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ZROCK Buzz and Volume Drop (Read 3474 times)
Glenn
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ZROCK Buzz and Volume Drop
05/04/23 at 17:00:21
 
I just installed my Zrock. I have two questions for those who already use this device.

First, my original intention was to install in between my pre-amp and UFO25. My pre-amp is a zero gain pre-amp from Denafrips so i did not anticipate any problems. However, in this position there was a very loud 'buzz' when in the active position. No buzz when the bypass was engaged. The output from the pre-amp is only 2.0Vrms. The only other variable might be that my DAC is connected to the pre-amp via XLR cables. Solving this problem takes me to my second questions.

I next installed the Zrock2 between my DAC (denafrips Pontus II) and my pre-amp. In this position the buzz was gone. However, when engaged at all but full position there is now a very noticeable drop in volume of at least 25%. Equally interesting, when i used the dial to set the level of the EQ the instructions suggested starting with the EQ fully engaged, then dialing back to increase volume to the maximum point (ie. as the highs become more engaged), and to stop when the volume starts reducing again. In my set up, volume was maximum when the EQ was fully engaged and only got quieter until I hit the noon position. The problem is, with the EQ fully engaged for reasonable volume, the sound is far far too bassy unless i have my amp set for very quiet listening. which means the ZROCK is only useful for extremely quiet listening, and not for beefing out the sound at regular volume.

Sigh. Anyone have any insights?


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Niagara 1200, Sonos Port streamer, Denafrips Hermes DDC, Denafrips Pontus II DAC, Denafrips Athena pre-amp, Decware UFO25 amplifier, Klipsch Cornwall IV speakers
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Lon
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Re: ZROCK Buzz and Volume Drop
Reply #1 - 05/04/23 at 17:14:06
 
In regards to the volume drop . . . I don't have that issue to the same extreme but I am using much more gain with the balanced out of my amp and the ZTPRE. Have you tried the EQ curve with the switch down in the back?
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HR-1,ZBIT,ZROCK2,SEWE300B,CSP3-25mod; Rega RP3 all GrooveTracer mods;PSAudio:PST+DSD, DAC Mk II, P15,NPC,PowerBases,AC-12 pwr cbls, Reference spkrcbls; Mapleshade SamsonV3; VooDoo:Cremona+Amati interconnects, IsoPods; headphones: Sennheiser HD800S,ZMF Ori,Oppo PM1
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Glenn
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Re: ZROCK Buzz and Volume Drop
Reply #2 - 05/04/23 at 17:50:27
 
thanks Lon. I have tried the switch in the back in both positions. Same result, although the problem is worse in the down B position as it has a greater reduction in highs.
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Niagara 1200, Sonos Port streamer, Denafrips Hermes DDC, Denafrips Pontus II DAC, Denafrips Athena pre-amp, Decware UFO25 amplifier, Klipsch Cornwall IV speakers
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Lon
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Re: ZROCK Buzz and Volume Drop
Reply #3 - 05/04/23 at 18:57:18
 
Interesting . . . because on my ZROCK2s the up position has a significantly larger reduction in highs.

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HR-1,ZBIT,ZROCK2,SEWE300B,CSP3-25mod; Rega RP3 all GrooveTracer mods;PSAudio:PST+DSD, DAC Mk II, P15,NPC,PowerBases,AC-12 pwr cbls, Reference spkrcbls; Mapleshade SamsonV3; VooDoo:Cremona+Amati interconnects, IsoPods; headphones: Sennheiser HD800S,ZMF Ori,Oppo PM1
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Tony
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Re: ZROCK Buzz and Volume Drop
Reply #4 - 05/05/23 at 02:55:27
 
Hi Glenn,

Like you, I have my ZRock between my Pontus and my preamp. As you said, twisting the knob clockwise to about 5:00 would be too loud and too much bass. Going back to about 1:00 works best for me for bass, and then I add volume from either the preamp or amp.

I reread your post and cannot tell if, once you find your ZRock sweet spot, can't you then increase volume from the amp or preamp?
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SE84UFO25 | Ic0n4 Passive Preamp | ZBIT | Sonore opticalRendu | Denafrips Pontus II | Denafrips Gaia | Decware I/Cs | Decware Pwr Cbls | ZWIRE Speaker Cbls | Omega SAHOM & KEF KC62 | Furman Cond l GIK Room Trmt
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Glenn
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Re: ZROCK Buzz and Volume Drop
Reply #5 - 05/05/23 at 22:56:45
 
Hi Tony - you are right i can increase the volume - but my pre-amp is a zero gain amp and my main amp is the UFO25 which, as you know has limited watts. So long as nothing in my system causes me to to lose gain the UFO25 has plenty of power. But with the loss i am experiencing with the ZRock2 i pretty well have to run the pre-amp and amp at 100% to get the volume i want in my room when i am looking to feel the sound.

