Best way to A/B two different streamers

The dac only has one usb input?

Does it have an optical in?

You could do one usb, one optical, play nothing higher than 24/192 (depending on the optical out lf the streamer and in of the dac… maybe have to limit to 24/96)

then just switch between usb and optical on the dac?

Different inputs sound different even with the same sample rate.

SPDIF and Toslink and to some extent AES are similar but USB is a different animal.

The way I have done it is set the equipment on a table and run two identical USB cables. You need to put the DAC on standby and swap the cables and then listen again. If you do it quickly you can remember how each sound well enough.

The streamers are feeding the DAC on USB. Switchboxes come in configurations with 2 inputs (from each streaming source) and one output to the DAC. The switchbox changes the input between the two USB sources. Am I misunderstanding something? I'm guessing there could be some delays for the USB handshake to happen between devices when its switched. I'm just not sure how well this would work.

If the switch is configured the way you describe then you are not missing anything. Are you trying to compare the streamers based on their performance with a specific dac or on their own merit? If the streamers are built with their own internal dacs you can compare by running each to a separate input on your preamp- or through auxiliary inputs on an integrated amp if it supports multiple inputs. As @calieng mentions above- it’s better to keep the signal path apples to apples for your comparison. If USB is your thing be consistent with both during your comparison.

play one streamer swap usb play the same track level match both and you can ab both

One streamer is my computer with USB out (No DAC) and the new streamer has no DAC. I have an external DAC. I just want to verify improvements in the new streamer versus the streaming using my computer. I think the new streamer sounds amazing, but I want better proof to make sure I'm avoiding expectation bias. I have a 60-day window to return the streamer. The reason for this is it's a very expensive streamer so I want to verify the improvements are real.

Easy. Buy a Wiim Pro.

Connect via coax. Compare. 🎯

A bi-directional switch is a cheap investment for a quick A/B test. If you’re not concerned or counting on that component affecting the sound in anyway then go for it! You can level match your PC’s output to that of the streamer (pre dac) and compare away.

I wouldn't use a switch for several reasons:

1. I keep noticing that the differences between sources and between cables tend to be quite subtle sometimes, albeit still very important. Quick A-B-ing is not the best way to reveal them IME.

2. The logic behind using an A-B switch is something like this: if A>B (A and B are the components to be compared, > means "sound better to me than") then A+X>B+X is also true (where X is the sound impact of the switch and additional cables). This logic is flawed IMO. Just a crude example: say A and B sound very much alike, but A has better treble extension making it preferable. If switch X is rolling off the treble a bit itself, the advantage of A will not be heard anymore through the switch. Another example: A is a bit more refined and detailed, but also a bit boomy and PRAT is lacking compared to B, maybe because the bass of A is more extended and is exciting some room modes more, making it woolly and swallowing dynamics - so I'd definitely prefer B. The switch could reduce and tighten the bass a bit so that A+X (switch) sound more balanced and dynamic, while B+X sounds a bit bass light, thus making me make the wrong choice (A). Of course these are crude and oversimplified examples, but you get the idea.

I think your best bet is to listen to a song through A, than repeat the first 10-12 seconds, then listen to the same song through B, also repeat the first 10-20 seconds and finally listen again through A. I find the A-B-A testing much more revealing than the simpler A-B. This way you will quickly notice the main differences between the sound of A and the sound of B and then confirm and refine your findings through subsequent auditions (other, as different as possible, tracks to listen according to the A-B-A - or B-A-B sometimes, for a change - protocol).

I would not use a switch. Will confound the analysis.

After both are broken in I would try one day one then one day another. Do that a couple times to see if there is some really huge difference. Then I would listen to the music from one for a couple weeks. Then switch, listening for a couple weeks. Do this a couple times and the differences at all levels should become obvious. 
 

If you really want to understand the differences at all levels you have to listen to the music and not the equipment and the differences will unfold.

@ghdprentice - I tend to lean towards this approach.

OP - You should have a sonic memory for the computer, so listen to the new streamer for a few days or weeks and see if you feel that something’s different.  Then go back and verify. If you can’t form an opinion then you’re splitting a hair not worth splitting.

I have found that I have formed an opinion with something new and then when I switched back it was clear that my sonic memory was flawed.  Other times I’ve found it a relief to switch back. Other times the difference was so immediately obvious that I never bothered to go back. 

I just did a shootout like this a few days ago.

1) Connect each to whatever inputs available that both support the source resolution for testing.

2) Stream the same source material with both concurrently

3) Compare. I’d use a sound meter or similar app to make sure both are same volume.

4) Pick the winner and on to round 2 repeating same test but with different input configuration as the challenger if available.

5) Repeat as needed until a winner can be determined from among all the available streaming options at your disposal. 

My recommendation would be to listen to the streamer for at least 3-4 days to get to know its sonic signature. Then switch to your computer as streamer. Spend another 3-4 days if the differences aren’t immediately obvious. Make a playlist specifically for this comparison. Make notes of what you hear. 
If you must use a switch to go between the computer and the streamer, still avoid quickly switching back and forth. Go thru the entire song with computer then the same song in its entirety with the streamer. But…in my opinion using the usb switch can impair the sound quality and you will end up making a mistake…potentially…

FWIW, In every comparison in my system, my mac mini could not match the performance of a dedicated streamer. I used Auralic Aries G1 and Lumin U1 Mini for the comparison (USB cable was Audience AU24se+).

Willy,

You’re getting some non-optimal advice here.  People are right that you should NOT use a cheap switch.  Nor should you use an optical on one and USB on the other.  Neither will provide a valid comparison.

Pick 5 to 10 tracks that you feel are very well recorded and that you really enjoy.  Be sure to include some acoustic instruments and vocals that you’ll recognize as sounding “real” or not.  Some complex rock is fine too.  Be sure to include some cymbals and kick drum or bass drum.

Listen to the entire group and listen for specific things on specific tracks such as cymbal strikes, sibilant voices, deep bass, transients, handling of complex passages, clarity, soundstage depth, width, specificity, etc.  Take notes on how “real” each track sounded and of course, whether you found it emotionally involving.  Did it make you want to keep listening a lot longer or did you find yourself wanting to do something else?

Then go through the same group with the other streamer, hooked up EXACTLY the same way.  Go through the whole process 2 or 3 times.

Quickly switching back and forth between pieces of equipment within the same track seldom tells you whether you want to live with a new piece of equipment or not.

You should also stream the same song at least three times in succession to ensure that your connection is good.

Pay particular attention to sound stage as opposed to frequency response. If it wanders with the streamer, get a better connection [NOT cable] or streamer.

I’ve had streamer demos where that was not the case.

IMO, PC streaming is not worth mentioning.

@willywonka so…anything to report? Winner? No difference?

@audphile1 I had to move my system and haven't had a chance to compare the two yet. I'm absolutely positive it's an improvement. One immediate thing I noticed is its less fatiguing to listen to over longer periods of listening. This was a problem and I'm glad this is resolved. I'll report back when I get more time to compare the two. Thanks for everyone's comments and suggestions!

It’s not that complicated. Compare two ways and decide. Then compare to other options as needed. Yes, do play a variety of music of interest to you. Resolution of source material matters. The one that sounds best sounds best. A sound meter in addition to your ears to help shed light and assure similar SPLs is always worth it. Massed strings is a useful check to help sort out the champ. In many cases a quick a/b compare will immediately shed light on the differences.

@willywonka less fatiguing is definitely one of the improvements I’ve noticed as well. Pretty sure you won’t be going back to streaming using your computer.