APL Gravitas NB-Master og den ene powerconverteren.
Vis vedlegget 228110
Mvh.
SAL
Jeg har et spørsmål til hva denne forsterkeren egentlig er, fordi det verserer så fancy navn på de forskjellige delene. For meg ser det ut som en forsterker med rør i forforsterkningen og transistor i effektdelen, altså det vi vanligvis kaller en hybrid, men her snakkes det om power converters osv.
Kan noen forklare?
R
Hei Roger!
Alex forklarer litt her!
The middle Control unit is the "brain" of the amplification system with a master
microprocessor inside that monitors and controls everything. The two units you
see to the sides are the unique IGBT Balanced Power current converters that are
also microprocessor controlled and slaved to the master control unit. The system
can be expanded to 4 or 6 power converters total (2 or 3 per channel) when more
power is required for bi-amping or tri-amping.
As shown on the picture, with 2 power units, the power rating of the system is 350W per channel at 4
Ohms. Expanding the system with more power units allows for driving more speaker
modules with ease. For example, with our Gravitas NB-Master speakers, you can
have two power converters per channel - one powering the sub-bass and the other
one powering the rest.
The Control unit shown in the middle is remote controlled and has three single ended
inputs and one balanced. The inputs are routed to the unique H-Attenuator with precision steps ranging from 0.5dB to 1dB
per step. The gain is provided by a Single Ended tube stage featuring 6SN7
driver and 2A3, 45 or 300B output tubes (switchable). The tube stage is
transformer coupled to the Balanced power converters using custom Lundahl audio
transformers.
Since the Control unit is dual mono configuration with no
large power transformers inside, the power for the tubes is provided by the
current converter modules for each channel. There are 3 custom made umbilical
cords connecting the Control unit and the Power unit (total of 6). One signal,
one power and one control per channel.
Please do not confuse the HA-M
with a tube preamp (or amp) driving two solid state monoblocks! Every power
amplifier has a voltage gain stage in order to amplify the small signal coming
from your preamp (or any source) and a power stage so it can drive your
speakers. The Control unit of the HA-Master provides all the voltage gain, while
the balanced Power converters provide the ample current needed to drive the
speakers and have no gain. In other words, the HA-Master system is an unique
modular integrated power amplifier.
The HA-Master is an all-hand-made,
cost-no-object boutique, that offers unparalleled features and sound quality,
combining the sound of Direct Heated Triodes with an amazing power output
capable of driving the most difficult loads/speakers. The HA-M has no Negative
Feedback and no capacitors on the signal path. It is designed for the most
enthusiastic audiophiles who cannot settle for anything else but the best.
The Balanced IGBT voltage to current converters are linear, not switching mode
Class-D. Specially designed for linear audio applications power IGBTs are used
in complementary configuration. The Isolated Gate Bipolar Transistor is a
combination between MOSFET and BJT and brings the best of both worlds, in my
experience.
There are 4 separate IGBT modules in each power converter
working in parallel/bridged configuration. 1+1 in parallel and 2+2 bridged. We
are talking about nearly 44 Amperes peak output current.
Each power
converter and the power supplies are individually tracked by the built-in
microprocessor which is "reporting" to the main microprocessor in the Control
unit.
The power supply in each power converter uses 2 large 500W
custom-hand-made transformers for the total of 1000W. The AC power is rectified
by ultra-fast Schottky diodes with ultra-soft recovery. The DC power supply is
choke filtered and has nearly 470,000uF capacitor bank reserve.
The two main power converter units that come with the HA-Master system also include the
power supplies for each channel of the main Control unit, which is a true
dual-mono design and configuration. This completely eliminates not only channel
crosstalk but also electromagnetic interference (EMI) from large transformer
magnetic fields to which the tubes and the audio output transformers are very
sensitive. Simply, there will be no hum.
Best
Alex Peychev
Mvh,
SAL