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Issues with the DAC?

Fahad

Well-known member
Jan 30, 2020
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Having a strange problem when I select the DAC input on my Preamp. There is a hum (or more of a hiss) that stays on for 20-30 seconds then it goes away by itself. So before I can do much experiments with disconnecting/ unplugging equipments to see what's causing it, it just goes away by itself.
If I keep everything on and dont play any of the components, the hum sometimes comes and goes. But usually goes away completely after I start playing music. My DAC has a CD player and Chromecast audio connected to it. There is no such problem when I switch to the turntable input. I even connected an ifi AC purifier but didn't help.
Can any of the forum members give me some advice on this?
The only change I made was introducing an online UPS in the room which is connected to an outlet that doesn't have any HiFi equipment connected to it, only the chrome cast audio. The UPS is strictly for the TV and the Bluray player.
 

abacus

Well-known member
Sep 24, 2008
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Sounds like an intermittent problem with the DAC. (If the DAC is external you can try changing the cable or try another input to see if the problem goes away)

Bill
 

Fahad

Well-known member
Jan 30, 2020
66
13
545
Sounds like an intermittent problem with the DAC. (If the DAC is external you can try changing the cable or try another input to see if the problem goes away)

Bill
I have tried different cables, same thing.
I can try a different input in the pre-amp though
 

nopiano

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Feb 15, 2009
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I would trying disconnecting the UPS, because there’s a linkage via the Chromecast Audio. Any mains changes will definitely risk changes to earthing and/or noise.
 
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Fahad

Well-known member
Jan 30, 2020
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I would trying disconnection the UPS, because there’s a linkage via the Chromecast Audio. Any mains changes will definitely risk changes to earthing and/or noise.
you think and USB purifier like iFi or Jitterbug would help?

Not particularly sure why but I try to make sure for my Hifi, I dont have more than 3 connections per power strip. The room has 3 outlets
This is how I am connected:
Outlet 1: Tacima Conditioner 1: Power Amp, Pre Amp, CD player
Outlet 2: Tacima Conditioner 2: TT, DAC (both DC powered), Phono Stage
Outlet 3: UPS: Modem, router, TV, Blu Ray Player, Chormecast Audio

Too many stuff in one room? Maybe that's creating problems?
 

insider9

Well-known member
Sep 20, 2016
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Issue you're experiencing sounds like a fault of a component that's failing and is only intermittent for the time being. I wish I could be more helpful.

In fact I can be but it has nothing to do with OP. I'd recommend not using Tacima on your outlet 1. If you have a spare power strip give it a go. Never heard anything good from Tacima on amplification. Don't take my word for it. Try it for yourself
 

Fahad

Well-known member
Jan 30, 2020
66
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545
Issue you're experiencing sounds like a fault of a component that's failing and is only intermittent for the time being. I wish I could be more helpful.

In fact I can be but it has nothing to do with OP. I'd recommend not using Tacima on your outlet 1. If you have a spare power strip give it a go. Never heard anything good from Tacima on amplification. Don't take my word for it. Try it for yourself
Ok your first para is getting me all paranoid.

Regarding Tacima, I always thought my power amp sounds better connected straight to a wall. But I had problems with surge before and the primary reason I got the Tacima was for surge protection, that was quite a few years ago. I saw it was WHF 5 star rated and "Relatively cheap". So went for them.

I have actually been meaning to get a Belkin surge protector to replace the Tacima for the amps.
 

nopiano

Well-known member
Feb 15, 2009
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you think and USB purifier like iFi or Jitterbug would help?

Not particularly sure why but I try to make sure for my Hifi, I dont have more than 3 connections per power strip. The room has 3 outlets
This is how I am connected:
Outlet 1: Tacima Conditioner 1: Power Amp, Pre Amp, CD player
Outlet 2: Tacima Conditioner 2: TT, DAC (both DC powered), Phono Stage
Outlet 3: UPS: Modem, router, TV, Blu Ray Player, Chormecast Audio

Too many stuff in one room? Maybe that's creating problems?
I mentioned the UPS because it was new. Changes are often the cause, such as when people plug in a new phone charger, or a few months ago, Christmas tree lights!

