[manywelps]

So I got a HiFimeDIY Sabre USB DAC ES9023, and pitted it against my Fiio E10 (non-K) (WM8741), and predictably, the volume levels were different.
 
Test setup: Computer USB -> DACs (lineout, 100% volume everywhere on the comp)-> Schiit SYS (for switching inputs instantly) -> Takstar Pro80 (I know, cheap stuff, but low enough impedance I don't get an amp coloring them)
 
So I decided to get clever, and brought out a multimeter and generated a 1khz sine wave... and at full power, the dacs were basically identical (AC Voltage).
 
However, the Sabre dac is audibly quite louder.  I suspect this has something to do with impedance, but I'd like to know how the heck to volume match other than doing it by ear.  (The Sabre seems to have more bass at the same volume level, but the voltage difference makes me curious.
 
I then just used my ears on the sine wave, and got a good match, but then the music was louder on the Sabre again...
 
So my question is how the heck to I volume match for switching (objectively and without specialized hardware)?

 

[Music Alchemist]

You'll need an SPL meter...and also more resolving headphones.

 

[manywelps]

Super.
 
I will note I can hear a distinct difference between the dacs even with these headphones.  The sabre has punchier bass for some reason (not good or bad, just obvious)

 

[Music Alchemist]

  Super.
 
I will note I can hear a distinct difference between the dacs even with these headphones.  The sabre has punchier bass for some reason (not good or bad, just obvious)

 
Yeah, any headphone will do to an extent, but you may be surprised how much more detail you can hear with some of the better ones. At any rate, you need to isolate the variables when comparing objectively. It can be tricky. I recommend asking in Sound Science...but don't post your impressions of how they sound there, because that will just spark an "all DACs sound the same" flame war.

 

[manywelps]

> Yeah, any headphone will do to an extent, but you may be surprised how much more detail you can hear with some of the better ones.
 
Yeah I'm snooping around for some ESP-950s.  Unless I see a really good deal, I'm going to swing by SF Canjam and see if I can sample some high end headphones before I drop high hundreds on a pair.
 
> I recommend asking in Sound Science...but don't post your impressions of how they sound there, because that will just spark an "all DACs sound the same" flame war.
 
Perhaps I will.
 
They don't actually say that about DACs though, do they?  It's like all the CE, EE, and Physics questions that lead off with "In a perfect world..."
 
Crazy high end DACs might get indistinguishably close...

 

[Music Alchemist]

  Yeah I'm snooping around for some ESP-950s.  Unless I see a really good deal, I'm going to swing by SF Canjam and see if I can sample some high end headphones before I drop high hundreds on a pair.
 
They don't actually say that about DACs though, do they?  It's like all the CE, EE, and Physics questions that lead off with "In a perfect world..."
 
Crazy high end DACs might get indistinguishably close...

 
I noticed the Massdrop link in your signature. What price were they sold at there on the previous drop? I'm more interested in STAX, but wouldn't mind getting the Koss too someday.
 
I heard the Abyss, HE1000, HD 800, and HE-6 recently. Good headphones, but not blown away like I was expecting. I honestly like the $150 Yamaha HPH-MT220 more. Go figure.
 
Many people in Sound Science insist that either all DACs sound the same or the more expensive ones that sound different are inferior and a waste of money. Just ignore them.

 

[manywelps]

> I noticed the Massdrop link in your signature. What price were they sold at there on the previous drop? I'm more interested in STAX, but wouldn't mind getting the Koss too someday.
 
 
It was $700, when it was $1000 everywhere else.  It's now $730 everywhere else, so probably high $500's if I was going to guess.  Worst case we don't buy.
 
>I heard the Abyss, HE1000, HD 800, and HE-6 recently. Good headphones, but not blown away like I was expecting. I honestly like the $150 Yamaha HPH-MT220 more. Go figure.
 
Yeah the (non-ES) alternative for me would be a planar magnetic like the HE-400S or HE-500

 

[Music Alchemist]

It was $700, when it was $1000 everywhere else.  It's now $730 everywhere else, so probably high $500's if I was going to guess.  Worst case we don't buy.  
Yeah the (non-ES) alternative for me would be a planar magnetic like the HE-400S or HE-500

 
It's available for around $500 on the used market. And the entry-level STAX system is under $400 if imported from Japan. Just food for thought.

 

[manywelps]

> And the entry-level STAX system is under $400 if imported from Japan. Just food for thought.
 
The SRS-2170?  I heard that the koss was exchanging blows with the STAX-407, not the 207 (SRS-2170).
 
And on these dacs, the Sabre is colder and a hair more precise on the mid-high range, but the Wolfson has noticeably more control on the bass end.

 

[Music Alchemist]

The SRS-2170?  I heard that the koss was exchanging blows with the STAX-407, not the 207 (SRS-2170).

 
It's subjective. I know one person who likes the SR-207 more than the SR-009, and says they sound roughly the same, though everyone else feels otherwise. I heard the Koss was basically warmer sounding than STAX, which is not what I'm looking for. I kind of want to just save up for the SR-009.

 

[manywelps]

If the SR-009 was in the 1-2k range I would, 3.5k is just too much for me.
 
I'd probably go HE-6 if I was in the 1-2k price range.

 

[Music Alchemist]

  If the SR-009 was in the 1-2k range I would, 3.5k is just too much for me.
 
