Help me understand how to optimize bass on the Zu Definition Mk IV

Keep in mind, the sub amp is a Class D, with relatively low consumption requirements, and the amp has limited frequency duties in this application. You have far more influential opportunities elsewhere in the system to strive for more objective sound than worrying about the power cord and fuse to each Def4.

Phil

Totally true, Phil, I was just curious where Marc has gone with his power upgrades. I still have some work to do to reduce some background noise in my audio chain, particularly when using my turntable as a source. I agree that the subs are the least of my worries in that regard. I had wondered, however, if the power cords to the Zu's were introducing the possibility of some ground loop hum (heard through the compression tweeter), as they are currently plugged into a different circuit. Solving grounding problems has yielded tremendous gains for me in the past, on both the listening and recording ends of the spectrum. David

Yes, you should solve grounding problems. You're hearing hum through the Radian compression tweet? That's strange. No, the Zu Def power cables aren't introducing ground loop hum. But you probably have induced some ground loops in your system connections, and it's likely your ground points are not all on the same plane. Solutions are always elusive. If the sub amps' power is contributing, it's not the cords, it's having them plugged into a different circuit. By chance, do you have cable TV among the sound sources into your system?

Also, is any portion of your system balanced or running balanced or XLR cables? Mixing Bal with SE can also surface ground problems. What is your analog chain (phono-pre > pre) and is there an SUT in the mix? How many (if any) of your components have ground-lift switches? Do you have any passive components that are not separately grounded? What's your phono cartridge and tonearm, and how closely are they placed to anything else with a substantial power supply?

Just some questions for which answers may narrow your suspects.

Phil

David, Phil is right. Do not expensively spend on subs ancilliaries until you've got basic setup right. At that point if you're happy, and want to go on, my personal experience is that choice of pwr cords and fuse makes a difference.

I'm stuck with a little hum in my Zu sub amps that I'm still searching for a solution.

Yeah, I'm not too interested in spending much on power cords etc. at this point. I was just interested in the grounding posts you had installed on the Zu's and your overall power management scheme, as I've struggled with some hum and slight buzz in my system. I do have the subs on the speakers on a different circuit, which I realize is an issue, but was more practical given how things are arranged in my listening room. Also, I misspoke when I said the ground loop hums are coming out the tweeter... obviously they are oscillating at 60hz. I actually only have a small amount of 60hz hum present in the FRDs and not audible in the sweet spot. I do, however, have some hiss and buzz out of the tweeter when the phono is selected on my turntable. I was able to reduce the buzz significantly by running a ground wire from the lamp above my turntable (on a dimmer, which is a likely source of the problem) to the turntable itself and then to the preamp. I had considered a star grounding scheme for the whole rig, which worked wonderfully to lower the overall noise floor when I did this for the analog mixing setup in my home recording studio. In such a configuration with grounding posts on the speakers, I could then lift the grounds on all but one of the components for a single path.