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REVIEW: Holfi HOLFI Power 150 Amplifier (SS)

Model:	HOLFI Power 150
Category:	Amplifier (SS)
Suggested Retail Price:	$3,500
Description:	Stereo 150w, Zero Feedback, Class AB
Manufacturer URL:	Holfi

Review by Tone! on August 24, 2008 at 21:01:27 IP Address: 222.154.226.18

Add Your Review for the HOLFI Power 150

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HOLFI Power 150
Stereo Power Amp

Previous Conditioning
Over the last eleven years, flirtations with new amplifiers both tubed and solid state have always lead me back to my 1997 CARY CAD300SE Signature monoblocks. Sure, I could hear that they were a bit rolled-off in the tops; and I knew better bass could be had for less money. But their sheer musicality always brought me home again…

Musicality aside though, I have always known that there is a big downside with tubed power amplifiers. Because I listen to music as often and as long as the average forty-something watches TV, I have needed to replace my power tubes every year. This has been a costly and often frustrating exercise, as these 300B tubes often die slowly… with feeling.

This year I decided that I would sell the CARYs and seek out a solid state power amplifier to replace them. After all, it’s been more than a decade since the CARYs hit the market. Solid state amplifiers must have made some progress… surely?

But where to begin? I had a casual conversation with ARC Hi-Fi owner and fellow music-lover Terry Humphries, who encouraged me to listen to a new machine that had greatly impressed him. A day later a large box arrived on my doorstep containing a Danish solid state amplifier branded HOLFI; something of an unknown quantity to me.

A small amount of web-surfing confirmed that the HOLFI Power 150 is the entry level stereo power amplifier in a range of products manufactured in Scandinavia by Peter Holstein and team; Holstein obviously the ‘HOL’ in HOLFI.

Here we have a 150Wpc 2-channel power amplifier with a Class-A single-ended input stage combined with a Class-AB, push-pull, output stage. Interestingly, this amplifier also offers a future upgrade path that includes a fully decoupled DC battery option.

Zero Feedback Design
What interested me most in the HOLFI marketing gumph was the claim that this amplifier was a ‘zero feedback’ design. Negative feedback has long been considered the ubiquitous audio-circuit thief, allegedly responsible for robbing music of its otherwise lifelike qualities.

Conversely though, I was aware that even in low to medium power amplifier designs, judicious amounts of negative feedback are typically required to mask background noise and provide an adequate loudspeaker driver damping factor.

Was the 150Wpc HOLFI going to be some sort of hum-generator with unwieldy, bloated bass?
First Impressions
Aesthetically, the HOLFI is something of a plain-Jane. Not ugly; just a simple [heavy] black box sporting a very plain, genuine cherry-wood face-plate perfectly and cleanly engraved [how the heck do they do that with timber?] and bearing the HOLFI logo and model. I understand that a black-ash option is also available, but the cherry-wood matched the plinth of my turntable, so I was happy enough.

Hooking-up the HOLFI, I was impressed by the simple layout of the rear panel, featuring [what appears to be] quality WBT 5-way binding posts. Fit and finish is simply superb, if Spartan.

And in keeping with legendary Danish minimalism, the HOLFI features single-ended RCA connection only. Not a balanced output in sight.

A dedicated power switch at the rear of the unit allows owners to power down completely or to simply switch the amplifier into ‘stand-by’ with the front power switch. Standby mode leaves the HOLFI input stage warmed-up and ready to go, and reduces power consumption to a mere 12 watts. It is clear that the Danes know how to get these things right.

Dress-down Rule
Before I proceed further, it is appropriate that I explain my view on cables. There is no question in my mind that different cables produce many different sonic changes in an audio system. But I don’t believe that any component deserves special cable treatment to make it sound good.
So the bulk of my listening was conducted using very low cost, low capacitance, 24awg copper cable for both interconnects [1.5m] and speaker cables [5.0m].

I fully accept that others would be able to explore different cable options and no-doubt change or improve aspects of the sound. But for the purposes of this audition, I was keen to dress-down.

Power-up
I inserted the HOLFI into my audio chain using an earth ‘cheat’ power adapter to preserve the star-grounding principle that has helped to keep my system so very quiet.

For readers unfamiliar with this grounding technique, star-grounding simply requires lifting the earth on all but one component in the system, using the interconnects and speaker cables to extend the earth to the other components. This layout keeps potential earth loops to a minimum. I use my tubed preamplifier as the central grounded component.

