LSA "Discovery Warp One" Class D Power Amp Impressions

LSA "Discovery Warp One" Class D Power Amp Impressions











Click below for more information about the amp

Spoiler: Explanation about the amp from the designer

"I am the designer of the Warp-1 amp and hopefully can give you some more info here.

A while back, I needed a good Class D amp for some projects coming up. I also tried buying the 3E TPA3255 Class D amp from China - Inwould have used it if it sounded good enough. I listened to it and did not have the sound quality or features I was looking for to make it a higher end amplifier. I also designed mine to have high mechanical robustness and to be able couple the heat directly to the amp chassis without an internal finned heatsink.

The thread that discusses the core amp board that I developed is here (I am xrk971 on DIYA):

www.diyaudio.com/forums/group-buys/340880-tpa3255-reference-design-class-amp-gb.html

I set out to extract everything I could from this amp. We did the layout using state of the art techniques to reduce impedance of the large current paths, reduced loop area to reduce noise pickup, use 2oz copper traces and 2mm thick PCB. All the components are genuine name brand quality parts such as Nichicon, Wima, Elna Silmic etc sourced from Mouser. The output filter inductors are a key source of distortion and I spec’d ultra high current capable CoilCraft SER series which uses flat (rectangular cross section) thick copper wires and these alone probably cost more than the parts of the 3E TPA3255 amp (which retails for $75). The layout was designed by a veteran professional layout designer, JPS64 on DIY Audio with more than 35 years experience designing electronics for aerospace and audio industry.

There is a custom single ended / balanced input buffer on the Warp-1 that auto switches between RCA and XLR inputs with an internal relay. This buffer resides right on the input panel and uses state of the art best in class OPA1656 opamps and OPA1637 balanced line drivers. The buffer provides a powerful and transparent low impedance drive to the balanced inputs of the amp. There is switchable gain on the buffer (internal DIP switches). You can select 0dB/6dB/14dB/20dB. It’s set up for 6dB from the factory. Combined with 22dB gain of TPA3255 that gives a nice 28dB overall gain. The amp board has lost filter feedback (PFFB) capability built in bit is not enabled as that feature limits output power to 75w. The design of this buffer is so transparent and natural sounding - it’s one of the reasons why you won’t get as good of sound from a run of the mill TPA3255. This buffer is an improved custom version of the BTSB buffer on DIYA. More info in that here: www.diyaudio.com/forums/group-buys/358142-btsb-buffer-se-bal-se-bal-buffer-gb.html

All of this is powered by a custom 600w ultra quiet SMPS that also provides the 12v to power the dual rail DCDC converter to make the +/-12v for the buffer. The SMPS is oversized to allow maximum headroom and was developed using a special topology specifically meant for audio. It does not suffer from SMPS hiccup mode under large capacitive loading. And it’s ultra quiet. The measured noise floor of this amp is -125dB relative to 50w output at 0dB. That’s less than a 1uV rms noise. You cannot tell the amp is turned on with your ear pressed to the speaker.

The power/standby switch in the front activates the PSU enabled mode and has built in fine delays to prevent speaker pop.

Details such as double high strand count silicone jacketed wires connect the amp to the pure solid copper premium Viborg binding posts to ensure the lowest possible impedance path.

All of these details when combined in a heavy gauge CNC aluminum chassis with 6mm thick bottom and top plates that are powder coated make for a superb sounding and mechanically robust and beautiful amp.

This amp, although it uses a regular TPA3255 chip, its PCB layout and choice of superior components permits it to have an incredible harmonic profile that is dominant second order (vs third as most other Class D amps) at lower powers. This gives the amp an organic and non-fatiguing sound that you can enjoy endlessly. The low noise floor lets you hear small details not possible before. The low impedance layout and wires and copper binding posts give it incredible grip in the bass area.

I hope this helps answer why this amp is different than a $100 3E TPA3255 from AliExpress. Of course, I invite you to compare them side by side for a listen. For maximum impact try to use a source or preamp with balanced outputs.

Regards,
Viet Nguyen

Here are some photos of the details that set this amp apart. These are from the pre-production sample so wires are not perfectly neat.”


Closeup of the buffer board and front end of amp:



Closeup of the thick copper wire CoilCraft inductors. Not the TPA3255 chip is mounted on the bottom and is in thermal contact with the chassis through a heat transfer block.



This is the custom 600w SMPS that handles the power on sequence with a soft start front panel switch:



This is a closeup of the Viborg solid copper binding posts with enameled brass knobs:

Spoiler: Click for specs and marketing details

Our new Discovery Warp One, 150wpc, stereo amp will be the sonic class leader at its price point. It outputs 250 watts at 4 ohms. Is is 2 ohm stable as well. It is the perfect mate to our DPH-1 preamp/DAC above.
The Design is finished and we will ship in late July 2021.
The Warp-1 amp utilizes the class-leading Texas Instruments TPA3255 "Purepath" Class D amp Reference Design as our initial inspiration, but with extreme care in the layout design and choice of high performance componentry to ensure that the amp operates at its true potential.
The state of the art layout was made using double planes stitched together with thousands of vias wherever an ultra-low impedance path was needed. We do this to ensure extraordinary signal transfer which gives you ALL The Music and Dynamic Contrasts.
Attention was paid to keep current loop areas as small as possible. Power input paths were kept as short as possible as well. The signal integrity is our primary focus here. Paying attention to these parameters yields phenomenal low noise for Blacker Blacks and Deep Soundstage that will amaze.

The ground paths were designed with a star hub topology (note that the power entry jack is in the middle of the board). Ultra-high current low distortion CoilCraft flat copper wire SER shielded inductors for the output filter provide unfettered current flow while ensuring the minimum in distortion. These are techniques found in Amplifiers at 5 x the price.
The PCB is an extra thick 2mm FR4 with 2oz (70um thick) copper traces and electroless nickel immersion gold (ENIG) finish. All of these finer points add up to a sum that is greater than its parts, thereby yielding a Class D amp that sounds dynamic, engaging, natural, and non-fatiguing… so you therefore get a product that performs at many times it’s price --- but most importantly honors the Musical Event in a very real way.

