Logo_testata_ReMusic
English

Shootout Test | Eleven Passive Preamps
with Transformers

24.10.2012..
..

Here the first shootout test that ReMusic proposes to the audio enthusiasts.

 

Firstly, allow me a consideration.

 

Personally, I do not believe very much in shootout tests. They are always incomplete and maybe a bit unfair. It is extremely difficult, for a reviewer, facing and resolving an exhaustive article that, at the same time, is descriptive, as well as relating to the listening and to the criticism towards a single device. In fact, it can be very hard to understand exactly the tested object, its electric features and put it in the best condition to perform. I already consider a good result offering to the public a balanced and substantially correct judgement that takes into account the preparation and the experience of the reviewer.

Just imagine how complicate and hard a shootout test can be. Infinite are the variables as well as the characteristics of the components, the cables, the speakers and all the other accessories. Just think of all the times that by changing a main cable the result is substantial, sometimes even striking.

 

So why a shootout test?

Because I want to draw the enthusiasts’ attention to a specific typology of devices, unfortunately not very known in the audiophile world. Besides, who knows them often renounces to deepen their knowledge since they are very difficult to find or because their cost is excessive.

 

I am talking about the magnetic passive preamplifiers.

What are they?

Let us start saying that the passive devices are those that do not require to be supplied and therefore are not crossed by any electric tension.

Passive amplifiers have just the resistive attenuator and the input selector, sometimes also the remote control. Hence, only the motor of the potentiometer or of the resistive attenuator will be supplied.

Instead of the resistive attenuator, it is possible to use some transformers that assure the galvanic isolation between inputs and outputs avoiding all the problems linked to the sensitiveness of the capacitive loads. In this case, the preamps are called magnetic passive.

Practically the audio signal, instead of being attenuated by the potentiometer, crosses a single winding transformer whose length varies at the varying of the volume. But not just that. In the case of the transformers is also possible to generate an output voltage gain.

 

From this moment on the diatribe is open.

Yes, because there is no alternative on the opinion on the preamps with transformers: you love or you hate them.

Also among technicians, we find supporters and detractors.

I just want to say that the use of a coupled transformer on the signal path generates, in some occasions, a sound so beautiful that the audiophile does not want to comeback!

 

I know, I know. Now the hell breaks loose. I can imagine comments and considerations: “it is a coloured sound…it is a disguised sound…the signal suffers many abuses… it is not a correct sound…”. Obviously you can say what you want and have your personal opinion. I only say that what prevents me to use stably an excellent preamp with transformers in my chain is the fact that I am an audio reviewer. Anything I would compare will result a looser at my ears. Anyway, if you are curious, I tell you which my favourite preamps with transformers are:

  • if I had a lot of money I would choose the Audio Tekne TP 8301 MKIII or, as an alternative, the Zanden Model 3000
  • if I did not have much money I would choose the Antique Sound Lab Flora with the substitution of capacitors and tubes

Now back to our passive preamps with transformers. I would like to introduce the eleven preamps following a rigorous alphabetical order:

  1. Audio Tekne 9701 | Japan
  2. Cello Etude | USA
  3. DaVinciAudio Labs | CH
  4. Fidelity Research AS1 | Japan
  5. Luxman AT3000 | Japan
  6. Music First Audio | UK
  7. Promitheus Audio TVC | USA
  8. Promitheus Audio TVC Reference | USA
  9. Stereo Knight Magnetic Silverstone Balance | USA
  10. Stereo Knight Silverstone SE | USA
  11. The Mod Squad Line Drive | USA

The most attentive enthusiasts have surely noticed that the last two are passive preamps without transformers. Bravo. Nevertheless, they will be assessed like the others.

They cover all the price ranges, some are no more in commerce and you can find them, quite difficulty, only on the second-hand market.

For this shootout test, I have been aided by our collaborator Marco Fontanelli and by Antonio Palmieri, Atelier del Suono’s boss and owner of almost all the tested devices. To simplify things we have inserted the eleven passive preamps, in turn, in the same system with the same connection cables. Furthermore, to evaluate the performances, we have focussed only on few parameters: the more emblematic to determine the difference of quality among the devices. We have used only two LPs: Jazz by Ry Cooder and Slow Train by Hans Theessink. The parameters are: control of the low frequencies, imagine and tone colour.

 

The control of the low frequencies, marked “BC” (Bass Control), is very important for the ability of the passive preamps with transformers to reproduce valuable harmonics from five-hundred Hz down. Hence, it is basilar not loosing the capacity of control to avoid neutralizing this ability.

The recreation of the image, marked “I”, is evaluated on the basis of the dimension of the soundstage and its three dimensions.

The tone colour, marked “TC”, is what can make us recognize the musical instrument, where, usually, the harmonic richness allows more tonal definition.

 

To each one of the passive preamps, we have given a FV (final vote) – from three up to nine - that is equal to the sum of the vote assigned in common for each parameter.

 

Let us describe now the system we have assembled to test the eleven passive preamps.