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Niagara 1200, Sonos Port streamer, Denafrips Hermes DDC, Denafrips Pontus II DAC, Denafrips Athena pre-amp, Decware UFO25 amplifier, Klipsch Cornwall IV speakers
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Glenn
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Posts: 21
Re: ZROCK Buzz and Volume Drop
Reply #6 - 06/05/23 at 17:16:20
 
A brief update for anyone following this thread.

The volume drop off when theZROCK2 was in ahead of my pre amp had to do with my pre amp's impedance. Steve wrote: "The ZROCK is designed to go between your dac and preamp, however your preamp has an input impedance of 12K. That will create a large volume drop. We recommend 47K or higher."


I am now working my way through Decware support. Steve offered some suggestions and is sending a new tube in case it is a tube issue, failing which, i will send it back for repairs.

Two further observations. First Decware support has been great. Second, notwithstanding the buzz, when the Zrock2 feeds into my UFO25 Amp, and i don't have the volume issue i can really see its value and the improvement it makes to older music with poor bass.

I will keep you posted.
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Niagara 1200, Sonos Port streamer, Denafrips Hermes DDC, Denafrips Pontus II DAC, Denafrips Athena pre-amp, Decware UFO25 amplifier, Klipsch Cornwall IV speakers
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Zork
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Re: ZROCK Buzz and Volume Drop
Reply #7 - 06/05/23 at 20:40:20
 
I leave my ZR2 engaged at all times in position A on the back selector and dialed to 1 o'clock and I rarely move from that setting.  It adds a little bit of nice to most all music I play.
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Glenn
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Re: ZROCK Buzz and Volume Drop
Reply #8 - 08/28/23 at 19:51:36
 
I thought i should report on the conclusion of my ZROCK2 buzz problem.

In case you are new to this thread, i purchased a Zrock2 - but found it had a prominent buzz of +5db when my 25th anniversary amp is dialed past 1oclock in volume. This means it is good for boosting bass for low volume listening, but not for 'fixing' low bass records (say early Motown) when played at a higher volume.  

I sent the unit back to Decware. Steve was unable to detect any problems with the unit. After listening to the recording i provided he agreed there is a buzz and concluded it must be entering the unit via a connector. I decided to have the unit returned to me, notwithstanding the buzz, as it still work well to improve bass, etc. at lower volumes.

After reinstalling the unit, i checked my interconnects carefully. (I use Decware Silver Reference interconnects through out my system). I also made sure they do lie across my power cable,. Buzz is still there.

So - i have decided to live with the problem and limitations. If anyone else has experienced and solved a buzz in their Zrock2 - please let me know.

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Niagara 1200, Sonos Port streamer, Denafrips Hermes DDC, Denafrips Pontus II DAC, Denafrips Athena pre-amp, Decware UFO25 amplifier, Klipsch Cornwall IV speakers
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Mamu
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Re: ZROCK Buzz and Volume Drop
Reply #9 - 02/15/24 at 23:24:10
 
Connected my brand new ZROCK2 and welcome to the world of BuzzHum.  It is almost like having a high-quality fridge in the listening room (I am exaggerating a bit; must be frustration, although I can hear it all around the room if I leave it on).

It is not audio hum. it is the equipment that makes sound; something inside, in the back of it.

Changed locations, interconnects, swapped the tube; nothing worked.

To eliminate the impact of any wires and of proximity to other audio electrical equipment, I took the unit to my bedroom and plugged in power socket surrounded only by pillows and quilts - there you go, hums on happily.

So, how can I explain it?
 Maybe It does not like power it gets.  I am in Australia and obviously ordered ZROCK2 for our voltage specifications, which is 220 - 240 V; but maybe ZROCK2 is more power sensitive than other equipment (my SE84UFO25 is dead quite) and needs exactly 230 V.
I’ll try using dedicated power conditioner or linear power supply or something like that and hope it will work.

Or should I assume that this low-level hum/buzz is simply part of the design and leave with it.
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1stwattlife
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Re: ZROCK Buzz and Volume Drop
Reply #10 - 02/21/24 at 16:18:01
 
Mine went away plugged in at another location, I reinstalled with an isolation transformer and there are no issues, but I made more than one change so this is anecdotal at best...

You can email decwarecustomercare@gmail.com if you continue to have problems.
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