The USB devices to me should be ‘icing on the cake’ not to fix something that’s not right. Something is not right here! As insider9 says, try removing things, such as the Tacima strip, in case that helps. But a problem that changes during warm-up sounds more like a fault than a wiring issue.
 

insider9

Well-known member
Sep 20, 2016
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Ok your first para is getting me all paranoid.

Regarding Tacima, I always thought my power amp sounds better connected straight to a wall. But I had problems with surge before and the primary reason I got the Tacima was for surge protection, that was quite a few years ago. I saw it was WHF 5 star rated and "Relatively cheap". So went for them.

I have actually been meaning to get a Belkin surge protector to replace the Tacima for the amps.
Apologies, never meant to make you paranoid. It's just a bizarre issue that I'd want to rule out everything before I get a technician to look at the potentially failing unit. Hopefully it's all good. I'll keep my fingers crossed. But definitely try Belkin in place of Tacima you're not the only one to experience this on an amp.
 

Fahad

Well-known member
Jan 30, 2020
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545
Apologies, never meant to make you paranoid. It's just a bizarre issue that I'd want to rule out everything before I get a technician to look at the potentially failing unit. Hopefully it's all good. I'll keep my fingers crossed. But definitely try Belkin in place of Tacima you're not the only one to experience this on an amp.
No worries mate, you are only trying to help.

My DAC is the longest standing component in my HiFi setup. I had briefly considered replacing it with a CA CXN but wasn't sure if the DAC on the CXN would be much better than the one on my Marantz CD player, so decided against it. The MF DAC comes with the cheapest looking DC adapter which is going to be replaced by iFi 5V adapter soon, maybe that will help? Fingers crossed, really dont want to buy another DAC now. Saving up for a Rel/ SVS sub.
 
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Fahad

Well-known member
Jan 30, 2020
66
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545
Just ordered a Belkin surge protected power strip.

To pin point the issue a bit more, seems like the noise comes mostly when the DAC input is selected to a source that does not send an audio signal.

Just a while ago, when I switched all the components on, the preamp input was DAC and the DAC's default switch on selection is USB (nothing connected there). There was a buzz. When I changed the it to my CD player, the buzz was gone.

Then I was listening to turntable for a while and by then the CD player went to standby mode. So when I switched the preamp to DAC input, there was a buzz again. The buzz was gone immediately when I switched the CD player on.
 

nopiano

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Feb 15, 2009
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Just ordered a Belkin surge protected power strip.

To pin point the issue a bit more, seems like the noise comes mostly when the DAC input is selected to a source that does not send an audio signal.

Just a while ago, when I switched all the components on, the preamp input was DAC and the DAC's default switch on selection is USB (nothing connected there). There was a buzz. When I changed the it to my CD player, the buzz was gone.

Then I was listening to turntable for a while and by then the CD player went to standby mode. So when I switched the preamp to DAC input, there was a buzz again. The buzz was gone immediately when I switched the CD player on.
If a component isn’t connected to an input, or it’s connected but turned off, it’s possible that input will ‘play’ noise. Especially in the first example.

In effect the unused input is open to random noise, be it from the mains, or some sort of radio frequency, perhaps radiated from another device nearby. That’s why you can buy shorting plugs.
 

Fahad

Well-known member
Jan 30, 2020
66
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545
If a component isn’t connected to an input, or it’s connected but turned off, it’s possible that input will ‘play’ noise. Especially in the first example.

In effect the unused input is open to random noise, be it from the mains, or some sort of radio frequency, perhaps radiated from another device nearby. That’s why you can buy shorting plugs.
will these help?

 

nopiano

Well-known member
Feb 15, 2009
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will these help?
They look like dust caps only. I’m afraid these are not cheap, but this is what I meant, though you may well find copies on eBay. You can see that they connect electrically to both signal and shield.

Do try unplugging everything first though, then reconnecting until the problem occurs, as you may well be able to fix it for nothing.

