Assistent 100 Mark - II

Assistent 100 Mark – II

6.900,00 7.500,00 

SKU: N/A Category:


:::   integrated stereo high performance tube amplifier   :::

If you are looking for an integrated amplifier for your rack instead of Prometheus monoblocks, the Assistant 100 – Mark 2 is the best choice. Assistant 100 has two mono channels from Prometheus in one housing and has the name “male amplifier” in the scene – because it takes two men to act. But first to the story of why an update for Assistant 100 was announced. Back in 2000, after a long period of work, I finally had the 6C33 with 2 tubes per channel – 4 of which i planned a stereo integrated amplifier – in a push-pull circuit. That was also a challenge, as in the end there should be at least 80 watts available per channel. No sooner said than done at the end of a load of 8 ohms about 25 volts at the output of the transformer.

So far so good. But the balance sheet with regard to the performance made me frown. On the one hand, there was the heating power of the 4 x 6C33, which already faded 200 watts alone, and there was also 200 watts of anode power loss in Class A operation – making a total of at least 400 watts and all of this from scratch without first a single tone in the Speaker. In the further course of sales of the integrated amplifier it turned out that the 6C33 is extremely capricious.



It could not tolerate more than 200 volts at the anode anyway and when the anodes were still supplied with signal voltage by the transformer, the day was over and the tube was in the bucket. That was the situation with 80 to 100 watts of output power per channel. The situation only got better if you reduced the signal level, but then you were at 30 watts – and that with the effort. So the concept had no future, I had to recognize it here with a heavy heart. A 2 x 30 watt amplifier can be developed just as well with less effort.

So I decided to discontinue the product over the years. I had “burned” an infinite amount of time with the construction and a great circuit board so that you could build more than one amplifier. With hand-wired devices, the replica is a single ordeal. In conclusion, I have to state that the tube is only suitable for what it was made for, namely as a series regulator in power supplies, there is no voltage increase on the anode, which ultimately always caused the tube to die. That was a very bitter experience. And that applies to both PP and SE concepts, just keep your hands off this part, you will quickly lose the fun of it. I still have about 100 printed circuit boards in stock, if you are interested, you can inquire and try an amplifier with reduced power with it – and my circuit on board doesn’t hum either – like all my amplifiers don’t hum!


pwer consumption: 200 – 350 Watt max., “stand – by” mode: 50 Watt
power output: 2 x 80 w sinus wave – 1khz

distortion 1khz / 8 ohm:
2 watt – 0,06 %
10 watt – 0,06%
50 watt – 0,15 %
80 watt – 0,25 % !!!

bandwide: – 1db / 45 khz, -3 db / 5 hz up to 60 khz
damping: 8 ohm load – 6
s/n – ratio: better 80 db


Enough words about the past, let’s turn back to the current model. There was also a lot to observe at the beginning of development with the GU50. This tube did not like the max. Values ​​of e.g. the anode voltage. This is set to the safe value of 650 VDC. As always, we donated a fully automatic bias circuit to both tubes on the end tubes. I am glad that we at AudioValve have this construction, which does the setting up of the optimal anode quiescent current completely on its own. I really wonder how the competition believes without being able to sell this device for the future ?? !!

Also when choosing a base for this tube, you have to do the right thing, otherwise it will take revenge. In the first samples we had china – base made of ceramic, which led to glass breakage of the GU 50, because the mechanical prestress on the contacts was great. These sockets belong in the trash. We then found the original base for the tube in Ukraine and since then the problems have been over. Another great thing about this base is that it secures the tube to prevent it from falling out. The base “defends itself” to give the tube back – well done!

As always, the circuit board is made of one piece. Power amplifier, pre-amplifier, power supply and all other necessary components, all together on a perfectly routed circuit board. Then you only have to pull a few wires, to the mains transformer and transformer and you have a super integrated amplifier with 2 x 80 watts. I am also happy to make this circuit board available to interested users – for a fee. The two control grilles of the end tubes of a channel are fed from 12AU7. Basically, the driver is the same as the one we use in Assistant 50. This driver has enjoyed great popularity among Assistant 30 and 50 users for over 20 years.



There are LEDs on the bias controller that signal the intact function of the end tubes. If they are off, everything is fine and the regulation is working. If one of you lights up, the tube must be replaced at the relevant place. And what does the Assistant 100 – Mark II sound like? The GU50 is an audio tube through and through. In our concept, it is inexpensive to obtain and does not require any selection because the autobias arranges everything independently. Ok, this tube is also looking for your master, who knows how to handle it. But because of its originally intended use, it offers a completely different basis for a promising concept than the 6C33 – so it is all long.

