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garthr2
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Electrical Noise in Solid State Amps

Greetings,

I recently aquired some Sennheiser HD-595 headphones, which are very nice indeed. These are highly efficient and require little power to sound great. Now, what I've discovered is when I plug them into my Harman 3480 (with no music playing,dead quiet room) , I hear an electrical zzzzzzz sound in the background(the zzzzzz sound does not get louder when the volume is turned up). This is not a ground loop humm , which is common. I suspect it is the power supply , and I'm hearing a wave in the current. I've tried other Sennheiser headphones also, same sound, so it's not the phones.

A friend has a Denon 395 receiver, which when plugged into does not exhibit this sound.

I'm auditioning a Marantz PM-7001 integrated amp this week, and the first thing I heard when I plugged headphones in was the same zzzzzz sound, but to a lesser degree than the Harman.

So, I wonder if this is common to solid state amps or am I just experiencing some defective or less than stellar amps here ?

If anyone has some decent sensitive headphones , when you plug them in(quiet room, no music playing)do you hear anything in the background , or is it dead quiet?

I'd appreciate any feedback about this. I'd like to know if this is common or should I be looking elsewhere for an amp. Harman had sent me a replacement for the 3480, yet it exhibited the same sound. So, 0 for 2 from them. They apologize and tell me I shouldn't experience this ..... hmmm..... what to think .

Thanks for reading, Garth

Amp_Nut
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Re: Electrical Noise in Solid State Amps

Headphones, when plugged into the appropriate outlet ( Headphone socket) should largely be Very quiet... atleast where the background noise is barely audible ( ie you would have to focus or strain to hear it )

Seems that something is not quite right.

Jan Vigne
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Re: Electrical Noise in Solid State Amps

Welcome to the world of highly efficient transducers. They do wonderful things with dynamics but can show off every wart in the system. I'm going to make some assumptions and they might not be accurate but at least it's a start. I assume the two HK's and the Marantz were all plugged into the same AC outlet in your house. I will also assume you took your headphones over to your friend's Denon. That would place the AC line feeding the various amplifiers on a different circuit with different noise potentials. I would intially look for commonalities and differences. Take your amplifier over to your friend's house or have him bring his amp to your house. Listen for the noise where it did or did not exist previously. If something changes, there's a good likelyhood it is due to the chhnge in AC service. If this is the case, you need to either move or get some filters on your AC lines.

That's where I would begin. Let me know what happens after you try this experiment.

garthr2
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Re: Electrical Noise in Solid State Amps

Thanks Jan for the suggestion ....... which I did this afternoon...... and it's the usual good news/bad news. The good news is I don't have to move ...... the not as bad news is the amps are less than stellar. The Marantz exhibits less of it, but if it's dead quiet when I plug in the 'phones ...... it is easy to notice. If you've ever been out walking on a quiet night and heard the power lines above you buzzing ..... there you go ...... that's what it sounds like.

So ..... from here more searching for a quiet amp . I'll give Harman one more try at it.

Thanks for the replies.

-Garth

Jan Vigne
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Re: Electrical Noise in Solid State Amps

I don't understand. Did you find noise from the AC lines at your friend's house also?

garthr2
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Re: Electrical Noise in Solid State Amps

Sorry ..... I wasn't so clear. The amps at my friends house has the same noise characteristics as they do at mine.

-Garth

Jan Vigne
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Re: Electrical Noise in Solid State Amps

That still wouldn't rule out AC line noise. Do either of you have your system plugged into an AC line filter with RFI and EMI filtration?

garthr2
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Re: Electrical Noise in Solid State Amps

No, no AC line filtering . Both are plugged into Belkin surge protectors. I've also tried various outlets with and without the surge protectors, and no difference.

ohfourohnine
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Re: Electrical Noise in Solid State Amps

I think the sad fact is that most headphone sockets in receivers don't involve the most pristine circuitry. They're just added extras. Have you tried those phones with a dedicated headphone amp or with any source, for that matter, and found that the annoying sound was eliminated? As I recall, those phones are fitted with a mini-plug as standard and require an adapter for the plug on your receiver. If I'm correct, you might take off the adapter and try them on an iPod. That should help clarify the issue.

garthr2
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Re: Electrical Noise in Solid State Amps

Clay, These HD-595's are one of the increasingly few that still put on the 1/4" plug. My CD player has a headphone output(also becoming increasingly rare) , and everything is blissfully dead quiet.

