Digital amp beat them all? Audio Physic Strada .

The german magazine Stereoplay has(in its June issue) a review of the new Audio Physic Strada monoblocks.
Like most german audio magazines this has also a preferance for ranking products in a hierarcic manner.
Interestinly, the new monoblocks from Audio Physic gets
60 point (on a scale that end with 63 points), while the
mag´s former reference Krell FPB 650 M gets 59 p.
For your knowledge;Electrocompaniet Nemo gets 58 p, the same as Pass X-350.
Althought the fact that I am sceptical about ranking systems
in Audio,I find it remarkable that a digital amp allready
can compete with some of (what is regarded) as "top-flight"
The Strada monoblocks has a switched powersupply and some
innovative curcuitry,e.g. it seems to be handling signals
of low amplitude in analog way, and switches over to digital mode for higher amplitudes in some form of bridge
output section. Sorry, my understanding of technical german
isn´t splendid.
They deliver 255 W/each in 8 Ohms, and costs about 15000 Euro a pair.
What do you think? Are digital amps taking over the scene
in the years to come, or will there be a "resistance movement" corresponding to that of CD-anlog?
Sounds like good news, although I do not agree with their high Krell ranking, unless they are bass heads over there. The digital TACT has been getting rave owner reviews too. It looks like the future alright. If digital can be made cheaper, smaller, cheaper, more efficient, cheaper, and all the time sound better - it will be a winner.
We all tried the digital revolution in CD and its suck......
Now the digital amp...........................even though I didn't hear it myself. I already believe that it is a sucking product. Why? Signal come into the digital amp, then amplify digitally I assume and then lastly converting it back into analog signal then go to the speakers....... What do you think it will sound like?
With CD reproduction most of the tiny information like the harmonic, ambient are already gone. It is very dry already. Now add the digital amp into the equation, it will become even dryer and this is before the digital amp converting the signal back to analog. After that what left?
If the German magazine said it is no. 1, then one less magazine to read or more product catalog to read.......'s just there are more and more artificial imaging lovers(even more possibility to create!). In fact I do not accept TACT performance as a true reproduction of a recorded music.
...after auditioning TACT RCS2 in my analogue setup I've said to myself addressing my dealer: How dare you to give me that artificial mega-buck crap???... and came back to my simple and passive preamp. Was this an attempt to "correct" or digitalize the turntable's ability to naturally image without any correction engine...???

