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wee tee cee
10-02-2018, 16:20
Help folks,

My Lenco is crackling away whilst idling-stylus above the record!

I tried re terminating the ground wire at the amp end-better but still not right.

If i touch the tone arm or pick up I get an audible hum.

redirected the ground wire away from power cable etc-made it better but the crackling remains.

your thoughts folks!!!

Audio Al
10-02-2018, 17:36
Needs more milk ;)

Barry
10-02-2018, 21:17
If you get an audible hum when you touch the pick up arm, then there is a problem with the earthing of the metalwork of the arm and/or the TT chassis. Are the two earthed together or separately?

wee tee cee
11-02-2018, 08:38
Dont know Barry -will have look inside today see if anything obvious appears.

Shovel_Knight
11-02-2018, 08:57
When I got my Lenco (a very early example of GL75), the factory wiring was very weird. It did not have a separate ground lead, and left and right signal returns were joined together and connected to tonearm ground. Needless to say, there were unhealthy amounts of hum.

I changed the power lead to a 3-core flex and grounded the motor and the top plate to mains earth. After that, I separated the left and right signal returns and tonearm ground. At first I connected a separate wire for the tonearm ground, but there still was some hum. When I connected the tonearm ground to the top plate (grounded to mains earth), most of the hum went away, but I have never been able to get rid of it completely.

Barry
11-02-2018, 14:26
That is how I would arrange things - but it might be a good idea to check that the metalwork of the headshell is not also earthed through a connection to one of the signal returns.

wee tee cee
11-02-2018, 14:40
Opened it up.

The ground wire had been soldered with the wire from the arm but was just lying at the bottom of the plinth not connected to anything.

I placed a crimp on it and attached it to a bolt under the chassis.....rice krispies are gone but its humming like a pish soaked tramp.

Will have to do a bit of googling regards earthing points on the lenco chassis.

Thanks for the advice folks ....im really struggling with getting to grips with vinyl (i hope its worth it!)

struth
11-02-2018, 14:42
sounds like connecting it is producing a ground loop

brian2957
11-02-2018, 14:52
Opened it up.

The ground wire had been soldered with the wire from the arm but was just lying at the bottom of the plinth not connected to anything.

I placed a crimp on it and attached it to a bolt under the chassis.....rice krispies are gone but its humming like a pish soaked tramp.

Will have to do a bit of googling regards earthing points on the lenco chassis.

Thanks for the advice folks ....im really struggling with getting to grips with vinyl (i hope its worth it!)

Tony theres a wire runs from a tab at the bottom of the arm to the earth post on the phono stage .
I will try and get over this week mate .

wee tee cee
11-02-2018, 15:51
will step away till help arrives.

Checked lenco heaven-hum issues are rather prevalent!!

Barry
11-02-2018, 15:54
Interesting - I briefly had a G99, used with a separate arm, and didn't experience problems with hum.

Gazjam
12-02-2018, 23:23
Tony theres a wire runs from a tab at the bottom of the arm to the earth post on the phono stage .
I will try and get over this week mate .

Maybe wait till eveningtime so I can tag along Sir?

brian2957
13-02-2018, 01:35
Yup , hopefully Thursday night mate . If that's OK with Tony .

wee tee cee
13-02-2018, 15:01
Aye spot on....fish stew OK?

Audio Al
13-02-2018, 16:19
Aye spot on....fish stew OK?

I made a fish stew 2 days ago :)

hifi_dave
13-02-2018, 16:35
Interesting - I briefly had a G99, used with a separate arm, and didn't experience problems with hum.

That's because it is an arm issue.

wee tee cee
13-02-2018, 16:41
changed the interconnects just in case they were picking up rfi from the balanced mains box .....(one was 7m long piled on the floor)

nope....hum city!!

Will wait for the cavalry...

wee tee cee
14-02-2018, 15:12
It lives.....Brian talked me through it.

My soldering skills aint up to much-i was sweating like a guy defusing a bomb.

dry joint on the arm tab and a poor connection on the phono plug.

Vinyl is an awful lot more demanding than digital!!!

Sounding not too bad though!!

brian2957
14-02-2018, 15:20
Nice one mate . Me and Gary will still be over tomorrow night if that's OK :)

wee tee cee
14-02-2018, 15:34
Thanks Brian....look forward to breaking bread with you guys.

Still trying to get used to the vinyl crackles-but Stevie is sounding pretty good!