Marantz PM6006 DAC noise using TosLink / digital / optical

[hybridauth_Facebook_10210916369251950]

Hello,

I've just bought a Marantz PM6006 integrated amp and a pair of B&W 685 s2. Today, I noticed there is a buzzing noise when using the optical connections (to my computer). Here's the situation:

1. This buzzing noise is exactly like that emitted by fluorescent lights. It's not the white noise you hear when the volume is cranked all the way up. It does sound like ground loop [the track on Wikipedia: https://en.wikipedia.org/wiki/Ground_loop_(electricity)].

2. This noise is present only when using the optical connection with my computer on (after the driver loads). It's all fine using analogue inputs.

3. The noise is barely noticeable with the speakers until the volume is over 2/3 and silent. However, it's quite noticeable across most of the volume range when using closed headphones.

At the moment I live on the campus of a school and know no one else with a device with Toslink connections. I bought the set online but they have a store about 90 minutes' drive away, so if I really can't determine whether it's the DAC I could visit them and have them test my amp out. So here I hope to get some help / information on related issues:

a. Is this a 'ground loop'? I tried to plug the amp to a different socket but that changed nothing. I connected the <Signal GND> on the back to the heater in my room, and that changed nothing.

b. Since the noise is here only when the DAC is on, is the DAC somewhat faulty?

c. Can I rule out the Toslink cable?

d. Can it be my computer? In other words, can the source of the optical signal introduce the buzzing noise?

I got this amp with an integrated DAC because I wanted to hook it up to the computer. I'm not looking for extreme HiFi experience. If I can get rid of the buzzing it'd be great.

Thank you very much!

 

[davedotco]

Given the usual caveats that I have not seen or heard your setup, the obvious answer is that it is noise from your computer getting onto the SPDIF data stream.

It seems unusually severe but such noise is not unusual, particularly with headphones and is one of the reasons a usb connection is preferred by many.

As a student, surely you have people around with other brands and types of PC, not all will have Toslink out, but surely some will. can you try one?

I am assuming you have a laptop, though if it is a desktop, a change of soundcard might well help.

As I feel it is more likely to be the computer rather than the amp, a relatively inexpensive solution would be a cheap usb dac, available from about £25. The Behringer UCA202 is a known good solution and easily available from music shops or online.

You will not be using the Marantz's onboard dacs in this scenario, but they could come in useful for other sources down the line.

 

[hybridauth_Facebook_10210916369251950]

Thanks for the reply.

Just to further clarify: This noise is present even when the volume is turned all the way to min (but you need to use the headphone (closed) in a very quiet room and switch between different sources to notice).

I built the PC myself. Indeed, I concur it's probably the part that converts signal to the red light that introduces this noise. I'll try to ask around to see if someone has a desktop like mine (most ppl have only notebooks these days).

I do have a 3.5 mm to RCA connector, and from the onboard line out to the amp sounds fine. There is no buzzing noise.

Given the usual caveats that I have not seen or heard your setup, the obvious answer is that it is noise from your computer getting onto the SPDIF data stream.

It seems unusually severe but such noise is not unusual, particularly with headphones and is one of the reasons a usb connection is preferred by many.

As a student, surely you have people around with other brands and types of PC, not all will have Toslink out, but surely some will. can you try one?

I am assuming you have a laptop, though if it is a desktop, a change of soundcard might well help.

As I feel it is more likely to be the computer rather than the amp, a relatively inexpensive solution would be a cheap usb dac, available from about £25. The Behringer UCA202 is a known good solution and easily available from music shops or online.

You will not be using the Marantz's onboard dacs in this scenario, but they could come in useful for other sources down the line.

 

[davedotco]

Absolute first thing to try is another laptop with toslink out. This will tell us a lot.

See if you can do that and report back.

 

[Sixtyten]

I had the exact same issue with the PM6005. Or rather I had the same problem with two PM6005 amps. Low buzzing noise through every pair of headphones I own. Marantz, didn't believe me. Even a recording of the sound didn't convince then there was a problem with both the first one (which they repaired after the optical connection fell off the back, because it hadn't been attached properly in the factory) and a second one which still had the buzz. They told me that it was performing as expected and it wasn't faulty. Which means my cheap and cheerless Pioneer home theatre amp must be faulty as it doesn't have buzz through any source - even the optical digital one.

