I do not really know why I have driven this project forward not many years ago. I think I was busy with a lot of other developments as well as trivial things like earning money for example. Perhaps mine is simply unaware that their headphones and amplifiers are experiencing a large hipe for years.
Anyway, the beginning of 2014 resulted in discussion with colleagues that I would have some products in my program that seemed almost ideally suited to put with the requirements of the headphone market apart.
No sooner said than done.
First, the IMPEDANCER befell a technical revision, it was expanding the range of applications for the RKV Mark 2 significantly, especially as a female teflon connector for headphones STAX was inter alternates. The bias voltage was obtained from the voltage signal, so no external power supply is in advance required. VERTO was born and VERTO laid the foundation for all further considerations in this topic, culminating now in the product with the name LUMINARE.
I can excuse at this point only for me actually that I started so fundamentally important development in the headphones sector so late (I slept through) and had thus deprived the public a potentially groundbreaking product. Many of you have their money invested now possibly poorly because there was nothing else on the market – that really am sorry.
But now back to Luminare.
It seemed to me as the basis for such a project, the OTL circuit of the RKV downright awesome. First, they had already claimed stable over decades in the market and on the other they had characteristics that should prove to be just the Luminare be extremely efficient and more full development. There would be for example the superior damping factor, low internal resistance, high bandwidth, and not least the low harmonic distortion he always particularly distinguished the RKV.
Now it was in principle “only” about output transformers so be interconnected in the OTL principle, which can be obtained if possible upright with transformer all these benefits. The advantage to couple a outpt transformer to an OTL circuit is that the repercussions and influences on the circuit itself ( either headphones or transformers ) are considerably lower. And this brings a projection on presence in the music, the listener will appreciate very quickly.
Everything else on this project was for me then just “routine”. A new circuit board develop, expand the circuit according to the light of all electro – physical principles and my over 45 years of experience in this topic.
And ladies and gentlemen, I am more than satisfied with my work, I hope you are there also – Helmut Becker
The initial work on amplifiers for electrostatic headphones, ranging in AudioValve back to the year 1984. For this period Becker developed a stereo signal modulated constant current source realized with tubes of the type 6CK4, Headhpone for Jecklin float (s. diagram). The principle worked very well and was sold at the DIY scene and also submitted for a patent. Becker had at that time, however, his entire creative force for the development of medical laboratory equipment for hematology, to determine the clotting times of blood plasmas such as Quick, PTT, AT-III, etc. dedicate came across Europe in every hospital to use (blood coagulation ball – method). For this reason, the passion for audio electronics unfortunately had to again and again stand back and “ESV” never went into production. But documents from this early history prove that Becker with completely unorthodox creative solutions to progressive ideas for converting audio tube concepts – also worked for electro static Headphones – and since everything to be able to take park in claim without a university measuring instruments. So it’s not that Becker has dealt only recently with the topic headphone amplifier, but for over 30 years.
power consumption: 60 VA nominal – 100 VA full load
power switch ON / OFF
auto gain switch for STAX
2 x switchable inputs 1+2
input 1: set XLR jacks with parallel RCA
input 2: RCA only 2 pair jacks as signal IN / OUT loop
1 x RCA PRE – OUT, 20 :1
2 x NEUTRIK Combo jacks 6,3mm + XLR
1 NEUTRIK 4 pin headphone jack
1 x STAX Teflon female connector
1 x ALPS Potentiometer
1 x 3 mode switch, LI – OTL – STAX
and more …
|LOW IMPEDANCE mode: – test load 32 Ohm:
( max: 4,5 watt power output / ch. )
|OTL mode: test load 220 Ohm.
( max: 3,5 watt power output / ch. )
|STAX mode: ( auto gain control )|
|1 Khz – 0,1 watt – 0,06 %
1 Khz – 1 watt – 0,15 %
1 Khz – 4,5 watt – 1 %
10 Khz – 0,1 watt – 0,06 %
bandwide: 15 – 100.000 Hz
min.: load 3 ohm ( 3 watt / 0,33 watt – 0,15% )
|1 Khz – 0,1 watt – 0,015 %
1 Khz – 1 watt – 0,08 %
1 Khz – 3,3 watt – 1 %
10 Khz – 0,1 watt – 0,08 %
bandwide: 12 – 150.000 Hz
max. load 2000 ohms
|bandwide: 15 – 150.000 Hz
bias: 300 + 580 VDC
Vpp: max: 1700 VAC
gain: 34,5 dB + 15,5 dB = 50dB
Description of some technical details …
The output impedance at Luminare with negative feedback (physical concept: closed loop) is defined as follows.
The control is based on the principle of negative feedback of the open loop gain ( 133 dB ) of the amplifier. However, since there is
a closed loop. Dynamically because the amplifier tries to keep active voltage at the output losses in upright because he
continuously compares its actual value (feedback) to the desired value (signal) and continuously readjusts addition,
through the entire range.
Example: The OTL mode provides Luminare 1V without load resistance and 0.998 V at 60 ohm load resistor.
From these data you calculated easily approximated the output impedance of the amplifier for this load resistance 0,12 ohm.
The fact of wanting to determine the output impedance by incorporating the tubes, is simply nonsense.
It’s not the tube determines the output impedance, only the overall OTL concept. of the circuit is the basic for the definition of the
output impedance of this circuit concept – this applies equally to RKV 2 + 3 and Luminare. The output transformer is not
part its gain loop. Who is interested in the incoming circuit design, can read my patent in 1982.
|This LED indicates when the bias voltage built up for the Stax headphones and stable.||If you turn on the amplifier, reducing the volume and wait until this red LED goes off. As long as this red LED seems light up, all outputs of the amplifier is short-circuited and thus protect the headphones when the amp load or un – load the internal caps. This is always the case when the amplifier ON and OFF switches.||The transformer was installed outside of the amplifier. This has the advantage on that the heat of the power transformer remains from the device and, second, that no stray magnetic fields cross the output transformer or the circuit board and modulate them. In addition, the transformer was covered with a layer of transformer sheet and thus absorbs stray magnetic fields. Then the transformer with a 2-component potting shed was in a metal cup.|