I'd probably go HE-6 if I was in the 1-2k price range.

 
My basic plan is to get the 009 from PriceJapan for around $2,700 and use the STAX SRM-323S amp to start with. ($875 retail; under $450 from PJ; could get it for around that price from someone I know who modified the voltage to work in the US.) If I like it enough, I would eventually upgrade to the DIY T2 amp, which will probably cost five figures...
 
Most serious HE-6 owners modify it and use it with very expensive speaker amps. I heard it on a MOON Neo 430HA ($4,300) and could tell even it wasn't doing it justice, despite having more than enough power. (It's apparently more about the quality of the amp's design and such.) The HE-6 is definitely on my wish list.

 

[jcx]

asking in the Sound Science forum may put the question in front of more eyeballs with some of the needed expertise
 
 
SPL measurement at the headphone is not easy, you need some sort of coupling arrangement and even Tyll with a full on artificial head and calibrated measurement system has repeatability issues: http://www.innerfidelity.com/content/expert-tests-innerfidelitys-headphone-measurement-repeatability-and-reproducibility-page-2 - basically can't replace headphones on the dummy head precisely enough for the differences to be inaudible - although his numbers are just good enough if the headphone wasn't moved between measurements
 
so the better plan is to measure audio signal voltage at the headphone connector - ideally with the headphone plugged in
 
some multimeters could be fine - but not all do AC well at the audio standard 1 kHz
 
PC soundcards aren't calibrated but just to match you really only need repeatability between measurements over your test duration - just about any should be OK for that
 
you would need some toys those of us with electronics labs can whip up in minutes to split the signal, possibly attenuate in a divider and make a switch to keep the amplified V from damaging your PC sound input
 
you may be able to cobble together standard Y adapters, keep V low enough depending on your headphones, amp
 
 
it looks like the Schiit SYS does switch but puts both inputs thru the same volume control pot - so by itself it won't let you change levels between the 2 input channels to match
 
 
and I don't know the nitty gritty on driving multiple USB DAC from the same PC, same sound source at the same time - could be latency issues in the PC and in the DACs buffers and digital filters
 
a little searching found: http://yabb.jriver.com/interact/index.php?PHPSESSID=56h02noka7134uk04eqoev8mc2&topic=79067.0 discussion of trying multiple USB DACs together
 
I think I would want to do the level matching in the PC in the digital domain - if the sw were easy to make 0.1 dB adjustments between the audio streams
 
 
a indirect comparison but possibly an easier 1st pass could be trying: http://www.libinst.com/Audio%20DiffMaker.htm with the USB DAC outputs recorded on a good PC ADC - the motherboard chipsets often aren't very good but may be a start to debug the process - should show "clearly audible" differences
 
a "prosumer" soundcard like the ESI Juli@ would have better numbers than motherboard PC sound system ADC

 

[bgentry]

Your testing methodology is terribly flawed. There are two big problems:

1. That HifimeDIY "DAC" has an amp in it. But it automatically switches from line level to headphone level when it detects headphones. So your voltage measurement won't be correct unless you measure with the headphones plugged into that DAC to "load it".
2. The SYS is NOT designed to switch an amplified signal to headphones. It's designed as a passive preamp to switch between line level devices. The impedances presented at input and output of the SYS are 10,000 and 5,000 Ohms. That's going to interfere with the signal to the headphones in some way whether it be level, or impulse response, or both.

What you really want to do is run the two DACs through the SYS and then into an amplifier. That way the headphones are driven from only one amplifier. You'll still want to measure the output of the amp to make sure it's delivering the same Voltage with both DACs as input; that way they will DEFINITELY be matched. Also, without an external amplifier, you are measuring the performance of the AMPS that are built in to both DACs as part of your evaluation. That doesn't isolate the DAC component well at all.

I like your idea of a test. It just needs to be done differently to be effective.

Good luck!

Brian.

 

[manywelps]

 

It was $700, when it was $1000 everywhere else.  It's now $730 everywhere else, so probably high $500's if I was going to guess.  Worst case we don't buy.  
Yeah the (non-ES) alternative for me would be a planar magnetic like the HE-400S or HE-500

 
It's available for around $500 on the used market. And the entry-level STAX system is under $400 if imported from Japan. Just food for thought.

Out of curiosity, what's the source for the entry level stax.
 
 

Your testing methodology is terribly flawed. There are two big problems:

1. That HifimeDIY "DAC" has an amp in it. But it automatically switches from line level to headphone level when it detects headphones. So your voltage measurement won't be correct unless you measure with the headphones plugged into that DAC to "load it".
2. The SYS is NOT designed to switch an amplified signal to headphones. It's designed as a passive preamp to switch between line level devices. The impedances presented at input and output of the SYS are 10,000 and 5,000 Ohms. That's going to interfere with the signal to the headphones in some way whether it be level, or impulse response, or both.

What you really want to do is run the two DACs through the SYS and then into an amplifier. That way the headphones are driven from only one amplifier. You'll still want to measure the output of the amp to make sure it's delivering the same Voltage with both DACs as input; that way they will DEFINITELY be matched. Also, without an external amplifier, you are measuring the performance of the AMPS that are built in to both DACs as part of your evaluation. That doesn't isolate the DAC component well at all.

I like your idea of a test. It just needs to be done differently to be effective.

Good luck!

Brian.

Welp.