How to get rid of 50hz noise (BeoGram 7000 connected to Almando Multiplay v3)

2 replies
NR
nrcw
Bronze
2 posts
Posted August 8, 2025 at 22:33 GMT
#1644930
Hi all! I recently purchased a BeoGram 7000 black edition which we find gorgeous. It came with a MMC2. Unfortunately, my cable setup is not working flawlessly and it keeps producing a 50hz sound. On one side of the living room, the BeoGram is located:
  • Original cable with DIN plug
  • DIN to RJ45 (provided by Steve)
  • RJ45 goes into single wall socket
On the other side of the living room, the Almando receiver is located:
  • RCA to DIN cable (provided by Steve)
  • DIN to RJ45 (provided by Steve)
  • RJ45 goes into double wall socket
Other facts:
  • The cable between both ends of the wall sockets, is a double shielded cat7 cable.
  • The double wall socket is shared with another cat7 cable used for wired internet from the modem to a switch.
What I've tested so far:
  • I have connected the BeoGram directly to the Almando using Steve's cables. Everything works perfect. The problem is, there's no room to keep my BeoGram next to the Almando (see attached picture). It's supposed to sit opposite of the TV across the room.
  • I disconnected the cat7 cable from the double wall socket and attached an RJ45 connector with a crimping tool. Unfortunately, the 50hz hum still persists.
Does anyone know whether it might be fixable with a different cable (compared to the current cat7 cable), or if there's a different solution? Any help would be greatly appreciated!
Attachments (1)
Mark-sf
Mark-sf
Bronze
596 posts
Posted August 9, 2025 at 04:22 GMT
#1670662
I am not familiar with the Armando; however, CAT7 cable is not intended for analog audio use even when it’s shielded. Frequently, a hum issue will be the result of either a coupling problem due to proximity of AC mains lines when run with the CAT7 in the walls or a ground differential issue or loop between where your turntable is plugged in than your system across the room.  Since the RIAA amplifier in the 7000 is not a balanced output there is no common mode rejection along the signal run. I would approach determining which type of hum you have by running a CAT7 cable across the room in lieu of you in wall set up. If the hum goes away you have in-wall coupling which may be mitigated by using isolation line transformers to convert your single ended connection to balanced on bot sides.  If the hum is sill there you then have an AC mains grounding issue, and you need to disconnect the grounded shield from the Almando end. You also might try reversing the mains plug on one side if its a 2-prong one.
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