What would cause noise (ground noise?) when touching the volume control and tone controls?

@cleeds Ah... it's a "new to me" preamp, but it's a used unit.  Fairly new though.

@antigrunge2 I don't have a phono setup, just a streamer connected to a DAC and the DAC connected to the preamp. 

I can reach out to the preamp maker, just wanted to see if I could solve it myself before doing so.  :)

@atmasphere Yeah that's what it appears to be.  I'll reach out to him and maybe he can help me solve it without sending it back for some TLC.  

@daveyf  I really should put more detail when I post. Yes, it is a tube preamp. I did tap on them gently to see if I could detect anything. 

@audio-union Good idea, I can check with my little plug checker. That outlet may have an issue. 

@audio-union  I just checked my outlet ground with my checker and it doesn't show any ground faults with the wiring. 

@imhififan  I did a continuity check with my Fluke and it does beep when touching the center ground pin of the power cord and then touching ground points on the preamp chassis.  It beeps when I touch the grub screws holding the knobs on the pots as well.  I opened the preamp and all the grounding/shielding is in place and looks to be well done.  Otherwise the chassis is wood with metal top, front and back plates.

It could just be the nature of the beast.  Tube quality is unknown so I'll try some new ones before going further.

So I tried a few more things but I'm still getting the buzz/hum.  When I touch the ground stud on the back of the preamp (for the phono stage), it goes silent.  Maybe I can run an external ground wire?

@daveyf I'm going to not mention the manufacturer right now until I get a chance to speak with them about it.  I don't want to cause any issues for them in case the issue is really mine and not theirs.

I did try the cheater plug to remove the ground and the noise was still there so I'm thinking a tube or maybe a bad transformer?  We'll see, I'll update the thread as soon as I can.  :)

I fixed it.  The left channel output ground wire had fallen out of its terminal block.  It's quiet now.  :)