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General Intro

As a compact version of our unique AM modular tube amplifier system, the V.S.O.P allows access to our AM2 6V6 All-Tube circuit at a more accessible cost.

An optional OP Phono amplifier in passive RIAA design, or an optional Digital to Analog Converter (DAC) make this a really versatile integrated component.

The Circuit

As an accessible high performance Swiss Made unit, the V.S.O.P.'s circuit is three-dimensionally decoupled on a cast iron base frame, and uses the same components as in its "more elaborate" stablemates from our AM Modular series, the AM5221 or AM 6221 :

  • Shortest signal path, connectors and cables used for connecting separate components are eliminated.

  • A design that eliminates impedance and gain mismatch and reduces the number of active circuits.

  • Separate power transformers for tube and solid state sections.

  • Separate ground wiring together with central ground connection and ground lift for best signal purity and lowest hum and noise.

  • A bootstrapped ECC 81 / 12AT7 for Preamp and phase shifter duties.

  • Two 6V6 tetrodes per channel in ultra-linear configuration in the power output stage.


Component Parts

The V.S.O.P. uses high quality components throughout the circuit, such as :

  • Perfectly symmetrical output transformers with 14 distinct windings on a M74 core made from heat-treated M111 oriented grain core.

  • Mundorf and SCR polypropylene capacitors for signal path.

  • 105°C electrolytic capacitors for filtering and ...

  • Double layer Zincor PCBs.




Class of Operation


2x 6V6GT and 1x ECC81 per channel
Input Voltage

Output Power

8 Watts @ 8 ohms

Optionally with 4 0r 16 ohm output
Input Sensitivity

360 mV
Input Impedance

100 Kohm
Frequency Bandwidth

25Hz - 60KHz (+/- 2dB)

NO Negative Feedback



4 x RCA

1 x RCA Coax (digital-ready)


Price    $ 5,990

SPECIAL OFFER - contact us   $ 5,590

MM / MC Stage   $ 750    Special offer $ 650


Handmade in Switzerland


About the Tubes & Rolling Options



The 6V6 "Leader Board" Power Tubes - NOS

Bendix Red Bank 5992 1950s : Very slow warm-up, but when hot this tube had an extremely detailed sound. The bass was deep and well damped. Highs were extended but not at all harsh. Without a doubt, this was the best sounding hi-fi tube. Rating: 98 


Mazda (French military) 6V6GT 1950s : This tube had powerful and balanced bass. The mids were also nicely balanced and the highs were detailed. This is an excellent tube and a very musical one at that. Rating: 95 


RCA 7408 1960s : This bottle had powerful hi-fi sound, aggressive, powerful bass and extended highs. Rating: 96 


Sylvania/Silvertone 6V6G 1930s : This tube was much louder than other "Gs" in the test. Well, balanced with good bass, mids and highs. Great example of the 6V6 sound. Rating: 96 


GE 6V6G 1949 : This tube had a fat, deep and round bass. The mids were balanced and the highs were sweet. Rating: 94

Pope 6V6GT 1957-1960 : The Pope 6V6GT was made in a Philips Holland factory near the border of Belgium. The Pope 6V6GT is made the same way as the old Amperex Holland EL34... rugged. The sound is what Philips Holland tubes are famous for: Great life in the mids, wonderful extension, and humanity! Rating : Kevin Deal's Recommendation

Current Production 6V6 "Killer" Tube : Tung-Sol 6V6GT


Why did we chose the 6V6 for the V.S.O.P ?

The 6V6 tube types are usually found in amps with less than 30 watts and feature the prototypical “American” clean tone. 6V6 tubes are known to be very musical, and produce exceptionally clean tones that can be described as being intricately complex with a singing quality.      


A bit of History

"Baby Blues Bottle"

VTV MAGAZINE  -  Issue # 10  -  SUMMER / FALL 1998

The story of this small beam tetrode does not start with beam tetrodes; it starts with early power pentodes. And it begins with a common misconception: those who worship the might and power of RCA will be disappointed to hear that European firms were the first to pioneer audio output pentodes. RCA, and the rest of the American radio industry, were three years late to the party, and had fixated on triodes for this job until the greater efficiency of the pentode at low plate voltages could no longer be ignored.


Philips introduced the first, the B443, in 1927. It was followed by the Mullard PM24 (1928), then by later Philips versions 0443 and E443 (1929), then by the Mullard PM series (1929). All were directly heated. The first one with indirect heating was the Mazda AC/Pen of 1930. A very successful tube in the UK, it engendered a long series of pentodes, then beam tetrodes.


American firms eventually caught on. Champion showed the P-704 in 1930, followed by the Arcturus PZ. These types apparently were not especially reliable, and produced less than 2 watts in single-ended class A audio amplifiers. RCA, the alleged powerhouse, finally put some of its large engineering staff to work on it, and introduced the 247 in late 1930. It was the first American audio pentode to be a real success. Bubble-envelope 247s and ST-envelope 47s are found in scores of radio receivers of the 1931-35 era. And they became the basis for an entire family of pentodes with about 10 to 12 watts of dissipation.


Manufacturers kept pushing for more power at 250 volts (a typical B+ value in 5-tube radios). 45s were good, but their direct heating and low sensitivity made them difficult to use in AC-DC and farm radio circuits. 50s were too inefficient and required too much plate voltage. And the arrival of indirect heating meant that the 47 was going to be pushed out of the way. RCA and/or GE were responsible for most of these developments.