It is a topsystem, not only for its high cost, but for the care put in assembly with synergy all the components and the cables:

  • DaVinci Grandezza pickup
  • DaVinci Grandezza 12 inches tonearm
  • In Unison TT DaVinciAudio Labs turntable, Micro RX1500 flywheel with DaVinci motor, Target PRO wall supports
  • ART MC8 L.E. phono step up
  • AN Il King phono stage
  • the eleven magnetic passive preamps in turn
  • Audio Note Ongaku Kondo power amp, Japan 1996-98, with 211 Pasvane tubes on direct input
  • custom speakers of Altec derivation, sealed enclosure, 38 cm broadband without crossover, with Altec horn tweeter and Murata super tweeter, Foundation stands and TAOC feet
  • cables between step up and phono stage: Audio Tekne ARA500, between phono stage and preamp: Cubala Sosna Emotion, between preamp and power amp: Harmonix GP, between power amp and speakers: Harmonix 101

The listening test begins.

We have tested the eleven devices three times. A real torture.

We have agreed on the performances of every single device, on the votes and on the final evaluations. Incredible, our friendship is safe!

 

Here the results:

Stereo Knight MSB – A true balanced apparatus. You can see the four containers for the transformers. The manufacture is catchy with a cabinet made of aluminium and opaque Plexiglas, the cost is not excessive. The BC deserves a low vote due to the poor control, the poor depth. Same vote for the TC because is not convincing and the voices are not very realistic and somehow misted. A high vote for the I, thanks to the praiseworthy depth. The test has been made in unbalanced mode. Final Vote 5

Stereo Knight Siverston SE – This is the younger brother and also less expensive than the first one. The transformers are two and it has only unbalanced inputs. Low votes in all the three parameters. This machine does not match up with the others. FV 3

Luxman AT3000 – Now we are talking business. Remarkable BC with important and convincing details, good control and articulation. High vote deserves the I, as it is extended in the three dimensions outlining a wide soundstage. TC remarkable indeed. The instruments and voices are given back with a strong sensation of realism. FV 9

Music First Audio – Acclaimed by the international critics and tested by ReMusic. In this case, it has not fully persuaded, puzzling on the performances that we have evaluated as mediocre. BC not too much convincing mostly for extension; the control, not always enough sure, made transpire some blunders. The dimension of the I is not wide mostly in height. TC is little convincing with a light rosy hue colour. FV 5

Audio Tekne 9701 – Beautiful object. With the 9701 is immediately clear how much improvement in terms of listening pleasure you can get with this kind of device. The BC is of top level. Besides, it is evident that the reproduced sound goes down of an eighth downwards. I is of great make, extended in all directions and accompanied by a tangible sensation of presence of voices and instruments. The TC is amazing. Great is the sense of naturalness of the emission. FV 9

Fidelity Research AS1 – It is a pity that the F.R. AS1 preamps are not easy to find and the few are in the hands of their happy owners. The Fidelity Research AS1 are no more in production and in Europe not many have come. Atelier del Suono has provided one exemplar to ReMusic. The vote is the highest in all the three parameters. An excellent level. FV 9

DaVinciAudio Labs Grandezza – The Swiss company knows what means using high quality transformers. But mainly it knows “how” to employ and treat them. BC exceptional, very extended, sure, detailed and articulated as few do. The I is wonderful with connotations of clearness, the three dimensions are very wide mostly in depth with a sound that seems coming from far beyond the back wall. The TC leaves no doubt and convinces immediately by infusing in the listener relax and involvement. FV 9

Promitheus TVC – This model, like the following of the same company, is made of precious Merbau wood, ligneous essence known for its rigidity and compactness. All of a sudden, we are in chasm again. We agree to listen to it without a direct comparison with other machines of a different make. Pointless. The Promitheus shows its limits in all the parameters. FV 3

Promitheus TVC Reference – Older brother of the former one with balanced inputs and outputs that we have not utilized. The sound of the Promitheus Ref is different and better. The BC is decent and not despising. The I is the most valuable feature with a discrete spatiality. The TC is not its best parameter. FV 6

Cello – Who does not know the company born out of the brilliant mind of Mark Levinson? Here we are talking about a simple passive preamp, without transformers. The greatest delusion. Cello for me is a myth but this passive preamp, notwithstanding the high quality of the few components - once for all the potentiometer – has not given a sound performance equal to its emblazoned name. The performances are good but not exceptional. I remind you that this is one of the two preamps without transformers. Everything on the average. FV 6

The Mod Squad Line Drive – If the Cello has been a delusion, the Mod Squad has been a pleasant surprise. The making is very clever although a bit “homemade”. The listening test has given high votes for I and T, while the BC is lower, as the extension is missing. Also in this case it is a preamp without transformers. FV 8

 

Hereafter a synoptic table of the results and votes that have been assigned. The only thing this table does not say is how extenuating has been this test. We have made more than the thirty-three expected changes of devices.

