Fixing rumble on Lenco 75 : need help !

[steffrance]

I own this nice Lenco 75 that as be refurbished (quite a good job has been done) but I stil got a noise sounded in the mediums.
This rumble is displeasing and i tried to fix it but it’s still going on .
Arm is Pro-ject carbon with Pickering XUC cartridge . The turntable is placed on pro-jet damp-it to avoid vibrations .

It may be the bearings .

Can anyone give me advice to solve it ?

 

[ejp]

They rumble. Just accept it. It's an idler-wheel design and that's what you get. Mine rumbled from the day I bought it in 1976 to the day I sold it in 1987. Very good turntable in other ways, but not this one

 

[Galu]

Rumble is often part of the vintage listening experience. A little amount in the background can contribute a degree of "analogue ambience" to the sound.

You may be overly focusing on the rumble. Try to focus on the music instead and eventually your brain may learn to accommodate the rumble.

 

[steffrance]

Sometimes i can get out of focussing ont the rumble and sometimes it really **** me of ...

 

[Galu]

refurbished (quite a good job has been done)

You don't say which specific features of the L75 were refurbished.

However, you say you suspect the "bearings". Was the platter bearing not included in the refurbishment?

Lenco Heaven provides a guide on platter bearing maintenance:

https://www.lencoheaven.net/forum/index.php?topic=2022.0

 

[Bon]

This rumble is displeasing and i tried to fix it but it’s still going on .

Try this experiment. If your phono stage has a mono switch, play a mono LP with the phono switched to mono. I bet the rumble greatly decreases compared to playing the LP in stereo. This will show that the "rumble" is vertical vibration impressed on the platter arising from the idler. This is a feature of the Lenco drive system which was designed in the mono era when there was no out-of-phase component to the audio signal. The drive system was never designed with stereo in mind. The tapered horizontal motor pulley does provide a convenient continuously variable speed adjustment but with this vertical rumble penalty. An idler with precision ground tyre and precision low noise bearing is the best chance of minimising the vertical rumble. The platter bearing is unlikely to be the source of the rumble.

 

[audiobasic2000]

Good Morning, steffrance:

Have you checked to see if the transport screws have been removed (or at least lossend)? They are number 7 in the list from the link provided.

Lanco L75 top plate

Thanks.

Sincerely,
Kingsley.

 

[DNic]

The rumble is not normally the bearing if it gas been refurbished as on the bearing they run very quite. The noise is most likely coming from the motor or idler wheel itself.
Dis-connect the break under the platter, it is not needed & just a source of noise. The run the motor up to speed (try 45 RPM). Turn the motor off & on run down does the unit still rumble.

Cheers

 

[krca45]

My L75 run silent for six months and then that typical "rrrmmm, rrrrmmm" sound began.

Will try to change idler wheel, I'm not expert for idler drives, just cannot see what might be the cause for such typical sound ( had in the past Garrard with 10" plate, it rumbled but not horribly ).

In my case I don't think it's from the motor.


BTW that original chipboard box is horrendous resonator box - the table should be plinthed properly.

 

[steffrance]

Thank you all for your messages
I do not have a lot of time theses days but I will check things soon
I will keep you inform

cheers

 

[steffrance]

The problem was a mismatched between the cartridge (pickering XuV) and the background noise . A try has been done with an ortofon cartrige and it seem better.
I bought a audiotecnicha 740ml that should attempt the hum