The Class D amplifier is just the core, and it must be supported by a state of the art low-noise power supply and buffer preamp, both of which are custom made for Warp-1. An oversized 600w switch mode power supply provides the amplifier with an abundance of power on-tap without a hint of hesitation. Bass Slam will delight you track after track.

The Warp-1 has a custom made signal input buffer that accepts either balanced (XLR/TRS) or single ended (RCA) sources and utilizes our choice for best results --- the superb sounding state of the art Texas Instruments OPA1656 operational amplifiers for signal conversion and amplification. The buffer has a DIP switch that allows selectable gains to match any source. The gain on the input buffer can be selected from 0dB, 6dB, 14dB, and 20dB. The TPA3255 amp has an intrinsic 22dB of gain so the setting from the factory is 6dB for an overall 28dB gain. For most systems this will be the perfect setting to ensure trouble free, low-noise operation.

Some applications may require lower gain so 0dB can be selected for overall 22dB of gain. The 14dB setting will give an overall 36dB of gain which might be useful when playing from a less powerful source – perhaps a Lower Gain Preamp. We would prefer that the 20dB setting not be used as this is just too much gain for most applications.

These components and techniques combine together to yield an amplifier that has a performance in the rarified air of 130dB signal to noise ratio. Even without a source playing, the Warp-1 will be absolutely silent with the ear pressed to the speaker cone - you cannot tell the amp is turned on unless the LEDs were glowing. This amp can be used in every type and sort of High Performance Audio System with spectacular results.

The Warp-1 amp redefines what an affordable Class D amp can sound like.


THD+N @ 1kHz at 50W
< 0.0027% into 10 Ohms
< 0.0057% into 5 Ohms
14" wide x 10" deep x 3" high

MAXIMUM AUDIO OUTPUT CURRENT: 17 A peak, per channel, both channels driven

INPUT SENSITIVITY
Low-Gain = 2.7 Vrms, Gain = 22 dB
Mid-Gain = 1.4 Vms, Gain = 28 dB
High-Gain = 0.55 Vrms, Gain = 36 dB
Gains Selectable via DIP Internal Dip Switches on Input Buffer
INPUT IMPEDANCE: 25 k Ohms (Single Ended or Balanced Inputs)
PROTECTION CIRCUITS
Fully Electronic, No Relays
Mute Sequencing
Distortion Detection (Clip Warning)
Short Circuit Protection
Over Current Protection
Over Temperature Detection and Protection
SOA Detection (Output device safe operating area)
PSU Fault Protection
OUTPUT VOLTAGE INTO VARIOUS LOAD IMPEDANCES
27.0 Vrms into 10 Ohms < 0.0052 % THD+N
27.0 Vrms into 5 Ohms < 0.0056 % THD+N
22.4 Vrms into 10 Ohms < 0.0038% THD+N
22.4 Vrms into 5 Ohms < 0.0064 % THD+N
15.8 Vrms into 10 Ohms < 0.0048% THD+N
15.8 Vrms into 5 Ohms < 0.0057 % THD+N
11.2 Vrms into 10 Ohms < 0.0058 % THD+N
11.2 Vrms into 5 Ohms < 0.0059 % THD+N

SNR & DYNAMIC RANGE
Rated output relative to output noise, inputs shorted: 115 dB
NOISE VOLTAGE
Output noise voltage, inputs shorted: -119dBV, 1.1 uVrms

 

Golden Age of Class D?



Ok hear me out…is Class D good now? I have to admit I have not spent really anytime with higher-end class D offerings before recently purchasing my NAD M33, and more recently, listening to the LSA Warp 1 Power Amp. I have heard a decent amount of sub-$1k Class D offerings, you know cheap integrated amps, home theater amps, etc. They always sound fine for TV and stuff, but just don’t sound REAL. My experience with the LSA Warp 1 and the NAD M33 suggests to me that it is time to lose the Class D Bias. I did an extensive amount of listening focused on the LSA Warp 1 loaner, and along the way learned a lot about my preferences, my biases, and spoiler alert, I learned that the LSA Warp 1 is a killer amp, especially at the asking price.

Testing Methodology

I listened via Roon, but quickly made a Spotify version of my playlist, available here: https://open.spotify.com/playlist/363pxgIuAjRPDSL6MI6Vsk?si=f1fb6ebfccd34b08 Going back and forth between amps, all and all probably listening to this playlist about a dozen times over the course of a week.

What follows will be my abridged listening notes when A-Bing amps, at the end I will summarize my findings if you want to skip to that.

As far as gear used for the review, I used the M33 as a preamp when comparing the LSA Warp 1, and the modded Akitika GT-102 Z4 and listened via Graham Chartwell LS6F speakers. For the monoblock Aegir comparison, I used Pi2AES->Yggdrasil A2-> Freya+->Amps and listened nearfield via Graham Chartwell LS3/5A.

This post is not about the M33, but my quick thoughts on it since I will be using it for comparison sake, as a preamp, and because people are not really familiar with it around here. Sweet is the one word I would choose to describe the sound, it has tons of nuance and sweetness. Where it lacks lushness or organicness it fills in the void with realism, air, and finesse but in a really natural fatigue-free way. Its bass is not the star of the show, and the stage could be deeper/better (I am sure the built-in ESS DAC is doing no favors here), but I just find it to be a joy to listen to and every speaker I have hooked up to it has been enhanced by the pairing. So while it is not perfect, it is a class D chameleon at least based on my biases about class D, it is good for all-day listening, preserves great detail for background listening, and is just a seamless joy to use. Everything you could ask for in a living/family room sort of amp.

Battle of the Class D



I first listened to the playlist via the NAD M33 to set my baseline for comparison. Everything sounded pretty nice and well sorted, other than the track “Maybe You’re The Reason” by the Japanese House (spoiler alert, this track sounded like trash on every setup I tested). Read my thoughts on NAD M33 above if you want a general sense of its character.

