Possible phono stage hum problem

[diviy]

If I turn the volume up with no record playing I get a hum .My deck is a sl1210 with a Music Fidelity X-VPLS vs3 phono stage with the earth modded to one of the rca channels so my question is does the phono stage earth through the rca connectors or the case if it earths from the case if i run a cable from the earthed phono to the case could this fix the problem ? I have tried everthing else ie changed rca,repositioned unit`s etc .
any idea what else I could look at PLEASE DOING MY FECKING HEAD IN.

Gerry

[CageyH]

Have you connected the tonearm earth to the phono stage?

[struth]

Earth cable from tt to phono and even phono to amp as well if ness. certainly sounds like an earth hum. There should be either a binding post or a black wire from the tt, and a binding post on the phono stage.

[Firebottle]

Hi Gerald,

DON'T PANIC.......... Sorry couldn't help that :eyebrows:

OK, take things one step at a time. Usually the phono stage is earthed through the interconnects to the following amplifier.
Firstly lets see if the hum is from the phono stage or the deck.

Disconnect the deck from the phono completely, turn the volume up to see if you have any hum. If you do it's coming from the phono stage.
If so it 'could' be caused by the loop formed from both interconnects to the amplifier. Disconnect one interconnect to see if the hum goes.
If you find the hum increases when you touch the case of the phono then it's likely the case isn't earthed via the interconnect. Try connecting an earth wire between phono case and amplifier case.
If you've still got hum the phono stage needs improvement.

Next connect one signal lead from the deck and turn the volume up. If no hum that's good. You might find that if you put your hand near the pick-up arm or touch the deck chassis you get some/more hum. This isn't necessarily a fault, particularly if the deck has a separate earth lead. If so connect this earth lead to the earth terminal on the phono, this should stop hum from contact to the deck chassis.

If you don't have a separate earth lead it is probable that the deck chassis is earthed via the signal leads. Now connect the other signal lead to the phono stage. If all is good you should have no hum. If after connecting the second signal lead you get a hum then it could be a loop caused by the two signal leads. Partially remove one of the phono plugs from the phono input so that the outer connection is broken but the inner pin stays connected. Do you now have no hum but left and right playing from a record?

:) Alan

[diviy]

I have now swapped head shells ,phono leads tried extra earths even checked continuity on all earths all ok still got hum baffled now :doh::doh:

[diviy]

I have now disconected the turn table from the phone still got hum ,I then put a earth cable between the pre amp and phone stage hum still there if i remove any of the rca when system is connected up them hum increases the deck is earthed via a rca that have check with a meter so do asume its time to open up then phono stage to see if there are any dodgy conections .

Cheers Gerry

[struth]

Dnt want to state the obvious but the phono stage is into a normal line level and not the phono one of the A65 I presume Forget that its too obvious... Dont know what else to think tbh unless the phono stage is faulty or you are picking up some sort of mains hum off another cable.

[YNWaN]

Is there anything with a transformer in any other piece of equipment that is close to your phonostage as this is a well known cause of the kind of problem you describe. Try moving the phonostage away from other equipment.

Oh, also the base station for a cordless phone can cause problems even from a few feet away.

[Stratmangler]

Here's a view of the rear of an A65, where have you plugged the X-VPLS in?

http://listeninn.com/Pictures-Used/Used-Integrated-Amplifier/Arcam-A65-Plus-7.jpg

[diviy]

Plugged into the ac/dvd socket even tried it in the tuner sockets .I do have the timestep power supply on the same shelf but still get hum when power supply in not connected

[Stratmangler]

Move the Timestep PSU away from the amplification devices.

[YNWaN]

When you say the Timestep is disconnected do you mean unplugged from the mains or just from the deck? The transformer in it will still be radiating quite a strong field if it is plugged in and this is likely to be causing the hum you describe.

[diviy]

I have unplugged it compleatly

[YNWaN]

Well it's not that then.

[walpurgis]

It may have been mentioned. Is the signal return (neg) common with the case earthing? If in doubt try touching a piece of wire between a bare piece of casework or a screw head and the outside of a connected lead plug (the metal negative outer. I'm assuming they're RCA phono) whilst the unit is connected up and switched on. Have the volume low to avoid nasty noises through the speakers. If the hum goes, you'd need to join the signal earthing with the casework.

[Jason P]

Try moving the XLPS around - by that I mean altering it's orientation, point it up, down put it on it's side - my reason for saying this is I had the same problem on mine, it went away if I put the 'stage on it's end. Turned out to be a dry joint on the back side of the earthing post... took me ages to find it!

[walpurgis]

I had a casework earth break on an X10-D. As soon as the earth was reconnected (commoned to the signal neg side), the hum went.

[diviy]

Finally sorted dry joint on the phone stage happy days .com