Yes, it seems too much to ask to make a quiet headphone on some amps. The funny thing is, my friends Denon DRA-295, is a rather dull amp to my ears, and inexpensive...... yet the headphone output was also quiet. So, it seems cost has nothing to do with quality here. The Marantz PM7001 was supposed to have an excellent headphone output..... well ...... supposed to . Can anyone build a clean, decent heaphone output in an amp? I'm sure someone does...... I' hoping

A NAD dealer told me the output of the C720BEE/C320BEE was excellent....... I hope it's not more heresay !! I'm not interested in a headphone amp either ..... that just means more connections and outputs and another amp....... I want to minimize my "stuff" gathering and keep it simple as possible....... if it is possible anymore

- Garth

Jan Vigne
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Re: Electrical Noise in Solid State Amps

Let me pursue this idea a bit farther before ruling out AC noise. You took your amp over to your friend's house and plugged it into the same outlet or surge protector with his Denon. Your amp still had the same amount of noise at his house as it did at yours? No change? I ask because even half the noise would still indicate an AC line problem. And, whether the noise was the same or not, I would still suggest you investigate a quality filter. This would go to the construction of the power supply and not necessarily a difference in line quality.

I wouldn't be at all surprised should the headphones exhibit no noise on an iPod since it is a battery driven device. A noise issue is typically due to noise on the AC that is not filtered by the power supply of the amplifier. If it comes in dirty, it can easily go out just as dirty. With a battery powered device lots of problems simply don't exist.

Should you try the NAD, you obviously want to listen in the shop. If it is quiet there and noisy at your home, that would still lead me back to AC line problems. While you're at the NAD dealer's, ask about a quality line filter with the above mentioned filter elements and ask if you can try that at home. It is possible the amp's are at fault, and headphone amps are notoriously poor quality, but most situations I've encountered with this sort of noise are generated by the incoming AC line. Sorry to be so stuck on one topic, but I do think this is where your answer will be found.

garthr2
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Re: Electrical Noise in Solid State Amps

The noise was the same level everywhere I tried. BTW....I plugged in my headphones to my Sony home CDP-397 player with a headphone output..... where everyhing has always been dead quiet. I don't own an ipod. So ..... plugged into the same outlet ..... the CD player is quiet .... the amps are not. If it was the line .... wouldn't the CD player make some noise also?

Hey ..... I don't mind the questions at all ....... that's how I learn things ...... it sure beats no inquires at all !

Jan Vigne
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Re: Electrical Noise in Solid State Amps

" ... wouldn't the CD player make some noise also?"

In a rather sweeping statement, no. No more than your CD player could drive your loudspeakers properly. The operations of the power supplies in each unit are similar in nature but quite dissimilar in purpose. Somewhat like trying the iPod suggestion but ... uh, different.

I hate to be dense, though it seems I'm finding myself in that predicament all too frequently in the last month or so, but what does this mean? "The noise was the same level everywhere I tried." Please tell me what exactly you've tried and where you've tried it. Also, when HK said this shouldn't occur, did they offer any suggestions?

garthr2
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Re: Electrical Noise in Solid State Amps

"The noise was the same level everywhere I tried." ...... means the zzzzzz sound was the the same decibel level no matter where I plugged it in. I tried different plugs, bed,bath,living rooms, the kitchen and basement. The same with my friends house. I also kindly borrowed his Denon ..... brought it over to my home ..... and it was still quiet..... I even went into my closet with the headphones on, plugging and unplugging them in via an extention headphone cord..... and dead quiet.

Harman told me I should not be hearing any noise through the headphone jack , and only offered to replace the unit, they do not diagnose or repair units per case. Marantz was as bad ...... the poor "so called" tech person did not even know what the PM7001 was ..... and told me "none of our techs have been trained on it yet." She searched her database about the unit, but could find nothing. It's sad you can't talk to someone who knows anything anymore with many many companies .... it's alot of phone jockies in front of computers.

Well, if it is the AC line ..... why does the Denon not make any noise and the others do even when plugged into my outlets ? It seems obvious, but maybe I'm overlooking something else.

I do appreciate your help !

Jeff Wong
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Re: Electrical Noise in Solid State Amps

I was thinking the noise could be from a dimmer switch, until you made it clear that your friend's amp did not exhibit the noise at your home. Is it the exact same model? I wonder if something isn't properly grounded in your amp, or you just have a bad transformer.

garthr2
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Re: Electrical Noise in Solid State Amps

My friend has a Denon DRA-295, mine are a Marantz PM7001 and Harman Kardon HK-3480. It's hard to quantify how loud they are in words of course ..... the 3480 being loud enough to hear in the background of quiet passages on a CD..... the Marantz is less prominent.

Jan Vigne
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Re: Electrical Noise in Solid State Amps

The problem is in the power supply and how it is rectified, filtered and regulated. Why the Denon has no problem here is something I don't know other than to tell you the power supply is probably laid out differently. Or, the headphone output may be taken from a different location in the amplifier on the Denon. Headphone outputs are seldom a priority in most amplifiers today. And part of the problem is the high efficiency of your headset. You have a design that falls outside the "normal" curve which designers count on.

I will offer a few suggestions and then I have to say you are pretty much on your own as far as my ability to help is concerned.