LSA Warp 1 vs NAD M33

• First impression with only about 10 minutes warmup up on the amp (brand new) was that vocals were not quite “right". They seemed less accurate and drier. I feel this phenomenon became less pronounced as the amp burned in a little, will comment more on this later as it was my primary concern about the amp.
• The LSA has a really really great sense of plankton to the sound for a lack of a better word. Feels textural and meaty, especially in the bass region.
• Percussion has really nice drive that gets you toe taping, but I did find it to sound a bit brash and grating compared to the M33 which seems a bit more finessed and accurate.
• Very dynamic sounding but not fatiguing as I expected from class D presentation.
• Has a more forward vocal presentation.
• Has a flatter soundstage with more defined edges, while the M33 feels airy and trails off into space, the LSA has a more defined boundary to the sound
• You get a great sense from the LSA that it is grabbing the drivers by the balls. Very controlled and punchy without bordering on overblown or artificial.
• If the M33 is seen as delicate, sweet, and nuanced, I would say the LSA is forceful, dynamic, and ultra ultra-clean, but without any fatigue or annoying sheen despite being fed from an ESS DAC.
• I felt addicted to the LSA at low volume, probably due to just how dynamic and defined it sounds. At the beginning of “Tenderness” by Jay Som there is this really hushed performance before the track kicks in, and it sounded so spooky and captivating from the LSA.
• I adore Big Thief and have listened to them a ton, but I feel like I had never truly experienced the guitar solo in their track “Not” until hearing if from the LSA. Crunchy, visceral, drop everything attention-grabbing. There is lots of little background sounds during the solo, cymbal strikes, etc. and they all are just perfectly placed and enhance the whole presentation. A+ stuff.
• The more I listened the primary strength of the LSA became clear, LAYERING. This amp layers better than any power amp I have ever listened to. Yes, the stage is flatter, but it is made up for by superb layering especially in the vocals. The background vocals in “Ultralight Beam” and “Levitating” were absolutely jaw-dropping.

NAD M33 vs LSA Warp 1

• When I returned for another listen on the M33 it became immediately clear that it oozes nuance in a way the LSA did not. It is funny because the LSA sounds more detailed when you listen, but the M33 must just be a tad more resolving as some nuance to the sounds really pops.
• The M33 is SO MUCH SLOWER than the LSA. I never thought of the M33 as slow, but it sounded downright syrupy after switching back from the LSA. LSA is clearly a very fast-sounding amp.
• Yep, as I covered above, the LSA has better layering and separation, things are presented in a very delineated way. M33 by comparison has a deeper/wider and more diffuse stage.
• M33 sounds a bit looser after coming from the LSA. I think this is part of the M33s ability to trick you though into thinking things feel a bit more holographic and realistic, kind of hiding the Class D DNA a bit.

But what about Class AB?



I have been wanting to see how my modded Akitika GT-102 Z4 sounded with the LS6F, so I thought this was the perfect chance to try it and see how a Class AB amp fared against these Class D offerings. This GT-102 has better wiring and upgrades to some higher quality/bigger capacitors. A bit more robust sounding than the stock GT-102 and with better bass response.

Akitika GT-102 Z4 vs Class D

• The bass sounds really hollow from this amp after coming from the Class D offerings, which is surprising as that was never a characteristic I perceived before
• Vocals do sound more natural than either of the Class D amps, but they sound less isolated in space, overall more smearing of vocals and instruments
• Dua Lipa “Levitating” is not hitting for me at all from this amp. Sounds a bit ragged, vocals are grating, fuzzy edges and not enough separation. Does sound a bit faster than the M33, but prefer this track from both Class D amps. This has been a go-to family dance song recently, so maybe I have just become accustomed to the class D sound for this track.
• The Kelly Lee Owens cover of “Arpeggi” on the other hand sounds stellar from this amp. Significantly more texture, atmosphere, and “spooky” sort of vibes than the class D amps.
• Overall a bit of a mixed bag, some strengths of Class AB (or shortcomings of Class D depending on how you look at it), became apparent. The biggest surprise to me is this amp did just sound a bit hazy in comparison when normally I always considered it to be very squeaky clean in its presentation.

What you are waiting for: LSA Warp 1 vs Aegir Monoblocks



I think this is the comparison point that most of you will find more interesting, as more people are familiar with what the Aegir sounds like. Quick disclaimer, the recommended for the LS3/5A is 25-50 WPC. The Naim Uniti Nova and the Aegir monoblocks have shown me that there are some benefits to giving them some extra juice, but the LSA Warp 1 is not what I would consider an ideal pairing as it is 150 WPC. I just opted to be very careful with volume control.

Aegir Monoblock vs LSA Warp 1:

• Oof where is the bass. Aegir is not a bass titan, and the LS3/5A rolls off at 70hz, but I have gotten used to the pairing and don’t really find myself wanting for more bass in my small nearfield space. But yeah, after listening to these tracks on the other gear, I was missing some bass response.
• And here is the Aegir’s strength…the Fleet Foxes track “Blue Spotted Tail” was so arrestingly stunning, that it caught me off guard and made me forgot for a moment that it was even on my playlist before. It was like hearing it for the first time despite it being like the 10th time I had listened to it in a few days time. Space, realism, Robin’s voice like an angel from on high, what this hobby is about.
• Aegir really proved its prowess on the Laura Stevenson track “Living Room, NY”, a personal favorite of mine. Just oozed plankton and made all these little nuanced sounds/details in the track come to life.
• After vocals and piano, I think one of my favorite things for judging setups is saxophones. Maybe it is because I spent a good decade of my life playing jazz/band/orchestra tenor sax, but when it is GOOD I really notice. Aegir brought the saxophone in “Robber” by The Weather Station to life, you could really hear the wind and the reed of the saxophone in a way I had not experienced in the other setups

LSA Warp 1 vs Aegir Monoblock:

• Losses a bit of the holographic presentation of the Aegir
• Still maintains that sense of tons of plankton that I observed with the other setup, dialed up to 11 being fed by the Yggdrasil.
• Vocal accuracy issues I noted when the amp was cold/new before seem less pronounced, overall just a bit less girthy and wet sounding than the Aegir.
• Guitars just sound great from this amp. Solos just feel like they hit just right every time and draw me in. Part of it is the guitar energy/tone, but I think a lot of it is the stellar layering of this amp for the support pieces to solos.
• Bass is undeniably more satisfying sounding than the Aegir. Clean, just a bit round sounding. Aegir is undeniably weak sauce in the bass department with the LS3/5A, while the LSA might hit just a bit too hard for these polite little British monitors
• Experimenting with the SS buffer and tube modes via the Freya+, the tube mode helps unfold the flatter stage of this amp a bit.
• Have I mentioned vocal layering enough yet? The choir chorus stuff in “Ultralight Beam” is straight-up legendary sounding.
• I felt a bit separated from the vocal performance in “In a Good Way” by Faye Webster. Kind of like the sensation of being behind the glass in the studio listening to playback vs being in the room. On the other hand, the guitar work on this track sounds outstanding.

