Solid State Power Amp Reviews

Living Sounds Audio Discovery Warp-1 power amplifier Page 2

The Warp 1 in the listening room
Bill Leebens, Underwood HiFi's PR guy, told me that the amp I was sent for review was "broken in" and verified as working, so I got right down to listening to music. I recently had my Benchmark AHB2 power amp connected to my listening room system, driving a pair of Bowers & Wilkins 808 speakers. Ahead of the power amp is the Benchmark LA4. Sources were a dCS Bartók DAC/streamer and a recently installed phono rig: Technics SL-1200MK7 turntable, vintage Shure V15 Type III HE cartridge, and Pro-Ject Phono Box RS2 phono preamp. Connected to the Bartók via RCA S/PDIF is the DV-981HD universal disc player from the late, great Oppo. The room has a vaulted ceiling and is a big open space that blesses my mid-'70s raised-ranch house. Filled with leafy indoor plants and bathed in light on sunny days, it's a treat to experience music in that space.

I swapped out the Benchmark power amp for the Warp 1 and immediately needed to adjust the LA4 gain downward.

Those big, vintage B&W speakers are good at many things, but their strongest suit is low-frequency reproduction. They can move a lot of air quickly and project the lowest octaves in visceral ways. They don't need a ton of amplifier power, but they do need an amplifier that can push the power through with speed and authority. At this task, the Warp 1 delivered. I spent hours streaming all manner of fun, punchy music from Qobuz and my NAS library, via the Bartók. My favorite rock, soul, blues, and funk tunes took on full-bodied punch that made the beat stand out and got feet tapping. Many times, I rose from my seat and danced around the room, which probably looked uglier than Elaine's dancing in that Seinfeld episode (footnote 4).

A particularly good workout for the woofers is the music of Jack White. Both his recent solo album Fear of the Dawn and the recent, deluxe reissue of the White Stripes' Elephant make masterful use of the lowest octaves in the service of rock music, punch without annoying boom. The Warp 1 delivered quick, distinct bass, with no flab. It's also good with electric guitar tones, and it has no trouble when the playing gets percussive.

I then spent some time listening to a box set of CDs I remastered: the complete recordings of pianist Byron Janis on the Mercury Living Presence label (footnote 5). These recordings were made over the course of 5 years (1960–64) in seven different venues spread across three countries (US, UK, USSR). The sound and listening perspectives are different for each recording, but the instruments always sound as they should. Played with the Warp 1, the piano tone tended to favor metal over wood, but violins and woodwinds were not strident or exaggerated. The double bass and cello were firmly present. In comparison to the same music played with the Benchmark amp, the character was a bit edgy but not "glazed" as with older class-D amplifiers. That edge is good in that it highlights the music's forward momentum, but it can be a bit unsettling when things are at a climax and Janis is all-in leading the charge.

Switching gears, I spun some vinyl. Periodically, I search Amazon for "Blue Note Classic Series vinyl," looking for bargains. If an all-analog Classic Series LP is discounted below $20 including tax and free Prime shipping, I'll usually bite, even if I'm unfamiliar with the artist and the music. This has led to two happy discoveries: Extension by George Braith, and Destination Out by Jackie McLean. On the Braith album, I especially dig the organ playing by Billy Gardner, and Grant Green's guitar is a nice match for Braith's multisax attack. (He sometimes played two or more horns at once, sort of like Roland Kirk but not exactly.) McLean's album is borderline free jazz, meaning it's borderline not my taste. But the presence of Bobby Hutcherson's vibes is enough glue to keep it within the bounds of distinct rhythms and melody.

As the records spun, I periodically switched back and forth between the vinyl and streams of the albums from Qobuz. The McLean album is available as a 24/192 stream; the Braith album streams 16/44.1, likely from an old Capitol CD. I was surprised how similar the vinyl and digital versions sounded when it came to instrumental tone, but the digital Braith has less stereo width, and there is something a bit tame about the digital McLean. Both albums have the fully mature Rudy Van Gelder Blue Note sound. The Warp 1 amp brought forth the close-in details, firm bass, and snappy drum sounds. Hutcherson's vibes sounded full range, not just the clangy top.

