I built the preamp from Franks Ultimate Preamp thread and it sounds really good. https://www.diyaudio.com/community/threads/franks-ultimate-tube-preamp.12042/page-4s. Not sure how to link to that thread but I'll attach the schematic. Anyway, I tried something different and I used a 12 VDC external power supply with an 8-32V to 45-390V DC-DC High Voltage Boost Converter ZVS Step-up Booster Module to get 310V and filtered really well (4 stages). I also used an LM317 to get the 6.3 volts for the heaters.
At the risk of starting a thread debating the merits of my approach (which I am trying for fun), I have a question about grounding. I use a star ground tieing everything back to the 12VDC common. The system is super quiet and works as long as all the items connected to it are powered through the same power strip. If I connect something from a different AC source even if it is connected to the other plug in the same duplex receptacle I have a high-frequency buzz and some other noise on the system. As an example I have a Volumio connected to a DAC and if it is connected to the same power strip as the preamp it works great. If I connect it to another power strip connected to the same plug sounds like I have a ground loop.
I don't have experience with DC circuits without a tie to AC ground in the same box. Am I grounding this correctly tieing everything to 12 VDC common? The chassis is connected too. Any advice?
At the risk of starting a thread debating the merits of my approach (which I am trying for fun), I have a question about grounding. I use a star ground tieing everything back to the 12VDC common. The system is super quiet and works as long as all the items connected to it are powered through the same power strip. If I connect something from a different AC source even if it is connected to the other plug in the same duplex receptacle I have a high-frequency buzz and some other noise on the system. As an example I have a Volumio connected to a DAC and if it is connected to the same power strip as the preamp it works great. If I connect it to another power strip connected to the same plug sounds like I have a ground loop.
I don't have experience with DC circuits without a tie to AC ground in the same box. Am I grounding this correctly tieing everything to 12 VDC common? The chassis is connected too. Any advice?
Your link is not working, lets use this one:
https://www.diyaudio.com/community/threads/franks-ultimate-tube-preamp.12042/page-4
That's weird, can you try a different power strip? Maybe it wired out of phase or no ground connected?
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This sounds like a mains earth loop problem which can frustrating to solve whilst at the same time keeping equipment safe. Some basic info here - https://www.soundonsound.com/sound-advice/q-what-ground-earth-loop