BONUS LISTENING SESSION:



I didn’t feel quite done with this amp, and I still wanted to drill into whether some vocal accuracy concerns were in my head due to some of that first cold amp listening, or if they make actually be a concern for this amp. I think I finally figured it out after spending some time with the stellar AAA Nancy Sinatra collection that Light in the Attic put out recently. It comes all down to the perception of vocal cords. With the Aegir you get a greater sense of air and wetness from vocals that provide that last 5-10% of nuance to vocal performances that really pushes it over the edge. That perception at least of hearing vocal cords in the performance. Vocals did not sound bad with the LSA, I really enjoyed spinning this record via the LSA, it in no way sucked the soul out of things, and in fact, the extra dynamic prowess helped me feel more engaged at times. The Aegir felt a bit too diffuse/hazy/restrained after first spinning the record with the LSA. The LSA maybe just presents vocals a bit too forward for my particular sensibilities and preferences. Not dealbreaker territory, would just require some more careful gear matching for me and my picky tastes and the music I listen to. And heck, maybe you want more drive and gravitas from vocals. Lee Hazelwood on the tracks on this record does a great job providing that contrast. From the LSA he sounds very gruff, assertive, like a rumbly gravitas to his voice, that baritone really hits ya. Via the Aegir you are provided with a bit more nuance to his cowboy persona baritone like you can hear the age and experience of his voice by not smoothing over the bit of restraint and breathiness to the performance.

Final Thoughts / TL : DR

Pros:

• Layering. Holy cow, best I have ever heard.
• PRaT. This amp has it in spades, it gets you up and moving and grabs your attention, but is not fatiguing.
• A great amp to help cure a sleepy chain or recording. Provide energy and dynamics without over asserting itself.
• Guitar tone is super satisfying, and guitar solos absolutely rip.
• Bass is stellar. Clean, punchy, not bloated
• Dead quiet, I did not touch on this during reviews, but you would swear your system is turned off, absolutely zero noise.

Neutral:

• Vocals a bit forward/bold
• Would recommend a warmer preamp
• Very fast sounding amp, folks mileage can vary on this

Cons:

• Vocals lack the last 5-10% of nuance/realism
• A hint of Class D timbre/DNA. You are not going to be fooled this amp is not Class D, but even if you are sensitive to Class D offerings, you might be pleasantly surprised by this one.

This amp really impressed me and overall is a superb package, with great specs for a variety of setups, for a crazy affordable price to performance ratio. I mean heck, I was comparing it to the M33 which while not just an amp, is $5k MSRP, and it held it own and bettered the eigentakt purify based M33 in many ways. I think the comparison to the sort of similarly priced aegir monoblock setup demonstrates what we all know at this point, which is that in this hobby it comes down to synergy and preferences. I hope my thoughts and listening observations can help you know if this amp is a good fit for you. I can say based on my time with it that most people will not regret the purchase, it is kind of mind-blowing to me how cheap this is for what it accomplished with these different setups. I think especially if you have a need for a cool, quiet running amp in a relatively compact package that is really dynamic and atmospheric sounding, you can’t go wrong. If you love to blast guitar solos, buy this. If you want an amp with exceptional layering abilities, buy this. LSA is clearly doing really incredible work and I cannot wait to try some of their other offerings. Thank you to LSA, SBAF and @rhythmdevils for the chance to try this amp out.

 

Not sure if I'm in the right thread - but I just wanted to personally thank inoculator for a job very well done.

All of us at Underwood and the factory wish to extend our thanks

Best wishes,

Mark

 

As in, Mark Schifter?

 

Yes - that would be me.

I run the Product Development side for Walter at Underwood for these last 8+ years. All of the LSA, Core Power Tech and Emerald Physics products run through my desk.

Wally bought Core Power from my wife and I two years back now after my health problems became worse. It's been good for my family and for his.

At this moment - there are 21 new products I'm in Dev with for these companies -- planned over the next 18 to 24 months. It's been busy.

I am also managing some other outside importing ventures in headphones and turntables. One of these is heading to you folks next week. The LSA HP-Diamond Headphones from my friends at Kennerton.

Thanks for your asking -

Best wishes,

Mark

 

Impressions of the LSA Discovery Warp-1 Amplifier

Background

Specs of the amp are at the top of this thread, so I won't repeat them here.

The last time I bought a power amp was 25 years ago. At that time, Class-D amps were universally judged to sound horrible, and I agreed with that judgment -- perhaps unfairly, since I'd only ever heard really cheap Class-D amps, usually integrated into other components.

Back then, I don't think I ever heard -- or had even heard of -- a Class-D amp that claimed to sound as good as audiophile linear amps. But progress has allegedly been made, and I've read a bunch of articles about recent improvements in Class-D sound quality (Hypex seems to have particularly hard-working PR people), so I was eager to hear this new LSA Discovery Warp-1 and do some comparisons.

Room and Associated Equipment



Last year I moved from my city apartment to a cabin in the woods, and it's great except that the listening room is currently being used as a two-person home office, so my speakers are temporarily in the less-ideal location pictured above, with strong room modes at 28, 40, and 50 Hz (and multiples).

So I've got two radiused pucks in each speaker's port, which raises the cabinet tuning frequency from 25Hz to 31Hz and kills some of the boominess, and I plugged in a DEQ2496 to cut the peaks at 100Hz and below. Imaging suffers a little in this room, but the overall character of the sound is unchanged.

My chain is 44/16 and 96/24 FLAC through a Squeezebox Touch, to the DEQ2496, to a Benchmark DAC3 HGC, to the power amp, to Meadowlark Heron speakers. Analog interconnects are Kimber PBJ, speaker cables for this evaluation were old-school Vampire Wire ST-III. Digital cables to and from the DEQ2496 are... I forget, maybe Blue Jeans.

