New 28-bit DAC coming out.

[KSTR]

Once again: Sound Pressure goes with 1/r. If one is solving any equation of the style 1/(r+d) = x * 1/r (and thus xr + xd - r = 0) for r, x or d there is no squaring involved, nowhere.

 

[popej]

Where? The only time I've mentioned dB's was that "10% less SPL = ~ -1dB"

Yes, relation between % and dB could be the reason for misunderstanding.
For me, putting twice power into an amp gives twice SPL, which is +3dB.
You seems to assume, that +6dB is twice SPL.

Actually, I don't know, which approach is commonly used.

 

[popej]

Once again: Sound Pressure goes with 1/r. If one is solving any equation of the style 1/(r+d) = x * 1/r (and thus xr + xd - r = 0) for r, x or d there is no squaring involved, nowhere.

Yes, -1dB SPL is about 10% less SP, which means about 25cm at 2.5m distance.
But 10% less SPL (not SP) could be confusing.

 

[markus]

It just shows that localization perception is also based on level, ILD at work. Together with ITD this allows bass and even very low bass to be perceived as directional just as any other frequency range
While actual speakers will be seldom closer than 1.5m, nothing stops us from rendering phantom sources at closer distances, using crosstalk cancelling. This is tricky with low bass but not totally impossible.
The main point was debunking the myth that low bass < 80Hz cannot be localized and thus a mono sub can cover all possible scenarios. It can't.

And now back to thread topic again.

I guess what I’m trying to say is that, given how stereo audio is typically recorded, mixed, and mastered, “stereo bass” doesn’t really hold up in practice. While interaural level differences can technically work at low frequencies, real-world playback environments, like domestic living spaces, tend to disrupt that information so much that it becomes meaningless ("not localizable"). In that context, using mono bass to reduce resonances often yields better results than trying to preserve or create stereo bass.

 

[danadam]

For me, putting twice power into an amp gives twice SPL

SPL is proportional to V. Power is proportional to V².

2x power gives only 1.4x V and therefore 1.4x SPL. That's +3 dB.

If you want 2x SPL you need 4x power. That's +6 dB.

Actually, I don't know, which approach is commonly used.

A double for power quantity is +3 dB. A double for root-power quantity (like sound pressure) is +6 dB.

Power, root-power, and field quantities - Wikipedia

en.wikipedia.org

 

[nagster]

Bias voltage is for electret mics, most studio condensers are not electret they use amplifiers in the mic body.

neumann u87 internal amp at DuckDuckGo

DuckDuckGo. Privacy, Simplified.

duckduckgo.com

https://retrogearshop.com/cdn/shop/products/2.-AKG-C414-EB-Klaus-Heyne-Pair-Rear-Internal_2048x2048.jpg?v=1585333958

The Electret microphone capsule contains charged material, so an external power supply is not necessary.
Other condenser microphone capsules are not like that, and therefore require some kind of power supply.
Whether the microphone's preamplifier is built-in or external is a separate issue.

 

[popej]

A double for power quantity is +3 dB. A double for root-power quantity (like sound pressure) is +6 dB.

Power, root-power, and field quantities - Wikipedia

en.wikipedia.org

Root-power quantity: voltage, sound pressure.
Power quantity: power, sound intensity.

Now:
Power scale with voltage squared.
SPL scale with sound pressure squared.
While SP is root-power quantity, SPL is defined to behave like power quantity. It mimic SIL - sound intensity level, which is power quantity.

There is no problem, if we use SPL represented in dB. My question is, what does it mean twice SPL. Is it 3dB or 6dB?

 

[boXem]

Root-power quantity: voltage, sound pressure.
Power quantity: power, sound intensity.

Now:
Power scale with voltage squared.
SPL scale with sound pressure squared.
While SP is root-power quantity, SPL is defined to behave like power quantity. It mimic SIL - sound intensity level, which is power quantity.

The P in SPL means pressure, not power. SPL is the ratio of sound pressure over silence atmospheric pressure. So it is not scaling like power but like root-power.

 

[danadam]

Power scale with voltage squared.
SPL scale with sound pressure squared.

These statements are analogous only if by P in SPL you mean power. But Sound Power Level is abbreviated as SWL. SPL is Sound Pressure Level.

Power quantity levels are defined as 10 log(x/x₀).
Root-power quantity levels are defined as 10 log(x²/x₀²). This can be simplified to 20 log(x/x₀).

The squares in SPL formula are because SPL is root-power quantity.

My question is, what does it mean twice SPL. Is it 3dB or 6dB?

I would say, you convert your input SPL to an absolute value, double that, convert back to SPL and compare. For example:

• 60 dB SPL = 0.02 Pa
• 2 * 0.02 = 0.04 Pa
• 0.04 Pa = 66.02 dB SPL

So, double SPL is +6 dB.

