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Does your ZRock2 hum? (Read 4804 times)
DancingSea
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Does your ZRock2 hum?
02/11/22 at 09:08:53
 
Aloha,

My 5 day old ZRock2 has a hum.  Is this normal?  My ZBox has no such hum.  This is not a hum that shows up with the audio chain, but rather a physical hum to the box itself.  The rest of the stereo is off, only the ZR2 and ZBox have power.  And the ZR2 has an obvious hum.

Wondering if I need to send it back as well for repair?  I'm using 12AU7 tubes that have been used in the ZBox for a year with no hum.

It’s a 1 db hum, according to my meter.
Thanks
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Lon
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Re: Does your ZRock2 hum?
Reply #1 - 02/11/22 at 09:51:57
 
Oh boy, welcome to the world of hum. I have had ZBOX and ZROCK2 that have seemed to "hum," but the hum was actually caused by placement of interconnects near power lines, and other placement and environmental reasons. Study up on the forum about hum and see if you can lessen or remove it, or get in contact with Steve again for some personal assistance. It is likely not the unit itself, imo.
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Archie
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Re: Does your ZRock2 hum?
Reply #2 - 02/11/22 at 16:51:50
 
I second Lon's post.  I chased hum for years and gave up.  One day, purely by accident, I rerouted some ICs away from the wall power outlets and the hum disappeared.  My ZR2 is stone quite.  I'm not sure what 1dB sounds like but can you hear it more than a couple of feet away?  I think the goal of no hum is ultimately unattainable given all of the tubes, transformers and other variables involved.  It comes down to what interferes with the music and not what you can hear if you are on top of the amps and speakers.

Decware gear not only exposes flaws in source and music but it also exposes deficiencies in power and geometry.  That said, I did send back my ZP3 and Steve improved, but did not eliminate (see note above) the hum.
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DancingSea
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Re: Does your ZRock2 hum?
Reply #3 - 02/11/22 at 17:52:06
 
Thanks for the, no pun intended, feedback.  I did move the ZR2 to a more tightly packed lower rack that’s closer to all things electrical.  It’s where the ZBox has happily lived for 18 months and that fit nicely stacked together. In order to put the ZR2 after the CSP3, I need the ZBox between the ZR2 and the amp.  And I bought posh tubes for the ZBox, thus would like to use the ZBox anyway.

I’ll try moving the ZR2 back to the limelight of the top shelf where I did not notice a hum before, though was not looking out for one either.
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Archie
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Re: Does your ZRock2 hum?
Reply #4 - 02/11/22 at 18:00:14
 
For me, it's not where the amps are but rather how the ICs are routed.  Having ICs near or crossing power cords isn't an issue but being near an electrical outlet causes problems.  In my system anyway.
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DancingSea
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Re: Does your ZRock2 hum?
Reply #5 - 02/11/22 at 19:12:46
 
Moved the ZR2 back to where it was, both with and without the ZBox.  There's still a hum.  But it's not very loud, literally only 1 db.  The ZR2 was originally sitting next to, and directly connected to the CSP3 and I didn't hear a hum. When the CSP3 returns, I'll recreate the original topography and see.

The hum is not a big deal.  I'm just on guard for flaws after the CSP3 experience.

I'll chalk the hum up to bespoke antique Edison charm   Tongue
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JBzen
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Re: Does your ZRock2 hum?
Reply #6 - 03/21/22 at 13:37:37
 
Just acquired a Zrock2 and it does introduce hum into my system. If it is taken out no hum. The hum seems to abate after a couple of hours. Maybe why Steve suggests to leave it always on. Either case it is not of real concern being I’m nitpicking here.

