• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

Review and Measurements of Schiit Sys Passive Pre-amp/Switcher

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
13,493
Likes
5,662
Location
Seattle Area
#1
This is a measurement and review of the Schiit Sys switcher and passive pre-amp. It retails for just $49 plus shipping which is reasonable. The unit is on loan from a member so not new.

Schiit Sys 20180208_145701.jpg
I will do a teardown later but for now, there are just two inputs, one output, and a volume control in there. No other passive or active components.

Measurements
Let's start with frequency response at different volume control settings:

Schiit Sys passive volume frequency response measurement.png


Frequency response is essentially rule flat to 30 Khz which is nice.

Channel matching starts with a small deviation and grows to 0.5 db at 12:00 o'clock volume setting. Lowering the volume to 3:00 o'clock increases this error to 1.3 dB. So probably not a good idea to use it below 12:00 position.

Phase measurement between channels is boring and inconsequential:

Schiit Sys Phase Shift Measurement.png


Let's look at channel separation:

Schiit Sys Channel Separation Measurement.png


Bottom two lines are without Sys in the loop. Once we insert Sys in the path, we lose about 5 to 15 db of that. It sounds like a big number but the overall levels are still very good, ranging from -100 db to -125. You would expect some drop due to more cables, switches, etc. Not an audible concern.

Perhaps the most interesting measurement is the impact on THD+Noise at different volume levels:

Schiit Sys THD+N measurement.png


At full volume Schiit Sys is transparent. As we lower the level on Sys, naturally the measurement noise as a percentage rises leading to the graphs that you see. In other words you lose signal to noise ratio with passive volume controls.

The rise in distortion at high levels though is a bit puzzling (tilt up to the right). The output impedance of Sys varies with volume changes so perhaps that is interacting with analyzer input resulting in higher distortion.

Finally let's look at bleed-through from one input to another:

Schiit Sys Bleed Through Measurement.png


We have 70 db of separation between inputs at low frequencies, lowering to -55 dB/-60 dB at higher frequencies depending on what channel you look at. Using a 2 volt (RMS) tone generated by my analyzer at 1 Khz, I could hear the tone from the un-selected input at max volume of my Stax headphone. So probably best to mute the channel you are not using.

Conclusions
For $49, the Schiit Sys is a bargain. I know I can't build and sell it as cheaply to you. :) Measurements are fine. Nothing jumps out out of ordinary. If you need a passive volume control with dual inputs, I recommend this product.

Edit: See the hardware tear down here: https://www.audiosciencereview.com/...schiit-sys-passive-pre-amp-and-switcher.2338/
 
Last edited:

drconopoima

Member
Patreon Donor
Joined
Jan 14, 2018
Messages
49
Likes
27
#3
Conclusions
For $49, the Schiit Sys is a bargain. I know I can't build and sell it as cheaply to you. :) Measurements are fine. Nothing jumps out out of ordinary. If you need a passive volume control with dual inputs, I recommend this product.
Now I'm interested in how well the JDS Labs OL Switcher measures to compare against the Sys (I have it, I could give it on loan)
 
Joined
Feb 9, 2018
Messages
10
Likes
3
#5
Now I'm interested in how well the JDS Labs OL Switcher measures to compare against the Sys (I have it, I could give it on loan)
Firstly hi guys, new here not new to the hobby. As for the SYS vs the OL Switcher, frankly I can't "hear" a difference but I like the build on the OL Switcher a little better. It's not as heavy but the buttons/knobs feel better.

While the SYS is REALLY HEAVY and quite solid, my unit's button/knob are slightly lopsided... as in they are literally tilted a little off center. While it doesn't affect the workings of the amp... it is a little odd, that combined with it's lower number of outputs make it... less advantageous imo

Though it is in a sense easier to operate, it's just one button to push one knob to turn, I keep it in my speaker set up that my wife and I share and use the more "complicated" OL Switcher in my personal system. Both are good, one's heavier and easier to operate, the other is far lighter and more useful over all though

@amirm nice measurements, happy to see the SYS get's passing marks
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
13,493
Likes
5,662
Location
Seattle Area
#6

Speedskater

Active Member
Joined
Mar 5, 2016
Messages
196
Likes
50
Location
Cleveland, Ohio USA
#7
If those RCA jacks have plastic insulator rings, then it definitely needs a John Windt 'Hummer Test".
Bill Whitlock has short instruction in at least three papers.

AN007 Generic Student Seminar Handout
http://www.jensen-transformers.com/wp-content/uploads/2014/08/generic-seminar.pdf

AS032 Build the “Hummer” to Find “Pin 1 Problems” in Equipment
http://www.jensen-transformers.com/wp-content/uploads/2014/08/as032.pdf

2012 Seminar
http://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf

While the actual John Windt 4 page paper is in the great June 1995 AES Journal. This is something everyone should read and it's only $15 including shipping.
http://www.jensen-transformers.com/wp-content/uploads/2014/08/as032.pdf
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
13,493
Likes
5,662
Location
Seattle Area
#8
Wow, that is a pretty clever and simple test:

upload_2018-2-9_17-47-53.png



In essence it creates a situation that is worse than normal as to eek out borderline designs. If it doesn't hum with this scheme, it won't hum with much else.