Comparison

I'm comparing the Warp-1 to my Counterpoint NPS-200 MkII, which maybe isn't fair, since the Counterpoint cost $3000 in 1995 while the LSA apparently costs around $1500 today. But whatever. That's the amp I have. (And besides, regardless of how much some gullible audiophile might have been willing to pay for the NPS-200, it's last century's technology. Today's products should be better, right?)

A brief description of the NPS-200, since probably no one here is familiar with that amp -- except maybe Mark Schifter, whom I coincidentally met at Counterpoint's headquarters in like 1994:

The NPS-200 is a two-channel 100Wpc @ 8 ohms hybrid amp designed by Mike Elliott. The basic topology is a differential tube voltage-gain stage (one 6922 per channel) with a tube power supply (one 6CA4 per channel), followed by a novel -- in 1995, anyway -- transistor output-stage circuit that culminates in eight big Sanken bipolars per channel.

It would measure poorly, relative to the LSA amp. Its voicing can be altered by messing with some bias resistors in the output stage, and mine has been deliberately adjusted for a little high-frequency rolloff (0.5dB down at 10KHz, 1.5dB down at 20KHz) to sweeten the treble. And Mike was only willing to admit in the published specs to 90dB SNR and 0.5% THD anyway (although to be fair, it does measure better than that).

Despite the relatively poor measurements, the Counterpoint amp sounds fantastic in my system, even in this room. Solid lows, beautiful highs -- kind of the best of SS and tubes -- but its defining characteristic is midrange purity and realism: Clear, natural vocals and believable acoustic instruments, precisely located across a wide soundstage.

The biggest problem with the Counterpoint amp is that it draws a constant 150 watts whether it's playing music or not, and mine has been on 24 hours a day, 50 or 51 weeks a year, for 25 years. They charge around 30 cents per kilowatt-hour here, so I've paid for that amp a few times.

I didn't see a quiescent-current spec for the LSA amp, but I'm certain that it will be much less expensive to run, even if it's kept on continuously.

Setup

Getting the Warp-1 into my system was a little more difficult than I expected, because my speakers are biwired, and my amp has two pairs of binding posts per channel while the Warp-1 has only one pair. And my four pairs of speaker cables are terminated with banana plugs that unfortunately can't be daisy-chained. And I couldn't find jumper wires, so for this comparison I used homemade Y-shaped speaker cables instead.

Which was fine, except that the Warp-1 backplate design makes the connections very crowded.

The binding posts are really nice, but I had to carefully clock the spades to keep the speaker wires from pressing the reset switch or the power switch, and to allow the power cord and interconnects to be attached. And until I added electrical tape, I was pretty nervous about the spades shorting against each other or something else.



Something that @Core Power Tech may wish to consider for future products: It would have been easier to wire up the amp if the speaker binding posts had been at the left and right edges of the backplate, with the RCA/XLR inputs inboard of them and the power cord and switches in the center.

Also, two other areas where I think usability improvements could be made:

1. The user's manual points out that the back-panel RESET button can not only be pressed to reset the amplifier circuitry after a fault, but can also be held down to mute the outputs while changing cables, etc. It would be nice if the pushbutton were replaced with a toggle switch -- or if LSA wanted to get fancy, a 3-position on/off/momentary toggle -- so the outputs could be conveniently kept muted when necessary, without having to hold the pushbutton.

2. The amp sits on polymer rings held by grooves in its four feet. Those rings seem to contain plasticizers that migrate out and will mar certain materials and finishes; they had started to leave faint marks on my wooden floor after just one day. They should be replaced by rings that won't damage the surface they're on.

Sound, Finally

Ok, so the sound.

I started my evaluation with a couple tracks I've heard probably a thousand times each: Chesky's recording of Rebecca Pidgeon singing "Spanish Harlem", and Muddy Waters' "Country Boy" on the MoFi pressing of Folk Singer.

The very first thing I noticed was that vocals leap out of the mix with the Warp-1. I see that @Inoculator called this a "more forward vocal presentation", but in my room the effect was much more pronounced than I would have inferred from that description.

This is good and bad. On the one hand, the separation gives the impression of a deeper soundstage -- sort of a 2.5-dimensional boost to the imaging -- which is nice. But it also emphasizes the biggest difference between the Warp-1 and the NPS-200: Naturalness of the vocals.

I listened to some more "audiophile" recordings that I know well, and to live recordings of voices that I know well -- Ani DiFranco, Liz Phair, Steve Poltz -- and they didn't sound exactly right from the Warp-1. There was a little bit of softness around the edges -- /p/ and /t/ often sounded closer to /b/ and /d/ -- and also a slight hollowness, like the singer had taken a step back from the mic.

Acoustic drums also sounded slightly damped. Not as bad as tea towels draped over the drum heads, but a little bit in that direction.

Piano, interestingly, sounded fine to me. I don't play, but sometimes I really notice equipment differences on piano recordings. Not this time, though.

Anyway, I eventually stopped listening to one-mic-in-an-old-church audiophile test tracks and switched to just normal rock and pop.

And now we were getting somewhere. Nearly all of that music sounded good, even though the Warp-1 probably still sounded different from my amp. If I could rapidly A-B then maybe I'd have been able to hear and describe the difference, but I don't think that's important. I mean, who's to say how an electric guitar through effects pedals and a ton of processing is supposed to sound?

Without that reference, I couldn't say how accurate the Warp-1 was, but it did play clean and clear and satisfyingly. I was hoping to have that experience where you're listening to familiar tracks on new equipment and you hear notes -- or entire instruments -- that you've never heard before, but I unfortunately didn't. Oh, well. It wasn't for lack of resolution or detail; the amp presented instruments with solid clarity.

Where the Warp-1 sounds great, though -- and I mean really great -- is on dance music.

EDM has never sounded better on my system. And the louder I played it, the better it sounded. Programmed drums were super crisp, with none of that rounded-edges sound that I heard with real drums. Electric bass was insistent and impactful. Synth was crystal clear. When I ran out of volume adjustment with R 128 enabled, I disabled it so I could crank the volume higher. The room was shaking, I was sweating, my sound-level alarm was flashing red and showing 101 dB -- omg it was awesome.