Yes the signal is being sampled to be transfered to the digital domain and than amplified with room correction or other artificial imaging that can be set up through the appropriate software.
Marakanetz, can you be more specific as to the abberations you heard via the Tact? I do believe that a turntable requires some "correction" (RIAA) to restore the original sound. Edle, I believe it is possible to keep the signal in the digital domain with out converting to analog. I also believe that most new recordings are mostly digital requiring analog conversion on most home systems. Blind prejudice is not going to further the development of our hobby. Call me a heretic, but I prefer digital to the scraping of stone against plastic at varying speeds with little opportunity to reconcile the unavoidable inconsistentcies of differing speaker /room interactions.
...first RIAA is needed for the records produced before 1954 i.e. before RIAA standard of mastering records. So RIAA equalisation makes nothing to the records produced after 1954(or maybe earlier).
Second somehow the placement of the musicians in the stage had been altered as to comparing to the no-preamp. Every instrument sounded brighter but at the same time clearer. The worst thing happend to the human voice that is being first echoed wherever you need it and wherever you don't and again changing(doesn't matter sometimes to worse sometimes to better) depending on the recording.
The thing is that my analogue rig is well established and reproduces darn good whatever had been placed on the record and in most of its cases do not need a correction or any artificial imaging. It has no floor or ceiling and images to the level of live performance exept huge symphony orchestras that need to be heard live only.
How can Tact reproduce 8Hz? To tell you simply it can't since digital freequencies are limited. With larger number of upsampling you may improve bass but the highs will cut off. So any digital device might be good for all audiable freequencies but in order to image it has to use a digital correction engine like in Tact.
Well, according to the measurments in Stereophile,the
monoblocks are down 1 dB at 100 kHz..
I also make a translation from german to english, and quote
"Madonnas voice seems -while the other amps make it compar-atively cooler and more pale, more free, more female and warmer" .
I, for my part, have a pragmatic attitude towards audio,
if it sounds good, it is good, independtly of the technique
being used. So I will look forward to see the opinion of
other magazines about the Stradas.There is a mag in Germany
called Audiophile (owned by the same publishing house as
Stereoplay) that will publish a review in their next issue,
will be out in September. Audiophile´s favorites are e.g.
Accuphase A-50 V, Lamm M1.1, Pass X 600, ML 33H, and Spectral DMA-360. No Krell amp reviewed,yes I´m not a fan
of Krell.
Better still, will be to find out for ourselfs, if digital
amps can be superior, but for my part I dislike shows.
Having heard to many probably good products sound terrible, expensive new loudspeaker from an European company that begins with L, this winter in a show in Stockholm. And
a lot of amps that were clipping........
BTW, wouldn´t it be a good idea to have different fees at
shows;by paying extra (one day), there could be a (strict)limitation in the numbers of visitors!
Then it will be easier to us, to find out if digital amps
can compete with "traditional" amps. Please be open-minded!
Aren't digital amps and TacT's 2 different things with different uses? Why summilarily dismiss all digital amps because you don't care for what a TACT does? Because they are both digital? Contempt prior to investigation is generally not the best approach. I have a Spectron Musician II digital amp and do not find it dry or artificial in the least. It is superb in clarity, imaging, highs, lows, and very neutral to my ears. It will be even better after I get my Supratek pre delivered. And the list price is about half that of the Audio Physic Strada. Please listen to one before you tell people it sucks cause its digital. Some well-respected ears have spoken very highly of the unit. If you think it sucks after a listen, well thats fine and I would respect your opinion. After all, matching taste with equipment is part of the fun.
why comment. I guess we all have our particular phobias. For nine months I used the Bel Canto EVo 200.2. When used with my Classe' integrated as a preamp, it tended to be just a touch dry. My Cary SLP 2002 solved that slight problem. It also played great detailed bass, but without weight. Mine had a 500VA transformer that I felt was a little less than what a 120wpc amp needed. B&W speakers like their current, so I sold it.
Bel Canto has introduced the EVo2 as it's high current version. 120wpc still, but with a 1500VA transformer. Mine was delivered two weeks ago. What was slightly less than perfect has been remedied. I now have all the highs and midrange of my Cary Rocket 88 (retubed ) with great but not overstated bass.
I'm sure there are some who will still find fault with the EVo2, after all, it's only $2995 retail.YMMV
Rockhead has a good point, just as in other technologies people will prefer one appraoch more than another. This is even more of an issue with what a new (in the big picture of things) approach. While it may not be perfect (what is?) I can't help but believe that there is great promise here (perhaps more so than in any other approach). Next digital cross-overs. Marakanetz, thank you for your explanation, your opionion is valued.
A few corrections.

RIAA equalization has been in use SINCE the 1950s. I believe it was established as the standard for the modern 33rpm LP.

Upsampling will make no difference to bass .. its aim is to ease the implementation of the brick wall filter which prevents aliasing distortion, according to Nyquist's theory of sampled signals.

The mechanics of sampling and quantizing a signal introduces quantization noise and limits the upper frequencies (due to aliasing distortion) but it does not selectively remove details or harmonics. Digital equipment also has practical limitations (jitter, DAC non-linearity) which are worth discussion.

In summary ...
We all have a preference for the sound of analogue or digital .. personally I like both in different ways, at different times and in different moods. But please, don't pretend you know what you're talking about technically when you clearly do not. It helps nobody. DOes anyone have a link to how digital amps work ? I'm interested to know.
Whatever there are pros or cons about digital amps/preamps, I'm damn sure that this new high-tech is now mega-overpriced and in most of the cases still "factors out" leaving one on the nominator and the classic analogue amps/preamps in denominator.
Do your algebra instead of reading or listening to the reviews and factor out extra zeros :)
Well Dinos .... you question is answered. There will be much resistance due to the general hocus-pocus explanations of why digital must be bad "and so I won't even bother to audition" attitude.