I’ve learned how to adjust it. So at this point it is not going anywhere Tongue

John
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funch
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Re: Does your ZRock2 hum?
Reply #7 - 03/22/22 at 04:49:31
 
Another cause of hum is the interaction of transformers. I had a Schiit Loki+ EQ, that has a couple of small inductors inside, picking up hum from my clone HP amp, as well as my DAC, through one inch-and-a-half-thick MDF shelf below. Took the EQ out, and no more hum.
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DancingSea
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Re: Does your ZRock2 hum?
Reply #8 - 03/22/22 at 05:21:48
 
Just to clarify, in my system the ZR2 has a low level physical hum to the box itself.  It does not introduce hum into the audio chain beyond that box hum.  The speakers remain very quiet.
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JBzen
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Re: Does your ZRock2 hum?
Reply #9 - 03/22/22 at 11:02:20
 
Funch, you may have a point there! My DIY DAC is encased in corian with a toroidal power tranny and enameled twisted wire connecting the RCA jacks to the output capacitor. I've known for a long time now that is a source of noise in my system. The Zrock sits about 6" lateral to it. Guess I should finally make a metal case for the DAC and get some shielded internal interconnects. Weather is warming up around here so it is a good time to weld something up Cool

John
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Burgermeester
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Re: Does your ZRock2 hum?
Reply #10 - 07/29/22 at 11:18:32
 
Since I know nothing about electronics I thought it was about time for me to speak up.

Most audio racks I see (mine included) are open on all sides, with components stacked on successive shelves.

I've never heard anyone talk about what sort of material those shelves "should" be made of from an electrical isolation POV. An inch of steel must be different from a half inch of maple.
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Same Old DD
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Re: Does your ZRock2 hum?
Reply #11 - 07/29/22 at 13:12:52
 
A lot of equipment makes a physical hum when operating and there are huge numbers of products and varying ways to isolate that 60Hz droning sound from other more sensitive equipment. Some gear you can just lay your hand on it and tell if it is on or off.
Steve sells some isolation products which look to be very cool and even sciency solutions. I would love to try some, but I don't have anything that contributes substantially to this problem.

I can certainly tell if my Zens are on or off by touching them, but a rubber matt keeps any of that movement from transferring to the rack/stand. It's minor.

My rack is a DIY affair made from an inch and a half thick doubled MDF shelves, open on all sides held together with all thread columns at each corner. Very '80s and not at all elegant, but it allows me to level each shelf perfectly front to back, diagonally and side to side and it works fine for me. It's pretty heavy!

As far as eletrical interference (transformers interacting with each other or with sensitive components like foil caps, which often sport some inductance, BTW) between two units in a system, I think distance between them is the most important factor rather than an attempt to cobble some kind of shielding between the two.
Even if some eletrical shielding is desired, you will need to ground the shielding somehow or all that energy you just attracted to a plate of light steel or something will just sit there with no place to go and your shielding will not really do much.

Maybe someone with a proper Degree in electronics engineering can pop in with a more studied response.

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Same Old DD
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Re: Does your ZRock2 hum?
Reply #12 - 07/29/22 at 13:37:28
 
Hey, Burge, I've never seen much on which materials are better, either, except that it seems many like hardwoods for equipment racks, especially maple for some reason.

I would too, but not much discussion out there about which is better for electrical isolation between components.

I'll get the popcorn ready while we wait.
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Lon
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Re: Does your ZRock2 hum?
Reply #13 - 07/29/22 at 13:41:06
 
To me "electrical isolation" would require some form of circuitry or at the least "isolated" outlets, etc. not a "rack." A ZLC or a PS Audio Duet, a DC eliminiation device, or some such thing.

I have Mapleshade Audio racks for two systems, 2" maple shelves, and I love them. I don't think the maple has any special characteristics per se, it's not like a musical instrument, but the rigidity and density I believe contributes to the vibrational isolation and a bit better sound. I love the looks too. . . my wife. . . not so much.
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Same Old DD
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Re: Does your ZRock2 hum?
Reply #14 - 07/29/22 at 15:01:07
 
I think that way too, although grounding a shield creates a circuit. But not all gear is completely  "Faradayed,"  trying not to invent an adjectival term for everyone to hate, but no better way to express this factor comes to mind.

