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ZROCK3 Impedance Questions & Compatibility (Read 1161 times)
ozark1
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ZROCK3 Impedance Questions & Compatibility
05/30/24 at 06:58:19
 
My current system:

Schiit Bifrost 2 DAC...SE/2V Output/Output Impedance 75 Ohms

Khozmo Passive Preamplifier...SE/64 Step Shunt Attenuator With Remote/5K Output Impedance (I don't know the input impedance but have reached out to Khozmo and waiting for reply)

Schiit Gjallarhorn Solid State Amplifier...SE/10 WPC/Input Impedance 20k Ohms

For reference, the ZROCK3 has Input Impedance - 47 K Ohms and, "Will Drive Preamps or amplifiers with input impedances of 24K ~ 200K".

I'm undecided on where to place the Z3, between the DAC -Preamp or between the Preamp -Amp. I still need the input impedance for the Khozmo which I am waiting for. Any suggestions are welcomed and I'm wondering if I can make this work or will I be replacing equipment. I listen at lower levels in an apartment and the Z3 sounds perfect for me. I'm 100% digital, Flac, downloads and Qobuz.

Thanks!
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100% Digital - CDs Ripped To FLAC - Qobuz
Cambridge CXN100 (Pre-Amp Mode) >>
ZROCK3 (On Order) >>
Schiit Gjallarhorn Amp >>
KLH 3 Speakers
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mrchipster
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Re: ZROCK3 Impedance Questions & Compatibility
Reply #1 - 05/30/24 at 19:28:14
 
The ZROCK seems to have been designed primarily to go between source (DAC,etc) and pre-amp but can certainly be used between pre and amp.

I have the ZROCK2 (not 3) and find I can only really use it between the source and pre-amp in my Decware system. Chain = Streamer/DAC > ZBIT > ZROCK2 > CSP3 > UFO25.
When the gain is set just right across the whole chain, I get a really full and enhanced sound. I tend to get a slight buzz when I push the gain too far (which doesn't happen too often at all) and only can be heard between tracks or quiet passages. Again, with my current gain settings across the board I hardly if ever hear it. My Zrock has the full Anniversary mods since I wanted it to keep up with the UFO25 and CSP3 which has full A-mods as well. In my case the Zrock's knob is set to around the 12:30 - 1 o'clock postion. That's all I really need when my DAC is connected. I use a little more when the TT is connected. (FWIW)

If I place the ZROCK2 between CSP3 and UFO25 I get a buzz no matter how I structure the gain. I tried this because I wanted to use both my DAC and TT through the CSP3 without changing IC's. I can't use it this way and since I use the DAC most of the time I don't mind connecting the TT to the Zrock when needed. (my component layout makes it easy to do)

Since you seem to only have one source, connecting the ZROCK3 between source and pre should work great for you.

Input impedance of pre and amp is certainly a consideration and definitely follow up with KHOZMO or Steve for a definitive answer. However, I have read in other threads that the Zrock can possibly work with impedances as low as 10k (someone please correct me if I'm wrong) but almost always seems to be system dependent. Obviously, the higher the better but may work fine in your application. Again, Steve would know better.

If the impedances work out with your system (which is very nice by the way) you should definitely try it both ways. Can't hurt and then you can see where the synergy lies.

The ZROCK2 was a great addition to my system and I think it will be what you're looking for. Here's hoping it all works out and good luck!
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SE84UFO25 - CSP3 (A-mods)
ZROCK2 (A-mods) - ZBIT
Cambridge Audio CXN V2 (ModWright)
Cambridge Audio CXC
Zu Audio Soul Supremes
VIABLUE IC's & Spkr cables ; DSR3 IC's
Audio-Technica TT
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ozark1
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Posts: 13
Re: ZROCK3 Impedance Questions & Compatibility
Reply #2 - 05/30/24 at 22:58:25
 
Thank you for the reply. It does look like it would work between the preamp and amp but I would prefer it between the DAC (only source) and the preamp. My thinking is that the signal would be attenuated by the preamp in this manner before hitting the amp, reducing noise, hum, etc. Placed after the preamp, the amp would amplify 100% of the unattenuated Z3. On the other hand, maybe the output level control on the back of the Z3 will help with matching. I'll wait for Khozmo to reply.
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100% Digital - CDs Ripped To FLAC - Qobuz
Cambridge CXN100 (Pre-Amp Mode) >>
ZROCK3 (On Order) >>
Schiit Gjallarhorn Amp >>
KLH 3 Speakers
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ozark1
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Posts: 13
Re: ZROCK3 Impedance Questions & Compatibility
Reply #3 - 06/03/24 at 22:25:26
 
The figure I got back from Khozmo concerning the input impedance of my passive preamp:

"It varies from 0R (mute) to 500K (max)"

I'll contact Steve eventually and go over the details.
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100% Digital - CDs Ripped To FLAC - Qobuz
Cambridge CXN100 (Pre-Amp Mode) >>
ZROCK3 (On Order) >>
Schiit Gjallarhorn Amp >>
KLH 3 Speakers
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Steve Deckert
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If the 1st watt
sucks why continue?