For me I'd rather get a $1k integrated and pay off the house ... so it will have to get a lot cheaper. But I'm very interested in it. Audio Physic has a good reputation to lose, so I'm sure they've researched it.
I´ve heard the arguments before!There has to be ...because
..To be more specific: there is an audio society here in
Sweden called Ljudtekniska sällskapet "The society of sound technique". Their guru often has some splendid explanations
of why products have to sound in a certain way, even before
he seems to have listen to the products in question.
One member thanked him, because "before, I thought I heard
that SACD sounded better than CD, but after talking to
the (name of the guru),and after getting his technical explanations, I realised, that I was totally wrong!"
The question: are the Stradas overpriced or not, can not
be easely answered without a general discussion of the whole
audiomarket! To me, quality of components in an amp,the
built quality, the efforts and intellectual challanges that
are laid down in a certain product; these factors play a
great role.Please note, that digital amps can be realised
in different ways, and that the Stradas doesn´t use
the Tri-Path building blocks, used in several other digital
I´m not trusting magazines that much, but their findings
may or may not have significance to us, as consumers. That
is our own choice.
I´m not saying that the Strada monoblocks are splendid
products,because that I don´t know. Certainly they are not the end of the road, but I find them interesting enough.

Seantaylor99, the Tact and Spectron web sites have rudimentary explanations of how thier specific gear works, as is usually the case there is more than one way to skin a cat. In the not too distant future your price point may be met on the used market. Like all new technology the first products tend to carry more of the R&D costs.
I hope all of you appreciated my reference to analog for the sarcastic rhetoric that it was. While it's true that I do in the end prefer digital to analog, I am not deaf to the charms of analog. I was just trying to reflect how ugly prejudice can be. Marakanetz, I'm not sure I'm following you. Why critcize digital for not being able to produce 8 Hz. I doubt many cartridges could stay in the groove at that frequency. I can't imagine many (any?) recordings having that information. I have to wonder how you can acurately play back vinyl with a passive pre-amp (I am under the impression that you use the Marchand?). I don't understand your reference to algebra. Are the zero's nothing or digits ($?)? Are you suggesting that digital will never add up to the totality of analog? You have obviously made the comparisons, and I have to respect your right to opinions, but I'm still confused by them.
My opinion is that one should buy with ones ears. That said I am very interested in a meaningful discussion of the pros and cons of technologies. I believe most of the real answers to the analog vs digital debate lie in the realm of real world engineering and manufacture, where theoretical performance is compromised by imperfect components. For example the aliasing filter, jitter and DAC linearity in CD players, and the mass, rigidity, and acoustic isolation in turntables.

But at the end of the day I wouldn't part with either my CD player or my turntable, or any of my LPs or CDs. long as 8Hz is on the groove it's being transfered there to the cartridge and it's being transfered further on to the amplification diveces. Certainly the amplification will not be on the same level as the audiable freequencies and there will be the output curve. Different cartridges can deliver the same 8Hz with the different amplitude depending on how accurate can cartridge read. My Lyra Helikon I believe does it on the respectful level.

On the digital level it's just being simply cut of and 8Hz is toooooo far away from the cutoff point.

The zeros are the values in this particular case that standing after the first digit. In Digital case there are more than you need so if you factor them out you will still end-up with analogue way as more valuable investment still.

Maybe it will be the other way arround later on who knows...?
Marakanetz, are you suggesting that analog is a better investment because it might be able to reproduce inaudible sub-sonic information that no musical instrument or human voice (that I am aware of) can produce (and if such information were available might cuase nausea in some individuals)? Ironicaly the only place where these sounds ((?) perhaps tactile sensation is a better phrase)might be available is on video sound tracks which is only practical on digital video and usually unavailable on vinyl.
Vinyl and 8 Hz reproduction? You get serious problems with
warped records, then these sub-frequences, if sent further
up the chain, will charge your amps in vain,and your woofers
will flutter.Marakanetz it´s a good idea, to adjust the
weight of the cartridge, its suspension, and the mass of
the arm so that sub-sonic information (low frequency rumble
and that of warps)form a high-pass filter . This was shown
several years ago, I think in the 70´s, by a dane named
Paul Ladegaard.Like Unsound, I think you have come a bit
off target!And the frequency respons curve in Stereoplay
shows that the Stradas are only down by a fraction of a
dB at 10 Hz. Their subjective bass reproduction is said,
in the review, to be better(lower, with more grip and with
more corpus)than any amp tested before, including Krell
FPB 650 M.
Sorry, correction;should be:to adjust or match the weight of the cartridge,its suspension,and the mass of the arm, so that they form a highpass filter, that rejects low frequency information like rumble and signals from warped records.
The comment about Audio Physic Strada was that they deliver:

255 W / each in 8 Ohms, and costs about 15000 Euro a pair. What do you think? Are digital amps taking over the scene in the years to come?