I found this when I was trying to get a grip on how signal cable placement contributed to interferences, aside from getting them away from power cables.

BTW, your earlier suggestion that I use my best cable to power my isolation transformer set up was very effective. I owe you a  "Thank You"  for the suggestion. THANKS!

I have purchased two more higher grade, braided and shielded power cables and now I have my power supply, turntable, preamp and both Zens with shielded power cables. I need a couple more to get it all nailed down.
Noise is down to nothing I can hear without placing my ear right at the full range drivers. Nothing I can hear from two feet away.

I think you are right in that it is the rigidity and mass of thick wood that does the work in a component stand.

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Lon
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Re: Does your ZRock2 hum?
Reply #15 - 07/29/22 at 15:05:46
 
Power cables are such a trip! And can yield great results, glad that my advice bore fruit.
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Same Old DD
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Re: Does your ZRock2 hum?
Reply #16 - 07/29/22 at 15:09:37
 
Thanks again! That was something I had not yet thought out completely, but your suggestion gave me enough pause to explore further.
Smiley Smiley
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__Jon__
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Re: Does your ZRock2 hum?
Reply #17 - 08/02/22 at 19:11:14
 
You can use a variety of materials to isolate, thin steel sheets being one, but google will reveal many more varied and expensive options. It's been a while since I looked into things, but I think in general one is isolating magnetic fields more than "electricity" itself. Generally interposing one of these materials between devices shields the center and concentrates the field towards the edge of the material. Positioning and routing of cables has to be done thoughtfully but shielding could be something to try if there is a problem. I'm using it on the undersurface of the 2" thick hardwood rack between a large isolation transformer and the tube DAC above it.  
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Showme
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Re: Does your ZRock2 hum?
Reply #18 - 08/31/22 at 23:03:10
 
I had him through my speakers from the Zrock. Steve swore no hum when at the mothership. I simply got rid of it and couldn’t be happier. A piece of gear that in the end I realized I just didn’t need.
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Tony
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Re: Does your ZRock2 hum?
Reply #19 - 09/01/22 at 04:18:55
 
Yes, mine hums.

From the listening position however,  I don't hear it. Still,  it's close. My ZROCK is plugged into a power conditioner that plugs into wall socket that is wired directly to fuse box. My guess has been that hum is due to power conditioner. It's good,  not excellent.  My weak link.

Any suggestions for improvement are welcomed.
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Paul2
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Re: Does your ZRock2 hum?
Reply #20 - 09/01/22 at 17:08:27
 
I have fought hum issues in the past.  Last year to placate my insurance provider I upgraded every thing from the pole on the street to my listening room.  Now have two dedicated circuits for stereo gear.

The cost for the upgrades came to $3000.  Not chump change but worth it in the long range.  I have used power conditioners in the past but none now.

Oh, NO HUM !
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Tony
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Re: Does your ZRock2 hum?
Reply #21 - 09/02/22 at 14:45:21
 

The cost for the upgrades came to $3000.  Not chump change but worth it in the long range.  I have used power conditioners in the past but none now.

Oh, NO HUM !


Hi Paul2,

That is an impressive intervention and congratulations on the results.  

I have had two types of hum.  I successfully managed the first hum from the amp by replacing a blown a fuse.  The second one, the ZRock hum, has resisted my efforts.
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Paul2
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Re: Does your ZRock2 hum?
Reply #22 - 09/03/22 at 10:30:43
 
Recently I came across a You Tube video posted by the ultimate golden ear, Mike Fremer.  He had his electrical service in his home evaluated and found there were issues that needed to be addressed. The work done was very similar to what I had done in my home.

I am aware that not all people can do this type of upgrade of their homes.  Reasons like apartment living or even financial concerns.  Some have found that power conditioners help although that was not the fix that worked for me.

The issue of hum can manifest itself from a failing tube, degraded contact with interconnects or speaker connections.  Most of us plug and forget these things and never go back and use any preventive maintenance.  Also, grounding issues play into this hum deal.

All this said with a wink of an eye.
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