Listened to one track like that, then when my ears stopped ringing I got my concert earplugs and felt / listened to a few more at the same level. I was really impressed. My Counterpoint amp will play that loud, but it doesn't slam like the LSA.

Here's a photo of amazing sound coming out of the Warp-1:



Conclusion

I'm convinced. Class-D has improved.

I guess I'd say that if you primarily listen to intimate acoustic recordings, and if your ideal hi-fi experience would be to close your eyes and believe that the performers are right there in your room, then this amp might not be for you. There's something missing -- and not just tubey second-harmonic bloom -- that makes vocals and some instruments sound just a little less present and real to me.

But if your taste runs to music that's more fun, and you want an amp that'll play it with precision at basically any volume level -- without straining, without adding any background noise, and without breaking the bank -- I think you really should audition the Warp-1. As far as I know, there are still available slots on the loaner tour...

 

Yes, more people should sign up to hear this unique amp, and I'm happy to add more people to the list. LSA sent this to us specifically for reviews and exposure, so I actually would like more people to sign up. You would be doing LSA and myself a favor.

 

I want to thank Inoculator and Fastfwd for their extensive and thorough reviews. It’s great to get feedback like this from experienced users with good ears. I know that a lot of work goes into writing these reviews and the time that you take to carefully setup your system and listen.

As the designer of the Warp-1, I would like to understand more about what appears to be a recurring comment regarding “vocal accuracy.” Or why vocals appear to sound forward. There are two major things that need to be satisfied for a signal from an amp to be accurate: its frequency response, and it’s temporal accuracy - that is, how the signal responds to a sudden step function, and its decay. Also of importance is the shape of the harmonic distortion profile. This is where naturalness or harshness comes from. From a purely technical standpoint, I believe the Warp-1 has a flat frequency response over what is considered “the vocal” range, and over the audible band (20Hz to 20kHz).

When I listen to an amp to assess its tonal accuracy or intrinsic voice signature, I try to avoid any EQ or items in the playback chain that alters the frequency response of the amp. The shape of the frequency response is the single most dominant item in the “voice” of an amplifier or speaker. If you still have the amp, I would ask that you listen again and leave out the DEQ2496, and play the DAC source directly to amp, or at most through a well known neutral preamp. See if the vocals still have the issue you pointed out earlier.

Thanks,
Viet

 

Just so you al know, @xrk971 (Viet) is the designer of the Warp 1. Working on getting him an MOT title. As a designer he is just curious to know more, similar to how Barry at Austin Audio Works wanted to know more about the perceived lack of bass and slam in his back amp.

 

Really appreciate you engaging around here, always great to get to chat with the designer of the gear we are testing! I really enjoyed my time with your amp, and absolutely could see purchasing it for future setups if I was looking for something with those specs.

I wish I had the technical savvy/knowledge needed to be more helpful in helping diagnose this. I would be happy to dive a bit deeper on my experience with vocals from the Warp-1, and what I heard. I want to first clarify that this is not some sort of glaring/distracting issue, and probably is a non-issue for most folks even if it is a thing.

I think my opinion may have been slightly colored by my very first impression when the amp was cold, and looked to be brand new (I was first on the tour). I only warmed up for about 10 minutes before I dove in. The first few tracks I listened to I felt the vocals were not quite "right", or what I perceive to be right based on my time with these artists both live and recorded. Accuracy is obviously pretty tough to judge though because accurate compared to what right? I was coming from about 300 hours of listening to the M33 in the past months, so little differences were going to jump out at me. As time went on I had fewer accuracy concerns and shifted more to focusing on the vocal presentation. The vocals certainly sounded forward to me on this amp, but I think that is just because they are so precise/clean/delineated from the rest of the sound. While I prefer a more relaxed/wet/lush vocal presentation, I think the worthwhile tradeoff is the stunning layering I mentioned in my review. The Warp-1 was literally the best amp I have ever heard when it came to presenting harmonies/background vocals/etc. Not the deepest stage, but not a hint of congestion due to how well sounds layer.

I also should have probably given some disclaimer about Graham Chartwell speakers as they are supremely natural-sounding, BUT they are so incredibly picky about amplification, especially my LS3/5A, less so the LS6F. I have been through about a dozen different amps with the LS3/5A speakers and still feel I have not achieved optimal synergy. Every time I change a part of my chain it requires adjusting position, minor changes/adjustments just really swing their presentation and sound. At suggested 25-50WPC, the Warp-1 maybe have just been a bit too much juice, hence the vocals feeling pretty forward and losing some nuance.

My hope is that some of the upcoming members are a bit more knowledgeable than me and can dive deeper on this. When it comes down to it, I probably just prefer some harmonic distortion in my vocals or something. I think my recent infatuation with the Sugden A21SE further confirms I like a pretty colored amp. I don't have the Warp-1 anymore, but if I did I would be happy to test straight from my DAC to the amp and use Roon DSP volume control so that no preamp is in the chain (although I really enjoyed the sound of the amp with the Schiit Freya+ flavor in there, better stage, more natural vocals).

@xrk971 are you also the designer of the upcoming el34 push-pull integrated from LSA the VT70? I am very interested in that as I enjoyed a PrimaLuna EL34 offering with my speakers in the past. Hopefully, if I get my ears on that amp at some point I could be more helpful by giving my take on that amp in comparison and provide a calibration point?

 

Hi Inoculator,
It’s interesting that you mention you used it with an LS3/5A. I made an homage to the LS3/5A but with modern accessible drivers and my own crossover based on an inverted passive Harsch topology that I developed. It happens to be voiced to have almost an identical step response function to a Sterling LS3/5A. However, it’s different in that it has a very benign impedance curve. This speaker will be a new product soon but was the very first speaker I tested out the Warp-1 with when it arrived from the factory. Here is my video of the first sound from the first test of Unit 1.

it was recorded from my phone and the source was an Amazon Dot playing Amazon Music.

No, I did not design the new VT70. I have listened to it though. It’s a nice amp!

 

Glad you're participating here.