Sticking with jazz, I spun the Analogue Productions/Verve reissue of Night Train by the Oscar Peterson Trio. This record takes a less in-yo-face approach than Van Gelder Blue Note; the trio is more real than super-real. Unfortunately, the master tape has audible wow at times (also present on the HDtracks download and the older CD reissue), so I can't say it sounds just like three great musicians in front of me, but it has the life force lacking in many modern jazz recordings. Peterson grunts and hums as he sweats over the keyboard, yet he never sounds like he's pushing himself to the limit. On the left, Ray Brown plays his bass like a cucumber-cool expert. Ed Thigpen's drums, to the right, are miked close and bright. The HD and CD versions are too bright, all metal edge of the hi-hat and no cymbal body, all brush strokes and no snare head. The LP, as played through my system with the Warp 1 amp, sounded just right.

As my review deadline approached, I had one more dance with the Warp 1, this time streaming from Qobuz two of my favorite country music albums. Willie Nelson's Red Headed Stranger is a sparse recording, but there are nice little sound "Easter eggs" in there, such as when sister Bobbie Nelson's piano quietly enters the verse in the title track when the "yellow-haired lady" walks into the saloon, soon to be gunned down. The piano sounds like what you'd be likely to hear in a real saloon, a neat little trick typical of Nelson's genius for making a lot of music out of a few instruments, words, and notes.

Contrasting the stripped-down sound of Nelson's album is Johnny Cash's American II: Unchained. Backed by Tom Petty and the Heartbreakers, the Man in Black leans toward the rowdy end of country. It's a loud, sharp-edged, Rick Rubin–produced 1990s album, particularly Cash's cover of Soundgarden's "Rusty Cage" and his own "Country Boy."

The Warp 1 did an equally good job with both albums, keeping the loud and hard stuff unmuddled and rendering the subtle and unsubtle details of Nelson's masterpiece. I finished up my listening with a big grin on my face, the good-feelings synapses in my brain firing wide-open.

A class-D keeper
There are two ways to think about the LSA Warp 1. You could think of it as a category killer, a great-sounding amp at a bargain price, class-D finally brought to fruition for almost all budgets. Or you could think of it as a low-risk/high-reward way for an open-minded skeptic to give class-D a try.

The phone number on Underwood HiFi's website gets you right to Walter Liederman. Talk to him about an in-home trial (footnote 6), but be forewarned: Your ears' old ideas about class-D amps may be proven wrong, and your mind may be changed

Footnote 4: youtu.be/jsl3IBAsEH4.

Footnote 5: Released on March 24, Byron Janis's 95th birthday, this set, from Decca Classics, is now in retail worldwide.

Footnote 6: Another reason to be forewarned: In an industry full of 30-or-more-day money-back guarantees, with free shipping both ways, Underwood HiFi charges a restocking fee on returned products. Here's how it works: Take original sales price, subtract shipping cost. A customer who returns the product within 30 days can get back that net price minus 15%. For example, If you paid the $1195 sale price, you could get about $985 back if you return the Warp 1 within 30 days, plus you pay return shipping. This is one of the cost-saving measures that lets Underwood sell products cheaper, and that's cool, but you should know how it works before buying.—Jim Austin

COMPANY INFO
LSA Electronics
89 Kahana Makai Rd.
Lahaina
HI 96761
underwoodwally@aol.com
(770) 667-5633
underwoodhifi.com
ARTICLE CONTENTS

COMMENTS
cognoscente's picture
Submitted by cognoscente on July 7, 2023 - 10:12am

Thank you, good to know, so nice to read .this brief history about amp types.

I was never a believer in tube amps, they have limited listening hours and lack control and detail. And I was never a believer in class d amps, which sound too cold and artificial. I swear, swear, by toroidal transformer class a/b amplifiers.

