Hum from the phonoamp?

[bastlnut]

hallo leifhellmusic,

if you disconnect the phono stage from the Primare, does it still humm? the same with the cd?

how old is the Primare amp? how many hours has it played?
try leaving it on for a couple of days, even if it is not playing music, and see if it still does humm.
the sudgen phono stage should always be left on, and not turned off ever.

take the bottom cover off the Thorens and look at the solder connections for the signal cable. is there a bridging wire from the ground to any of the signal wires? if so, make sure the black wire comming from the arm is connected only to the ground wire, and the chassis is connected to the ground as well, and cut the bridge wire and bend it so it makes no contact with anything.

maybe this will lead to an answer. we must find out which component is causing the humm, it could even be the Primare. then it is a warranty question, the problem is solveable.

regards,
bastlnut

[leifhellmusic]

Hello bustlnut,

The Primare is young (about three months) and it has played more than 200 hours. I never switch my gear off, they are constantly on. There is no hum from the Primare at "normal" output levels, only when I turn the volume pot to maximum level. In that case the hum from phono is considerably higher than from CD (of course no signal in either case).

I will investigate the groundings in the turntable.

Thanks and regards

leifhellmusic

[seppstefano]

... and, regardless of hum, I would recommend to make a listening session without the back cover...

I had a TD160 and sound cleaned when I simply removed the bottom cover and coupled the chassis to the shelf with some IKEA glass pastrels (I know, I should have tried some mega-ultra spike, but pastrels were available for free )

Removing the cover seems removing many unwanted resonances too.

Stefano

[sreten]

Hello bustlnut,

The Primare is young (about three months) and it has played more than 200 hours. I never switch my gear off, they are constantly on. There is no hum from the Primare at "normal" output levels, only when I turn the volume pot to maximum level. In that case the hum from phono is considerably higher than from CD (of course no signal in either case).

leifhellmusic

Hi,

It is normal for hum and noise from an MC phono input to be much
higher than that from a CD input, at normal volume settings though
the hum and noise should be inaudible.

Completely disconnect the turntable and set volume to maximum.
This gives your reference level, reconnecting the turntable should
not make the hum it noticably worse, if it does sort out the earthing.

/sreten.

[leifhellmusic]

Hello bustlnut,



Hi,

It is normal for hum and noise from an MC phono input to be much
higher than that from a CD input, at normal volume settings though
the hum and noise should be inaudible.

Completely disconnect the turntable and set volume to maximum.
This gives your reference level, reconnecting the turntable should
not make the hum it noticably worse, if it does sort out the earthing.

/sreten.

Humming problem solved! First of all I´d like to thank all who have concerned about my hum problem. I sent some pictures to Stefano showing my setup and he humbly suggested me to move the phono amp from the on top of amp position (how stupid can you be?). As the phono amp is not very heavy I put my hand under the phono amp and lifted it about 5 cm. The hum decreased! Now I have placed the phono amp on a separate shelf and no hum anylonger. Thanks Stefano, bustlnut and sreten who helped me to discover my stupidity.

Regards

Leif

[seppstefano]

Glad it helped Leif,
nevertheless, as soon as you have time to mess with your Thorens, give a listen to a LP without the bottom cover of the Thorens and let us know.

Stefano