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Review and Measurements of Sabaj D5 DAC & Amp

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Then he should know the insidious nature of bias...he may understand electronics but that doesn't mean he understands psychoacoustics.

Would he be willing to take a controlled test? Might be interesting.
Jim does test his gear at the same level in an acoustically treated room etc. Not sure he double bind tests DAC's though.
 
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BTW, it was transient detail that Jim says the DX7s is filtering. He improved it by replacing the burr brown op amps to AD ones but it was still there. Because of this filtering of transients, he uses that DAC with is Bricasti M7 reverb unit, because he likes that combo.

According to Jim, audio test equipment isn't capable of measuring for this as music would need to be the source of the test. However, I always thought slew rate (measurable) was related to transient response. At least in amps anyway.
 

solderdude

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Transients in music are much slower than the slew rate of any DAC and decent opamp.
Just have a look at the waveform of any 'transient' in music recording and you will see none of them are anywhere near as fast as a 20kHz 0dB sinewave. These 'transients' can span many samples in a 44.1 file.
Most opamps in DAC's have very little gain and thus very wide bandwidths... much much wider than the DAC can achieve.
All 'filtering' in a DAC is done in the DAC chip or preceeding digital filter.
NEVER in an analog post filter or IV stage.

Let's assume we are talking about 44.1 frequencies. In this case the fastest a signal can be is about 21kHz at 0dB.
When A DAC (with a s steep reconstruction filter) reaches 20kHz at 0dB it can reproduce the fastest transients that exist in a 44.1 recording.
Changing an opamp will not change anything about that (unless one starts to use TL081 opamps or so)
Everything points towards his findings being subjective and sighted.
 

BDWoody

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Well the driver does not make those decisions. They pick whichever tyres get the best lap times.
To torture this further... Maybe tires are more like speakers, subject to an almost infinite combination of things that matter and impact real performance. The DAC is more like a processing chip in the engine control computer...
 

SIY

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According to Jim, audio test equipment isn't capable of measuring for this as music would need to be the source of the test. However, I always thought slew rate (measurable) was related to transient response. At least in amps anyway.
"Slew rate" is thoroughly irrelevant in this context.

If there's level-matched double blind comparisons to back up claims of hearing unmeasurable differences, that's great. If there's not, the claims have all the evidentiary weight of the Cottingley Fairies.
 
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Transients in music are much slower than the slew rate of any DAC and decent opamp.
Just have a look at the waveform of any 'transient' in music recording and you will see none of them are anywhere near as fast as a 20kHz 0dB sinewave. These 'transients' can span many samples in a 44.1 file.
Most opamps in DAC's have very little gain and thus very wide bandwidths... much much wider than the DAC can achieve.
All 'filtering' in a DAC is done in the DAC chip or preceeding digital filter.
NEVER in an analog post filter or IV stage.

Let's assume we are talking about 44.1 frequencies. In this case the fastest a signal can be is about 21kHz at 0dB.
When A DAC (with a s steep reconstruction filter) reaches 20kHz at 0dB it can reproduce the fastest transients that exist in a 44.1 recording.
Changing an opamp will not change anything about that (unless one starts to use TL081 opamps or so)
Everything points towards his findings being subjective and sighted.
Interesting, thanks.
 

Jimmy

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Normally you use an analog low pass filter in a DAC output stage that removes out of band noise, but that is not what solderdude is refering to.

The question raised is if there's something that can't be measured (with adequate equipment, which is not cheap, and with the necessary knowledge), but is still audible, and the answer is no.
 

solderdude

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Aaaaa ??? Are you sure ?
Yes, I am sure.
As Jimmy already mentioned.
The post filter is NOT a reconstruction filter nor part of it.
It is there to filter out HF noise coming from the DS DAC chip it is not designed to filter audio.
The actual reconstruction (or with some filters partly reconstruction) is done in DS DAC chip.

Only the very first CDP had very steep reconstruction filters which were a challenge to build.
Luckily Philips had to resort to oversampling as they needed to get 16 bit resolution from 14 bit DAC chips.
 
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I feel a bit bad quoting Jim and him taking flack for it, so here is a link to his website for anyone interested in what he does. I figure a bit of free advertising makes amends? lol

He basically says if anyone believes that test equipment can tell you how something will sound, then sure, design your equipment that way, but even the makers of the best test equipment in the world have never claimed their equipment can tell you how something will sound. He uses test equipment for what it is for, to check for errors in designs, but then uses his ears for if it sounds good. He also says the makers of test equipment have never claimed everything in audio can be measured.
 

SIY

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I feel a bit bad quoting Jim and him taking flack for it, so here is a link to his website for anyone interested in what he does. I figure a bit of free advertising makes amends? lol

He basically says if anyone believes that test equipment can tell you how something will sound, then sure, design your equipment that way, but even the makers of the best test equipment in the world have never claimed their equipment can tell you how something will sound. He uses test equipment for what it is for, to check for errors in designs, but then uses his ears for if it sounds good. He also says the makers of test equipment have never claimed everything in audio can be measured.
Jim knows his audience.
 
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He certainly does and these are some of his client list (taken from his website). I do appreciate many people have impressive client lists who you can also argue are talking out of their arse.

