X-LPSvs hum problem

[diviy]

If I turn the volume up with no record playing I get a hum .My deck is a sl1210 with the earth modded to on 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

[jc]

I'm not sure why this particular mod is done to the 1210 but the following quote covers my opinion on your hum (found while looking for why)

The deck itself is double insulated, so long as the wires arent connected at the deck end but only at the mixer end you'll be ok.

If the grounding lead is left unconnected then at high mixer gain levels or with nice bass speakers you'll usually get a background hum whenever the deck channels are faded up. This is much less of a problem on home hifi but is very serious where the decks are feeding a nightclub-sized PA with all the exaggerated bass they tend to incorporate.

It doesnt matter if your mixer is double insulated or earthed, you should always connect the black wire, the audio ground reference and the mixer chassis will be connected internally.

I've seen all manner of weird and wonderful mods and attempts to stop a Technics buzzing, in every case it's been because someone has either incorrectly replaced the fixed-in phono leads or chopped off the black ground lead, or otherwise somehow tried to reassemble the deck after repair.

The headshell of the technics is connected to the pcb under the yoke assembly by a very thin black flexible wire and has to be trapped with a brass terminal as the headshell connecter is assembled onto the end of the tonearm, this is something that's sometimes not put back (either by ignorance or carelessness) if the tonearm is disassembled for fault finding purposes. The wire sometimes breaks as it passes through the yoke assembly due to constant flexing in a similar way to a wiring loom in a moving head scanner...and also gives rise to annoying, intermittent hum.

Credit to KevinE on the BlueRoom forum.

[diviy]

I have now totally disconnected the deck and with the phono stage on the hum is still there !!!

[jc]

How high are you turning the volume to hear the hum?

The phono input is a very low level input and more susceptible to hum due to the higher gain required from the amplifier. Is the hum fixed in volume or increases with the higher end of the volume scale?

[diviy]

zero is at 35 past the hour at about 9 to 11 you can hear it and from there to 25 past it it increases

[PinkFloyd]

Dec 22, 2014 17:03:39 GMT diviy said:

If I turn the volume up with no record playing I get a hum .My deck is a sl1210 with the earth modded to on 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

Try a CD player as source with a "compact disc" playing....... does the problem still persist?

[PinkFloyd]

Have you eliminated the amp as the culprit? How long has this problem existed? Come on all of a sudden or a long term problem? Have you swapped out a new pair of interconnects?......... lots more detail required.

Mike.

[PinkFloyd]

I'll ask the question again........ it's been doing your "fekkin'" head in for how long? If it's a problem that has just started to show it's ugly face then it will likely be a faulty component somewhere in the chain.... we just have to establish WHAT part of the chain needs fixing.

Isolate as much as you can..... remove the turntable from the equation and go "amp and speakers only" does it still exhibit the same noise?

Don't automatically assume the source is the problem, it's a process of elimination and be prepared to find the unexpected.

[diviy]

Its been going on for mths been bed bound so its only now I can get to the hifi all the leads are the same. no hum if cd player connected up .
System consists of a Arcam A65 as a pre 2x Arcam as mono blocks creek evo cd player X-VPLS v3 sl1210 with a timestep power supply and Kef Q30 speakers.I have even tried running it off a different mains spur but still get the hum .

[jc]

Dec 22, 2014 20:28:25 GMT diviy said:

I have now totally disconnected the deck and with the phono stage on the hum is still there !!!

remove the phono stage and leave leads connected to preamp. Any different?
Humour me here, record deck direct to same line in on pre without XLPS, it'll sound super crap but is the hum still there.
Replace phono stage and run earth lead from screw post on XLPS to a rear case screw on pre. (you will need bare metal on pre, if screw has paint beneath, scratch it off.

[Deleted]

All my equipment hums!!!!
It's the electricity. If I sit reading I can always hear the amp and CD player humming. They are not faulty it's what they do.

[diviy]

insert quote here

remove the phono stage and leave leads connected to preamp. Any different?        hum gone

Humour me here, record deck direct to same line in on pre without XLPS, it'll sound super crap but is the hum still there. now gone

Replace phono stage and run earth lead from screw post on XLPS to a rear case screw on pre. (you will need bare metal on pre, if screw has paint beneath, scratch it off.
adding earth lead increases hum

[jc]

OK, have you ever opened the XLPS to replace a tube or any else?

I ask because, there is an earth lead that runs from a board inside to the internal side of the rear panel and is held in place by one of back panel screws. If, like many, you have missed this lead when closing up, this could be the source of your hum...

Additional thought, does the power supply for the XLPS buzz or hum too?

[diviy]

Problem sorted dry joint on the earth on the board redone joint and sounds so much better