 

Fahad

Well-known member
Jan 30, 2020
66
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545
So after multiple experiments, seems like DAC IS the culprit. Connected CD player directly to PreAmp and removed all the DAC connections and the system is completely quiet now.
Not sure if the problem is with the power supply of the DAC (dont have a 5V adapter in the house to do the test).
The Marantz internal DAC isn't bad at all, I had never had the CD player connected directly, it was always through the DAC. Now I am wondering whether investing money on a new DAC is worth it or not. The DAC did make the Chromecast sound better though.
The HiFi dealer I go to always gives me a good deal on a new purchase when I return an older equipment. Can't decide whether I should use the deal for a new DAC or a subwoofer.
 
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nopiano

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Feb 15, 2009
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So, just to be clear, before the problem you were using the MF DAC quite happily as described? And you've eliminated from the investigation the new UPS, and the cables to and from the DAC?

I'm puzzled as DACs are amongst the most dependable bits of kit But I'm sure your dealer can test it - and they surely will if you want to PX it!
 

Fahad

Well-known member
Jan 30, 2020
66
13
545
So, just to be clear, before the problem you were using the MF DAC quite happily as described? And you've eliminated from the investigation the new UPS, and the cables to and from the DAC?

I'm puzzled as DACs are amongst the most dependable bits of kit But I'm sure your dealer can test it - and they surely will if you want to PX it!
Before the UPS, I actually didn't use the DAC for the last 2 - 3 months. Every time I listened to music, which wasn't very much due to work pressure, it was just vinyl. I was having some small ground issues with the vinyl (very light hum which easily gets drowned by music), which was a bit unusual, but I did have that in my older apartment. That hum also, kind of came and went. (this hum is a lot different then the one I get from my DAC).
Strangely, for the last 24 hours I have the DAC unplugged, the slight turntable hum is also gone.
 

Fahad

Well-known member
Jan 30, 2020
66
13
545
Before the UPS, I actually didn't use the DAC for the last 2 - 3 months. Every time I listened to music, which wasn't very much due to work pressure, it was just vinyl. I was having some small ground issues with the vinyl (very light hum which easily gets drowned by music), which was a bit unusual, but I did have that in my older apartment. That hum also, kind of came and went. (this hum is a lot different then the one I get from my DAC).
Strangely, for the last 24 hours I have the DAC unplugged, the slight turntable hum is also gone.
I still wonder whether a good DC power supply like the iFi one can help. But we have no dealers where I live and if I have it imported, the cost of returning it (if it doesn't work) will be the price of the adapter.
 

millennia_one

Well-known member
Sep 1, 2014
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I still wonder whether a good DC power supply like the iFi one can help. But we have no dealers where I live and if I have it imported, the cost of returning it (if it doesn't work) will be the price of the adapter.

I think in this instance what's happened is your DAC has received a static jolt enough to make the DAC/DSP chip act up and become unstable, It's possible I've done it a couple of times.

Just send it in for service and be done with it don't waste money, find out what the real problem is, it not as if you can use it right now.
 
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millennia_one

Well-known member
Sep 1, 2014
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So, just to be clear, before the problem you were using the MF DAC quite happily as described? And you've eliminated from the investigation the new UPS, and the cables to and from the DAC?

I'm puzzled as DACs are amongst the most dependable bits of kit But I'm sure your dealer can test it - and they surely will if you want to PX it!
Not really, they're computers and easily corrupted by external factors such as shocks and grounding issues they're very delicate on the inside. Some more susceptible than others
 

Fahad

Well-known member
Jan 30, 2020
66
13
545
I think in this instance what's happened is your DAC has received a static jolt enough to make the DAC/DSP chip act up and become unstable, It's possible I've done it a couple of times.

Just send it in for service and be done with it don't waste money, find out what the real problem is, it not as if you can use it right now.
Yeah guess that would be the best option, if I dont have to spend money!!
Really hope its nothing big.
 

nopiano

Well-known member
Feb 15, 2009
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Strangely, for the last 24 hours I have the DAC unplugged, the slight turntable hum is also gone.
That still makes me suspect the wiring somewhere. But the DAC needs checking in another system. I agree not to spend money on other devices/gadgets until you get to the bottom of the issue.
 

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