1) Try a decent AC line filter. I would suggest a Panamax product since they have done the best job for the least money when I've had this sort of problem with clients. A simple surge protector's filtration is not sophisticated enough to eliminate the amount of RFI and EMI you seem to have on your lines. For about $150 you should be able to get the best filtration of these two areas that Panamax has to offer. The unit should be available as an audition piece with a refund if it doesn't solve the problem.

2) If nothing else, try a ferrite ring on your AC cable just as it enters the amplifier. You can buy ferrite rings at Radio Shack for a few dollars and they simply clamp onto your AC cable.

3) Step down to a lower efficiency headset or trim the level of your outgoing signal to lower the level of the output. A small trim pot in line with the headphone output should do the trick there. I would start with a 100kOhm pot. Once again Radio Shack should have the parts required to do a simple volume control/trim pot in a project box with ins and outs attached to the box. Lower the level of the headphone output and then use your amplifier's volume control as you would normally.

4) Buy a decent headphone amplifier. Depending on cost, this should get you a power supply designed specifically for the small wattage amplifier required for headphones.

Good luck and keep me posted.

Jeff Wong
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Re: Electrical Noise in Solid State Amps

Ah, with the back and forth between you and Jan, I misread/misinterpreted something and got confused (perhaps due to the 2 Harmons.) For some reason, I got the impression you and your friend tested identical Denons after the Marantz and Harmon were exhibiting hum to try to eliminate a variable.

So, you've brought the Marantz and Harmon to your friend's place, and they still exhibit this noise... it seems odd that 2 of your amps are having the same problem. Was there an electrical problem at your place that might've cooked both pieces? A power surge or brownout?

garthr2
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Re: Electrical Noise in Solid State Amps

Jeff, No ..... no power problems this summer .... thankfully. The Marantz I just bought last week to audition..... so it was like that out of the box. I've also noticed a fair amount of signal bleed over , say I have my Dish Network reciever hooked up to the tuner or aux jack, and I switch over to aux/dvd ..... the signal bleeds over enough to hear it through the headphones also. I had a old Yamaha receiver that did that too.

Jan , Yes ..... these heaphones are so effecient it makes any abnormalities stand out like a sore thumb. They are really sweet though ..... and it took me many trials of headphones to decide on these ..... so changing them is not much of an option as of today. Probably the only ones that wouldn't be so efficient would be the HD-580/600/650 . I tried the HD-555,HD-280,HD-201 and RS-140's before these ...... and with all but the wireless RS-140 , the noise of the Harman came through. The wireless ones had their own problems.....the background sounding like your'e next to the ocean at all times !

Yes, a noise filter may still help .... I'll look into the ones you suggested . I also saw a little device called a "Noise Havester" from PS Audio. Have you heard of it or used it? In regards to Panamax ... is there a particular version you'd recommend ... something like the M8DBS-EX ?

Thanks again !

Jeff Wong
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Re: Electrical Noise in Solid State Amps

Maybe your dish network is the culprit. Quite often, satellite TV is linked to ground loop noise in audio systems.

http://www.epanorama.net/documents/groundloop/index.html

http://www.epanorama.net/documents/groundloop/example_systems.html

I haven't tried the Harvester yet, but, am curious. I use a number of PS Audio products in my main system.

garthr2
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Re: Electrical Noise in Solid State Amps

That would have been an idea , except the noise is heard more from the HK and less from the Marantz with nothing else plugged in but headphones(no inputs at all) ..... and again , the Denon made no noise with and without connecting any inputs.

Jan Vigne
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Re: Electrical Noise in Solid State Amps

I understand why you like the existing headset and offered the suggestion to change as a possibility not expecting you to take me up on that. But you still might try the trim pot. You won't loose any of the quality of the headset (no more at least than a volume control of any sorts inmposes on the signal) but it will place the signal farther above the quiescent noise floor. If the noise stays constant in level, which I believe you said it does, this pot will essentially lower the noise floor of the system. The headphones won't play quite as loud. But you should still be able to reach levels which could permanently damage your hearing. And, if you are playing the headset that loud, the AC noise won't be of any consequence.

I have no particular recommendation on the Panamax. Look at the specs for filtration and choose whichever model suits your budget. As to the PS Audio unit, I don't know anything other than what I read about it. I think someone in Stereophile liked its results but they didn't have your problem. As is typical with Paul McGowan lately, he has been rather closed lipped about what exactly his line conditioners actually do and how they do it. The ads and reviews read a bit like the old Tice clock. The more you own, the more the benefits. That approach to achieving results always makes me nervous. On the other hand, I have a passing familiarity with Paul and know he is an excellent engineer. I would contact PS Audio and ask a few questions before I laid down some cash for this item, if I was trying to solve your problem. I will give you my recommendation on the Panamax products since they have worked for me in the past. If you try the PS Auido unit, let us know what happens.

