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This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Hi all, I hope im posting in the right place- noob here!
I had the turntable up and running with no issues on a beocenter 1600 which unfortunately packed up beyond repair. I have got hold of a beocenter 2600 which generally seems to work well, the odd sticky button but nothing major. the tape and radio work absolutely fine but I have hooked the Beogram up to the 2600 with the 5 pin din plug and I can hear a hum through both speakers, the audio seems quieter than it should too.
Ive been searching the web for the last few hours but to no avail, I've wiggled plugs, checked the Din plug on the turntable, wires all seem good, no cross overs or ground touching things it shouldn't - I don't think the issue is the turntable as it worked ok before - its not moved. the hum seems to intensify when the arm is moving on the electro magnet, or when I touch any metal part of either the amp or turntable.
Any suggestions or help would be appreciated.
Try running a wire from the chassis of the Beogram to the chassis of the Beocenter - if the hum goes, it is an earth problem.
Peter
What Peter said.A bent grounding leaf inside the DIN socket wouldn't be a first.
Martin
Thanks both,
i gave the wire a go and checked the socket over, I actually removed it and no damage, wire made no difference. Only thing I did notice is that the ground wire from the top pin on the DIN and the ground from the chassis were soldered to the same point inside the 2600, on the 1600, they’re completely separate, I’m not really sure how these units are grounded as there is no Earth wire going to the mains socket.
They don't have to be wall-grounded, just to each other. (It is absolutely unnecessary, and in fact B&O systems are designed *not* to have this done, but crazy people have been known to connect a wire from the chassis of both, to a grounding pin or clip, either with a broken-open AC plug or to metal building electric conduit or metal plumbing. But it should not make any difference! Just wait for someone to tell me that wiring a chassis ground defeats some safety feature...)
One other thing to check: your report, "the audio seems quieter than it should too" can be a missing (or failing) RIAA phono pre-amp when one is required, certainly possible on older gear. Another possibility matching your description, which I have done -- but unlikely if you are using the same turntable and the same cable -- is that on B&O gear, swapping the In vs. Out pins when connecting (or soldering up) the DIN adapter, i.e. amplifying totally silent unconnected input plus just the signal leakage from the output pins! But this is pretty obvious if it happens, because you have to turn up the volume very *very* high to hear the leaking signal.
I hadn’t quite got as far as a DIY ground wire to the mains but at least now I understand how it’s meant to work!
i took the amp apart and found nothing again, so decided to (before I go down the route of testing the preamp for issues) to cut the old DIN plug off the turntable and solder a new one on which did the trick! All works a treat now.
Shouldn’t have assumed it wasn’t the turntable!
thanks for your helps!