know the problem is elsewhere.
thanks tvad. that amp has won just about every award there is. interesting company and one that i think is going to do very very well. never heard the amp but would like too. quite a value.
Not a suggestion to replace your amp. Just a suggestion to put the amp in your system as a tool to troubleshoot for hiss, as I know it's quiet.
actually, no need to change the amps...if i put my ear to the rear tweeter, i get the same sound just faint. the description earlier in the thread is best, like putting your ear to a sea shell. i am beginning to think it is normal or some sort of power sound in my house. now i am just curious about how much different the 3250 would sound as 2 chan so i am going to switch them anyway. this could push me to let go of the big krell if i get the same punch from a smaller amp...
It's normal.
wish i was.
I have no white noise at all, are you running the loudspeaker cables over the power cables by accident? Otherwise start by disconnecting all devices and reconnecting them one by one
here is the response from krell (2 days later)...

Through Watts it doesn’t surprise me to hear some background hiss through the tweeter. It is normal unless it is excessive..

so i guess it is normal! thanks for all your thoughts.

i did switch my amps today not just for trouble shooting, i really wanted to hear how the 3250 sounded alone anyway. it really reinforced how much control the fpb600c has, most notably in the mid and low bass as well as presenting a ton of air between instruments. actually very disappointed in the sound of the smaller (which really is not small) amp. a $6000 amp should sound much better in my opinion. the flip side, the big amp is a stellar old amp (not that old)...


after doing some reading in old threads re hiss, i went through and shut down one at a time and it seems the theta is the root. when powered off, the hiss is reduced and the only remaining noise is a very, very faint noise, more buzz than what i had, at the tweeter audible from about 4", significantly less. now i am thinking about shorting plugs on the theta unused inputs as a possible solution.