Your amp is faulty. Although, Marantz will never, ever admit it. They'll "mmm" and "ahh" for a while, get you to send it to their (frankly) incompetent repair agents, then shrug their shoulders and say "it's supposed to do that". If you dig your heels in they might deign to exchange it. Likely with one that manifests the same proble,

Fortunately, my Hifi dealer, heard the sound and they argued the toss with Marantz. The A19 I got as a replacement upgrade, shows the Marantz PM6005 as the badly made child's toy it is.

 

[hybridauth_Facebook_10210916369251950]

Thanks for sharing your experience.

What makes me suspect the amp is one thing I haven't mentioned here yet (just realized):

The amp has automatic standby if no sound is played for 30 minutes. With my computer on and the amp input selected as Optical 1, if the system plays no sound the amp will go into standby after 30 minutes - despite buzzing all the time. If the buzz comes from the computer, surely it's some sound, isn't it?

I had the exact same issue with the PM6005. Or rather I had the same problem with two PM6005 amps. Low buzzing noise through every pair of headphones I own. Marantz, didn't believe me. Even a recording of the sound didn't convince then there was a problem with both the first one (which they repaired after the optical connection fell off the back, because it hadn't been attached properly in the factory) and a second one which still had the buzz. They told me that it was performing as expected and it wasn't faulty. Which means my cheap and cheerless Pioneer home theatre amp must be faulty as it doesn't have buzz through any source - even the optical digital one.

Your amp is faulty. Although, Marantz will never, ever admit it. They'll "mmm" and "ahh" for a while, get you to send it to their (frankly) incompetent repair agents, then shrug their shoulders and say "it's supposed to do that". If you dig your heels in they might deign to exchange it. Likely with one that manifests the same proble,

Fortunately, my Hifi dealer, heard the sound and they argued the toss with Marantz. The A19 I got as a replacement upgrade, shows the Marantz PM6005 as the badly made child's toy it is.

 

[muljao]

Buzzing may be electrcal sound (maybe not registered as an actual audio). You have got probably the best advice already in trying another computers optical. Why not try that and then not have to second guess the inner workings of the amp ansd what it thinks a sound is.

As said there is a reason usb is often preferred when using computer audio. Also have you tried a different toslink?

 

[hybridauth_Facebook_10210916369251950]

Thanks you, but I have not managed to find anyone with a device that would let me hook up my amp. I'll have a look at the office to see if those computers have optical out.

As regards USB, I've also read someone mentioning buzzing noise from that connection.

Buzzing may be electrcal sound (maybe not registered as an actual audio). You have got probably the best advice already in trying another computers optical. Why not try that and then not have to second guess the inner workings of the amp ansd what it thinks a sound is.

As said there is a reason usb is often preferred when using computer audio. Also have you tried a different toslink?

 

[ID.]

The puzzling thing from my perspective is that using an optical connection is supposed to prevent potential noise from being transmitted through to the DAC. USB needs to have galvanic isolation (which really should be built in to the DAC), but optical should prevent noise from the computer being transferred to the DAC.

Is the noise still there if you select the optical input but don't have the computer attached (either no optical cable going into the amp or the optical cable only connected to the amp with the other end hanging loose)?

I agree that it would be best to get something else with an optical output to test it with. Maybe someone around you has a TV or DVD player with an optical output. I know PS3s have an optical output. Perhaps PS4s do as well.

 

[davedotco]

The puzzling thing from my perspective is that using an optical connection is supposed to prevent potential noise from being transmitted through to the DAC. USB needs to have galvanic isolation (which really should be built in to the DAC), but optical should prevent noise from the computer being transferred to the DAC.

Is the noise still there if you select the optical input but don't have the computer attached (either no optical cable going into the amp or the optical cable only connected to the amp with the other end hanging loose)?

I agree that it would be best to get something else with an optical output to test it with. Maybe someone around you has a TV or DVD player with an optical output. I know PS3s have an optical output. Perhaps PS4s do as well.

This is puzzling me too.

However the noise as described sounds like a switch mode power supply which suggests it is getting into the data stream inside the computer, and is therefore, to my mind, the first thing to check.

Maybe it is a noisy dac, this is a budget model and this level of noise is considered acceptable? It does not sound that severe on speakers only really on headphones.