Compared to the “part” with the 6C33, the power loss of the amplifier has dropped by half – however the weight has remained the same, I hope this is not a drawback for you now ;-). The Assistant 100 is similar to its little brother Assistant 50 to operate via an FB and also preconfigured for retrofitting with our DAC. In addition to 5 x RCA inputs, there are also 2 inputs for XLR cables on the back. The LS terminals are arranged next to it. There is also a TAB-REC that loops through the signal from the selected source.

Our logo is lasered and illuminated on the windscreen. The desired color of the LED lighting must be specified when ordering. Otherwise the product is easy to use. On the back is the main power switch, which must be set to ON if you want to switch on the device via the FB, because it has no power otherwise. On the left on the front is the display for the selected input. If the amplifier is in “Operate Mode”, the LED of the selected source lights up, this LED flashes during the MUTE function and in STAND BY mode all sources LED are off. Have fun with the assistant – the AudioValve team wishes you 100 Mark 2




Hifi magazines

Audio Art Magazine
Equipment collection
Assistent 100 (Top-level Special Edition)
Exquisite Delight in Superior Sound
Integrated Valve Amplifier
The output power of each sound channel is 110W (8Ω load). The used valve: EF86 × 2, ECC82 × 2, QQE 03/12 × 2 and 6C33 × 4. Input terminal: 5 sets of
XLR and 5 sets of RCA. Output terminal: 1 set of TAPE OUT (RCA). Damping: 20. Input impedance: 47 kΩ. S/N ratio: > 80 dB. Total harmonic distortion: <
0.15 % (- 50 watt). Frequency response: 5 Hz – 60 KHz. Dimensions (WHD): 550 × 170 × 450mm, weight: 45 kg. Import general agency: Dian-Li (03-
Written by Shu Shihao
Helmut Becker, the boss of AudioValve, is a fairly “distinct” designer. The
products designed by him never follow the trend but each piece still can
manifest his insightful opinion about sound. Though it always takes longer time for
this company to promote new products, the waiting is definitely worthwhile.
Take Assistant 100, the subject of this
review, for example, Helmut Becker
employs the rarely seen 6C33 valve
and adheres to his distinct design
principles, to produce through delicate
work the only two integrated
amplifiers in the world till now.
First use of gauge design
This time, we went to visit Mr. Chen,
who is the shopkeeper of T&V Pro
Audio in Tao-yuan city. He is a musiclover,
and also a veteran hi-fi fan.
Once he heard the sound from Audio
Valve in a music exhibition hall, and
since then he cannot tear himself
away from the sound and has
immersed himself into the business
world as an agency of Audio Valve. He
explains that T&V not only relates with
his work (audio and video), but also
stands for “Technology” and
“Vacation” which implies it “enables
you to enjoy the vacation via
technology”. Through this, we sense
his great passion for promoting music
appreciation. Since he is an exclusive
dealer for Audio Valve, of course he
has the greatly praised Assistent50
integrated amplifier. From appearance
and shape, these two products are
almost alike. But, Assistent 100 is of
much bigger volume and 20kg heavier
than the other. Assistent 50 can only
be started via remote control while
Assistent 100 has switches on the
panel. As one more special point to
mention, Helmut Becker designs two
small gauges on Assistent 100, which
adds perfect classical tone and also
funny experience when they light up
in case of big output power.
Assistent50 uses two QQE 03/12
power valves, while Assistent 100
employs four legendary 6C33 power
valves. How legendary? Let me tell
Valves from a MIG Fighter
During the cold war between United
States and Soviet Union, in 1976, the
legendary pilot Victor Ivanovich
Belenko from Soviet Union drove a
MiG-25 Foxbat, the “top secret” at that
time, across the iron curtain and
landed in Japan. Certainly, Soviet
Union wanted Japan in any case to
return the fighter, but before giving it
back, US military experts had already
reached Japan and dismantled this
fighter. The experts gasped with
admiration at the technology and skill.
Moreover, they surprisingly discovered
on this MiG-25 the valves which were
quite obsolete at that time. Yes, exactly.
The valve always used on
communications equipments is 6C33.
It’s said this type of valve is designed
to resist the strong EMP produced
from nuclear explosion, since the
common crystal will lose function in
the event of EMP while 6C33 can
work normally. Besides, this type of
valve not only meets the high G
requirements of fighters, but also has
quite long service life. They can even
resist the nuclear explosion, not to
mention the electro-magnetic
interference in general environment.
In the acoustic application, what’s the
strength of 6C33 that makes DIY fans
so enthusiastic about it? It mainly lies
in its low internal resistance which
simplifies the manufacturing of output
transformer. Moreover, its plate current
is above 200mA and the peak value
even exceeds 1A, far higher than that
of the commonly used power valve.
What’s more, 6C33 can work under
rather low voltage (about
150V~200V), which also reduces the
requirements on all components
within inside. However, though 6C33 is
of good use, the circuit design is
rather difficult. The machine is likely to
get burned if not the design is not
careful enough. Certainly, with
appropriate design, the exquisite
sound will naturally come at your
fingers’ ends.
Complexity for Stability
What on earth did Helmut Becker
employ to handle this valve? The
answer is the exclusive ISBR
(Interactive Servo Bias Regulator).
To be exact, it’s the evolution version
of ABR (Auto Bias Regulator). The
four pieces of 6C33 used on Assistent
100 not only adopt auto bias, but also
each power valve is equipped with
auto-detection circuit. When the
valves are ageing or of malfunction,
the nearby LED lights will indicate the
state. Compared with the general valve
amplifier, though Assistent 100
produces high distortion at low input,
the distortion value remains almost
the same till whole output, unlike the
general valve amplifier which
produces higher distortion as the
output increases. So, at high output,
the distortion of Assistent 100 is
apparently much lower than the
general valve amplifiers. To respond to
the trend of environmental protection
and energy saving, AudioValve for the
first time applies Intelligent Power
