Referral Rewards Program

Thanks for watching our video. Before you get too far into the nitty-gritty, we want to tell you about how to earn our Pulse Analog gear for free!

You may not know this, but one of the major expenses in selling our gear is actually selling our gear. So instead of spending all kinds of money promoting our pre-order campaign, we want to spend that money on gear for you. The program is simple:

The easiest way to get referral credits is to share our campaign using the share buttons to the left of the video at the top of the page. As long as you're logged in to Indiegogo, each time you share using those buttons, Indiegogo tracks contributions that come in from those shares. Once we see that you've hit a referral Threshold (a little homage to one of our heroes there), our system will mark you down for that piece of gear. Simple!

You can track your referrals, too! Just log in to Indiegogo, click on your name in the upper right corner of the website, then click on My Profile. At the top of the next page, click Referrals. On the next page you’ll see how many people have clicked your share, how many of those people backed the project, and how much, in total, you’ve referred to the campaign.

And now, back to our originally scheduled programming...

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Pulse Analog Audio Components

Digital audio, with all of it’s endless possibilities and advancements, falls short in a few key areas. First off, no matter how high your DAC’s sampling rate is, you’ll never be able to hear it ALL, as there’s simply not enough bandwidth or a high enough slew rate for high resolution audio playback.

Secondly, the grounding of a digital audio system is generally not centralized and/or well managed which contributes to the ever present issue of grounding loop noise. Thirdly, the impedance matching of the audio source and next stage doesn’t match well, resulting in the need to keep swapping out audiophile cables to compensate for the mismatch.

Our solutions for these complex problems are actually relatively simple. With the release of the following Pulse Analog components, we’re able to accomplish the following.

• Every Pulse Analog components featured here provides an ultra-high bandwidth with super fast slew rate resulting in your music being true to itself. Highs will be smooth, yet defined and not overbearing, while still allowing you to hear the difference between your high resolution music files in comparison to normal CD quality files.
• With our currently available LPS4 and our soon to be released LPS8 super regulator controlled power supply, you’ll have a single device to supply power to your entire audio source system without the ground loop or reintroduced ground noise. Pulse LPS4 has been proven work so well that it received the “Greatest Bits Award” from AudioStream for its ability to pair not only with our Pulse DAC but a variety of other source gear as well. Go ahead, give the review a read.
• From DAC (analog output) to Pulse Preamp, from Pulse Preamp to Pulse Power Amp. The output impedance and input impedance of next device is always incredibly well designed and perfectly matched by the LH Labs engineering team, making the whole system work in unison with sound perfection as the ultimate end-result.

Without further ado, we’d like to introduce you to the complete Pulse Analog suite of components.

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Pulse Power Amplifier

Amplifiers have a very simple, but very important task. They take the audio signal from their input, amplify the signal by adding more "juice," then pass it along to your loudspeakers. It sounds easy, but it's actually quite difficult to make amplified audio sound "unamplified."

With this in mind, we decided to attend to the amplification process, with a focus on a more efficient use of power. Ultimately, we developed three solutions that improve the sound quality, and ensure that everything can fit inside a very small footprint.

• Multi-Zone Class A (MCA): With our innovative MCA Amplification, Pulse Power Amplifier automatically adjusts to the most efficient amplification level to fit your listening volume.
• Bipolar Instant Power (BIP): With BIP Boost technology, Pulse Power Amplifier holds power in reserve for sonic events that have more "boom." Pulse Power Amplifier’s bipolar power design will make the power output slew rate faster than ever. You need more bass power, you’ve got it, instantly.
• Ultra-Wide Bandwidth: True to LH Labs' design philosophy, Pulse Power Amplifier has an extremely wide effective bandwidth. Smart power management: With an automatic shut-off mode, Pulse Power Amplifier provides power when you need it and smart energy management when you don't.

Two Configurations

*Special note: Only one S100 is required for a stereo sound system.  However, if you choose to pre-order the M200 mono block's you'll need TWO of them to make stereo sound.  Pricing of the M200 is per amplifier.  

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Pulse Tube Headphone Amplifier

You've gone and done it. You've spent a good amount of money on a set of headphones. You've spent time with them and you think they sound superb. But can they do better? Enter our solution to your question, Pulse Headphone Amplifier.

One Configuration To Rule Them All

Pulse Tube Headphone Amplifier is built with a hybrid solid state/tube topology with dual 6922/6DJ8 tubes in the voltage amplification stage, with a constant current source to make it more linear.

Circuit Topology

Pulse Headphone Amp's voltage amplification stage works directly with its analog volume control circuit. By doing it this way, it won't attenuate your music in the first buffer stage of headphone amp like other devices (which decreases the SNR performance). It's the best variable gain design available, by maintaining the best noise floor and signal to noise ratio.

We know the importance of slew rate, which is defined as the rate at which voltage can change within the amp over time. Our current feedback structure is placed at the output, keeping Pulse Headphone Amp's slew rate above 2000V and preventing odd order distortion anomalies. Many of our competitor's slew rates clock in at only 20 to 100V.