After a quick double-check, I powered-up the HOLFI. Once the expected ‘click’ [no thump!] passed through my speakers, a small green light illuminated on the HOLFI front panel; and I was met with a very soft but annoying hum. The hum was just what I had feared; this was a zero feedback design after all…

Half a minute later, during which time I had promptly decided that the hum was a definite show-stopper for me, the noise completely disappeared and was replaced by an absolute inky-black silence.

Subsequent experiences confirmed that if I let the HOLFI return to a totally ‘cold’ state, the temporary hum during power-up returned. I guessed that the hum was produced by an internal component that had now warmed-up and was ready to boogie… so boogie I did!

Listening
Just a few notes in, I was immediately struck by a couple of distinct sonic attributes.

There was detail galore! Not the all-out information assault that one can expect from some of the lesser [and greater] op-amp amplifier designs; just glorious extension at both frequency extremes. Spatial clues that had previously remained unresolved were clearly and comfortably presented.

Dynamics were explosive. With its relaxed, tube-like presentation, the HOLFI was able to lull me into a false sense of security; then a surprise crescendo would literally erupt from my speakers reminding me that this amplifier was no under-damped, flea-powered weakling.

Also, I suspect largely as a result of the superior retrieval of detail, the imaging was superb; indeed the best that a solid state power amplifier had yet produced in my system.

Most noticeably, the music was very relaxed, refined and fluid. Almost as if a lot of previously present ‘junk’ in the music was missing. The sound was so clean, pure and articulate.

Treble was effortless, grainless and possessed a flawless crystalline quality. Bass too was impressive; and whilst clearly not in the unbelievable ‘thunderbolt’ camp, was deep, tight and textured.

Without dissecting every sonic aspect of the sound; and without dragging readers through every disc rotated, I liked the HOLFI… A lot!

But something was wrong…

Flawed
The music lacked some ‘meat on the bone’. The sound wasn’t harmonically threadbare by any stretch, but something in the middle was missing. The HOLFI seemed to expose the upper half of the mid-range to the exclusion of the lower.

The steel strings on Ricky Lee Jones’ big acoustic guitar on ‘Last Chance Texaco’ were beautifully captured, but the body of the guitar was absent.

On her sublime version of ‘Que Sera Sera’ Holly Cole’s voice was crystal clear and extended, but much of the harmonic beauty in her lower registers was MIA.

Keb Mo’s wonderful voice on ‘Tell Everybody I know’ was intimate and expressive, but lacked the rich, resinous character that I had come to expect.

Listening to ‘Time’; the sumptuous opening track to her excellent ‘Regarding the Soul’ album, Dee Carstersen’s standing harp strings started strongly at the upper frequencies. But as she plucked the descending scale, the notes faded out in the mid-range; only to fade back in and finish strongly at the lower frequencies.

Time and time again, I felt myself missing the ‘chest’ of many vocalists.

And I had more concerns: There I sat with a mammoth 150Wpc on-tap [12 times the power of my CARYs] yet when I tried to wind up the wick, the music just seemed to get harsh and uncomfortable; without getting loud.

Zubin Mehta’s unmatched DECCA Analogue account of Tchaikovsky’s ‘Marche Slave’ with the Los Angeles Philharmonic Orchestra sounded so very reined-in. Here was my favourite orchestral war-horse in full cry… and I wasn’t getting excited at all.

Something was very wrong indeed…

After several days of listening and experimenting, I offered my feedback to ARC Hi-Fi: “I love it mate, but I’m gonna need to keep looking…” I reported to Justin Lewins.

To his credit, Terry Humphries contacted me within hours and arranged a time to meet me at home to check on the situation. He and Justin arrived fully prepared and equipped to remedy the situation.

Both Terry and Justin were quite familiar with my system and knew that previously; in the CARY’s even hands, most of the goods were delivered.

Yet Terry had only recently given the HOLFI a few months of solid assessment in his own home rig; and he knew the HOLFI sounded better than the sound he was hearing in my living-room. He elected to operate immediately…

The Solution
Terry produced two small jewelry cases from which two sets of small conical component feet emerged.

