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Post by millst on Jan 21, 2016 11:14:38 GMT -5
This is because once Dolby Digital came out and receivers went from 2 channels up to 5 then to 7 and even 9 the amps inside the receivers got skimpy. They had to. With only 120V of juice from the wall sockets in American homes - usually fuses blow at 15 amps - that's only 1800W for the entire power line - every outlet in an entire room usually. So how much power can a receiver consume? The old 150 wpc that was easily doable with a stereo receiver became impractical in a 7-channel receiver. So they skimped out on the amps. The design is that the powered subwoofer will do all the heavy lifting so the receiver amps do not have to. Music evolved to have tons of deep bass in it to accommodate iPads listeners with skimpy earbuds. That fit right into the design of modern HT systems where the sub produces all the bass. So the younger generation knows that subs produce the bass and trying to get bass from your fronts is as pointless as trying to get it from your tweeters on modern HT receivers. The music they listen to masks just how bad the amps SUCK in their systems. There are some problems here. Fuses are not a brick wall either. Circuits put out way more than 15 amps, just not continuously. Amps have capacitors to bridge gaps, too. Your speakers are pretty efficient. You only need 1 watt to get 90dB from a meter away. That's pretty loud. You definitely don't need 150 watts in your apartment. Given your situation, I find it highly unlikely that you are driving the Fusion amps to distortion. They should sound the same as your old receiver. Either the Fusion is misconfigured/damaged (as I already noted) or your old receiver is distorting the sound, but in a way you like (think how people prefer the distortion of tube amps). Let's say there is a hump at 200Hz. This could be simulated with the Fusion's parametric EQ. It would be difficult to match without some measurements, however. -tm |
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Post by B-613 Command on Jan 23, 2016 18:37:30 GMT -5
Good points.
I just watched a movie called Act of Valor which has a lot of blow em up shoot em up helicopter boats navy seals raising hell action flick - played some heavy action parts with and without sub and the difference in realism was pretty huge. The sub definitely helps for HT no doubt. It's probably the type of music I listen to but I can cut the sub off for music and not miss it.
I just bought a Krell Showcase 5 amp. It pumps 125/250 wpc into 8/4 ohms. That's more than enough power for me in my situation. I'll be able to test my theory soon enough. It gets here in next week maybe later thanks to winter storm Jonas. We'll see (hear) ....
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Post by B-613 Command on Jan 23, 2016 18:46:11 GMT -5
There are some problems here. Fuses are not a brick wall either. Circuits put out way more than 15 amps, just not continuously. Amps have capacitors to bridge gaps, too. Your speakers are pretty efficient. You only need 1 watt to get 90dB from a meter away. That's pretty loud. You definitely don't need 150 watts in your apartment. Given your situation, I find it highly unlikely that you are driving the Fusion amps to distortion. They should sound the same as your old receiver. Either the Fusion is misconfigured/damaged (as I already noted) or your old receiver is distorting the sound, but in a way you like (think how people prefer the distortion of tube amps). Let's say there is a hump at 200Hz. This could be simulated with the Fusion's parametric EQ. It would be difficult to match without some measurements, however. -tm I did not see this post when I made my last reply. I've considered the high possibility that my old JVC receiver is warming up the music in ways I like, I've tried to simulate the extra bass using the EQ on the Fusion and it is still not even close. The midrange clarity is so far apart I do not think an EQ can fix it. Let's see how the Krell amp sounds. I wanted the Krell Showcase setup but the pre-pro in that is too old for the $$$. The Fusion has modern codecs - same price - so as a pre-pro should be close to the Krell Showcase processor. Sure the Krell processor may have an advantage in sound quality over the Fusion but the modern codecs can more than make up for the difference (I hope at least). |
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Post by millst on Jan 23, 2016 19:30:51 GMT -5
The Fusion has a full parametric EQ that is much more capable than the bass/treble controls. I'd imagine you can dial it in, but it would take some effort and equipment (computer, calibrated MIC, cabling, etc.). If the amp works and you're happy, then that makes it easy.