How about this amp which is already here!
206.5 W / each in 8 ohms
Distortion 0.1%
Freq. Response -0.08 decibels 10 hertz and 20 Khz.
THD less than 0.037%

This second amp appears to be very close to the Audio Physic, and COSTS WAY LESS.
And which amp might that be Albert? Inquiring minds are dying to know!
8Hz is away from the cutoff ?? What cutoff is that ? The only cutoff I am aware of is at around 20kHz for the anti-aliasing filters. I'm not aware of any low frequency rolloff in the redbook standard. I'm getting tired of these half-truths. By all means describe what you hear, but leave technical explanations out unless you really know what you're talking about.
I'm not talking of 8Hz as the freequency reproduced on the same level as all 20Hz...20KHz audiable freequencies. I'm talking of 8Hz harmonical components of an audiable freequencies that can go upto 52KHz. They're signifying the tembre of a particular voice and instrument. Making the sound of tum or drum 3d and more real(for a small example). Analogue playback starts from mechanical transfer that has no limit to the freequencies whatsoever.
Whenever it's 8Hz or 32kHz it's all there in the stylus in the first place...
Shortly saying we've got two ways to create imaging: one way is to get as full range as possible capturing all the sub and over-harmonics or with current digital limitations we should create a digital immulator of 3D space by micro-phase shift(s) of a different channels according to the room dimensions or whatsoever(when you will get a chance to deal with TACT you'll know better).
The first analogue way creates a natural(or at least as closed to) and the other way creates pseudo-imaging.
I've clearly stated what I've heard from the same source with different setups before that the placement of instrument/musicians was different but although more clear in the sound stage. Thus from that I'm making my conclusion here. I've actually expected TACT to do some magic, but was dissapointed for the price you'll have to spend for that unit vs. more valuable analoge options.
Once again to say I've "factored" it out leaving 1 in numerator and analogue in denumerator.
Actually I was being kind of mean. The specifications are from the Yamaha RX-V2200 A/V Receiver.

I hoped to make a point that specifications are pretty much meaningless, we must all take the time to listen with our ears and our hearts and quit being influenced by the data.
I agree to that Albert, most measurments (on amps)doesn´t tell us much about how the amp actually sounds.Some well- reviewed amps that I have read about recently, have rather high figures of intermodulation distortion.Probably, the usual,static measurments miss important information of an amps behavior under more realistic, transient signal conditions.But some measurments, e.g. an amps delivery of power into a reactive load, tells us somthing about the amps ability to drive real world loads, i.e. speakers.
Stereoplay has an interesting hypotesis that valve amps and digital amps have one thing in common, namely that they are less prone to be affected by back-EMF sent (back) from the speakers to the
amp(s).And perhapes they can be made,so that they pollute
the mains less than conventional amps?

