Need Advice: Vinyl Hum Issue

Hi everyone,

I’m looking for advice on a hum issue that only occurs with my vinyl setup. My digital chain is completely silent.

 

Important clarification:

I have been using the KEF KC62 via the high-level (L connector) for some time without any hum issues. The problem only appeared after I replaced the bare speaker wire connections with spade connectors at the Willsenton R8 binding posts to make the connection cleaner and more secure.

System Overview

Speakers

• KEF R3 Meta

• KEF KC62 subwoofer

What Changed Before the Issue Appeared 

• KC62 high-level connection remained the same (L connector)

• Only change: 

  • Bare wire → spade connectors at the R8 speaker binding posts 

• Tube rolling done around the same time: 

  • 6SN7: Stock → Ray Select

  • Power tubes: Stock KT88 → Tung-Sol EL34  

Prior to installing spades, the system was hum-free.

Digital Chain (No Hum – Completely Silent) 

• Cambridge EXN100 streamer/DAC

• RCA out → Willsenton R8 integrated amp

• Speaker outputs → KEF R3 Meta

• KC62 connected via High-Level (L connector)  

 Result: Dead silent, even at higher volume

Vinyl Chain (Hum Present) 

• Rega Planar 3

• RCA out → Cambridge Alva Duo phono stage (MC mode)

• RCA out → Willsenton R8 integrated amp

• Speaker outputs → KEF R3 Meta

• KC62 connected via High-Level (L connector)  

 Result: Audible hum

Detailed Symptoms  

• Hum is present only on vinyl

• Hum increases with volume

• When the KC62 is disconnected, the hum disappears

• However, with the sub disconnected and volume above ~10 o’clock:

   

  • Audible vibration / rattling

  • Woofer cones fluctuate excessively, especially on low-frequency passages 

• Touching the RCA plugs does not eliminate the hum

• I have not yet tested touching the tonearm

• Digital playback remains silent under the same conditions

What I’m Trying to Understand 

1. Could the spade connectors be creating: 

   • A different ground reference than bare wire?

   • A tighter mechanical ground path exposing a phono grounding issue? 

2. Is this a known interaction between: 

   • Tube integrated amps

   • Phono stages

   • High-level subwoofer inputs 

3. Best practice for integrating a KC62 with a tube amp + phono stage

4. Whether switching the KC62 to line-level RCA is recommended for vinyl use

5. Whether tube rolling (EL34 + Ray 6SN7) could increase sensitivity to grounding noise

Goal 

• Silent vinyl playback

• Proper subwoofer integration

• No hum, no woofer over-excursion, no vibration 

Any advice or shared experiences would be appreciated.

 

Thanks!