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Re: ZROCK3 Impedance Questions & Compatibility
Reply #4 - 06/07/24 at 20:45:48
 
If the impedance varies from zero to 500K that means it is a shunt attenuator.  The ZROCKs would not be compatible with that on their output.

On the ZROCK3, the output level becomes the input gain control when hooked directly to a power amp.  It is simply adjusted down until you hear no hum or noise.  You can think of it as adjusting the overall gain of the ZROCK3.
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ozark1
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Re: ZROCK3 Impedance Questions & Compatibility
Reply #5 - 06/07/24 at 21:29:48
 
Then the ZROCK3 would be OK between the preamp and the amp (with my current setup)?

Would replacing the Khozmo preamp with a ZBOX work?

DAC >> ZROCK3 >> ZBOX >> Amp

OR

DAC >> ZBOX >> ZROCK3 >> Amp
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100% Digital - CDs Ripped To FLAC - Qobuz
Cambridge CXN100 (Pre-Amp Mode) >>
ZROCK3 (On Order) >>
Schiit Gjallarhorn Amp >>
KLH 3 Speakers
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Dominick
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Re: ZROCK3 Impedance Questions & Compatibility
Reply #6 - 07/06/24 at 16:15:51
 
Ozark1,

Since the ZBOX doesn’t produce any gain past its input…I would say it would be better to place the ZBOX right after your DAC and before your ZR3.  

Info taken from the ZBOX page…

The ZBOX is not just another buffer stage, if it were it would only make things sound marginally better.  It works by creating a starved voltage condition in the filament of the tube that in turn causes an increase in favorable harmonics and a decrease in objectionable distortion.

OUTPUT VOLTAGE:
The ZBOX when turned fully up will always only put out slightly less than what goes in.


If you are dealing with hum…maybe look into getting a quiet tube with low microphonics.  

I’m dealing with a slight hum issue myself in a similar setup.  I run a

Schiit Bifrost2 > ZBIT > ZROCK2 > CSP2+ > 2 SE84C+ amps in a mono configuration.  

Just this morning I was watching TV through my headphones going from my DAC into the ZBIT, ZRock2, CSP2+, and then into my Grado’s.  I noticed that I was getting some hum.  When I bypassed the ZROCK2…I get no hum. So now I have some tweaking to do….back off the ZBIT and / or replace the tube with low microphonic tube.   Right now I run a 7062 tube in the ZRock2…which I really like….especially when I play vinyl.  I’m guessing my 7062 may need to be refreshed.  I know Steve eliminated the bypass switch with the ZROCK3, but I find it very useful.

Hope this helps.  

Dom
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Rasp. Pi 4 [Roon], Schiit Bifrost True Multibit DAC, ZBIT, ZROCK2, My Audio Cables Ultra Silver+, ZSB, CSP2+ 25th, DAG Cables, DHC1, Torii MKIV 25th /2 White Zen SE84C+ 25th mono’s, Rega P2 Turntable, White top ZP3, Velodyne Dual Firing Sub, ERR’s [Bubbinga Wood]
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ozark1
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Posts: 13
Re: ZROCK3 Impedance Questions & Compatibility
Reply #7 - 07/06/24 at 22:32:04
 
Dom,

Thanks for the reply, hopefully I won't have any problems with hum but I try to learn all I can now if it does show up.

A while back I purchased a Schiit Loki Mini+ (4 band) and noticed a very slight hum (maybe noise is a better description) when the unit was placed between my Khozmo preamp and the amp. I moved it between the Bifrost2 and the Khozmo preamp and it was dead silent. The preamp was attenuating the output of the Loki along with the noise. This is my thinking. I didn't reallly like the Loki so it's boxed up.

I'm going to try it both ways when I get the Zrock and Zbox and see what happens. I like experimenting. The one piece of gear I'm not willing to replace is the Bifrost2. I really like the sound that comes out of it. I thought about upgrading to the 2/64 card but never did, I'm happy.

I also run the output of my TV and 4K disc player by optical to my Bifrost2. Sounds great! I ditched my AVR a few years ago. Nothing wrong with them but I prefer simplification as I get older.

Jon
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100% Digital - CDs Ripped To FLAC - Qobuz
Cambridge CXN100 (Pre-Amp Mode) >>
ZROCK3 (On Order) >>
Schiit Gjallarhorn Amp >>
KLH 3 Speakers
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funch
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Posts: 158
Re: ZROCK3 Impedance Questions & Compatibility
Reply #8 - 07/07/24 at 22:12:21
 
The Loki+ uses inductors that pick up magnetic fields. I had one but had to sell it because of that.
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