Weird Metallic Ping Sound with Pioneer DDJ, Turntables, and Phono Pre-Amp

Hey guys, I hope you can help me with this weird issue because it's really taking the fun out of mixing records. I enjoy recording my mixes and listening to them later but the problem is a weird ping sound on bass kicks that is really annoying.

Long story short I have 2 Vincent PHO-8 Phono Pre-Amps between my Technics Turntables and my Pioneer DDJ-1000. The reason for that is the audio quality is terrible with turntables directly connected to the Pioneer DDJ-1000 because it has a poor internal phono pre-amp. Everything worked fine previously. The audio quality using vinyl was bad but I didn't have this annoying ping sound until I added the Vincent PHO-8s to the setup.

Here is a sound clip I recorded of the ping sound along with a song sample. https://soundcloud.com/nevereal-1/weird-turntable-metallic-ping-sound

This sound happens when I tap the body of my turntable with the stylus down on a record. It mostly happens during songs on the bass kick. Seems to be related to low frequency sounds.

This only started happening after I began using Vincent PHO-8 Phono Preamps between my 2 turntables and Pioneer DDJ-1000. I can still hear the ping sound with headphones through the Pioneer DDJ so it's not related to the USB connection, cables, speakers or anything like that. This does not happen when a single Vincent PHO-8 is connected to my Clarett 4-Pre DAC to my PC.

Here's the really weird part: The ping sound goes away when I adjust the Pioneer DDJ-1000 channel gain up or down to particular levels. I theorize it's because of the Vincent PHO-8's faulty RIAA Equalization, which I saw a forum post about.

Vibrations in the environment are not causing this issue, I wish it was that simple. This ping sound occurs regardless if I am using speakers or not. It occurs even when using headphones while the room is completely quiet and there are no vibrations.

One of the most peculiar things about this problem is that I can make the ping sound become more quiet to the point it disappears completely by raising or lowering the gain to particular levels. However, the ping sound itself does not become louder when the gain is raised. I can raise the gain and yet the ping sound will become more quiet.

Obviously the simple solution is to adjust the gain but it doesn't stay consistent for all tracks. I have to re-adjust the gain to get rid of the ping sound every time I start playing a different record.

I have also considered buying a proper DJ mixer like a Pioneer DJM mixer to see if that fixes the problem but I was hoping there would be some way to fix this issue without having to buy another mixer.

Any ideas? Thanks!