-tm
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Post by B-613 Command on Feb 1, 2016 15:32:38 GMT -5
Got the Krell today. It sounds fabulous but there is a really loud hum coming from all the channels - especially the center channel. The hum is so loud I cannot even hear what i'm listening to - it's at least 100dB or so. I was aware of the fact that by using unbalanced connections I was opening myself up to the possibility of hum but this is ridiculous !!! Does anyone have any ideas on how to fix this  ? |
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Post by geebo on Feb 1, 2016 16:15:47 GMT -5
How can it sound fabulous with a 100dB hum? Just curious.
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Post by monkumonku on Feb 1, 2016 16:22:14 GMT -5
How can it sound fabulous with a 100dB hum? Just curious. Because it has a Krell label on it? |
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Post by geebo on Feb 1, 2016 16:24:38 GMT -5
How can it sound fabulous with a 100dB hum? Just curious. Because it has a Krell label on it? Oh... |
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Post by B-613 Command on Feb 1, 2016 20:52:12 GMT -5
Bad choice of words. What I meant was that as far as I can tell the signal is getting through - I hear voices loud and clear but with an annoying loud hum. Not sure if that has any significance to finding the problem - the fact that I do get audio - not just hum.
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Post by B-613 Command on Feb 1, 2016 21:21:27 GMT -5
I searched the internet on this subject and found some advice. The first step to debugging this was: I unplugged everything from the Krell amp except my speakers - no hum. When I reconnected the unbalanced RCA connectors the hum came back. Any one of the 3 unbalanced connectors created hum when connected to the Krell. I turned off and even unplugged the Emp Fusion 8100 and still got hum. I unplugged the RCA connectors from the Emo Fusion 8100 pre-outs and still got hum. It seems as if my connectors are acting like little antennas?
I'll have to look into this more tomorrow. Is it possible that cheap connectors could be causing this issue?
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Post by millst on Feb 2, 2016 9:57:11 GMT -5
Did you disconnect everything from the Fusion? I would start with anything cable TV (coax) related since it is a common culprit.
-tm
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Post by B-613 Command on Feb 3, 2016 23:59:50 GMT -5
I researched this problem further. Older Krell amps like this one use shorting pins in the balanced inputs whenever single-ended connections are used - they are removed whenever balanced connections are used. A common problem with Krell KAS and KAV and Showcase series amps is that the original owner of the amp uses balanced connections so they remove the shorting pins and effectively forget about them and lose them. Later on they sell the amp to someone like me who wants to use them for unbalanced connections and without the shorting pins in place they do suffer issues like the one i'm having.
There are quite many threads out there where someone bought a Krell amp and tried to use unbalanced connections with it and ended up with a humming sound like what i'm getting. They eventually learned about the shorting pins and once in place the hum went away.
I contacted Krell and bought a handful of these shorting pins. When they get here i'll put them where they belong and try again. I hope this will resolve the issue. Fingers crossed. I know .. use the force ...
I'm glad I found Emotiva for another reason. I just bought replacements for all of my interconnects. Emo cables are quite good for the money. I looked closely at my interconnects today and was sadly surprised. I do not know what I was smoking the day I first hooked up this amp but I used a component video cable as my unbalanced interconnect for the front and center channels. Not a brilliant idea. I was using a spare subwoofer cable for my coaxial digital audio connection.
If the shorting pins doesn't fix the humming issue i'll seriously look at getting the Krell Showcase processor and using balanced connections. I'll have to give up my Emo and with it DTS-HD MA on the BluRays i'm getting from NetFlix. I guess i'll downmix those to DTS-ES. Not going to worry about that yet.
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Post by B-613 Command on Feb 9, 2016 0:19:34 GMT -5
Got the shorting pins from Krell today. The hum is still there but it dropped from around 90 dB before to about 50 dB now. Still - if I disconnect all inputs from the Krell and turn it on there is no hum. If I make single-ended connections between the Emo and Krell amp and leave the Emo off and turn on the Krell there is no hum now (there was about 90 dB or more before it was loud enough to scare me). When I turn on the Emo i'm getting around 50 dB of constant hum that does not move up and down with the volume. It's just loud enough to be a nuisance but not loud enough to where I cannot get a good feel for how the Krell is going to sound.