 

[Cbdb2]

The Electret microphone capsule contains charged material, so an external power supply is not necessary.
Other condenser microphone capsules are not like that, and therefore require some kind of power supply.
Whether the microphone's preamplifier is built-in or external is a separate issue.

My bad, you are right about electrets not needing external bias. But the point I made still stands. Most studio condenser mics have built in preamps that need phantom power. These preamps have noise that limit the S/N of the recording so a ADC thats 28 bits has no noise advantage over a 24 bit ADC.

 

[popej]

So, double SPL is +6 dB

IMO we shouldn't ignore mathematics. Twice in logarithmic scale is 3dB. The convention to use 20*log for root-power quantities ensures, that level values behaves the same as level values of power quantities.

SPL is the ratio of sound pressure over silence atmospheric pressure.

The ratio squared.

 

[boXem]

IMO we shouldn't ignore mathematics. Twice in logarithmic scale is 3dB. The convention to use 20*log for root-power quantities ensures, that level values behaves the same as level values of power quantities.


The ratio squared.

Lol, I am out.

 

[yyzsb]

I find it hard to take this DAC seriously when they talk about burn-in.

Do you recommend a "break-in" period? And should I keep the D-1 on stand-by or DC off?​

We generally burn-in for minimum 160 hours (7 days) and exercise the noise-gates around 200,000 cycles during burn-in. Just before a D-1 is shipped, it is given a final critical listening test of at least 10 minutes. We see no need for an additional “break-in” period, but it certainly won’t hurt.

Stand-by (sleep mode) or DC off are both are fine. Personally, we leave our D-1 units on standby, but turn the OLED display off. See the FAQ entry above “OLED Display Health.” If left on over some years, OLED can tend to leave a “residual” echo on the screen substrate.

 

[EERecordist]

I find it hard to take this DAC seriously when they talk about burn-in.

It is a reliability burn in, not sound quality conditioning.

Electronic devices fail on a bathtub curve - high failures in the early hours, then rising failures toward end of life.

For a high priced low volume product, it is not expensive to do. It is pretty standard for high reliability low volume products such as military.

You can see my essay with many great ASR contributors at

Reliability Science in Audio Equipment

Some time ago I worked in semiconductor reliability for a Fortune 50 company. I have worked on software reliability. Here is a simplified discussion of quality and reliability for audio equipment. I would term quality as ship and pre-ship quality and reliability as quality over time. The short...

www.audiosciencereview.com

 

[KSTR]

I find it hard to take this DAC seriously when they talk about burn-in.

You just happen to be preconditioned in the wrong way by the abuse of the term "burn-in" in audiphile circles.

This here is not about burn-in of the user ;-)

As mentioned by @EERecordist, it about reliability and quality control, though perhaps in this case even more for reasons of device parameter stabilization.
Pretty much standard in professional industrial gear, besides mil/medical/aerospace stuff.

 

[yyzsb]

We should ask the designer of the DAC if that was the intended purpose. On a DAC, the reliability burn-in thing does not seem to be that common with DAC manufacturers. I do know that I received 2 brand new D-1's with what was supposed to be 0 hours on it. I thought it did not sound good at all at first and needed about 150 hours before it got really good.

BTW - I just found out that there is a new transformer-based passive converter for RCA connections. I heard a prototype (built by someone else) before on the D-1 and have been waiting to buy a real production version. This is going to be for my $400 Schiit Aegir v1 Class A amp to connect with the D-1. The amp drives my RAAL SR1a phone. This combo was so good that I sold a $7k tube headphone amp and went with the $400 amp.

The UTB Transformer Interface Box was designed for situations where a D-1 destination (power amplifier, headphone amp, preamp, etc.) does not have XLR diff-bal inputs. The UTB uses a pair of ultra-high-grade Lundahl LL1585 line transformers to convert the D-1 XLR diff-bal output to an unbalanced RCA feed.

Use a highly-shielded XLR balanced cable to connect the D-1 to the UTB input, with a very short RCA cable at the destination end. We recommend Gotham 11301 “Ultra-Pro” cable for all D-1 analog interconnects.

The superior Lundahl xfmrs are performance-rated to a much higher maximum headroom level than the D-1 (+28dBu @20Hz), which means HDR-A dynamic range is preserved.

 

[RandomEar]

We should ask the designer of the DAC if that was the intended purpose. On a DAC, the reliability burn-in thing does not seem to be that common with DAC manufacturers. I do know that I received 2 brand new D-1's with what was supposed to be 0 hours on it. I thought it did not sound good at all at first and needed about 150 hours before it got really good.

Electronics do not "burn in" in any audible sense. There is also no audible difference between the D1 and any other competently designed DAC running the same filter and settings. All that happened is that your brain got used to it and you lost that "new stuff!"-feeling.

