I had a frustrating experience. I have hinted at my possibly selling my home. That means I have to get into my basement/garage to finish the space to get a higher sale price. That forces me to decommission the power supply to my stereo. That meant pulling my Torus WM45 and Benjamin panel off the wall. As well as converting my main service loadcenter back to stock.
In doing this I landed a 10 awg NM-B branch into my panel as I would tell any client to do, then brought the circuit to a metal double duplex box in the wall and landed the 2 x duplex with wire nuts like any contractor would do.
Preparing to sell I only wanted to reconnect my vinyl for the interim. I hooked up my rack mount Torus RM20 to the new branch wire and plugged my preamp, monoblocks and phono preamp in. BBBZZZZZzzzzzz.
WTF. I spent 2 solid days doing everything. And I mean everything. And this was an odd fault. The intensity rose and fell with the volume on the preamp, irregardless of the selected source or if the pre was muted. I had up to 60db of hum when the volume was maxed. About 45 db when set to upper listening levels. It even hummed with the pre turned off, but at a slightly different frequency.
I changed the branch wire between Romex 10, 12, MC Cable, Oyaide cable, my twisted cable. I changed duplex, wall boxes or no box at all. I went in and out of Torus or wall or a mix of both. I changed powe cables, interconnect, tubes. I moved equipment around. Cheater plugs. Ground lift switches. In doing so I also ran into additional issues such as if I touched the preamp and moved my hand near the crossover it injected a new very loud feedback. I left no stone I could think of unturned.
I eventually rolled my large transformer back in front of my panel and reattached the original direct wired power stip I made. Still a buzz. AARRGG.
What have I not done. Lets connect everything. Lets put the digital back in. Why additional noise would help, I dont know. Mind you I had tried inserting the RCA from my DAC into its slots in the pre, but, the dac was not plugged into the wall. I was more wondering if noise was getting into open RCA on my pre. I had also tried lashing wires between all my gear. This time I reconnected the DAC and plugged the power cord into the wall. Immediately the noise dropped a lot. I then plugged in the server and booted the system. DEAD QUIET. Not a peep. Back to normal.
I don't have my hear around exactly why this happened. My amps are transformer coupled. That means the signal hot pin is not mechanical connected. It should also be noted now, my phono preamp is a Channel D lino 3.3. Its battery powered. The power cord does not have a ground. Someone else can chime in and explain. I think its something like the signal from the pre was never able to reference ground. Not until the DAC was connected and did that for it.
As a learn for people reading. There are SET owners using transformer coupled SET. If your also using a battery powered phono stage, hum might be from that source not grounding the signal in reference to the amp. I am just speculating. Others may know better.
This may also be a reasoning why ground boxes may help. I find for audio in your electrical supply, a single point ground works very well. But Mesh Grounding is another very effective ground. With a Mesh in a data center, the metal floor and all the racks holding the servers are bonded together with many many jumpers lashing the entire ground plane together. In a sense with your stereo, all your interconnects and power cords are making a Mesh. The addition of a ground box or multiple ground.boxes for signal and chassis may make for a more efficient Mesh that is then attached.to the single point ground bonded to the utility. A fixed reference.for all. A very effective ground scheme overall.
Rex
In doing this I landed a 10 awg NM-B branch into my panel as I would tell any client to do, then brought the circuit to a metal double duplex box in the wall and landed the 2 x duplex with wire nuts like any contractor would do.
Preparing to sell I only wanted to reconnect my vinyl for the interim. I hooked up my rack mount Torus RM20 to the new branch wire and plugged my preamp, monoblocks and phono preamp in. BBBZZZZZzzzzzz.
WTF. I spent 2 solid days doing everything. And I mean everything. And this was an odd fault. The intensity rose and fell with the volume on the preamp, irregardless of the selected source or if the pre was muted. I had up to 60db of hum when the volume was maxed. About 45 db when set to upper listening levels. It even hummed with the pre turned off, but at a slightly different frequency.
I changed the branch wire between Romex 10, 12, MC Cable, Oyaide cable, my twisted cable. I changed duplex, wall boxes or no box at all. I went in and out of Torus or wall or a mix of both. I changed powe cables, interconnect, tubes. I moved equipment around. Cheater plugs. Ground lift switches. In doing so I also ran into additional issues such as if I touched the preamp and moved my hand near the crossover it injected a new very loud feedback. I left no stone I could think of unturned.
I eventually rolled my large transformer back in front of my panel and reattached the original direct wired power stip I made. Still a buzz. AARRGG.
What have I not done. Lets connect everything. Lets put the digital back in. Why additional noise would help, I dont know. Mind you I had tried inserting the RCA from my DAC into its slots in the pre, but, the dac was not plugged into the wall. I was more wondering if noise was getting into open RCA on my pre. I had also tried lashing wires between all my gear. This time I reconnected the DAC and plugged the power cord into the wall. Immediately the noise dropped a lot. I then plugged in the server and booted the system. DEAD QUIET. Not a peep. Back to normal.
I don't have my hear around exactly why this happened. My amps are transformer coupled. That means the signal hot pin is not mechanical connected. It should also be noted now, my phono preamp is a Channel D lino 3.3. Its battery powered. The power cord does not have a ground. Someone else can chime in and explain. I think its something like the signal from the pre was never able to reference ground. Not until the DAC was connected and did that for it.
As a learn for people reading. There are SET owners using transformer coupled SET. If your also using a battery powered phono stage, hum might be from that source not grounding the signal in reference to the amp. I am just speculating. Others may know better.
This may also be a reasoning why ground boxes may help. I find for audio in your electrical supply, a single point ground works very well. But Mesh Grounding is another very effective ground. With a Mesh in a data center, the metal floor and all the racks holding the servers are bonded together with many many jumpers lashing the entire ground plane together. In a sense with your stereo, all your interconnects and power cords are making a Mesh. The addition of a ground box or multiple ground.boxes for signal and chassis may make for a more efficient Mesh that is then attached.to the single point ground bonded to the utility. A fixed reference.for all. A very effective ground scheme overall.
Rex