Until I was able to buy a new Nad C298 class d amplifier as a real bargain. And this Nad is already a bargain compared to the Nad Master series or competing amplifiers from Primaire or T&A with the same Purifi Eigentakt module. Of from Purifi of couse. Anyway, the Nad C298 now replaces the power amp section of my Hegel H360, which only serves as a USB receiver, proprietary re-clocking and preamp. DA conversion is done via the HoloAudio Spring 3 3.

It was immediately clear, the Nad C298 sounds fresher, clearer, more detail, more crips and attack and with a tighter bass. You can better hear the piano strings vibrating, the fingers sliding over the strings. Then you would say it also must sounds more tangible, more "live" present (in-the-room), more real with all those extra details? But that's the funny thing about human hearing. So no. It sounds also clinical, the feeling, the emotion is gone. In other words, the music is gone. At the Nad, like all the sets of my audio friends, you listen "to a set" and not to "live" present music (in the room). Your ears tell you. I'm exaggerating to make my point, you have to sit down (and listen carefully) to hear the difference, but still, then the difference is obvious. As if the Hegel is squeezing detail to provide more power, to sound more muscular, more mature, more "live" present, while the Nad is doing the opposite, as if it squeezing the power in the bass to bring out more detail to the surface. To sound fresher, younger. I say my Hegel H360 sounds like a Ford GT while the Nad sounds like a Porsche 911. Which one is more fun to drive? It just depends on what you prefer. I can switch with both power amps available. Still, I almost always choose the Porsche. I'm more of an audiophile than a music lover after all. I want to hear everything. The art of omission! Not really I'm afraid.

Probably a (for me) priceless class a/b amplifier can offer the same freshness, clarity, detail with the same crips, attack and tight bass as this Nad while retaining the musicality, the emotion and live (in-the-room) feeling, perhaps but as said that is unattainable and that's why I don't even want to know. I'm happy with my Porsche. And Bugatti ... whatever

Kursun's picture
Submitted by Kursun on July 7, 2023 - 12:21pm

Would you believe toroidal transformers are actually inferior to EI transformers?

http://www.soundstagenetwork.com/maxdb/maxdb071998.htm

https://sound-au.com/articles/xfmr-dc.htm

This hobby of ours, hi-fi, is a hobby of prejudices!

Ortofan's picture
Submitted by Ortofan on July 7, 2023 - 1:24pm

... record review, or little more than an advertisement for this product?

How did it perform/sound compared to the Benchmark amp?

The B&W 808 speakers have a minimum impedance of 4 ohms and can handle up to 200W on a continuous basis. The LSA can't sustain even 100W into a 4 ohm load without shutting down.

The LSA can't meet its rated power output, doesn't have a load-independent frequency response and has relatively high levels of IMD. The designer needs to go back to the drawing board.

If the amp contains special Coilcraft inductors that are supposed to remove/filter class-D switching noise from the audio output, then why did JA1 need to use an Audio Precision AUX-0025 passive low-pass filter between the test load and the analyzer. Either the filter built into the amp functions as claimed, or not.

As stated above, if you're in the market for a class-D power amp, then choose the NAD C 298, instead.

https://www.stereophile.com/content/nad-c-298-power-amplifier
https://www.hifinews.com/content/nad-c-298-class-d-power-amp

Kursun's picture
Submitted by Kursun on July 8, 2023 - 9:46am

-"If the amp contains special Coilcraft inductors that are supposed to remove/filter class-D switching noise from the audio output, then why did JA1 need to use an Audio Precision AUX-0025 passive low-pass filter between the test load and the analyzer.

Filter was used during NAD C 298 tests too:
-"The C 298 has an output stage operating in class-D, so I inserted an Audio Precision auxiliary AUX-0025 passive low-pass filter between the test load and my Audio Precision SYS2722 system (see the January 2008 "As We See It"). This filter eliminates RF noise that could drive the SYS2722's input circuitry into slew-rate limiting, and I used it for all the tests other than frequency response."