Management on Assistent 100 to
control the electric current required by
the amplifying circuit, enabling the
optimal efficiency between the power
supply input and the power output
without influencing the sound
performance at all.
High heat has always been a fatal
weakness for 6C33 valve amplifiers.
Therefore, the valves are always
exposed for air cooling. But, Assistent
100 adopts a nearly closed box
structure, then how to resolve the
problem of heat dissipation? The fact
is that it’s quite easy by using the four
fans. Two of them are installed on the
left side of the box and started when
power on. The other two will work
synchronically only if high power, and
will stop when the gauge light is off.
You don’t need to worry about the
impact of fans on the sound quality at
all. We cannot hear any noise from the
fans even when we listen closely. It’s
evident that Audio Valve employs highclass
The “cathode coupling output circuit”
always used by Audio Valve is also
applied on Assistent 100. Unlike the
general valve amplifiers whose power
valve plate is connected with the
output transformer, the output
transformer of Assistent 100 is
connected with the cathode of 6C33,
which results in the amplification
factor being 1. So, much higher
amplification should be added on the
front end to obtain sufficient gain. On
the front end of 6C33, AudioValve uses
two EF86, two CC82 and two QQE
03/12 for primary amplification, phase
splitting and driving. Though
complicated, this can be aimed to get
the most stable working state.
Fairly soft, beautiful and
This time, we experienced on the site
Assistent 100, the “Top-level Special
Edition”. It’s specially designed for
Taiwan market. And the sales agency
particularly asks the factory to set the
acceptable input voltage range to ±
5%. If the voltage is out of this range,
Assistent 100 cannot be turned on. To
better enjoy the beautiful sound of
Assistent 100, we suggest you adjust
well the power supply beforehand. I
have already heard of the sound quality
of Audio Valve amplifiers, but this time
we used the valve amplifiers I’ve
never listened before. My first concern
is whether Assistent 100 still retains
the beautiful sound quality as
consistently produced by Audio
Valve? We played the third song
“Times of Your Life” in Joanna Wong‘s
new album “The Adult Storybook”.
Upon hearing her voice, at once I felt
quite relieved. The sound from
Assistent 100 is fairly soft, beautiful
and comfortable. It has all the flavor of
valve amplifiers, and, besides, has
very good resolution. The sound of
piano, guitar and string instruments feel
very exquisite and gentle. It is of high
fidelity and excellent resolution.
Moreover, the background is
exceptionally pure and clean. Joanna’s
voice has no much exaggeration, and
neutrally and directly passes to my ears.
You can even hear each tiny element in
the sound when she sings lightly,
without any careless feeling given by
common high power valve amplifiers.
Rich tone variety
Then, listen to the first song I Love You
Porgy in the “Joshua Bell at Home with
Friends”. The piano touch key at the
right start is quite clear and full, like a
real acoustic grand piano in front of my
eyes. Bell’s violin has a strong flavor of
wood, presenting a noble and dignified
taste. The trumpet played by Chris
Botti is quite smooth and tender, like
feeling the silky velvet. All these prove
that the sound quality presentation of
Assistent100 is of superior level.
Coming to the melodious violin playing
at the beginning of the second song, we
can sense that the rich overtone
structures and the end-rhyme is fairly
charming so that the sound even at the
high position is not irritating but naturally
extending upward. Through Assistant
100, the abundant tone variety created
by Bell is just like Leica camera
displaying rich tones and appears
versatile, with awesome beauty and
fidelity. When listening to this album, I
even particularly turn up the volume to
check whether Assistent 100 can really
maintain the low distortion even at
greater output. Amazingly, no matter
how big the volume is, I didn’t feel any
“noisy” sound or “dry” musical quality I
heard from other general amplifiers.
Instead, the whole listening experience
is quite smooth, full of sweet taste and
moisture, which is indeed rarely
Low frequency of abundant
In the new album promoted by RR,
Britten’s ORCHESTRA, the
performance of the orchestra presents a
very good sense of layering from near to
far, forming a fine musical picture woven
in silk. In fact, the low-frequency of
Assistent 100 is not too much, but it
has a perfect proportion with medium
and high frequency, with very good
layering. When the drum is being
beaten, the vibration of the drum head
can be heard quite clearly, with the
vibration wave lingering in the air. The
sound is cohesive without the
pressure feeling, which is the best
portrait of loose and comfortable
state. On the site, it works with the
highly efficient Dynavox GEM Opal
speaker (reviewed in the No. 160
publication), which better
demonstrates the loose and
comfortable feature of Assistent 100.
At the same time, the design of high
electrical current in Assistent 100 takes
under good control the 12-inch low
frequency woofer of GEM Opal. The
low frequency line ends very clean,
presenting an excellent transient state
between dynamic and static ones. In a
word, I think the sound of Assistent 100
is whole and comprehensive. It can
definitely pass the “Twenty Factors of
Stereo” with high scores.
Incomparable musicality
You may know the Buddhist word
“TiHuGuanDing (being enlightened)”,
but only few of you may know what
“TiHu” really refers to. Tihu is actually a
kind of finest cream repeatedly
extracted from the cow’s milk. As for me,
the sound quality of Assistent 100 is
the most wonderful “Tihu”, which, with
the balanced and exquisite overall
performance, makes the sound of
Assistent100 quite pleasant to hear,
even repeatedly. The stereo fans who
have listened to the high-power valve
amplifiers of AudiValve must know the
sound of such products is no never
coarse. It’s like a martial artist with deep
internal force, giving out exquisite sound
through a skillful way. It’s the same for
Assistant 100 using 6C33. Mr. Chen
from T&V told us he always got
indulged in listening to Assistent100 in
the audio-visual room for a whole
afternoon, forgetting the surrounding
world. Isn’t this the best evidence for
the incomparable musicality of Assistant 100?


