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Buzz / Humm Pro-Ject DS2 Amp Box to Marantz Cinema 70s Pre Out

Otac0n89

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Joined
Aug 14, 2024
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Location
Germany
Hello,
I have a technical question to my Movie / Music Setup, I use the following setup:

Polk ES60 Speakers --> Pro-Ject DS2 Amp Box --> Pro-Ject Pre Box DS2 Analogue --> Fix Line Out (RCA) --> for Music Wiim Ultra (RCA) / for Movies Marantz Cinema 70s Preout Fronts (RCA)

The System works great, but I get a really annoying Buzz / Humm from my Polk ES60 Speakers if I use them with the Marantz Cinema 70s PreOut as Frontspeakers. If I use the Wiim Ultra, there is no buzz or humm noticeable.

I tried different Line Inputs from the Pro-Ject DS2 Pre Analogue, but the buzz / humm would be the same. I tried different PreOut Input of the Marantz, still the same. If I disconnect the RCA from the Marantz Cinema 70s and leave the signal chain on, then the buzz / humm stays the same.

Does someone has a suggestion how I can solve the problem or another idea what I can try?

The Pro-Ject DS2 Amp Box has an Inputsensitivity of 550mVrms, maybe it is too low for the Marantz Cinema 70s Inputs? In the Wiim App I changed the Line Out Level (mVrms) to 500. Is there an Option for the Marantz Cinema 70s ?

Sorry for my bad english,
a german guy here ;)
 
Hello,
I have a technical question to my Movie / Music Setup, I use the following setup:

Polk ES60 Speakers --> Pro-Ject DS2 Amp Box --> Pro-Ject Pre Box DS2 Analogue --> Fix Line Out (RCA) --> for Music Wiim Ultra (RCA) / for Movies Marantz Cinema 70s Preout Fronts (RCA)

The System works great, but I get a really annoying Buzz / Humm from my Polk ES60 Speakers if I use them with the Marantz Cinema 70s PreOut as Frontspeakers. If I use the Wiim Ultra, there is no buzz or humm noticeable.

I tried different Line Inputs from the Pro-Ject DS2 Pre Analogue, but the buzz / humm would be the same. I tried different PreOut Input of the Marantz, still the same. If I disconnect the RCA from the Marantz Cinema 70s and leave the signal chain on, then the buzz / humm stays the same.
This is strange. Do I understand correctly that there is no connection at all between the audio chain (Pre Box/Power Box) and the Marantz? And it buzzes if you power on the Marantz? If yes:
  • Does the buzz increase when you turn up the volume at the Pre Box?
  • What is the distance between the Marantz and Pre Box/Amp Box? If they sit on top of each other try to move them away.
 
This is strange. Do I understand correctly that there is no connection at all between the audio chain (Pre Box/Power Box) and the Marantz? And it buzzes if you power on the Marantz? If yes:
  • Does the buzz increase when you turn up the volume at the Pre Box?
  • What is the distance between the Marantz and Pre Box/Amp Box? If they sit on top of each other try to move them away.
It buzzes if it is connected to the Marantz and if it is not connected, i tried different inputs on the Pre Box and it was always the same. I use the Fix Output on the PreBox, so I have volume control via the Marantz or the Wiim. I just tried the variable Output, if I increase the Volume the buzz / humm gets even worse. If I use the Wiim Ultra there is no buzz.

The distance between the PreBox/AmpBox and the Marantz is approximately 1 meters.
 
So I tried now different connections to limit the problem:

- I tried to connect the Project DS2 Amp Box directly via RCA to the Marantz PreOuts, buzz and humm is still there
- I tried to connect a different Power Amp (Fosi Za3) to the Marantz PreOuts, no buzz or humm present
- I tried to connect the Fosi Za3 to the Pre Box and then to the Marantz PreOuts, no buzz or humm present
- I tried an another Powersocket for the Project DS2 Amp Box, buzz and humm ist still present

So I guess the Project DS2 Amp ist the Problem. Like I said in the first post before, there is no buzz or humm present if I use the "Music" Signal Chain (Project DS2 Amp -> Project DS2 Analogue Pre -> via Fix LineOut (RCA) ->x Wiim Ultra), only if i use it with the Marantz or if there is no connection.
 