Leon Russell
Byron Miller
Goerge Duke
John McLaughlin
Frank Zappa
Stevie Wonder
Bill Withers
Tina Marie
The Mentors
Jay Ferguson - Spirit
Felony
Chester Thompson - Genesis
Frank San Pedro - Crazyhorse
Alphonso Johnson
Paramount Pictures
Warner Bros. Pictures
Billy Graham Ministries
U.S Air Force Band
Patrick O'Hearn
Hans Zimmer
Gary Wright
Jim Messina
MA Recordings
Pony Canyon Records
Ray Kimber - Kimber Kable
Disney Corp.
Vanessa Williams
BET - Black Entertainment Television
Lenny Kravitz
Peter Frampton
Smash Mouth
Gorky Park
Magic Mountain
Dolly Parton's Dollywood
Jeff Lorber
Rhodes Piano Corporation
Basson Sound
Hasbro, INC
Ken Kashiwa
The Rippingtons
Rick Braun
Henry Kaiser
Chad Wackerman
Steve Kimock
Greg Karukas
Chaka Khan
Stanley Clarke
MGM Grand
Pete Anderson
Dwight Yoakum
Yes
Billy Sherwood
Euge Groove
Flock of Seagulls
 

SIY

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I can give you a similarly impressive client list for all sorts of quacks and cults.

Sorry, the guy is peddling nonsense.
 
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I can give you a similarly impressive client list for all sorts of quacks and cults.

Sorry, the guy is peddling nonsense.
I'm sure that's true. I'd like to see some of those lists if you have any to hand though. However, never heard anyone say anything but good things about Jim's work. I have a feeling if you had a conversation with Jim, you would find he is more alike to yourself than not. He is always calling out snake oil peddlers.
 

solderdude

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This is not about Jim at all nor his reputation.
It's about the remark that measurements can not tell how something sounds.
While I would say that it is true for anything to do with acoustics it certainly isn't true with electronics.

Those making the claim can never seem to prove anything in well performed blind tests.
They make the claims and don't have to prove or show it to others. These claims are almost always made sighted.

Also I have never seen any of those wizards make a claim backed up with measurements (other than the measurements currently available) or by nulling with real music samples.
How come they find something that can't be proven to exist ?

When they are so brilliant one would expect those brilliant minds to come up with repeatable research showing this.
Nothing of the sort is found anywhere.
There is a reason for that, and it ain't 'we don't know how to measure everything yet'.
 
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I'm not sure what you mean by nulling with real music samples? If you take two identical DAC's and change the op amps in one, then record the signal from each DAC, they won't null, because they will not be identical right? So for Jim to claim one DAC sounds better to him than another (the worse one measures better) in terms of transient details, he could not prove this through nulling as both DAC's are different in many components, so they will not null.
 

SIY

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They may very well null to an extremely high degree unless you change out opamps without knowing exactly what you’re doing. But yeah, it’s easy to get different high quality DACs to have an extremely deep null, thousands of times lower than hearing thresholds. Likewise, it’s trivial to use music as a test signal, and anyone who tells you differently is mistaken.
 
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Ah
They may very well null to an extremely high degree unless you change out opamps without knowing exactly what you’re doing. But yeah, it’s easy to get different high quality DACs to have an extremely deep null, thousands of times lower than hearing thresholds. Likewise, it’s trivial to use music as a test signal, and anyone who tells you differently is mistaken.
Ah, ok thanks. So may be a null test would be a good addition to Amir's tests? if DAC A nulls with DAC B and DAC B is half the price, then why would anyone go for DAC A (besides features).
 

SIY

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You could, but it’s unnecessary. Basic math already gives you the answer. And of course, the multitone test is more rigorous than any music signal.

If you want an interesting demonstration of how bad your ears are at nulling, look up Bill Waslo’s string quartet test with the Sousa band embedded.
 

BDWoody

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He certainly does and these are some of his client list (taken from his website). I do appreciate many people have impressive client lists who you can also argue are talking out of their arse.

Leon Russell
Byron Miller
Goerge Duke
John McLaughlin
Frank Zappa
Stevie Wonder
Bill Withers
Tina Marie
The Mentors
Jay Ferguson - Spirit
Felony
Chester Thompson - Genesis
Frank San Pedro - Crazyhorse
Alphonso Johnson
Paramount Pictures
Warner Bros. Pictures
Billy Graham Ministries
U.S Air Force Band
Patrick O'Hearn
Hans Zimmer
Gary Wright
Jim Messina
MA Recordings
Pony Canyon Records
Ray Kimber - Kimber Kable
Disney Corp.
Vanessa Williams
BET - Black Entertainment Television
Lenny Kravitz
Peter Frampton
Smash Mouth
Gorky Park
Magic Mountain
Dolly Parton's Dollywood
Jeff Lorber
Rhodes Piano Corporation
Basson Sound
Hasbro, INC
Ken Kashiwa
The Rippingtons
Rick Braun
Henry Kaiser
Chad Wackerman
Steve Kimock
Greg Karukas
Chaka Khan
Stanley Clarke
MGM Grand
Pete Anderson
Dwight Yoakum
Yes
Billy Sherwood
Euge Groove
Flock of Seagulls
I bet the astrologers to the stars have impressive referrals as well.

Why would he be reluctant to take a blind test, or follow accepted methods of comparison? What would he have to lose?
 

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