“Finite Elemente Ceraballs!” Terry proudly announced. Both Terry and Justin had a confident smirk on their faces; not dissimilar to the look my brother wore back when we were boys… like the time he asked me to “Hang onto these two wires…” I felt equally dubious.

My own tubed preamplifier already rested on the highly regarded Black Diamond Racing Cones and I remember thinking that there was little point in throwing more exotica at the HOLFI given that it was so obviously flawed.

I was surprised that Terry didn’t even wait for the music to stop before applying the Ceraballs. To my absolute astonishment, the very moment that these insignificant feet were slipped beneath the HOLFI [and subsequently beneath my own tubed preamplifier] the music changed… dramatically!

Now this was more like it…



Paradise Found
All hype aside, this combination sounded seriously good. Immediately the mid-range beauty returned to the music.

Guitar bodies were restored. Fat bass guitar plucks appeared. Vibe decays hovered. Piano notes bloomed and became real. And voices regained their richness and tonal beauty.

But there was more…

The bass was deeper and more powerful; even in the upper bass. Basslines became ‘funky’ again.

All this without the typical trade-offs. The crystalline tops with sparkle and life all remained intact, unharmed… more likely enhanced.

Further investigation revealed that the ‘lack of volume’ problem had also been resolved. I now had real power at my finger-tips. It must be said that there is nothing quite like having dynamic headroom to spare when you’re in the mood for Grace Jones, Propellerheads, Kraftwerk or Zubin Mehta & the LAPO in full flight.

The HOLFI was now able to flex its Nordic muscles to the full; quite a liberating experience after my eleven years with the 12Wpc CARYs…

Sanity Check
Ever the skeptic, I carefully removed the Ceraballs while the music was playing to double-check what I thought that I had just experienced.
Sure enough; as I removed the first Ceraball from beneath my tubed preamplifier, I immediately heard the sound deteriorate again. Weird…

Sonic Attributes
So the HOLFI is now delivering the full banana. And whilst the previous flaws have been rectified, the other aforementioned strengths have been retained or further improved.

But my review wouldn’t be complete without making further mention of the very high degree of transparency and resolution now in residence.

Discernment
Through this whole process, one of the revelations for me has been the HOLFI’s ability to resolve plain old red-book CDs. Time and time again, I now find myself seeking out those early AAD CDs which previously seemed a bit ‘dead’. They now sound superb.

Call me crazy, but I can now hear that many of the later ADD/DDD re-mastered CDs are actually running out of headroom; the earlier, lower-level AAD iterations now sounding far more balanced and dynamic by comparison.

With the HOLFI driving proceedings, discerning between analogue and digital recordings is a cinch. In fact I now detect analogue tape-hiss on some CDs that claim to have a digital master; confirming in my mind, that once of a day it was more fashionable [and more profitable] for music companies to brag about a digital master… even if analogue mastering was behind the superior sound. After all; who could ever know?

This is not to say that all DDD discs are rubbish and all AAD/ADD discs are gems. No; there are good-uns and bad-uns in all guises. The point is that the HOLFI allows me to easily discern the differences.

This increased resolution is very good news for those readers who have [perhaps incorrectly] concluded that their older CD-player is holding their system back. Chances are; partnering with the right amplifier could deliver the real fidelity they crave, without requiring investment in yet another disc-spinner.

When it comes to high-rez sources, the black stuff still rules in our abode; and when spinning vinyl, the HOLFI has become something of a tuning tool, allowing me to hear small adjustments to my turntable and arm. Best of all, the odd LP nick or scratch now returns a small ‘tick’ rather than the big splashy ‘CLICK’ that previously haunted those same grooves.

The increased level of transparency is allowing me to adjust my hot-rodded Linn to [almost] perfection. As a result, well produced LPs sound sensational and lesser charlatans are quickly exposed.

The HOLFI marketing spin mentions a warm, tube-like sound. This statement is essentially true, particularly as the HOLFI compares to the palpable reach-out-and-touch-it sonic qualities that most tubed amplifiers [especially SETs] are able to deliver.
Whilst the HOLFI may well concede some small margin to the bottled amplifier varieties in terms of front-to-rear image depth, the HOLFI more than compensates with rock-solid, right-to-left hand portrayal. Superior detail retrieval wins the day here, allowing the HOLFI to render a more specific, clear-cut image.

