Why doesn't the Aero DAC have oversampling?

Oversampling is a technique to increase the sample rate of digital audio in an attempt to improve certain aspects of the signal, including antialiasing and noise.

To do this, the file is converted to a higher resolution (e.g. from 16-bit/44kHz to 24-bit/192kHz), converted to analog, and in the process one or more filters is used to correct for various issues inherent in the upsampling process.

This might make something sound better or not.

Oversampling has three big issues:

No new information about the recorded performance is added or created. Its chopping the original digital into lots more pieces only.

Upsampling creates imaging artifacts, frequency spectrum contraction, interpolation, aliasing and other issues. Various filters are used to help correct for these issues, but these affect the sound. Select a different filter, and the music sounds different.

The realism is compromised by these artifacts and other issues. Your ear is a magnificent instrument that can detect subtleties that affect the perception of realism. With the Aero DAC (and most R2R DACs), they have better realism, sound more "analog," and are less fatigue without using oversampling.

How do I play my DSD and SACD files on the Aero DAC?

Roon, jRiver, and many other music player software applications can decode DSD files to high-resolution PCM. All the advantages of DSD that higher resolution brings are preserved. And with the tonality, richness, and detail that the Aero’s ZOTL output stage provides, SACD and DSD are gorgeously reproduced.

Can I update the firmware on my Aero DAC?

LTA releases new firmware for the Aero periodically to address software bugs and optimize performance. Aero DAC owners can update the firmware on their Aero DAC via an easy-to-use software application available for MacOS and Windows.

Download the Serce Updater app below for each platform:

Updating Firmware on the Aero DAC

Once you have the app downloaded and installed, follow these instructions to update your Aero DAC:

  1. Connect the Aero DAC to your computer via USB.

  2. Turn on the Aero DAC.

  3. Launch the Serce Updater application. The Aero DAC should show up automatically (see screenshot below).

  4. If a new firmware version is available, click the “Update” button.

  5. Allow installation process to finish (should take less than a minute). Do not power down or disconnect the Aero DAC until the process is finished.

  6. Installation progress will be shown and you will be alerted when the process is complete.

Troubleshooting

If the Aero DAC does not show up in the updater app:

  • Confirm the Aero DAC is connected via USB to the computer on which you are running the updater app

  • Confirm that the Aero DAC is powered on

  • With the Aero DAC on, close and re-launch the updater app

Is the Aero DAC an R2R DAC?

The Aero DAC is an R2R DAC, otherwise known as a resistor-to-resistor ladder DAC.

We employ the Analog Devices AD1865 R2R DAC chip, which is a highly regarded R2R DAC chip. One well-known audio brand uses this same chip in their $153,000 flagship DAC.

What does the "headphone section" of LTA amplifiers sound like?

The title of this FAQ is a bit misleading (on purpose). Some amplifiers use entirely different sections of the amplifier for the headphone output vs the speaker output. This is not the case with Linear Tube Audio amplifiers.

In all Linear Tube Audio amplifiers, all the outputs - headphone, speaker, and preamp outputs - use all of the same circuitry, tubes, etc. There is no separate "headphone section" in LTA amps. This means you get identical sonic flavor no matter how you choose to listen.

How do I troubleshoot and replace a bad tube in an LTA integrated amplifier?

If you're hearing a scratchy, static-like noise, or you're not hearing anything, in one channel of your Linear Tube Audio integrated amplifier, there's a good chance a tube has gone bad. The challenge, with ten tubes in each amp, is figuring out which tube has gone bad.

In this video, Nicholas walks you through the procedure to identify the problem tube. Once you find the bad tube, contact us. We warranty our tubes for a full year.

Can I monoblock the ZOTL10 Mk II amplifier?

IMG_9782.JPG

Yes. All our power amplifiers can be used as either stereo or monoblock amps. You can switch back and forth between the two modes via a switch on the back of the unit.