If digital amps can compete in the High-end sector, only time will tell.But I find a big advantage in their superior efficiency! That is less disturbing to the environment,and
at the same time save us from some heat! (I have to admit,
that I now use a big class A amp.)My own belief, is that
we will see digital amps taking over the scene sooner that
many of us expected.Like all predictions, it can be wrong.
I live in Germany and read most of the commercial German audio press. For those of you unfamiliar with these magazines, they focus on different "target markets": low to middle class hifi (Stereoplay, Stereo, Audio), high-end (Audiophile, Image HiFi). Although they are primarily marketing devices for German audio manufacturers and distributors, these magazines do occasionally review unusual components outside the German market and have the advantage of publishing technical data, specifications, and photos of the circuitry.
Although I am generalizing and my German audio friends will hate me for this, German high-end enthusiasts tend to like a very "analytic," rational sound from a component "built like a tank" ("wie ein Panzer gebaut," a cliche one hears over and over in German circles), with solid, dependable workmanship. In amplifiers, they tend to like high-power, solid-state designs, to drive very inefficient, large speaker systems (the most important part of an audio system in Germany is nearly always "die Boxen"). There are exceptions to this rule (a relatively large interest in tube amplification, SET, retro, etc. and there are some exceptional small German tube amplifier manufacturers that you will never hear about in the USA), but this is the general rule.
I mention all this, to provide you with the context for this review of the AudioPhysic Strada--a digital power amp coming from a large, well-known German manufacturer of relatively inefficient speakers, with a lot of capital tied up in the press. On the face of it, I can think of no better magazine for the Strada to be reviewed than Stereoplay or Stereo. Both magazines have been ranking digital preamp and amp products very high in the last few years (I am thinking of TACT Millenium review, Sharp review, and the reviews of Accuphase, TAG McLaren, Z-Systems digital amp / pre-amo products as well the praise lauded on the Gryphon Callisto 2200--an entirely OpAmp design, which is usually considered the #1 integrated amp by these magazines, 100% Klang-Qualität, as they put it.)
Despite all this, who can answer this simple question: Why haven't alot of manufacturers (besides Sharp, Tact, AudioPhysic, and a few others) brought out digital amplifiers, although the microchips for these have already been around for a long time? Looking at the specifications (which albert potter is right to point out as "pretty much meaningless"), why don't alot of manufacturers produce digital amplifiers?
Well, because the resultant interferencee from the digital coupling signals on other pieces of equipment is so high that in tandem with a complete system, one can no longer speak of high-end audio with digital amplifiers. With a typical digital amplifier, a digital coupling signal of at least 1 volt dances on the loudspeaker cables, with lots of power, and possible interference. The interference frequencies (even filtered with multiple capacitor networks) are often over 1 MHz in 3 Volt region, and many harmonics come on top of that. The portion of the interference that is reflected onto the mains results in large AC interferences that cannot be completely eliminated. Also the interference that is sent to other components are incalculable. And think of the following: one can isolate the sampling signals of a CD player from the mains by using a mains filter or isolation transformer or power gnerator, so that other equipment will not be loaded with it. This is measurable and controllable. The interference from a digital power amp has a power and reaches a value that makes rectification almost impossible. It is much higher than a CD player. EMV problems that are trully unsolvable result. The extent of interferejce is so high that all benefits, like higher efficiency annd lower distortion, are meaninglless and the succes--from a high-end standpoint--is entirely questionable.
Dinos, I agree with you, digital amps will be much more common sooner rather latter. No, I don't think they will replace the majority of the amps out there right away. Many manufacturers and dealers are loath to invest large sums of money on R&D and marketing that might risk an established customer base. Why should they? Perhaps to avoid being left behind and loose there share of the customer base? Unfortunately many can not forgive the hype of "perfect sound forever" and carry a strong aversion to anything digital. In my limited auditions of digital amps I found them more in common with tubes than solid state. They exhibited a liquidity that tubes are known for. They presented the solid bass without the "electronic off flavoring" sometimes found on some solid state amps (especially on the "silent" parts). I think it's the upper end that is going to divide many listeners. I find them to be accurate and extended, other who have been with me at the same auditions found them "bright". I for one am excited by the promise of digital. I don't think we can go much further with current technologies. Whether digital amps are a step forwards,backwards or sideways, only time will tell. I'm optimistic that it will forward us into a better "audio" future.
...despite anything else, I would not refuse to win TACT RCS 2.2x and entered the lottery during the NYH exhibition yesterday.
Marakanetz, if you win, will you use it or sell it right away? Either way, good luck.
If I would use it it might add on some digital collection in addition to my analogue. CDs sounded wonderful(even with correction bypas) since the DAC inside this unit can be used successfully with any transport. As far as I know about TACT it still uses analogue controlled output stage. What about an Audio Physic?
...even if I use it for analogue i will not use a correction system. If I use it without correction the signal will not be converted to digital and will go straight to the analogue domain.
Marakanetz, I believe that the TacT in it's basic form is pure digital in and out, the only conversion being that of PCM to PWM. Digital crossovers are standard. AD input and DA output are options. By the way the designer states that the room correction offers the most improvement.
Hmmm... What I believe is that what TACT unit accommodates in one box isn't necessary to the vast consumer and that makes this unit overpriced (please forgive me in re-directing this discussion). There are some consumers that don't want built-in DAC or correction. I admit that this unit accommodates the state of the art DAC that is able to bring regular red-book CD playback to the level that is very close to vinyl even with poor transport. In fact if this unit had an option to break up into different boxes it would be much more marketable. TACT RCS is relatively new thing in the audio market and somehow already there are used units with drop bellow the half of its price. I'll expect this unit to be cheaper but than again TACT will come up with something new and will descontinue the previous as all the manufacturers usually do. In my situation I would just only ask the manufacturer to brew for me a custom unloaded version without correction and even DAC leaving only digitally controlled analogue volume control and get their DSP later until my CD collection will be someway even close to half of my analogue. My CD collection stays for not long and serves for information purpouses only(meaning i sell them right after I've listened to them and buy different ones) so the demand on reproduction quality is quite low in comparison to analogue. And finally It is not even neccessary to have separate boxes It is good enough have a basic preamp box that can be upgradable by insearting cards just like you do it on your home PC: card for DAC, correction digital Xover, phono, ADC etc...
I think, I'm finally beginning to understand you.I do believe that the Tact approach is revolutionary and as such be forgiven for not making typical components. Their attempt to tackle what many belive to be the final frontier, room correction has opened other possabilities as demonstrated by thier system approach. With digital crossovers that allow for proper time and phase, minimal driver overlap, minial lobing, super light drivers and flexibility of placement not only as a convience but for better perfomance. Thier amplifiers are part of this concept and allows for super fast control with little smearing. Maybe, I'm missing something but it all makes a lot of sense to me, and what I've heard suggests thier on the right track. Considering the R&D costs and the results I think we are looking at something that is closer to a bargain than not. Perhaps we need to let go of our previous concepts and allow for a different appraoch.
P.S. as this thread was started re: digital amps, I should point out that in theory the TacT should be able to play with the same resolution regardless of volume and never clip (Tube lovers rejoice, forget pleasent (even order) vs. unpleasant (odd order)how about none?).
Like the perfect sound forever with no distortion that was promised by the Compact Disc?
Touche, Albert. I have not heard claims that grand, yet. I hope you understand that I was merely pointing out that at least in theory, there is promise here. I'm hoping that infamous qoute won't prejudice all future digital pioneering.
I too hope it evolves to a point where we all may benefit.