I will put it on my todo list to build.
 

Speedskater

Active Member
Joined
Mar 5, 2016
Messages
196
Likes
50
Location
Cleveland, Ohio USA
#9
After looking at the photos in the other thread, it probably will pass the test. But any unit with RCA connectors that have plastic insulator rings is suspect.
It's Jim Brown's pet peeve. And don't forget Neil Muncy.
 

Wombat

Major Contributor
Joined
Nov 5, 2017
Messages
2,280
Likes
795
Location
Australia
#11
After looking at the photos in the other thread, it probably will pass the test. But any unit with RCA connectors that have plastic insulator rings is suspect.
It's Jim Brown's pet peeve. And don't forget Neil Muncy.
I think post Post #48 in this thread is more informative: http://www.whatsbestforum.com/showthread.php?23125-Another-ground-boxes-competitor/page5

A quote I remember from an EE forum: "There are too many dangerous amateurs in the audio field". Be wary of the advice given on the WWW.
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
13,493
Likes
5,662
Location
Seattle Area
#12
Now I'm interested in how well the JDS Labs OL Switcher measures to compare against the Sys (I have it, I could give it on loan)
Thanks for the offer. Do you want to see how much it costs to mail it each way? The box is not very expensive and hate to pay almost that much in shipping to send it back and forth. :)
 

drconopoima

Member
Patreon Donor
Joined
Jan 14, 2018
Messages
49
Likes
27
#13
Thanks for the offer. Do you want to see how much it costs to mail it each way? The box is not very expensive and hate to pay almost that much in shipping to send it back and forth. :)
Yes, after my post I remembered I went to the post office a pair of weeks ago to receive my HD 600 package and saw in the list of prices something like 35€ international shipping. It is not wise to send for review a 45$ product at that price.
 

Jimster480

Addicted to Fun and Learning
Patreon Donor
Joined
Jan 26, 2018
Messages
552
Likes
187
Location
Miami
#15
I have always wondered about these switchers, could we also test one of the $5 ones from ebay? There are various RCA switchers on ebay that are $2-10 with 2-6 inputs
 

Blumlein 88

Major Contributor
Joined
Feb 23, 2016
Messages
3,904
Likes
2,035
#16
I have always wondered about these switchers, could we also test one of the $5 ones from ebay? There are various RCA switchers on ebay that are $2-10 with 2-6 inputs
When CD and separate DACs with high output voltages were a new thing in the early 1990's I built something like those probably are. I used a plastic project box from Radio Shack, one of their ALPS volume pots. Put a couple input and one output pair of jacks with a switch. It measured well and sounded well when I put it in place of expensive preamps. Freaked out a number of people. A couple had to be convinced to let me plug it into their system. It weighed like 5 ounces or something and was a blue plastic box. The sound flummoxed quite a few people. Now I couldn't do that for $5, but a basic decent pot and not much else doesn't cause any real problems. You had to keep the cabling on the output very short however.

I had a couple tricks for improving channel to channel tracking that varied from sample to sample. And another couple tricks to improve interfacing with other gear. For the hair shirted I would parallel a stereo pot for one per channel and give individual channel control.

All the long winded way to say, these things are NOT all that complicated and work pretty well for cheap-o money. With so many DAC/pre's they aren't as useful as they once were however. There really aren't likely to be surprises testing these. Input/output impedance and parallel capacitance will tell you how well they will work.

In time and personally for several years, I went with various switched resistor versions. That is when I came to love repeatable levels controls with perfect channel to channel matching instead of an analog pot or slider.
 

amirm

Founder/Admin
Staff Member
CFO (Chief Fun Officer)
Joined
Feb 13, 2016
Messages
13,493
Likes
5,662
Location
Seattle Area
#17
So someone pleaded with me to respond to a question on Mike's thread so I did. Just a few hours later the post is deleted and I am banned from that thread too:

upload_2018-2-12_16-49-22.png


Yet they left the question in there.

Whoever said he doesn't censor anything was clearly mistaken. While I continue to hold no grudge against the company or its products, I can tell you that as individuals they are extremely unprofessional and lack proper knowledge of how to conduct themselves in public.
 
Joined
Jan 28, 2018
Messages
77
Likes
50
Location
Valencia California
#19
...and another thing...
You can always copy the question here, in it's own thread.
Answer it however you wish. The question will be answered and only you will have control of the answer.
Any more pleas for "answers" could easily follow the same format.
I'd vote for that.
 
Top Bottom