To address the issue of power reserve, Pulse Headphone Amp's output stage keeps twice its rated power in reserve just in case you want the cannons in Tchaikovsky's 1812 Overture to feel like they're taking aim right at you.

Amplifier Component Exchange (ACX)

The Amplifier Component Exchange is a module that inserts into Pulse Headphone Amplifier that allows you to swap out its active components (transistors and OpAmps). Basically, it's tube rolling... except it's with active components instead of tubes. All you have to do is follow a simple procedure that we provide you with, and you can swap in your favorite active components anytime without affecting your warranty.

The core value of ACX is simple. A lot of audiophiles buy different amplifiers just because they want to find the best sound characteristics to fit with their headphones, or vice versa. Larry and Gavin do this all the time, too. Tube rollers do the same thing looking for audio nirvana. ACX enables you fine tune the sound without buying any NEW amplifiers. Too good to be true? No. No, it isn’t.

We feel very strongly about ACX, and have decided to add it to every HPA. It increases our cost, but it adds so much additional value, that we think it’s worth it. Don’t worry, this addition doesn't affect your price. Each HPA will come with a pair of ACX #1 modules installed by default, and you have option to get other ACX modules.

• Future Upgradeable
  With ACX, your Pulse HPA is completely upgradeable. If you don't want to commit to additional modules now, you can do it later. The only risk is that the price for each module will be higher later.
• User Serviceable
  ACX modules are easily swapped in and out. All you have to do is “Read the manual first”! And power down your Pulse HPA, pop the top, remove two screws, pull out one module, insert another, replace the two screws, stick the top back on, and power up.

Remember, you’re not forced to buy only ONE. You can pick as many as you like. Have fun with it! You could even trade them with your Geek Force friends.

Please note: These ACX modules are not waterproof. You should not throw it into the fire. If you sit on it, it will break. Handle with care.

Five ACX-I Options

• ACX-I #1: Included
  

  This input module comes standard in your Pulse HPA. In features quad JFET transistors plus dual OPA1652 OpAmps biased to pure Class A. This is the structure when we want to have the best bang for the bucks.

• ACX-I #2: $89
  

  This input module features quad transistors plus dual OPA2604 OpAmps biased to pure Class A. These are the same OpAmps that we use in our first prototype Geek Out. To our taste, they have a traditional “Burr-Brown” sound. They’re a little bit dark, and a little laid back. Classic!

• ACX-I #3: $109
  

  This input module features quad transistors plus quad AD797 OpAmps biased in pure Class A. These OpAmps are famous for their transparency and clarity. If you’re a “clinician” (like Gavin in happy mode), this module is for you.

• ACX-I #4: $129
  

  This input module features ultra low noise quad transistors plus dual OPA1612 OpAmps biased in pure Class A. These are the same OpAmps we use in the IV stage of Pulse X Fi DAC. They’re very detailed, but still organic sounding. This combination is Larry’s personal favorite for classical music out of the five options we offer.

• ACX-I #5: $169
  

  This input module features ultra low noise quad transistors plus dual famous AD8620 OpAmps biased in pure Class A. Of all our options, these OpAmps are the most precise, the most technically perfect, high speed and low noise.

Features as Unique as Our Backers

• Ultra-wide bandwidth for high-resolution listening
• The most versatile headphone amplifier on the market, outputting 100 mW from the 3.5mm single-ended output (perfect for IEM's), 3,000 mW from the 1/4" TRS single-ended output, all the way up to 10,000 mW (for hard-to-drive cans) from the four-pin XLR balanced output.
• No gain switch needed. Each output connector is optimized for the proper power output of what will be connected to it.
• Fully-balanced analog volume control.
• Fully-balanced precision DC servo on each output.
• Instant Power and Current Feed technologies. You'll get the punch you need when you need it.

Tech Specs

The History of Pulse Headphone Amplifier

Back in 2009, Larry was on a quest to promote the importance of high-resolution audio. He had been building the first 32 bit/384 kHz bit perfect resistor ladder DAC, and so he was traveling to speak who anyone who would listen, which included a visit to Intel, one of his first investors, and International CES in Las Vegas.

At the time, he was demonstrating his DAC using a headphone rig. He'd chose the HD800 over-ear headphones from Sennheiser as his reference, but he couldn't find a headphone amp with a wide enough bandwidth to reveal the beautiful nuances of 384 kHz digital music; nor could he find an amp with enough power to effortlessly drive his big cans. He needed a fully-balanced, dual-mono amp with a DC coupled, non-negative feedback output. And since he was demoing 384 kHz music, he needed a bandwidth of at least 200 kHz.

He couldn't find such a beast, so he built it himself.

The feedback he received from his demonstrations was remarkable. Interestingly enough, he found that even people who didn't self-identify as audiophiles were touched by the music they heard through his rig.

After this experience, he went to work and finished the development of Da Vinci DAC. The headphone amp, sadly, has only been enjoyed by a very few people since. Now six years after its first development, we're excited to offer you the improved version of his latest (but not first) headphone amplifier: Pulse Headphone Amplifier.

Power Supply

Pulse Headphone Amplifier comes with an ultra low noise 12V DC switching power supply. However, we highly recommend that you use Pulse Tube HPA with our Pulse LPS4. Pulse Tube HPA requires 1.2A 12V, one 500mA 12V output from LPS4.