So I tried now different connections to limit the problem:

- I tried to connect the Project DS2 Amp Box directly via RCA to the Marantz PreOuts, buzz and humm is still there
- I tried to connect a different Power Amp (Fosi Za3) to the Marantz PreOuts, no buzz or humm present
- I tried to connect the Fosi Za3 to the Pre Box and then to the Marantz PreOuts, no buzz or humm present
Ok, so the Pre Box is not the cause.
- I tried an another Powersocket for the Project DS2 Amp Box, buzz and humm ist still present

So I guess the Project DS2 Amp ist the Problem. Like I said in the first post before, there is no buzz or humm present if I use the "Music" Signal Chain (Project DS2 Amp -> Project DS2 Analogue Pre -> via Fix LineOut (RCA) ->x Wiim Ultra), only if i use it with the Marantz or if there is no connection.
Try
  • Speaker - Amp Box. Nothing else connected at all. Does it buzz?
  • Speaker - Amp Box - Marantz. Nothing else connected at all. Marantz switched off. Does it buzz?
  • Speaker - Fosi. Nothing else connected at all. Fosi switched off, not connected to power. Does it buzz?
"Nothing else connected at all" means exactly this. No other inputs or outputs connected to any device, to eliminate any possible ground loops.
 
Ok, so the Pre Box is not the cause.

Try
  • Speaker - Amp Box. Nothing else connected at all. Does it buzz?
  • Speaker - Amp Box - Marantz. Nothing else connected at all. Marantz switched off. Does it buzz?
  • Speaker - Fosi. Nothing else connected at all. Fosi switched off, not connected to power. Does it buzz?
"Nothing else connected at all" means exactly this. No other inputs or outputs connected to any device, to eliminate any possible ground loops.
I tried all of your suggestions:

- Speaker - Amp Box = No Buzz
- Speaker - Amp Box - Marantz (Power Off) = still buzzing
- Speaker - Fosi = no Buzz

I also tried different RCA Cables but the results were the same.
 
I tried all of your suggestions:

- Speaker - Amp Box = No Buzz
- Speaker - Amp Box - Marantz (Power Off) = still buzzing
- Speaker - Fosi = no Buzz

I also tried different RCA Cables but the results were the same.
That's puzzling. What about Speaker - Amp Box - Marantz (power cable disconnected)?
 
That's puzzling. What about Speaker - Amp Box - Marantz (power cable disconnected)?
I tried this now too, but with the same result (buzzing).
If I do Speaker - Amp Box - Rca Cable I also get buzzing.
Maybe there is an issue with the rca connections of the project amp?
If I do the chain Speaker - Amp Box - Wiim Ultra, I get no buzzing, how can that be ?
 
I tried this now too, but with the same result (buzzing).
If I do Speaker - Amp Box - Rca Cable I also get buzzing.
The RCA cable acts as antenna.
Maybe there is an issue with the rca connections of the project amp?
If I do the chain Speaker - Amp Box - Wiim Ultra, I get no buzzing, how can that be ?
The only way I can think of is that the output impedance of the Wiim is much lower than that of the Marantz, so that it acts as kind of a short cut for RF. OTOH I don't think this is the real cause. Maybe adding a passive lowpass filter of 100 kHz at the input of the Amp Box could help as it seems the Amp Box is not designed to suppress RF signals at its inputs.
 
I tried now also the chain Project Amp Box - RCA via Line Out into Wiim Ultra - RCA via Line In to Marantz Preout Fronts, there is also no buzzing, just i would call it a slighty hiss noise.

I set the volume for the line in to 100% in the Wiim Ultra, but do I have to use the eq settings in the wiim or let it be on "flat" settings and do the eq in audyssey with the marantz?
 
I changed the devices now from Wiim Ultra + Project Amp Box to only the Wiim Amp Ultra. Again buzzing if I use the Line In from the Wiim Amp Ultra to the PreOuts of the Marantz.
So i got time on my hands and I removed every device and started "fresh".
I connected every device and cable one after another and it turns out it is the LAN Cable from the AppleTV what causes the buzzing. If I disconnect it, the buzz is gone, only a slightly hiss is noticeable (I think that is normal, because I set the Volume for the Line In Input in the Wiim Amp Ultra to 100%).

If i connect the LAN cable directly to the Marantz the buzzing also starts. I changed LAN cables to see if the cable is damaged, but the buzzing stays the same. I ordered now a Network LAN Noise Filter (ifi LAN i Silencer) to see if i cann get rid of the LAN buzzing this way
Does someone else has an idea why the Internet connection causes the buzzing and has maybe another solution for my problem?
 
I changed the devices now from Wiim Ultra + Project Amp Box to only the Wiim Amp Ultra. Again buzzing if I use the Line In from the Wiim Amp Ultra to the PreOuts of the Marantz.
So i got time on my hands and I removed every device and started "fresh".
I connected every device and cable one after another and it turns out it is the LAN Cable from the AppleTV what causes the buzzing. If I disconnect it, the buzz is gone, only a slightly hiss is noticeable (I think that is normal, because I set the Volume for the Line In Input in the Wiim Amp Ultra to 100%).
You could've gotten to this point much earlier if you had followed my advice in post #5.
 
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