parasound zDac owners - quick question


Im demo'ing a zDac. It has a really obnoxious transformer hum. My 2 zamp v3's have the same hum, so Im afraid this is universal for z products :(

Do any other owners of these have the same experience? I tried it with and without a power conditioner, in different outlets, and with different power cables. I even powered it on in a different room away from other audio equipment to eliminate potential field effects. No help.


You may have ground current problem at your house.Ground loops are a major cause of noise, hum, and interference in audio, video, and computer systems. Try using balance cables on your system or eliminate the ground to test with an adopter or transformer.
I used z products with no such issues.
Hi beewax
Thanks for the response. Im glad to hear that you have avoided the issue. I would agree that I probably have bad power. I have 2 zamp v3's, both of which hum (one isnt loud.) But I have 4 other amps with toroid transformers, and none of them hum at-all.
This zdac is the loudest, by far. Ive tried it in three different power conditioners, in different outlets, in different rooms...all the same result...even if its not connected to an amp or anything else.
Im thinking about taking it apart and see if it could be tightened or something applied to dampen it. Its pretty nuts. But I dont want to void the warranty.
I have zdac with no hum
Mine hums, and it's definitely audible from a foot or so away. I emailed Parasound about it. Richard Schramm attributed it to the toroidal transformer; he said some hum is normal, but it will be worse depending on the power in the home, dimmers, etc. I don't hear it from across the room like I did with an old Unico integrated amp I once owned (that hum just about drove me insane). It may be worth opening it up and seeing if you can tighten down the transformer a bit (while unplugged, of course). I have not tried this, but it could work.
Thanks for the feedback.
So it seems its possible to get one that doesnt hum, but at least Im not the only one.
I dont have any dimmers in my house, nor do I typically have any video sources or displays powered up, except my PC. I may try unplugging that and see if there is anyway the PC power supply could cause this.
Again though, all my z's hum, and none of my non-z toroids do. But this zDac is the loudest. At least I cant hear it from my listening position.
Ill probably try to exchange it and see it the new one is any better. If not, Ill probably open it up.
I just took delivery of a ZDac to replace a MuFi VDacII. The ZDac is dead quiet, but I might also be "cheating."

I'm running Balanced AQ interconnects, and have the ZDac plugged into a Transparent PIMM (that's also providing the power to my CDP). The power line itself is running audio only; no dimmers; no computers; and no video monitors.

Have you tried running the ZDac isolated? That is, by itself, away from other equipment, and without anything hooked-up to it. If not, consider plugging it into a quality surge protector/conditioner and, in turn, power that through an outlet that's on a line that isn't being shared by anything.

If the ZDac still hums after you've "quarantined" it on a clean line and by itself, then it's likely the unit is the source for the hum. If you do get a hum, try repeating the quarantine on a clean line at a friend's house. If the repeat trial also generates a hum, then you know it's very likely the unit itself.
Hello Courant,

Thanks for the input. Ive tried it totally isolated, in a power conditioner alone, in a separate room, on a different circuit on the breaker box than anything else. Same effect. I havent tried a different house; maybe I will. Again though, both of my zamp's hum, but none of my other toroid-powered devices hum.
Im probably going to exchange it and see if the new one does the same thing. If so, Ill have to decide if I can deal with it for the long term. It would be a shame to get rid of it after all this time.
Hello Lightspeed, I have the parasound 5250 amp. I had the same hum Fixed the problem w/HumX plug adapter.