Pulse Headphone Amp FAQ's

Q: The Pulse HPA is not fully discrete but is it still op amp based? Wouldn’t that make it similar to the Pulse DAC headphone out except with a lot more power?

A: Pulse Tube HPA is an opamp/discrete + solid state/tube hybrid. "More power" is one difference, but there are at least three other major differences:

1. Pulse HPA has THREE dedicated headphone output circuits, optimized for IEM's, standard headphone, and hard-to-drive cans. While Pulse DAC uses a gain switch (similar to other popular headphone amps), Pulse HPA uses separate, dedicated circuits.
2. Pulse HPA features an optimized analog volume control. If you use Pulse DAC is concert with your Pulse HPA, you have a combination of digital and analog volume controls. We'll publish an article on our blog about this soon.
3. Pulse HPA has no digital circuitry. It's pure analog!

Q: Has it been confirmed anywhere if a single LPS4 can look after both the Pulse and HPA? I assume it uses one of the 12v rails?

A: Yes. Please see the updated power supply area for a description.

Q: Is it required to purchase separate tubes for Tube HPA?

A: Yes. We offer a pair of JJ E88CC/6922 Tubes here on the campaign for $49.

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Pulse Tube Preamplifier

Put Analog Back Into Your Music

For so many of us, the drawback to listening to digital music is that is sounds too, well, digital. Pulse DAC does an amazingly well delivering both precision and warmth to your stereo, but if you really want to put analog back into your music, Pulse Tube Preamplifier is exactly what you’re looking for. Using 6922/6DJ8 tubes, Pulse Preamplifier provides you with a very wide bandwidth, and an extremely low noise floor. With its warm and charming characteristics, prepare to spend a lot more time listening to your music!

Pulse Tube Preamplifier features two analog inputs: One balanced and one single-ended. Choose between either of these inputs simply by pushing the volume knob in to make the selection. There are two outputs: One balanced, and one single ended. Volume attenuation is controlled by a large, comfortable knob on the front panel.

Circuit Topology

Technical Specs

Tube Circuit Design Highlights

• Active Biased Parafeed Single-ended (ABPS) Tube Buffer
• Ultra-wide bandwidth design (100k Hz in this stage)
• Bessel Analog Filter before tube grid
• Ultra-low noise discrete shunt regulator for B+
• Dedicated heater transformer and B+ transformer (only seen in very exotic designs)
• Soft start power network to make your tubes last longer.
• Zero global negative feedback

When Larry began talking about this tube circuit, he decided on a less-is-more philosophy. Because there are fewer components, each component's quality affects the overall sound more dramatically. His approach is to strategically pick the best components that in the end provide the most efficient use of power and signal. He ultimately decided on:

• 8 zero switching noise Schottky diodes
• 4 Elna Silmic II capacitors for power decoupling
• Nichicon MUSE-BP capacitors for active bias circuit decoupling
• Nichicon DB-GB series bipolar high-end capacitors for critical tube power coupling
• KOA non-inductive resistors in grid
• WIMA FILM CAPS to remove the final minor trace of power noise in B+
• Non-magnetic metal film resistors throughout

Note: Pulse Tube Preamplifier perks do not include tubes. However, we are offering a standard tube package as its own separate perk, which includes a pair of JJ/Tesla E88CC/6922 gold pin tubes.

Five ACX-I Options

With the shared technology of Pulse Headphone Amplifier, the ACX-I modules are able to be used in Pulse Tube Preamp as well. Essentially, you're able to purchase a set of ACX-I and interchange between both device if you'd like.

• ACX-I #1: Included
  This input module comes standard in your Pulse Tube Preamplifier. In features quad JFET transistors plus dual OPA1652 OpAmps biased to pure Class A. This is the structure when we want to have the best bang for the bucks.
• ACX-I #2: $89
  This input module features quad transistors plus dual OPA2604 OpAmps biased to pure Class A. These are the same OpAmps that we use in our first prototype Geek Out. To our taste, they have a traditional “Burr-Brown” sound. They’re a little bit dark, and a little laid back. Classic!
• ACX-I #3: $109
  This input module features quad transistors plus quad AD797 OpAmps biased in pure Class A. These OpAmps are famous for their transparency and clarity. If you’re a “clinician” (like Gavin in happy mode), this module is for you.
• ACX-I #4: $129
  This input module features ultra low noise quad transistors plus dual OPA1612 OpAmps biased in pure Class A. These are the same OpAmps we use in the IV stage of Pulse X Fi DAC. They’re very detailed, but still organic sounding. This combination is Larry’s personal favorite for classical music out of the five options we offer.
• ACX-I #5: $169
  This input module features ultra low noise quad transistors plus dual famous AD8620 OpAmps biased in pure Class A. Of all our options, these OpAmps are the most precise, the most technically perfect, high speed and low noise.

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Pulse Analog Product Diagram

Case 1: Stereo Amplifier

(Click here to see a larger version)

Case 2: Monoblock Amplifier

(Click here to see a larger version)