The Krell does sound better than my old JVC receiver - no huge surprise there - but not as much as I had expected. It does sound fabulous. I'm not disappointed at all with the apparent sound quality of the Krell Showcase amp (assuming I can get rid of the hum somehow). The bass response of this Krell is fabulous. I'd say it's a tiny bit better than the old JVC and both of these are an order of magnitude above the Emp and any other receiver i've heard that was made this century. I guess my real surprise from this exercise is just how close my old JVC comes to the sound quality of the Krell. It's not far behind it. The night and day difference in sound quality is between the old JVC and the newer receivers. Not between the Krell and all receivers. What i'm saying is that if I constructed a sound quality scale with the Marantz receiver I bought and sent back last year (SR5009) being zero and this Krell Showcase being 10 - not saying these are the best and worst sounding devices on Earth just what's been in my Condo hooked up to my speakers- the Emo would rank 1 or 2 and my old JVC would be about an 8.
The difference is speed and sustained current. The Venere 3.0 speakers have good detail and imaging. An amp needs speed to make them sound right. There are plenty of good sounding speakers that would not sound so different between these receivers. The Venere 2.5 is one of them.
I have no experience with problems like the hum i'm getting now. I guess that's one of the problems with buying used gear. When it works you can get some good deals. But when things don't work the way you expected ...
Tomorrow i'm going to isolate where the hum is coming from. I'll start with the Emo and move backwards.
I'm a brand-loyal guy. Once I find a brand I like i'll stick with them until they give me a really good reason to move on to some other brand. I love my Sonus faber speakers and probably this Krell amp. I'm trying to love this Emotiva receiver as a pre-pro. I expect that I eventually will. I hope so because Emotiva is the only company that makes pre-pros with the features I want at a price i'm willing to pay.
I've always wanted to own a Ferrari. I probably never will. I've always wanted to own a Krell amp (I love bass). One more thing I can scratch off my To Do list of life. Woo Hoo
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Post by garbulky on Feb 9, 2016 0:52:48 GMT -5
I don't know about you but the hum would drive me crazy! Hey do this. Disconnect the Fusion except for one cable. Is the hum still there? There is a thing called an RCA ground isolator that may help your situation. It's quite cheap about $15. www.crutchfield.com/p_127SNI1/PAC-SNI-1.html?tp=61807&awkw=75640380625&awat=pla&awnw=g&awcr=47623509025&awdv=cBut before all that mess....Are both equipment connected directly to the wall? Because if not, either the power condiitoner, or another peice of equipment on your power strip may be contributing to it. Try plugging it in to the wall. Then use something like an iphone to power the amp. Remember to turn the iphone volume on the headphone out DOWN LOW so you don't start with it being way too loud. Try it at a completely different room and see if the hum still happens. Something tells me it has to do with an external source. If it's NOT an external source, then you have problems! Things that can cause hum Dimmer switches Laundry machines Dishwashers FLOURESCENT LIGHTS Fans. And for weird vague reasons: power conditioners, power strips. |
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Post by B-613 Command on Feb 9, 2016 9:21:37 GMT -5
Great info. Thanks.
I have like 5 or 6 things plugged into a surge protector on each side of my entertainment center that all feed into the same power line. I learned in a college dorm room in the 80s how to connect 20 things into one power outlet (something useful from all those years in college) Still doing it. I had not thought about that thing causing problems.
I agree with you - if this hum is not curable I think i'll go back to my old system and get even more annoyed when people ask me why don't I buy newer/better stuff.