 

 

MODEL

Bass Control (BC)

Image

(I)

Tone Colour

(TC)

Finale Vote

(VF)

Stereo Knight MSB

1

3

1

5

Stereo Knight Silverston SE

1

1

1

3

Luxman AT3000

3

3

3

9

First Audio

2

2

1

5

Audio Tekne 9701

3

3

3

9

Fidelity Research AS1

3

3

3

9

DaVinciAudio Labs

3

3

3

9

Promitheus TVC

1

1

1

3

Promitheus TVC Ref.

2

3

1

6

Cello

2

2

2

6

The Mod Squad Line Drive

2

3

3

8

 

Let us start from the lower end of the chart…

 

Tail-end Promitheus and Stereo Knight Silverston SE. Budget devices that can anyway start to let understand what means using the coupled transformers in a system. They could be used with satisfaction between the active preamp and the power amp as simple coupled transformers. They can also display good skills if matched with attention and with care in choosing the cables.

 

First Audio and Stereo Knight MSB do not seem to deserve the attention that the international critics has reserved to them. Maybe they are not suitable for the reference system we have used. Joint winners just below the end of the chart. I think that choosing the power amp, mostly for the First Audio, is of fundamental importance in order to get a great outcome.

 

Promitheus Ref and Cello have the same score in mid chart. If the Promitheus Ref is an honest device, the performances of the Cello are not equal to its name.

 

The Mod Squad deserves the position of maid of honour. It is amazing and it is quite difficult to understand why it has not had a bigger commercial success. If you find it second-hand buy it immediately if in good condition and if at a congruous price.


Four passive preamps have deserved the top vote… Notwithstanding they have the same score, we have entered into the merits starting from the fourth classified, that is:

 

The Luxman AT3000 does not get on the podium because it cannot produce a detailed resolution enough attentive and precise, although of optimum make. Excellent device that deserves a place in the history of the international hi-fi.

 

Audio Tekne 9701 is in the third place for its low frequencies that are a bit less immanent in comparison with the other two classified. The rest of the parameters is given back with authoritativeness and naturalness.

 

Fidelity Research AS1 wins the silver medal. Amazing, I would have never bet on it at the beginning of this adventure. A real pity that in Europe are only few pieces, I suggest to have a listening session with this preamp.

 

And the winner is….

 

Da Vinci Audio Labs Passive Preamplifier Grandezza, doubtless the most performing of the series. The Swiss company has surpassed itself making a good looking object with top sound qualities. Of course, it is expensive like all the things with an intrinsic quality. It is more than a span above the others showing character, confidence and record transparency.

 

In conclusion, I want to remind to everybody that for this shootout test we have used components not commonly employed by the audiophiles, but that deserve a deeper consideration. Actually, the passive preamp with transformers is not commonly used in the normal audio systems as well as in the more valuable hi-end systems. Undeservedly, the passive preamp with transformers has been put aside. For this reason, I invite you to consider this kind of device and listen to it. You could be captivated.

 

Besides, I invite you to take this test as not definitive. Too often, an unhappy match with the rest of the audio chain generates a bad sound outcome: it is sufficient an inappropriate signal cable to neutralize or mortify a good sound. This rule is more important when the machines are like the ones we have analyzed in this review. The passive preamps with transformers need a certain care in choosing the connection cables, especially the signal cables, and need a certain care in the chain of gains, hence in choosing the components of the audio system. Pay attention, it is not necessary that the system has to be of great value, in the sense of top-level or very expensive brands, but it has to be a balanced and well-thought system

 

 

RIGHT OF REPLY | MANUFACTURERS FEEDBACK

Hello ReMusic,
I hope this finds you well and enjoying lots of beautiful music. I wanted to thank you for including an early version of the standard Line Drive in your passive preamp listening test - this came as a pleasant surprise. It put a smile on my face to see how well it held-up against some very prestigious competition.
The unit you chose was built sometime around 1987 - '88 - well over 20 years ago! The design had already evolved considerably by that time... I built the first model Line Drive in 1984 to correspond with the introduction and growth of the CD. As I quickly discovered, making a truly transparent passive preamp was a much more subtle and involved project than I had imagined! But I stuck with it, and the Line Drive evolved into a very good-sounding unit. It was very instructive to compare it with the active preamps of the day as it gave some insight into the colorations that most preamps added to the signal.
The Line Drive was a successful product through the late '80s and into the '90s when it was finally replaced by the TLC-1 (which included both passive and buffered outputs). It helped to establish the product category of passive preamps and is still enjoyed by many audiophiles today. If you are interested in more background information, the standard Line Drive (essentially the same as the one you used in your test) was reviewed by John Atkinson for Stereophile back in 1987.
Thanks again, and keep-up the good work!
Best regards,
Steve McCormack

15/01/2013

by Roberto Rocchi
Read more articles

Torna su

Advertising

 
DiDiT banner
Vermöuth Audio banner
Banner Extreme Audio
KingSound banner

Is this article available only in such a language?

Subscribe to our newsletter to receive more articles in your language!

 

Questo articolo esiste solo in questa lingua?

Iscriviti alla newsletter per ricevere gli articoli nella tua lingua!

 

 

 

Email:
Language:

Advertising

HighResAudio banner
Dream Streaming banner