Long-time listener's picture
Submitted by Long-time listener on July 7, 2023 - 5:25pm

"Class-D amplifiers started to appear in audiophile-grade components about 10 years ago..."

Interesting -- I recall auditioning a pair of Jeff Rowland digital monoblocks about 20 or more years ago.

Ortofan's picture
Submitted by Ortofan on July 7, 2023 - 6:40pm

... TacT Millennium, introduced in 1998. That amp later became the Lyngdorf Millennium. It incorporated technology from Toccata Technology. Toccata Technology was eventually acquired by Texas Instruments.

Two members of the Toccata Technology team were Lars Risbo and Claus Neesgaard. They went on to work at TI.

Subsequently, Lars Risbo - along with Bruno Putzeys and Peter Lyngdorf - co-founded Purifi, of which Claus Neesgaard is a co-owner.

JRT's picture
Submitted by JRT on July 8, 2023 - 11:47pm

If you want to try a TI TPA3255 based amplifier, consider trying the Fosi Audio V3 and 48VDC 5A switch mode power supply (avoid the 32VDC supply). At the online store at the Fosi Audio website, that bundle is priced at a penny under $110 and there is also a $10 off coupon, free shipping, and 24 month warranty. So it comes in at under $100 direct to your door.

That is a relatively recent addition to Fosi Audio's line, but has already received numerous favorable subjective reviews. And for objective measurements, Amir has posted a review, also very favorable, at his ASR discussion forum.

https://www.audiosciencereview.com/forum/index.php?threads/fosi-audio-v3-amplifier-review.45757/

Here is a Google websearch on the subject:
https://www.google.com/search?q=fosi+audio+v3

Here is another Google websearch specific to the youtube website:
https://www.google.com/search?q=fosi+audio+v3+site%3Ayoutube.com

It is useful to consider amplifier output signal voltage. Loudspeaker sensitivity is most usually specified as a voltage sensitivity relative to 2.83 Vrms pink noise signal across the loudspeaker input terminals, with output measured as B-weighted SPL with the propagation distance normalized to 1 meter. Amplifiers most usually are designed ro provide a constant gain in voltage (not power) when operating below significant clipping, often represented as 1% THD+n, which can also be stated as -20dB THD+n.

With 48VDC 5A supply, Amir measured -74dB (.02%) THD+n at 141 Wrms into 4 Ohm load, corresponding to 23.75 Vrms across that load.
(141*4)^(1/2)= 23.75 Vrms
And relative to 2.83 Vrms that is
20*log(23.75/2.83)= +18.5dB

At 1% (-40dB) THD+n, 160 Wrms continuous into 4 Ohm, corresponding to 25.30 Vrms.
(160*4)^(1/2)= 25.30 Vrms
And relative to 2.83 Vrms that is
20*log(25.30/2.83)= +19.0dB

And for 20ms IAW CEA-2006/490A (suitable for headroom for brief crests in the music signal), at 1% THD+n, 190 Wrms into 4 Ohm, corresponding to 27.57 Vrms.
(190*4)^(1/2)= 27.57 Vrms
And relative to 2.83 Vrms that is
20*log(27.57/2.83)= +19.8dB

For $100 the Fosi Audio V3 might be sufficient in some applications, but don't expect Purifi modules at that price.

-----

That said, if you want to spend $1.1k on a two channel stereo class D amplifier, then I would suggest that there are other better alternatives than anything utilizing the TI TPA3255 chipset.

For example, investigate some offerings from Buckeye Amplifiers, all prices direct, with free shipping. Buckeye's "Purifi 1ET400A Amplifier, 2-channel" is $1095. And their "Purifi 1ET400A Amplifier, Monoblock" is priced at $750/each, $1.5k/pair.

The new (currently on backorder) Buckeye "Hypex NCx500 Amplifier, 2-channel" for $1095 with free shipping. That uses a new improved Hypex module in competition with the Purifi Eigentakt modules.

