0

Phono One grounding

sarucyel

March 17, 2024 09:41

None

Follow

Hi,

I have a Phono One card between a Pro-ject turntable and a valve amp - before that it was going into a vintage but solid state amp and there was no humming, whereas now I can't make it go away.

I initially tried getting a grounded power supply for the Phono One but that alone didn't help, so I got another one for the turntable which made it even worse! Somehow a non-grounded tt into a grounded pre-amp gives a better outcome, though not perfect.

So I suspect I am missing something... I tried to connect the ground port of the tt to that of the Phono One but that produced not difference... Can anyone suggest a setup which would work like into my old solid state amp? Obviously this is a very 1st world problem but I would like to understand what's going on.

Many thanks in advance Vincent.

• Facebook
• Twitter
• LinkedIn

3 comments

• 0
  
  HiFiBerry team March 18, 2024 05:36

  Almost all turntable pickups have a separate ground connection. This is usually a separate cable. Did you connect this to the ground of the Phono One? 

• 0
  
  sarucyel March 18, 2024 09:48

  I (think?) I did... ie ground cable firmly screwed on the turntable side, then I put the G solder point (next to the R+ R- L+ L-) on the Phono One in contact with the other end... so no soldering, just touching to see if the hum would go away even slightly (it did not).

  I presume (though almost certainly wrong) that it's because I am not using the 4 other solder pads and RCA cables instead?

  Thanks Vincent.

• 0
  
  HiFiBerry team March 18, 2024 14:42

  "just touching" might not give a good contact.
  Grounding of turntables is needed as the output level of the pickup is very low and in addition to this input impedance is quite high. This hasn't to do with the fact that you're using RCA jacks instead of the solder pads.