BTW - I just found out that there is a new transformer-based passive converter for RCA connections. I heard a prototype (built by someone else) before on the D-1 and have been waiting to buy a real production version. This is going to be for my $400 Schiit Aegir v1 Class A amp to connect with the D-1. The amp drives my RAAL SR1a phone. This combo was so good that I sold a $7k tube headphone amp and went with the $400 amp.

Using isolation transformers is generally not recommended for low voltage analog connections like RCA and XLR. You almost always get problems in the bass region, which is clearly not something you would want. If there is any audible difference between using the transformer and not using it (in a controlled blind test) with the same devices, the transformer is making it worse and should be ditched.

There is generally no reason to use an isolation transformer on XLR or RCA lines, unless you've got a clearly audible ground loop or other obvious noise problems. If you need the conversion from RCA to balanced, just get the right adapter cable or use an active pre-amp which does it.

 

[yyzsb]

Electronics do not "burn in" in any audible sense. There is also no audible difference between the D1 and any other competently designed DAC running the same filter and settings. All that happened is that your brain got used to it and you lost that "new stuff!"-feeling.


Using isolation transformers is generally not recommended for low voltage analog connections like RCA and XLR. You almost always get problems in the bass region, which is clearly not something you would want. If there is any audible difference between using the transformer and not using it (in a controlled blind test) with the same devices, the transformer is making it worse and should be ditched.

There is generally no reason to use an isolation transformer on XLR or RCA lines, unless you've got a clearly audible ground loop or other obvious noise problems. If you need the conversion from RCA to balanced, just get the right adapter cable or use an active pre-amp which does it.

I am assuming you have not heard the D-1. I know that this is a measurement only crowd on ASR, and I believe the D-1 measures better than all other DACs. Just by the measurements alone I would think this DAC would stand above other DACs on this site. The measurement reports were why I initially wanted to hear this DAC.

The only 2 pieces of gear I have owned that did not improve with more hours was the $500 Schiit Valhalla 3 OTL/OCL (my current office preamp) and the Benchmark AHB2 amps, which I owned many times but no longer. Though I am interested to hear the D-1 paired with a AHB2.

There are 3 very respected audio guys that I know who have built transformer based passive switch/preamp. I heard 1 of them and the D-1's UTB was likely inspired by the one I heard since the 2 designers know each other. Then there is also this one.

ALLEGRI+ - Townshend Audio

https://www.youtube.com/watch?v=wB60Y5w4od4

townshendaudio.com

The Townshend guy is a genius in my books based on the podium isolation platform for speakers, which I own.

"There is generally no reason to use an isolation transformer on XLR or RCA lines, unless you've got a clearly audible ground loop or other obvious noise problems. If you need the conversion from RCA to balanced, just get the right adapter cable or use an active pre-amp which does it."

This is a very dangerous way to convert. Holo Audio Serene preamp guys told me that that could kill their preamp using such a cable. I sold the Serene after I heard the transformer passive preamp my friend made. The Serene could not compete sonically with the transformer. I believe the Serene also measures well like Benchmark LA4 preamp. I owned the LA4 or HPA4 for over a decade but sold it since the D-1 did not sound good going through it. The D-1 sounded best going direct into the amp or the transformer. First time the LA4 or HPA4 did something negative to the sound.

Last week I sold a CODA #16 amp ($$$) to replace it with the 30-year-old CODA #11 amp ($). This was because the D-1 direct into the much cheaper Class A CODA #11 sounded better to me. The #11 is slightly warmer than the #16 but less resolving. The D-1 makes up for the less resolution of the #11.

Since I owned the D-1 (Dec 2025) I have sold $27k worth of audio gear on USAM (yyzsb) because they became expendable. The Valhalla 3 OTL/OCL had a small part in that, but the main driver for all the sales was the D-1.

 

[RandomEar]

I am assuming you have not heard the D-1. I know that this is a measurement only crowd on ASR, and I believe the D-1 measures better than all other DACs. Just by the measurements alone I would think this DAC would stand above other DACs on this site. The measurement reports were why I initially wanted to hear this DAC.

You're in luck! People more qualified than you and me already tested the D1 in detail and also did extensive blind and sighted listening tests compared to an industry standard interface (RME ADI 2 FS B). They found that it measures excellent, just as transparent as the RME. But since there is no more transparent than transparent, both devices will sound identical. And their listening tests confirmed this assumption!

So as it stand now, the evidence supports that there is no audible difference between the D1 and other competently designed DACs on the market. If you assume that this is incorrect, feel free to provide evidence to the contrary. For example, results from well controlled double-blind listening tests.

The only 2 pieces of gear I have owned that did not improve with more hours was the $500 Schiit Valhalla 3 OTL/OCL (my current office preamp) and the Benchmark AHB2 amps, which I owned many times but no longer. Though I am interested to hear the D-1 paired with a AHB2.

