et3se high gain phono stage noise

[camiablue]

Hi,

I just bought a used (mint condition) et3se with the high gain phono stage. Love the way it sounds, especially through the line stages. But I notice that the phono stage has a hum (low static) noise. And the noise gets louder as I turn up the volume. Very noticeable past 60 (volume). I thought it may the the 12AX7 (Mullard) tubes. I replace them and the noise is the same. Has anyone else experience this? Again, it is only on the Phono source. Quiet as mouse with other sources. At first, I thought it was my rega P6 turntable. I had to turn the volume up because of the .35mV cartridge. That's when I noticed the noise. But after unplugging everything and just had my headphone amp plugged to ep1 out, the noise was very noticeable at high volume. Anyway to get rid of the hum? Thanks

[admin]

Couple of things I would check to rule out a ground loop. This would be a very specific 60 hz hum (presuming you are in the US). The other thing I am thinking is a mismatch between your cartridge output and the phono stage. You may need a step up transformer. You would notice this simply by having to turn up the volume more on your phono listening vs other line stage sources. Of course it could be a component failure as well, but I would rule out the first two to start with.

[AnotherJohnson]

.35 is borderline acceptable as an input to a 54 dB phono section. You really will do better with 58 to 64 dB of gain for that LOMC.

The need to run at 60 on the volume suggests this too.

Plug the ET3 into the same outlet as your amp. Check your interconnects. Make sure the phono ground lead from the arm is screwed tightly to the ground screw by the phono inputs in the ET3. Make sure the leads on the cartridge are seated on the pins. Reseat you’re tubes.

The ET3 is too new a model to need recapping.

it is probably the modest gain for the very low output cartridge (depending on room, amp, speakers and the like), but maybe you’ll be lucky and one of these other gremlins is responsible.

[camiablue]

I am in the US. I followed the advice and I actually unplug everything from the et3 except for the output to the speakers. Even with that, When I turn volume up to 100, the line stage (cd & aux (dac) source) has a very very low static, but the phone stage (phone source) has a much higher hum (static). I am wondering if all high gain phono stage exhibit this behavior? I still have my CJ PF2. I plugged that in and the phone stage on there does the same thing. I never notice it before because my old P3 has an MM cartridge and I listen to it with such lowered volume (25) that the hum never showed up. I just googled and it does sound exactly like the ground loop 60 hz hum. Will this happen even without any component connect to it? I even moved it to a different room. Is there a way to reduce and get rid of it?

[admin]

If it's 60 hz, it's almost certainly a ground loop issue. I would recommend getting a ground loop isolator RCA cable. They are cheap and will definitely tell you whether it is a ground loop. Like this: https://www.amazon.com/InstallGear-Grou ... NrPXRydWU=

To confirm that the hum is 60 hz does require a calibrating mic and setup. But some people can discern it accurately. I use this mic: https://www.minidsp.com/products/acoust ... ent/umik-1 with the free software: https://www.roomeqwizard.com

I find these tools invaluable not just for proper room setup but also I have used it for diagnosing my hardware (ground loops, faulting speaker components, and general room calibration).

Eliminating a ground loop can be tricky but if often takes a little experimentation. There are lots of guides of how to try and plug in components, like a star formation, but in my experience it's just trial an error and making sure everything is grounded properly.

[camiablue]

Thanks Admin