I confess frustration at the small amount of progress for the twenty years plus that has been devoted to perfecting music reproduction via CD.

Watch just one evening of Discovery Channel see the progress in the machinery for war and wonder how the vinyl LP can still take on all formats. I guess I had hoped for more.
Albert, am I correct in my assumption, that you are dissapointed so far by digital amplification? If so, could you elaborate? What needs to be improved upon? I'm very sure that I am not alone in respecting your opinion.
Not digital amplification, as I have not auditioned it in a situation where my opinion is valid.

My disappointment with digital is that it shares some faults with the modern computer.

Performance, chip sets, formats and even software seem to get "stuck" at a particular quality level with no way to upgrade without discarding the entire (old) system.

By comparison, LP's manufactured forty or fifty years ago still work in today's systems and every audiophile upgrade will continue to improve the sound of that old master.

I put so much time attempting to make digital (CD) work, that it is a sore spot for me. I'm not accustomed to putting in so much hard work only to fail.
On many levels I agree with you. I think you will agree that records made 50 years ago might be challanged by a new CD. CD's are now almost 30 years old now. A 30 year old CD is still viable ( vile ?). CD has been a disapointment, considering the promise ( hyperbole? ) Despite all the technological draw backs of LP's, on sheer sound quality it may very well be the best available source. When conviences such as recording (when not perverted by the powers that be),mobility and reduced maintance are put into the equation (never mind my pet hopes of room correction,crossovers and amplification) CD does gain quite a bit of ground. Thank you for contribution. Hope you can share your thoughts about other digital technology in the near future.