Buckeye's "Purifi 1ET7040SA Amplifier, Monoblock v2" is priced at $950/each, $1.9k/pair. That uses Purifi's newer improved higher current module, etc.

There are some very good amplifiers from NAD using the older Purifi 1ET400A modules, such as the C298 priced at $2.4k MSRP. Safe and Sound is currently advertising some factory refurbished units priced at $1.8k. But for only $100 more I would rather have the Buckeye monoblocks with the newer modules, higher current power supply, etc.

Ortofan's picture
Submitted by Ortofan on July 9, 2023 - 7:28am

... approvals from the relevant regulatory/safety agencies?
Photos of the amps do not appear to show the markings that would indicate those approvals.
Skipping that step is one way to reduce the cost of a product.

JRT's picture
Submitted by JRT on July 9, 2023 - 9:19am

Depending much on the device (consumer electronics are not medical devices or aircraft radios) the markings can be self-certifications of compliance to governmental regulations and/or industry standards, and do not necessarily require any validation with third party qualification testing or qualification testing by any regulatory agency.

https://emcfastpass.com/ce-mark-guide-electronics/

That said, below is an image of the 48VDC 5A external switch mode power supply sold by Fosi Audio, and included in the $109.99 ($99.99 with $10 off coupon) Fosi Audio V3 48V bundle. Notice the CE Marking and FCC Marking. The amplifier itself is a low voltage device, does not directly connect to powerline voltages.

Ortofan's picture
Submitted by Ortofan on July 9, 2023 - 9:57am

... UL/CSA safety approvals for the amplifier unit itself?

afgverhart's picture
Submitted by afgverhart on July 9, 2023 - 2:11am

It is always interesting to read all these comment from people who - I think - have never heard this amplifier in real life. Well, I did, actually, I own one after having owned nCore 400 mono blocks as well as a Purifi Eval 1 design. The Warp does indeed not have this typical class D top end that other class D designs tend to have. And yes, I have heard them all, well most of them at least.

My Warp One has been driving Dynaudio Contour 3.4 LE, Dynaudio Confidence C2 Platinum, Focal Scala Utopia Evo and most recently Dynaudio Contour 60i comparing it with a NAD M22 and a Hattor nCore class D design. The Warp One was the best sounding amp, again. It sounds detailed (but not too), with black backgrounds, it separates instruments excellently and best of all: it sounded most natural. The Warp has a flow to it - some call it PRaT - that I have not heard better from any class D design. and the bass reproduction is sooo nice and layered. It’s addictive.

My advice: don’t have yourself fooled by the above comments or measurements, but just listen to it before forming an opinion on it.

BR,
Richard

Poor Audiophile's picture
Submitted by Poor Audiophile on July 9, 2023 - 10:52am

"but just listen to it before forming an opinion on it."
That should always be the case IMHO.

JRT's picture
Submitted by JRT on July 11, 2023 - 5:33am

This Living Sounds Audio Discovery Warp-1 power amplifier has a reset switch on the rear panel.

When was the last time you had an amplifier in need of a reset?

What makes this amplifier vulnerable to a control failure in need of a reset? What is the behavior during that failure? What happens if the consumer fails to push the button?

Ortofan's picture
Submitted by Ortofan on July 11, 2023 - 11:32am

... circuit breaker, rather than having a fuse.

David Harper's picture
Submitted by David Harper on July 12, 2023 - 4:31am

in need of a reset? My schiit Vidar amp when driving my magnepan LRS speakers often shuts down due to current/thermal overload. It's no big deal I just turn it off and on again, turn the volume down a bit, and it's good to go.

Delius T's picture
Submitted by Delius T on July 13, 2023 - 11:19am

So, he is out of jail?

Mark Schifter of AV123 Indicted by Grand Jury on Five Counts

https://forums.stevehoffman.tv/threads/mark-schifter-of-av123-indicted-by-grand-jury-on-five-counts.209712/

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