One truly outstanding attribute of the HOLFI, is its ability to make utterly satisfying music at very low listening levels. I consider the HOLFI to be world-class in this respect. This quality alone has permitted me to burn the midnight oil and trawl through one revelatory album experience after another, listening at very low levels without sacrificing that indescribable enjoyment factor that great music replay evokes.

Summary
So my quest to replace my beloved single ended triode power amplifiers with a solid state cousin has drawn to a close.

Our living-room now enjoys absolute system silence at idle so I am able to leave the HOLFI fully-powered 24/7. This ensures that it is always warm, willing and able to please; and I’m not wasting electricity nor heating the room in the process.

Purchasing the HOLFI has completely removed the amplifier maintenance factor too. No more costly tube replacements or biasing duties required here. Yet combined with my tubed preamplifier, the HOLFI has preserved that special bloom, intimacy and spaciousness for which tube amplifiers are justifiably legend.

But there is one caveat! It should be stated that the HOLFI delivers a degree of sonic honesty that some music-lovers may not wish to hear. This is not to say that it is bright, dry, ruthlessly revealing or sterile. It is not. The HOLFI character is ever so slightly warm and very refined. But if you partner the HOLFI with substandard equipment, the big Dane will let you know in seconds.

It’s fair to say that not every system will be ready for the truth; the whole truth and nothing but the truth.

However, for the music-lover who has spent years perfecting their system and is looking for an essentially neutral, revealing and very powerful 2-channel amplifier, the HOLFI squarely hits the mark.

I for one am particularly enchanted by its relaxed, tube-like sound, devoid of the associated tube sonic trade-offs and ownership liabilities.

On a final note, I know most readers will think that I have broken my own ‘dress-down’ rule by inserting the quite expensive Finite Elemente Ceraballs to bring the HOLFI on song. And of course, they would be quite correct.

But let’s face it; sometimes, you just have to break a few rules. So sue me…

-Sondek
August 2008
Auckland, New Zealand
sondek@windowslive.com


Technical Data
HOLFI Power 150
Size - weight: 45,5 x 32,0 x 10,0 | 15,0 kg.
Current range: Standby: 12W | Operated: 80W -
600W
Rating: (230 V AC) 2 x 150W / 8Ohms | 2 x 220W /
4Ohms | 2 x 525W / 0,6Ohms (peak)
THD: < 0,05% / 1W / 8Ohms | < 1,5% / 150W /
8Ohms
Gain bandwidth: +0 / -3 dB: 1 Hz - 110 kHz
Recommended output impedance from preamp:
150Ohms - 1kOhms

Associated Equipment
Turntable
Linn Sondek LP12
[Modified]
Origin Live Advanced DC Motor Kit
Boston Audio Carbon Mat
Shelter 501 Mk. II

MC Phono Preamplifier
Musical Fidelity X-LP2 - 3 chassis
100Ohm cartridge loading

CD-Player
SONY XA-7ES
Fixed output tap

Preamplifier
Transcendent Sound Grounded Grid Kitset
[Modified]
12dB gain
20Volts maximum output
200Ohms output impedance

Loudspeakers
Infinity Composition Prelude P-FR
95.5dB sensitivity
Nominal 6Ohm impedance
4Ohm minimum impedance

Interconnects
1.5m Proel low capacitance

Loudspeaker Cables
5.0m Proel low capacitance

Tweaks
Black Diamond Racing Cones
Finite Elemente Ceraballs

Manufacturers
HOLFI, Denmark
www.holfi.com

Finite Elemente, Germany
www.finite-elemente.de

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Product Weakness:	Not cheap... but great value!
Product Strengths:	Transparent, refined, tube-like sound.

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Associated Equipment for this Review:

Amplifier:	Previously CARY CAD300SE Signature
Preamplifier (or None if Integrated):	Transcendent Sound Grounded Grid
Sources (CDP/Turntable):	SONY XA-7ES CD-player and Linn Sondek LP12
Speakers:	Infinity Composition Prelude P-FR
Cables/Interconnects:	Proel Low Capacitance
Music Used (Genre/Selections):	All types
Room Size (LxWxH):	3m x 4m x 1.8m
Room Comments/Treatments:	N/A
Time Period/Length of Audition:	N/A
Other (Power Conditioner etc.):	N/A
Type of Audition/Review:	Product Owner
Your System (if other than home audition):	Home

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Atma-Sphere Music Systems, Inc.

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