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Beogram 8002 Channel Imbalance

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dbxdx5
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dbxdx5 Posted: Tue, May 28 2013 5:38 PM

I've noticed that records played on my 8002 present a stereo image that's shifted to the right by about 15 percent. That means I need to shift the balance control on my preamp 1 to 2 clicks to the left in order to get the image centered.

I had a loose RCA male plug going to the left input on my phono pre-amp, so I swapped in a new cable with a tighter connection, but that didn't make a difference. I plan to try a different phono pre-amp next to see if that's the problem, but in the meantime, I figured I'd see if anyone has experienced something similar or has any guesses to what might be going on.

Matt

dbxdx5
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dbxdx5 replied on Tue, May 28 2013 10:20 PM

One detail I forgot to mention: Lately when the tonearm moves back after the end of the record, the sound of the stylus moving through the mounted cleaning brush can be heard--but mostly through the right speaker. I know that means the muting switch is flaking out, but perhaps the fact that only the right channel is affected might help in figuring out what's going on with the channel imbalance? 

Dillen
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Dillen replied on Wed, May 29 2013 4:22 PM

There are no electronics in the signal path inside the Beogram.
There is only the cartridge, the leads and the muting relay.
The muting relay merely grounds the output when not activated (energized when playing) and
it's very common to find its contacts oxidized, particularly if not used for a long time, leading to lack of muting.
The relay cannot (unless something really strange and unusual has happened) mess up the signal amplitude.

If you are sure, the problem is not with the amplifier (if possible swap left/right signals to diagnose),
I suggest you replace the cartridge. There's really not much else that can cause those symptoms.

- And take off that cleaning brush (it lifts right off). Store it in a safe place - like f.e. the dustbin.
It's too hard on the cantilever suspension and it's doing its job sideways which helps nothing.
It's no good.  Find a small manually operated cleaning brush instead.

Martin

dbxdx5
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dbxdx5 replied on Wed, May 29 2013 5:44 PM

Thanks Martin. I feared it might be the cartridge, which is a MMC2 rebuilt by Axel. I have a rebuilt MMC5 that I'll swap in to confirm the diagnosis (after first swapping the channels to rule out the phono amp).

Regarding the mounted brush you're so fond of, I've left it in because it's such a pain to get a brush in there to clean the stylus manually. But I'll heed your warning and deal with the inconvenience. 

 

Matt

Dillen
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Dillen replied on Wed, May 29 2013 6:10 PM

Clean the brush while the cartridge hovers above a record.
That's how I do it.
The mounted brush is not doing any good. Quite contrary in most cases. You won't miss it.

Martin

dbxdx5
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dbxdx5 replied on Thu, May 30 2013 4:19 PM

Update: I swapped in a different phono amp last night and the problem disappeared. So that means the cart is fine, but I have a broken phono amp. C'est la vie!

Peter
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Peter replied on Thu, May 30 2013 4:31 PM

That is probably the best result you can have! I agree completely with Martin and the brush - I remember seeing the 8000 first demonstrated and the movement laterally of the cantilever was terrifying! Mine had the brushes removed as soon as I got them!

Peter

dbxdx5
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dbxdx5 replied on Mon, Jun 10 2013 5:39 PM

So I did away with the built-in brush on my 8002 as was suggested. Here's my question now: Is there a way to trick the 8002 to allow the tonearm to lower over the plinth so that I can clean the stylus using the Onzow Zerodust?

dbxdx5
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dbxdx5 replied on Wed, Jun 12 2013 2:28 PM

Hmmm... I'm going to interpret the silence as "there is no way to do what you're talking about." Wink

Dillen
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Dillen replied on Wed, Jun 12 2013 7:07 PM

dbxdx5:

Hmmm... I'm going to interpret the silence as "there is no way to do what you're talking about." Wink

Yep. There isn't.
You can trick it to think there is a record on the platter but you can' t make it lower outside of the
platter, the threaded spindle opto count NEEDS to be within acceptable limits.

Martin

dbxdx5
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dbxdx5 replied on Wed, Jun 12 2013 10:33 PM

Thanks Martin!

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