.

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Re: Electrical Noise in Solid State Amps

Jeff makes a great point. What you might have is a ground loop. Current might be leaking from the house ground to the dish ground, or vice versa. This would create a 60hz hum. The way to check to see if this is the culprit is to disconnect the coax cable from the sat. box. If the hum goes away this is your problem. But this hum would almost certainly occur through the speakers as well. So if no hum through the speakers means that this is most likely not the problem. Ground loops are more of a huuuummmm, than a zzzzzz. If you do have a ground loop you need a ground breaker. Mondial makes the "magic box" and Tributaries makes a similar product, I believe that these are around $100. Xantech makes a less expensive product but it reduces bandwith so much it creates problems with sat. and Digital cable for about $20 (Although it seems to work well with analog cable, other than the pictur quality loss.)

Jan Vigne
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Re: Electrical Noise in Solid State Amps

More than likely a decent line conditioner will solve this problem also. Most well designed units place all the plugs on a similar ground plane to help lower noise. What often happens though is a conditioner is plugged into a two wire AC distribution network in an older home. (In remodeled homes it's not uncommon to find a three pin plate covering up a two wire system.) The two conductor system has problems with ground and neutral being carried on the same conductor and the conditioner is far less effective at its job. This doesn't discount the possibility of cable or sometimes satellite TV causing problems due to a ground problem at the A/V inputs, but the problems are less with the AC conditioner if the video feed runs through the conditioner.

Another possible cause for the noise might be a reversed AC plug. If the amp is being fed a reversed signal you might find some additional noise on the line. You can check for this by removing the wall plate if you are very, very confident you know what you're doing. If not, don't mess with exposed wiring. Or, the better solution is to buy a line checker at Home Depot. I think they still run less than ten dollars and you can detect ground faults and miswired outlets by simply plugging the device into the outlet. For the dollars spent, this should be something everyone uses to check for miswired outlets before connecting your system together.

Have you tried listening to the amplifier with no source components plugged in? Just plug the unit into the AC line and listen for noise when no other components are connected.

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Re: Electrical Noise in Solid State Amps

I think you just have a couple of amps with crappy phone sections. Couple that with very efficient cans and you're hearing the circuitry flaws.

garthr2
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Re: Electrical Noise in Solid State Amps

By accident, I discovered a temporary solution to lower the 595's efficency. I have a headphone Y-splitter , which when combined with certain other headphones(I've got multiple real cheap ones from old walkmans) ..... makes them less efficient ..... so I need a little more volume to get the same level as before. This increases the difference between the music level and the base zzzzzz sound. Temporary ..... until I can get to root of all this.

The whole adventure here is like a perfect storm ...... combine highly efficent cans ..... amps of questionable quality ....... possible ac line noise ......and the fact that I don't listen to them very loud potentially makes a recipe for sour sounds

eagle
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Re: Electrical Noise in Solid State Amps

Another thing, if your a/c plug isn't keyed then you might lose the noise if you put the plug in the other way. Unless, of course, it's a three prong plug.

My pre-amp has a three prong plug, but my two amps have two prong without keying.

eagle
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Re: Electrical Noise in Solid State Amps


Quote:
Maybe your dish network is the culprit. Quite often, satellite TV is linked to ground loop noise in audio systems.

http://www.epanorama.net/documents/groundloop/index.html

http://www.epanorama.net/documents/groundloop/example_systems.html

I haven't tried the Harvester yet, but, am curious. I use a number of PS Audio products in my main system.

I have a problem like this when my tv is plugged into the preamp. There is a very loud hum. If I bypass the preamp and plug the tv into the subwoofer amp/xover there is no appreciable hum.The preamp has a three prong a/c plug but the sub amp and main amp are two prong.

A friend in the install business said it's probably a ground loop in the cable tv line. He suggested first grounding the cable splitter and if that doesn't work get an isolation xformer for the cable line in.

I haven't had a chance to try anything yet.

garthr2
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Outlaw RR2150 and a postscript

After a lengthy wait , I received an Outlaw RR2150 receiver. This is a very quiet amp, unlike the HK that sounded like a power sub-station from the moment you plugged it in and could be heard from feet away.I'm not talking about through the speakers, but from the amp by itself. The headphone output was very noisy also.

Best of all , the headphone output of the RR2150 is noise free and sounds excellent. The unit as a whole has really surpassed my expectations. I really didn't need a tuner, but it was worth a try, since I had been underwhelmed by Denon,HK,Yamaha,Marantz and NAD. Add to that there are few brands left that let you independently use 2 sets of speakers,and have tone controls ..... I was near the end of my choices.

So , in the end it was inferior electronics that was the culprit of the buzz in the background. I'm just glad to have it solved and can get back to listening in peace

Thanks for all the replies and suggestions.

-Garth

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