user manual


1 review for Assistent 100 Mark – II

  1. Helmut Becker

    Helmut Becker (store manager)

    Jeg har i mer enn 20 år testet enormt mange forsterkere, besøkt Hi-Fi messer, andre forhandlere og importører, samt reist over hele Østlandet og deler av Vestlandet og hjulpet folk med å bygge opp komplette anlegge, eller forbedre eksisterende anlegg. Så noe har jeg i hvert fall å sammenligne med.

    Audio Valve Assistent 100 Mk II vil appellere til deg som IKKE vil ha flere store transistorforsterkere, men være sikker på at du kjøper en forsterker som først og fremst tar vare på de musikalske kvalitetene, men SAMTIDIG presenterer musikken med alle detaljer og et raffinement, som gjøre at du kanskje reiser deg i stolen i ren ærbødighet over hva musikerne presenterer.

    Ren nytelse!

    Ikke lenger glassaktig klang på kvinnestemmer og metalisk lyd fra diverse instrumenter.

    Mange forsterkere som har varm lyd, har gjerne andre svakheter, som at musikken virker tammere, kjedelig og med utflytende bass.
    Nei, Assistent 100 Mk II får musikken til å leve.

    Selv på litt middelmådige innspillinger er selve formidlingen av musikken engasjerende og gir en indre nytelse.

    Ytelsen på 2×120 w bidrar til at du ikke trenger spesielt lettdrevne høyttalere til denne forsterkeren.

    På tirsdag hadde jeg besøk her på mitt kombinerte kontor og demorom i Krokstadelva av en kunde som hadde kjørt helt fra Grenlandsregionen og hit.
    Han har lang erfaring med Hi-Fi produkter og har hatt mye fint utstyr. Men slik han beskrev det han hørte her, vil jeg tro, at han nå fikk noe å tenke på.

    Jeg kommer til å ha med meg denne forsterkeren til Gjøvik, så har du anledning bør du ta turen innom mellom kl 11,00 og 14,00 nå på lørdag den 19. januar.

    Om du bor langs veien mellom Drammen og Gjøvik, eller i Mjøsregionen – og gjerne vil prøve denne forsterkeren hjemme i ditt eget anlegg, bør du kontakt meg snarest på e-post: eller ringe meg på 92 89 57 73.

    Dersom du bor et annet sted i landet og ikke har anledning til å høre denne forsterkeren på Gjøvik, vil jeg på det sterkeste anbefale deg å besøke mitt kombinserte kontor og demorom i Krokstadelva utenfor Drammen.

    Her tar jeg i mot kunder både på dagtid, kveldstid og i helger. Så bare sende en e-post til meg på: og foreslå en dag det passer for deg. Så skal jeg sette av god tid til deg.

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