When used in mono mode, power output of the amp doubles. For example, the ZOTL10 Mk II amplifier outputs just over 20 watts per channel in mono mode.

Related FAQs

Can I monoblock the ZOTL Ultralinear amplifier?

Yes. All our power amplifiers can be used as either stereo or monoblock amps. You can switch back and forth between the two modes via a switch on the back of the unit (in older amps) or inside the unit (in newer models).

When used in parallel mode (our more specific term for how the amp is operating when used as monoblocks), the power is increased to varying degrees based on the impedance of the speaker. Changes will be more significant at lower speaker impedances. Since all speakers have impedance dips, it should be significant for all speakers.

Running our amps in parallel offers other important performance gains, such as lowering the output impedance and increasing the current output capacity. Lowering the output impedance (by half) doubles the damping factor. This also means that the amps are more linear to lower impedances.

Here is a testimonial from a customer who upgraded from running one stereo Ultralinear+ to monoblocks:

“In my system...[the monoblocks] brought a more unrestrained quality when listening at higher volumes. Sound is projected more clearly and the speakers disappear to an even greater extent as sound sources. Any distortion that may have been present at high listening levels certainly was vanquished by the addition of the second amp. I expected more image specificity but this was not the case, nor did the stage get wider or deeper. Bass response got slightly tighter, which had the effect of making the system sound ever so slightly leaner on the bottom end. The richness of the lower midrange remained, however, affirming the most striking improvement of the PLUS enhancements--more meat on the bones as such, particularly for piano and strings.”

Related FAQs

Can I monoblock the ZOTL40 Reference amplifier

Yes. All our power amplifiers can be used as either stereo or monoblock amps. You can switch back and forth between the two modes via a switch on the back of the unit (in older amps) or inside the unit (in newer models).

When used in parallel mode (our more specific term for how the amp is operating when used as monoblocks), the power is increased to varying degrees based on the impedance of the speaker. Changes will be more significant at lower speaker impedances. Since all speakers have impedance dips, it should offer performance gain for all speakers.

Running our amps in parallel offers other important performance gains, such as lowering the output impedance and increasing the current output capacity. Lowering the output impedance (by half) doubles the damping factor. This also means that the amps are more linear to lower impedances.

Here is a message we received from a customer who upgraded from one stereo amp to two monoblocks:

Fast forward last night, the slam in the music was so punchy that I thought I needed to make some adjustments on the sub - except the REL wasn’t even on :-). Between the monoblock and new power cords/interconnects, the slam was so tight, it changed the sonic characteristics of the Spendors!  My head is spinning, it’s like a whole new system.

Related FAQs

What does the ZOTL10 Mk II amplifier sound like?

Here is how a selection of reviewers have described the ZOTL10 Mk II amp:

Part-Time Audiophile Review:

While it’s not exactly the “classic” sounding vacuum tube amplifier in many respects, it does seem to preserve those things that tubes do really well (think open, unfettered sound with highly natural harmonics) while minimizing their perceived shortcomings. This amplifier earns my accolades for its stunning sense of clarity, transparency, and precise spaciousness of sound.

Enjoy The Music Review:

I am smitten with the ZOTL10 MK II. Its brings out the best in any music you play through it. Rock, jazz, classical, pop – it doesn't matter. What made it so difficult to review this amp is the reviewer part of my brain would keep shutting off and I would just start listening to the music. I can't think of any better compliment than that.

The Audio Beatnik Review:

The ZOTL10 Mk.II also gave me a very realistic musical presentation… It plays music with wonderful harmonics and richness but with musically quick transience and very nice bass control. Mentioning the bass, it was able to carry the music with a really good rhythmic drive. The bass was also very well defined but not overly tight, and there wasn’t the least bit of “one-note bass.” There was also a very natural air around and within most bass instruments.