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Post by B-613 Command on Feb 9, 2016 16:29:32 GMT -5
Ran tests today: unplugged everything from Emo except unbalanced connections to Krell amp - no hum connected optical connector from TiVo to Emo - no hum connected coaxial from BluRay to Emo - HUM removed coaxial - connected HDMI from TiVo to Emo - HUM any HDMI connection into Emo - whether from TiVo - from BluRay or just out to the TV - get HUM at this point I decided to unplug the speakers from the Krell amp and connected them to the Emo - got HUM removed unabalanced connectors to the Krell - no hum - even when Krell is powered OFF still get HUM if the unbalanced connections are connected to the Krell removed connectors from Krell - no hum I do not understand this at all. I can connect the speakers to the Krell - connect it unbalanced to the Emo and power them both up and get NO HUM as long as nothing is connected to the Emo but an optical input. Once I connect anything to the Emo I get HUM - even if the speakers are connected to the Emo and not the Krell whether the Krell is powered on or not. I can unplug the Krell and the hum goes away. The only thing I can think of to try is first to use cheater plugs on the Emo and/or the Krell and see if that solves the problem. I looked at the RCA filters they're designed to eliminate alternator noise from car audio systems. I guess it could work for a home audio system just the same? |
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Post by MusicHead on Feb 9, 2016 18:18:19 GMT -5
It seems some sort of ground loop between sources and the Emotiva. An optical input is intrinsically isolated, it does not share a physical ground path with anything, being optical.
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Post by millst on Feb 9, 2016 19:58:09 GMT -5
Are you truly isolating everything when testing? Or are you leaving everything plugged into your surge protector?
-tm
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Post by B-613 Command on Feb 10, 2016 23:52:56 GMT -5
I actually got the hum to go away today but how seems odd to me.
I powered everything up and got hum as expected. I unplugged all my sources one at a time expecting the hum to go away with one of them: tuning adapter, TiVo, TV then BluRay - hum still there - all 4 of those completely unplugged still get hum. But if I remove the HDMI connections between the sources and the Emo the hum goes away even if the sources are all plugged in.
I have a 3.1 system and a 5-channel amp so I figured I'll bi-amp the fronts - probably will not improve the sound much if any but why not - and can we please not go into a discussion about bi-amping and bi-wiring and true bi-amping and all that this is an election year we have enough ridiculous pointless distractions already - so I ran a test to see if I could bi-amp my fronts with this setup - I connected the pre-outs for the SBL/SBR channels to the unused channels 4 and 5 on the Krell and moved my front speaker wires over to those channels and activated front bi-wire on the Emo - I did get sound from my fronts - what I did NOT get was ... hum. NO HUM. Somehow the hum is isolated when using the SBL/SBR channels in the bi-amp configuration.
I moved the front speaker wires back to channels 1 and 2 on the Krell which have FL/FR signals feeding into them and I did get hum as expected. I listened very closely to my front speakers and the hum was coming entirely from the midrange. No hum from the tweeters. No hum from the woofers. The crossover points are 220 and 2.2k Hz on the Venere 3.0
So I connected the SBL/SBR output channels 4 and 5 to the HF connectors on my fronts and the FL/FR output channels 1 and 2 to the woofer LF connectors on my fronts with the bi-amping clamps removed. I'm now getting almost no hum at all. There is a very tiny amount of hum coming thru the top woofers - maybe 25 to 30 dB - it varies as stuff comes on or off in the house - that may be the best i'm going to get. As it is now the hum is only audible when the system is muted. Once I turn on anything at all - even listening to TV at a low volume - it's too low to be discernible. But there is a very tiny bit of hum still there and I imagine i'd have more but the crossovers in my fronts are filtering it out.
I should point this out - I tried a ground-breaker plug on everything one at a time first and using a ground-breaker plug on the Krell amp stops the hum completely. Not on anything else - just the Krell. I may re-implement that. I discovered the solution I just described above purely by accident later on - I wasn't even looking for another solution. But since I found it now i'm thinking I should avoid using a ground-breaking plug on the Krell if I can - I just have a bad feeling about that monster not being grounded properly. You could execute most house pets with that thing it's got some serious juice running through it. Leaving it un-grounded seems like a bad idea. Is it? I was feeling like if I can remove the hum and leave that beast grounded properly then that's the route I should take. Has anyone out there left an amp un-grounded for any amount of time? Is there any danger in that?
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Post by millst on Feb 11, 2016 0:25:18 GMT -5
If a device is designed to have a three-prong cord and you lift the ground, then you are at risk. That ground is meant to save you from harm if say the hot somehow gets connected to the chassis. That's why those cheater plugs always have a little screw for attaching a ground strap. I have no idea what the odds are, but I wouldn't risk it.
I vaguely recall some issues with the rear surround connectors on the Fusion. You could always consider calling Emotiva and see if they'll help you out with your hum.
-tm
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