It should be easy enough to find out what is causing the issue, just do some basic fault finding.

Ie is the noise present..

With the optical disconnected at the computer end?

With the optical connected but the computer completely powered down?

Does it appear only when the computer is powered up?

On the computer headphone output?

Of course it might be one of those situations where the computet is a 'bit' noisy, the amplifier is 'not great' at rejecting the noise and the result just a little too noisy for normal use. Just a poor match in other words.

 

[hybridauth_Facebook_10210916369251950]

Hi,

So I went to the shop today. They could also hear the noise, and they have a demo unit that buzzes just as bad, perhaps worse.

I was given two options: Yamaha A-S701 for 130 euro more, and Cambridge CXA60 for 250 more:

Look: The cambridge looks much better; the Yamaha is bulky and a bit ugly. The Marantz looks the best.

Sound: Honestly, I could not hear much difference. They have some coloring differences, but not night and day. I actually preferred the Yamaha on the shop's Monitor Audio Bronze 2 (I think). The guy from the shop said the sound quality of the Cambridge is better, and that maybe with better speakers I could notice the difference. He's probably right, but I don't think paying more for the amp than the speakers (my 685 S2) is wise; besides, on Amazon US the two are sold at the same price. Lastly, with the volume knob cranked to max, the Yamaha has lower white noise. In fact, the Marantz sounded just fine to me.

Build: The Cambridge seems a little worse built. Its EQ knobs feel cheap (small plastic that are like the ones on the stereo in a 20-year-old car I had). It's also noticeably lighter. However, the transformer in the Yamaha is naked. The Marantz has build problem: maybe it's a design issue, since every unit I tested has this problem. The power supply is perhaps interfering with the DAC. The shop also has a Marantz CD player that supposedly uses the same DAC (?), and when using RCA connection the CD player makes no noise at all. So this is probably a circuit design flaw. If you like the looks (I do), it's better to just buy a PM5005. I could have saved 280 euro (it's that much cheaper than the Yamaha) - of course, since they take back the old unit I couldn't ask money back and a new unit.

So in the end, Yamaha A-S701 and 130 euros poorer after hours in the traffic jam.

 

[davedotco]

Have you got the Yamaha into your own system yet?

Do let us know what you find, hopefully a good result...*good*

 

[hybridauth_Facebook_10210916369251950]

Have you got the Yamaha into your own system yet?

Do let us know what you find, hopefully a good result...*good*

Hi, thanks. I've connected it up as soon as I got back. It sounds pretty good. The big difference is the absence of noise (both the buzzing, which shouldn't be there, and the white noise, which is very, very faint and you have to put your ears next to the tweeter to notice anything even at max volume) when there's no audio.

It does seem to be more powerful (which it is).

Very happy with this unit. Should have stayed at the town longer (very beautiful, tourist destination), had dinner there, and avoided the Friday afternoon traffic.

 

[davedotco]

Have you got the Yamaha into your own system yet?

Do let us know what you find, hopefully a good result...*good*

Hi, thanks. I've connected it up as soon as I got back. It sounds pretty good. The big difference is the absence of noise (both the buzzing, which shouldn't be there, and the white noise, which is very, very faint and you have to put your ears next to the tweeter to notice anything even at max volume) when there's no audio.

It does seem to be more powerful (which it is).

Very happy with this unit. Should have stayed at the town longer (very beautiful, tourist destination), had dinner there, and avoided the Friday afternoon traffic.

*good*

 

[ID.]

Good to see the issue resolved. It's a shame you ended up paying another 130 euros, but I hope you enjoy the Yamaha.

 

[LosAngelos]

We're in 2020 and exact same problem happens in PM 6007 .... what a shame.

I have this NEW amp PM6007 for a day, and unfortunately it's dac make noise same as in shown youtube video.

View: https://www.youtube.com/watch?v=dJ2O1o5KXUc&lc=UgxCrvCwBylh3KNsOaZ4AaABAg.9GozLwNXxwU9J6j-vflNjl



I connected Marantz ND8006's optical and coaxial out's to PM6007's digital inputs, both inputs makes left channel buzz, right channel white noise...Unbelievable, problem from PM6006 transferred to Pm6007, marantz never listened claims, it seems.