The top end was smooth and very extended. String and woodwind overtones were played beautifully. I was particularly impressed with the air around reed instruments and with the bite of horn instruments. Another important job of the top end of an amp is to have enough detail to help place the instruments and voices as they should be on the soundstage. In this area, I was very happy. The soundstage and imaging were very well portrayed by the Mk.II.

What does the ZOTL Ultralinear amplifier sound like?

Here is how a selection of customers and reviewers have described the ZOTL Ultralinear amp:

Terry London’s 6moons.com review:

Think of the ZOTL Ultralinear amplifier as a world-class SET for its inner glow of gorgeous color/timbres plus the sense of aliveness and dynamics of a more powerful push/pull. This amplifier would be welcome in any system with standard speakers and listeners who prioritize beautiful tonality and timbres, first-rate imaging and the aliveness and 'speed' of live music.

~Audiogon User dodgealum

In my system the Ultralinear conveys the natural warmth of acoustic instruments and voices without editorializing. It is exceptionally clean, quick and dynamic yet completely uncolored and free of sonic artifacts. When you listen through this amp your focus will be squarely upon the music, not the means (transistors or tubes) by which it is being reproduced.

~ The Audio Beatnik Review

I’ll start by saying this is the best Class AB amplifier I have ever heard. The first thing I noticed was that the LTA Ultralinear was the quietest amp I have ever heard; not the quietest tube amp, but the quietest amp. I think this enabled me to hear some of its most captivating qualities; its incredible sense of pace and rhythm, explosive dynamics, and micro-dynamics. I found myself tapping my foot almost as often as I do when listening to live music. The amp is so unbelievably natural that it was hard to think about anything but the music, the glorious music.

Will the headphone output on the microZOTL Preamplifier work with my "hard to drive" / "hard to pair" headphones? (Sennheiser HD650, HiFiMAN HE1000, HE-6, HD800)

In some cases, such as the HiFiMAN HE-6, HifiMAN Susvara, or AKG K1000 which has notably low sensitivity and thus requires several watts to power adequately, the microZOTL Preamplifier will not give you a satisfyingly loud and full listening experience.

Since the unique circuit of LTA amps reacts very little to different impedances, it is mostly a matter of sensitivity when it comes to which headphones the microZOTL Preamplifier headphone output works well with.

Whether it can "drive my headphones" often just means "will I prefer how my headphones sound with this amp?" We've read many accounts of people thinking their HE1000 or HD650 has never sounded better than with their microZOTL Preamp. I've also read one or two accounts of people saying the opposite.

We don't know what you like, but we do know that we've read far more mentions of the microZOTL Preamplifier sounding good with all kinds of headphones than not.

While we’re at it, we should also note that the headphone outputs on the Z10 Integrated and Z10e electrostatic headphone amp are more powerful and may work better for you if you have less sensitive headphones.

How do I change my LPS+ Linear Power Supply to work with 110V or 220V electricity?

Switching the LPS+ Linear Power Supply to work with 110V or 220V electricity is a simple process.

Look where the AC cord plugs in. You can see the voltage it is set to thru the window.

  1. Carefully pry the little door open from above the red window.

  2. Carefully pry the red fuse block out of the hole.

  3. Turn red fuse block over and reinsert.

  4. Close the door and it should say the proper voltage in the little red window.

  5. You're done.

Here are photos to help you.

Do LTA amplifiers have good bass?

Yes.

Many of our customers describe the bass as “thunderous.” Steve Guttenberg of CNET described the bass of the Z10 Integrated this way:

Bass depth and definition were well-ordered... There's no muddiness down there of the sort I get from a lot of tube amps.

From a technical perspective, ZOTL amps have a linear frequency response below 10hz +/- 0.5dB.

To put that number into perspective, the lowest most full-range speakers go to is about 20hz, with most being closer to 28-32hz. Even REL, arguably the world’s top subwoofer manufacturer, their flagship subwoofer goes down to 14hz.

So, whatever is in the music, our amps will be able to deliver.

Related FAQs