I actually own a GS Communicator Gram Amp 2. I have been using it for 6 months and I instantly noticed an improvement over the inbuilt phono stage on my Pioneer PLX500. I am slowly trying to improve the sound quality of my set up. It’s a budget set up and I have already upgraded the cartridge & headshell to an AT VM95E over the supplied one, that made a big difference too. 

I have a few questions to ask; any advice is welcome. 

Would the PSU1 upgrade be worthwhile on a budget set up? 

My TT doesn’t have a grounding attachment and the plinth/casing is all plastic. I heard somewhere that it maybe grounded through one of the RCA’s but I cannot confirm that. I do have a ground loop him but only if I turn my volume up very high to max which is generally beyond the actual listening volume, so I can live with it. Could changing my TT to one with a proper ground attachment help resolve this issue? 

My set up is the Denon M41 DAB, Pioneer PLX500 with AT V95E, L*nn Tukan speakers, REL Tzero Mk3 subwoofer and it’s running sweet. But just wondering if the PSU1 unit would make a big difference, or would upgrading the TT be a better path?

Thank you 

B 

I haven't tried your turntable so can't give specific guidance on it versus an upgrade. The PSU1 would help it to fulfil it's potential, if that helps.

I've looked at the photos of the back of your TT. Indeed it does not have a ground wire and looks to have captive cabling. 

The only way to find out the grounding scheme of your turntable is to get your hands on a schematic and have someone read it for you. That or take your TT to a technician and have them open it up. They may be able to add a grounding post for you but obviously this means modifying the turntable. 

Grounding issues can be difficult to figure out - sometimes they are due to things that have nothing to do with the turntable. I've heard all kinds of stories...sometimes it was house wiring that wasn't properly hooked up, certain types of appliances on the same circuit, a metal-bodied cartridge that needed to be isolated from the metal headshell, etc. 

Here is some info for you - note that I am not endorsing Soundsmith products, but they do have some decent advice about grounding and hum issues. Obviously do anything recommended there at your own risk:

https://sound-smith.com/hum-and-or-noise-problems - https://sound-smith.com/hum-and-or-noise-problems

Re: the PSU-1, I agree getting one on loan is the best idea. 

The Pioneer PLX-500 is marketed as being "internally grounded," which means it doesn't have the traditional thin ground wire found on most turntables. While this is meant to simplify setup, it often causes a "hum" or "buzz" in certain configurations—especially when used with older amplifiers or specific DJ mixers.

Here is a guide to diagnosing and fixing grounding issues on your PLX-500:

1. Check the Phono/Line Switch

This is the most common cause of noise. The PLX-500 has a built-in pre-amp.

 * If you are plugged into a PHONO input: Set the switch on the back of the turntable to PHONO.

 * If you are plugged into a LINE/AUX/CD input: Set the switch to LINE.

 * The Problem: If you set the turntable to Line but plug it into a Phono input, the signal will be double-amplified, causing massive distortion and loud buzzing.

2. The "Ghost" Grounding Fix

Even though the PLX-500 is internally grounded via the RCA cables, a ground loop can still occur if your mixer or amp expects a dedicated ground.

 * The Fix: Take a standard piece of speaker wire or any thin copper wire. Touch one end to a metal screw on the underside of the PLX-500 chassis and the other end to the GND terminal on your mixer or amp.

 * Why it works: This manually bridges the ground and often kills the hum instantly.

3. Move Away from Interference

The PLX-500 is a budget-friendly deck and its shielding isn't as heavy as the PLX-1000 or Technics models.

 * Keep it away from power bricks: If your laptop charger or a power strip is sitting directly under or behind the turntable, it can "leak" electromagnetic interference into the tonearm.

 * Monitor Placement: Ensure your speakers (especially powered monitors) aren't sitting on the same surface as the deck, as this can cause low-frequency feedback that sounds like a hum.

4. Reseat the Headshell

Sometimes the "buzz" isn't a ground issue at all, but a poor connection at the tonearm.

 * Unscrew the headshell, check the four small colored wires to ensure they are tight on the pins, and then screw the headshell back in firmly.

 * If the pins inside the tonearm are dirty, a quick dab of isopropyl alcohol on a Q-tip can fix a "static-y" buzz.

5. USB Connection Hum

If you have the PLX-500 connected to a computer via USB while also connected to a mixer via RCA, you are very likely creating a ground loop.

 * Test: Unplug the USB cable. If the hum stops, you need a "USB Ground Loop Isolator" or you should avoid using both connections simultaneously.

Is the hum happening on both speakers equally, or is it louder on one side? (This can help determine if it's a cable fault rather than a grounding issue.)