I'm not thrilled about using the DEQ2496, either, but I'm trying to use it as non-intrusively as possible: It's doing the EQ in the digital domain, so its analog output stage isn't involved, and it's only padding down a few frequencies -- none over 100Hz -- to kill room resonances. The DAC gets its input from the DEQ2496, and then there's nothing but wire between the DAC and the power amp.

To me, that digital EQ is what makes my system sound right in this room (i.e., it makes the system sound the way it does, non-equalized, in a better room).

The DEQ2496 has been in my system for months, and it was present with both amps while I was comparing them. Of course it changes the signal being fed to the amp, but at least it was making the same change for each amp.

Unfortunately, I no longer have the Warp-1, so I can't do any further listening.

 

Hi Fastfwd,
Thanks for clarifying where the EQ is applied. Below 100Hz, vocals will not really be affected if it was not in the signal chain. Although purely digital, I am not sure if the DEQ is completely “passive” in its effect on other frequencies or their phase. But as you don’t have the amp anymore, we can’t try anything in any event. Was there another person on the tour fir the amp?

 

@xrk971 Something just occurred to me. My speakers are biwired, as I mentioned above, but I neglected to say that the pair of low-frequency drivers are wired in parallel, so their nominal impedance is only 4 ohms. The speaker designer was emphatically in favor of minimal-as-possible crossovers, so I'm certain that he wouldn't have included a network to flatten the driver impedance curves, and I guess it's possible that the low-frequency impedance might dip below 4 ohms.

The Counterpoint amp is stable to 2 ohms. Is it possible that the Warp-1 would have had any issues with lower-than-4-ohm impedance at low frequencies, or with the transition from 4 to 8 ohms at the crossover frequency? I suspect that the answer's "no", but trying to run down every possibility...

 

Yeah, I don't know either. Like I said, I wish I didn't need it in this room.

There are at least 7 in the queue after @Inoculator and me.

 

The Warp-1 uses a TPA3255 chip in BTL mode. The datasheet says a nominal load of 4ohms. So that should be ok if the speaker is labeled 4ohms for the woofer. But if the woofer dips to 2ohms etc there might be an issue. To be stable into 2ohm loads, the amp need to be configured as a paralle bridge tied load (PBTL) monoblock. Do you have a published impedance sweep of the Heron speaker?

 

I emailed the speaker's designer. Unfortunately, he can't find an impedance plot -- these are 25-year-old speakers -- but he says that any midbass dip below 4 ohms would only be a tiny bit below.

So it looks like low impedance isn't the problem.

 

I think a part of this is that typically each channel is its own amp from input to output, which allows some customization. But since LSA is based on a chip driving both channels, inputs on one side and binding posts on the other makes a bit more sense to keep traces short.

There's probably still some room for design though

 

Thanks to @Core Power Tech , @rhythmdevils , and SBAF for this loaner.

I think what I can add to the aforeposted is a note on synergy. The LSA Discovery Warp One is, in my experience, a nice amp and a good value pending good synergy with the system at hand.

This is all I can really add to the aforeposeted because I have a super strange speaker setup. My main rig is an 18" Beyma SM118/N in a 24x24" open baffle, passively crossed over to a Faital HF146 on a Faital LTH142 horn. I listen to this plywood monstrosity at a distance of 6 feet. My other speaker setup is a Philharmonic-modified Pioneer B22 with a bucket sub, used nearfield on my desk.

Pic of the horn system: https://imgur.com/kmBZGXT

The B22 nearfield setup is... fine, but turned out to be a not-great place to evaluate the LSA amp (problems with ground loops that I don't think are the LSA's fault). The big horn setup was a better place to listen to it, but one with a bit of anti-synergy.

The reason I like the big horn setup is because it sounds AMAZING at low volume and very high volume. At low volume, the sound takes on this really palpable, visceral quality that makes it way more interesting to listen to than low-volume music generally is. At very high volume (90 dBa on my iPhone DB meter feels like too-loud-concert volumes, like that f'ing Los Lobos concert in Nashville where I damaged my hearing because I didn't have earplugs and the sound dude was insane), Meg White's kick drum feels like it's 9 feet tall and Bruce Lee is kicking you in the chest. Freaking awesome. It's insane to listen to music for any amount of time at this volume; I sneak in a minute or two of something like 7 Nation Army or Bullet In The Head at this volume like every 3 months tops, when some downtime for me aligns with my wife being out of the house (we both are WFH homebodies and I do most of the errands, so... not much loud music for me) and the MONSTER kick drum dynamics feel so f'ing good and satiate me for another 3 months.

The LSA amp sounds good at low volumes on the big horn system. But so does my $200 Crown X1000 amp. At high volumes, it's an anti-synergy story, with the mids becoming hot and harsh. The X1000 doesn't have this problem. Both amps offer up very good midbass macrodynamics and they both channel Bruce Lee very nicely through the Beymas.

I can imagine that the LSA would synergize much better with one of those low-efficiency, polite-in-the-midrange, reticent-to-wake-up-8"-woofer systems.

I do think there's a fair bit to like about this amp. Build seems price-appropriate, it's quiet, and it's not even close to backbreaking to move. Seems like a super nice Class D option at its price point ($1,500 at time of writing) if your speakers are likely to synergize with it.

EDIT: If the LSA amp was a headphone amp, it would synergize well with the speaker equivalent of an unmodded HD650.

 

Just my take on the LSA Warp 1 Discovery:

I was partners in an audio store that bought and sold preowned mid to highend hi/fi . I was there from about 1999 to 2011. As such, I have over the years owned or been intimately acquainted with so many amplifiers from the likes of Krell, Mark Levinson, Rowland , McIntosh, Audio Research, HH Scott, Fisher, Marantz, VTA, BAT, VAC, Plinius, Hafler, Harman Kardon, Yamaha, Laxman and quite a few more. These are some of the brands I can recall that passed my way when I was part of the store; some I owned personally as I purchased them, and others I got to audition for extended period of time from the time they came into the store until they left when they were sold.

So, To say I have some experience with audio equipment, especially amplifiers, probably more so than most, is an understatement.

Now, below is a partial list of amplifiers I have personally owned in the last 5 to 8 years, and to present. I say partial list because there may be others, but these are the ones that come to mind at right now.


