would going from 72/k boards to prefix k help with rfi and pops?

I have used a DL-103 with a Prefix K and never had any issues of RFI, pops, etc..  

It could be a sign of problems elsewhere and being caused by something else.

If you do elect to go for a Prefix, then best go for a later one with the improved RF mods, or else have it done at Naim.

Sorry if my post was confusing.  It is a problem with all cartridges not just the denon.   I guess I will try a new prefix, hopefully it will be as pleasing as the bare k boards.  But in the audio world,  you can never be sure.  Sadly - audition is not an option.

My age is showing, as I meant stage line k not prefix.

Is it hum, hiss or Radio Moscow? I had Radio Moscow on my superline, moved the system across the room, no different, added  1nF plug, made it bearable, put it on Fraim lite, total cure. It was a Target rack before and I can only surmise  all that metal was focusing the signal much as a multi element aerial does but earthing the metal of the rack had a minimul effect.. What is your set up like and what is near it?

In the U.S. and live near dozens of stations.  I can lift the needle, turn up the volume and listen to the radio sans tuner.    Op amp designs can cope, but I don't want to give up the K board sound.

Before the superline I had an Michell iso or at least the circuit board from one in a plastic box from a local components supplier and a transformer rescued from a scientific instrument that was being scrapped. This never seffered from RF but was an op amp design. With the superline changing my arm from a Rega 300 to an Aro made no difference to the radio reception, earthing the two racks did very little, the different metals in the welds or brazes probably added enough resistance to negate any attempt at equalising potentials.

What I was asking is how is your system arranged? wooden or metal rack and how is it constructed? Is it near any pipe work? What boxes are there and in what order? Cabling and earthing arrangements? What deck, arm etc?

Appreciate where you are going with this, but the only thing that can help is some type of rfi rejection built into the phono stage.

I guess you are talking rejection of radio break through as opposed to RFI. They are two different things... radio break through can be caused by poor electronics, or poor impedance matching and the non linearity properties of various components can demodulate or  discriminate radio frequency currents to cause audio interference (as opposed to radio frequency interference which you can’t directly hear)

Radio Frequency interference on the other hand  can effect the feedback and gain of circuits and so can affect how they perform at audio frequencies as well as proving intermodulation sums and products which can be buzzes and whines... but not detectable audio from a radio transmission.

I suspect if you are talking radio break through then the issue will be impedance or  grounding   related of inputs where connections etc are acting as a radio tuned circuit resonating at a particular frequency and not related to relatively high electromagnetic  field strength sources which causes RFI across most electronic components within that string field strength.  So with the former I would look at grounding, impedance matching, and the shape and path of high impedance interconnects or even if all else fails modifying the tuned circuit resonance by changing capacitance or inductance to change its frequency... the latter relies on the removal of local RF electromagnetic sources, or complete shielding and using chokes on interconnects and leads if you happen to live with a few hundred metres of a high power radio transmitter (which can be mobile mast, radar, TETRA, DVB etc and not just your local radio station)

Simon-in-Suffolk posted:

I suspect if you are talking radio break through then the issue will be impedance or  grounding   related of inputs where connections etc are acting as a radio tuned circuit resonating at a particular frequency and not related to relatively high electromagnetic  field strength sources which causes RFI across most electronic components within that string field strength.  So with the former I would look at grounding, impedance matching, and the shape and path of high impedance interconnects or even if all else fails modifying the tuned circuit resonance by changing capacitance or inductance to change its frequency... the latter relies on the removal of local RF electromagnetic sources, or complete shielding and using chokes on interconnects and leads if you happen to live with a few hundred metres of a high power radio transmitter (which can be mobile mast, radar, TETRA, DVB etc and not just your local radio station)

That's it.   So maybe some flexible metal conduit around the phono interconnects and ground wire?  I've tried everything I can think of.

majordude posted:

My age is showing, as I meant stage line k not prefix.

I briefly had a Stageline S in my system that was almost as good as a NAT 01.