The result reads like Genesis, with the 47 begetting the entire 10-watt to 12-watt tube line. It begat the 38 (1931), a small-er device than the 47 and the first with a 6.3v heater and cathode. The 38 begat the 59 (1932), with its 2.5 volt heater and dual cathodes inside a 47-like structure. The 38 also begat a smaller 2.5 volt ver-sion, the 33. The 59 begat the 42 (1932), with a 6.3v heater and the first cylindrical structure of the series. Then the 42 begat the 2A5, similar but with a 2.5v heater.


And finally, the 42 was put into the new metal envelope with the innovative "octal" base, resulting in the 6F6 (1935). Innumerable Zenith and Philco tomb-stone radios used a single 6F6 as the audio output. The only component hi-fi amplifier to use this tube was the very rare Stromberg-Carlson Custom 400 of 1952. There were a few smaller tubes of the series such as the 6K6GT, but the power pentode development receives less attention after the 6F6, because RCA's engineers were developing the beam tetrode 6L6. It seems VERY obvious that the 6V6 was directly derived from the 6F6, their ratings are so similar.


Judging from the little information we have, the 6V6 (very late 1936, introduced 1937) was developed by the same team that created the 6L6; Arnold Haeff, H. C. Thompson, T. M Shrader and Otto Schade are names which are likely to appear. I say "likely" because the 6L6 's development was heavily documented, while the 6V6 was just a baby 6L6 for use in single-ended mode in radios.




What they say ...

by ARVE AHEIM | January 7, 2015

The VSOP is not completely neutral. It has much in common with vintage tube amps based on EL34 tubes, and adds a nice tad of sound coloration in addition to emphasizing the dynamics.


This is actually a positive and welcome contribution for very many music recordings. Moreover, this characteristic presents itself without masking of details ... neither in terms of musical nuances or in terms of the overall sound.


The VSOP creates a very believable and palpable realism. My experience is that a certain coloration of timbre is actually easy to get used to, and might be nice in the absence of striking exaggerations, or the absence of certain frequency extremes.


To emphasize my point, the VSOP's exceptional dynamics are "only of for the good of the overall experience", particularly when having to fight against dynamic compression on many music recordings. Exactly what happens in this regard, I don't know, but the Swissonor-timbre makes such recordings more acceptable to live with ... in my view this is a big plus in view of "living with a component".




The VSOP is thus an excellent amplifier in general, as long as one takes note that it was primarily developed and designed for use with high efficiency loudspeakers with a sensitivity of 94 dB and above, such as Swissonor's own B.A.C.H. 8d/e and 12d models. In right setup, it is in many ways an especially good amplifier where the goal is to emphasize the dynamic aspects of the music. The overall sound is very classically tube-like, but without an overtly over-warm syrupiness. What you get with the VSOP is an exceptionally clean and natural tonal presentation with pristine details of all kinds ... not surprising really, because this is precisely what the 6V6 tube is known for.

by JASON KENNEDY | National Audio Show | September, 2015

I have remarked in the past about the quality of sound that Swissonor makes and this year they maintained that standard. Their systems have more vivacity and thrill power than most, and although they may not be the last word in finesse but you get a real sense of the musical energy, the joy in fact of the music. This year they achieved this with one of their refurbished Thorens TD160 turntables running a modest Ortofon Quintet Blue cartridge plugged into two Swissonor Historic 8910 mono phono stages that offer EQ for different cutting styles including acoustic and Blumlein varieties. A VSOP integrated tube amp and BACH 8d speakers completed an extremely entertaining picture.

LP Magazin - Germany

by THOMAS SCHMIDT | November, 2012


The Last Mile

"Do you sometimes dream of inner musical peace? About the end of the hunt for the supposedly ever better sound and the last system of your life? I'm one step further than you - I've found such a system.



In $10K Swissonor System : In both phono and line operation, the Swissonor V.S.O.P. is designed to be very balanced and to deliver a wide broadband. The S/N measurements are just as excellent in line operation as in the phono domain (-95.9 and -74.8 dB). The same applies to the channel separation.


The V.S.O.P.'s distortion at a nominal 2 x 5 watt output is already 2.8 percent (which is completely fine for a tube), but with a much more practical continuous output of 2 x 1 watt, it is only 0.57 percent. Since we are talking about an SPL of 94 decibels in this system with the Swissonor B.A.C.H. 8e loudspeaker, one can live with that "just fine".


The 8e loudspeakers have a very good level of efficiency, and a sound pressure level that increases steadily on the axis towards the highs, which at least stretches up to almost 20 kilohertz. Slightly angled - this is the setup recommended by the manufacturer and us - it is a bit more balanced and "round". Overall, the course is very balanced (mind you, we are only dealing with a 20-centimeter [8 inch] neodymium broadband driver!); only the peak at two kilohertz is also easily noticeable in terms of sound. The low frequency response, on the other hand, in our free-field measurement is significantly stronger than expected - the curve shown corresponds to a horn curve that is two-thirds open. So you can definitely play with the distance to the back wall - the B.A.C.H. 8e  does not necessarily have to be directly on the wall. The distortion behavior of the speaker is almost exemplary. Even at a loud 95 dB, no painful artifacts appear - long-term listening pleasure is guaranteed.

Bottom line ...

"You have to take a deep breath and then jump over your own shadow - but once you've heard it, you don't want to live without this system anymore, because you can't hear music more lively and organically than this".

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Handmade in Switzerland

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