AR-REFERENCE 75se.

EMOTIVA XPA2-GEN3.

PASS LABS X150.5.

PASS LABS X250/X250.5.

AUDIO RESEARCH D300. (Friend has it presently)

SIMAUDIO MOON 3. (Friend has it presently)

MAGNUS AUDIO 3xx something. It was class A. (Friend has it presently)

CODA No 8: (Partial Class A) (Friend has it presently)

MARK LEVINSON No334.

SONIC FRONTIERS AMP. (Friend has it presently)

MANLEY MAHI MONO BLKs.

Krell KSA 200s. (Presently in my stable of amps)

KRELL KAV 250a. (Presently in my stable of amps)

AYON TRITON 3 GEN4. (Friend has it presently....Ouch!)

VTA ST120, bought as a kit, with auto bias board added. (Presently in my stable of amps)

PARASOUND Halo A23, not the plus version.

MARANTZ 8B: Since 1963 when my father brought it home new. I've since installed auto bias circuit and regulated high voltage supply. (Presently in my stable of amps. It has been with me almost my entire life, and was the amplifier that started all)

So, as I said, this is a partial list as there maybe more.

But to the LSA WARP 1 Discovery:

I very recently bought one of these because I was looking for a Class D amplifier to run my subwoofers. I have two Definitive Technology SuperCube 1 subwoofers, but one of them has a blown amp. I looked around for a replacement amp, but could not find one. There was one, but the selling wanted somewhere in the neighborhood of $500.00 for it. Not for me, I am going to pay $500.00. So I took the Blown SC1 and converted it to passive.

I gutted the electronics, amp and preamp plate on back. I stripped the preamp plate of all boards and parts except the high level speaker binding points, and wired the speaker directly to two of them, red and black, using high quality 14 gage wire. I also added some fiberglass damping material, reinstalled the woofer with special toggle screws, and put the whole thing back together. I decided to do this because I had a Behringer Ultra Drive 2496 Speaker Management System which I had left over from when I owned a pair of Emerald Physics CS2 speakers. Well, converting the SC1 was a success.

Using the Behringer I am able to created digital crossovers of several types, with slopes of any where from 6dB (1st order) oct, to 48dB (8th order) oct. I can also apply EQ, Band Pass, High Pass, Low Pass, filters as I desire to tame certain room acoustic anomalies.

Again, I was very pleased with the results, so I figured if I could not find another SC1, not working, for a reasonable price, I would carefully remove the electronics from the working one I have, sell the working electronics off, and convert the second one.

Okay, so the way I was using the subwoofer in my system was to use the Krell KAV 250a to power the sub, and the Krell KSA 200s to power the main speakers. It all sounded great, but running the two KRELS seem to me to be a bit too much. After all, I had solar panels installed on my roof to lower my electric bills and perhaps to be more green with regard to the environment. Therefore, that is why I thought a Class D amp for efficiency sake was a good idea, but I wanted a good one. I was looking for a wyred4sound ST 500, the amp I had to power the two 15" woofers on my Emerald Physics CS2s. I remembered It sounded pretty good with regard to bass, but I was not impressed with it when I ran it full range on full range dynamic, floor standing speakers other than the CS2s. But since I was just looking for it to run subwoofers, I figured it would work well. Alas, though, it was not to be. So I was ready to pull the trigger on a brand new Wyred4sound ST500 MKII, when I came across an auction on Audiogon for an almost brand new LSA Warp 1 Discovery. I paid $856.00 with free shipping.

So, when I got it, I hook it up the way I described I had the two Krells hooped up, and everything was sounding great. But then I wanted to see how it worked as a full range amplifier. My speakers have ribbon tweeters, and all I can say is boy was a impressed. This amplifier gives up very little to any of the amps I mentioned above. If fact, with regard to some of them, class A, AB, D, etc., it gives up nothing! With regard to the bass, it gives 110% even when compared to my presently in house Krell KSA 200s. What am I thinking now: What was the reason for have a subwoofer? Gee, listening to the LSA Warp One Discovery, I forget. My mains have a bass that is super grippy, tight, controlled and detailed; mids and highs are detailed, revealing, non fatiguing. Oh my god, I can't stop listening, and keep pushing the volume higher: Still good until I start getting cell phone calls from the second floor from my significant other to my basement landline.

PS: These are the Class D amps I have owned: Emotiva XPA2 Gen3. Bought it new, used it with the same speakers I am using the LSA with. Packed it up and returned it to factory within one week. No regrets. Which is not necessarily the case with all the amps I have owned and let slip through my hands.

Wyred4Sound: ST500. Okay, but not the LSA. I suppose the MKII version is an improvement.

My preamp Is Audio Research tubes.


By the way, my speakers are pigs, 2.9/3.2 ohms DCR, or is that nominal impedance? But I love em.

 

I have been meaning to write up a summary of my experience. I handed it off to @spwath on the weekend and look forward to his thoughts relative to the Bel Canto

Bottom line is that this is a good if not great amp. It does many things right in the sense that I would be OK having this as my primary speaker amp for general music enjoyment.

It is well designed from an esthetic sense, is a solid functional unit, gets your feet tapping without any fuss.

there always has to be a but ....

it does not play best with my maggies - has enough drive to make them sing but the vocals did sound more forward, this could be that my M2X has recessed mids, that I switched off the Dirac and now no room compensation is "helping" room acoustics - who knows. Not unpleasant or shouty in any way just noticeable. It also seems to lift the bass a little more than any other amp I have had in the system ( sub off ) , including my AB 100watt amp ( from the same designer as the LSA ). Much like the former review, I could use this amp with my speakers and not use a sub.

a quirk - when powering up , the fault light triggers but immediately goes off and there is a audible buzz on the panels - higher than 60 , probably higher than 120Hz but it never occurred to me to measure it.

I also used the amp to test out my monitors which sounded absolutely superb, no audible noise and me Selah Veritas suffer from quite steep bass roll off at 80Hz , they sounded full and vibrant.

so as a person who has shunned anything aside from egg cooking class A, this amp shines and deserves an audition.

thanks for making the loaner possible @rhythmdevils and @xrk971

..dB