I totally believ that you've got that impression. However, semiconductor devices don't "burn in". They work within spec, often for decades. If you feel like the sound of a device changes, this is likely your brain tricking you. Bias is real and strong for all humans. I have seen absolutely zero evidence up until now to show that "burn in" exists in any form and again, you are free to provide some. Simply saying "but I heard it!" will not advance this discussion, because opinions are not facts.

There are 3 very respected audio guys that I know who have built transformer based passive switch/preamp. I heard 1 of them and the D-1's UTB was likely inspired by the one I heard since the 2 designers know each other. Then there is also this one.

ALLEGRI+ - Townshend Audio

https://www.youtube.com/watch?v=wB60Y5w4od4

townshendaudio.com

The Townshend guy is a genius in my books based on the podium isolation platform for speakers, which I own.

You sure can build devices with transformers in them. I don't see what's special about this particular one with the exception of marketing jibberish like "Fractal-Wire" and the lack of basic specs like frequency response. Being a genius also does not replace solid engineering.

"There is generally no reason to use an isolation transformer on XLR or RCA lines, unless you've got a clearly audible ground loop or other obvious noise problems. If you need the conversion from RCA to balanced, just get the right adapter cable or use an active pre-amp which does it."

This is a very dangerous way to convert. Holo Audio Serene preamp guys told me that that could kill their preamp using such a cable.

These are low voltage high impedance "line level" connections. There is basically no power flowing, only the voltage levels change. In that regard, line level signals are totally different than connections from the amp to the speakers. Where is this danger supposed to come from? At best, you surprise yourself with a short burst of noise or the volume is greatly attenuated in case the adapter cable has a different XLR pin out.

I sold the Serene after I heard the transformer passive preamp my friend made. The Serene could not compete sonically with the transformer. I believe the Serene also measures well like Benchmark LA4 preamp. I owned the LA4 or HPA4 for over a decade but sold it since the D-1 did not sound good going through it. The D-1 sounded best going direct into the amp or the transformer. First time the LA4 or HPA4 did something negative to the sound.

Again: Without solid controls (blind, level-matched), any listening test just generates noise. Humans are biased, placebo-like effects from buying new gear are strong and you cannot compare devices by listening to them hours or even minutes apart because our echoic memory is only a couple of seconds long. I understand that you did not know this at the time, but your listening comparisons did not generate reliable results and your impressions from these devices are most likely wrong.

That being said, I repeat what I wrote above: If you can prove actual audible differences between audibly transparent devices like an LA4 and your friends transformer pre-amp, the latter is broken and should be tossed. Because clearly, it introduces audible defects like changes in the FR, while the LA4 does not.

Last week I sold a CODA #16 amp ($$$) to replace it with the 30-year-old CODA #11 amp ($). This was because the D-1 direct into the much cheaper Class A CODA #11 sounded better to me. The #11 is slightly warmer than the #16 but less resolving. The D-1 makes up for the less resolution of the #11.

Since I owned the D-1 (Dec 2025) I have sold $27k worth of audio gear on USAM (yyzsb) because they became expendable. The Valhalla 3 OTL/OCL had a small part in that, but the main driver for all the sales was the D-1.

I am sorry, but you won't impress anybody on ASR with bragging about expensive HiFi equipment. We focus on what matters for good sound reproduction, which tends to be mostly uncorrelated to the price (maybe with the exception of speakers). There are a multitude of tests on the forum showing superb performance for a couple dozen or hundred dollars. And there are also some showing equipment for thousands of dollars being rubbish.

 

[yyzsb]

What is expensive about a $400 headphone amp (Schiit Aegir v1) and a $500 OTL/OCL preamp (not for the D-1) that I also use?

You're in luck! People more qualified than you and me already tested the D1 in detail and also did extensive blind and sighted listening tests compared to an industry standard interface (RME ADI 2 FS B). They found that it measures excellent, just as transparent as the RME. But since there is no more transparent than transparent, both devices will sound identical. And their listening tests confirmed this assumption!

I have this RME DAC side-by-side with the D-1. If you think they sound the same, then you have saved yourself a lot of money. You do sound convincing in your post. However, I know better and really have to discount everything you have argued. That is OK.

The only reason I have the RME is because the D-1 does NOT do DoP on SPDIF. I was listening to this RME via the OTL/OCL preamp last night with some SACDs (DoP SPDIF). There is a lot missing in the sound, but it is not bad. How do I know it is not as resolving on DoP via SPDIF as it could be. I had the Meitner MA3i DAC side-by-side with the RME both doing DoP on SPDIF, and the MA3i was so much better that even a tone-deaf person could tell the difference. I do not own the Meitner MA3i because I cannot afford it and I am just tolerating the RME. I am not bragging about anything audio, in-fact I have owned expensive-ish gear and now own some much cheaper replacements that sound better.

My office setup.