Abacus Ampollo Dolifet silber - Neuwertiger Rückläufer
Abacus Ampollo Dolifet silver - Like-new return
It is a customer return within the 14-day right of withdrawal.
The device is technically and visually flawless and originally packaged.
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- Reference amplifiers in Dolifet technology (Drain-Output Load-Independent Field Effect Transistor)
- Usable as a power amplifier or integrated amplifier
- Cinch and XLR input switchable
- IR remote control in full metal housing (ON/OFF, Volume, Source selection)
Elaborate and ultra-stable full aluminum housing
Sophisticated protection mechanisms
Inrush Current Limiting (Soft-Start)
Overload protection (automatically reduces the volume when triggered)
DC offset protection (protects the speakers from dangerous direct current, even at the moment of switching on)
Temperature monitoring of heat sinks and power transformer
Intelligent power supply with actively controlled power rectifier for the power section and separate power supplies for low-power and control sections
Hand-selected, parallel power MOSFETs in the output stages (4-fold parallel connected)
Switchable operating modes
Stereo
Mono bridged
Mono Bi-Amping
Left and right channel mixed or discrete
Resistor ladder potentiometer with 256 steps, featuring precision resistors for absolute channel matching and microcontroller control for perfect logarithmic regulation curve
When operating multiple devices (e.g., as mono blocks or for multi-way activations)
Remote control of multiple amplifiers synchronously, because functions are not switched but selected directly
Synchronization of volume controls
alternative setting of the volume via internal jumper
Standard in silver anodized housing with black print or black anodized housing with silver print
Dolifet - Dolifetter
First introduced with the ABACUS 60-120D, the Dolifet circuitry has now found its way into the
meisten amplifier and active speaker products maintained. It combines the load independence and
extreme control, which all amplifier circuit variants at ABACUS claim for themselves with even
greater bandwidth, stability, and low distortion. With the Ampollo, the speakers are connected to each channel
at the drain outputs of a total of eight power MOSFETs, four for the positive and four for the
negative branch. So, a total of 16 output transistors work here. They are precisely matched to each other.
"matched" and can jointly handle peak currents of many tens of amperes.
Over four special connectors per channel, it can be checked during the final inspection whether all FETs
correctly collaborate and truly distribute the effort evenly among everyone. For a
sufficient power transport, all critical traces are as large as possible
executed and additionally generously reinforced with tin on the underside of the boards
Power supply with spacious tanks
For an amplifier with extreme impulse response, a well-buffered power supply is essential because
for the crisp, short-term performance peaks, it draws energy from its "short-term storage," the
Electrolytic capacitors, or for short: electrolytic caps. These electrolytic caps provide the energy at the moment when the sine of the
Stromnetzes its performance minimum passes through, to then be recharged at the maximum. So that this
Charging as evenly as possible, but discharging into the final stage as quickly as needed
required can happen, the supply voltage passes on the way from the rectifier to the
Amplifier a three-stage filtering. First, it is buffered in 16 small capacitors, each with 220µF,
passes through one of four toroidal chokes per page and supply half, so that large
Stromspitzen cannot affect the transformer and the rectifier, in order to then in the 16 large
Capacitors with a total of 160,000µF charge capacity for the respective needs of the power amplifiers
to be ready.
Clever Rectifier
Behind the 600VA toroidal transformer optimized for audio devices is a rectifier with brains. In
conventional power rectifiers have a voltage drop of about 0.7V across all diodes. This is indeed
not much, but with the sometimes high currents that flow through, a considerable
Power loss occurs. The threshold of these 0.7V also leads to the rhythm of the mains frequency to
"hard" switching operations in the diodes and thus also interference signals at high power levels. In the smart,
aktiven Gleichrichter des Ampollo werden statt einfachen Dioden MOSFETs, also schnelle, leistungsstarke
Transistors cross-connected by a special controller in sync with the alternating current.
These transistors are selected to handle maximum power with minimal losses
can. For the symmetrical supply voltage and to make the two amplifier channels as independent as possible
voneinander zu versorgen, enthält die Gleichrichterplatine diese Anordnung insgesamt viermal. Also vier
Controller and 16 power MOSFETs.
| This circuit board is, so to speak, the heart of the amplifier, because from here the power amplifiers are provided with their | Leistung supplied. Additionally, it takes over the central distribution of the mass potential, so to speak, the |
| electric reference line, to which all circuit components in signal processing are oriented. | Mathematical Volume Control with Connections |
| If the Ampollo is to be used as a full amplifier, a precise and high-quality | Volume control is particularly important. Here, a development for the Preamp 14 is used, which |
| dort inzwischen zum High-End-Feature gemausert hat: the resistance ladder potentiometer. Here, the | precise ALPS rotary potentiometer not used directly for the music signal, but by a microcontroller |
| abgefragt, um paarweise Festwiderstände zusammenzuschalten. Hierdurch wird absoluter Kanalgleichlauf, | also ensures level equality between left and right. Additionally, the controller almost over the |
| gesamtem Regelbereich ein perfekter, logaritmischer Verlauf der Lautstärkeänderung erreicht. Die Querydes Potis erfolgt mit einem 8-Bit-Analog/Digital-Wandler und der Rechenchip "maps" diesen Wert auf eine | 10-bit relay chain. This allows the volume to be adjusted in 256 precise steps. |
| Over a special connection on the back, the control signal of this circuit can be | lead out and thereby control one or more additional Ampollos. If an amplifier is set to "Master" and |
| the others set to "Slave", allowing multiple Ampollos in a bi-/multi-amping setup | or adjust the volume synchronously in a multi-channel system. |
| For operation as a power amplifier, when the volume is already set on the source device or preamplifier | will be, the gain factor can be set to one of 5 fixed values via internal jumpers. |
| Size/Property | Value |
| Power connection: | 230V AC, cold device connection |
| Power consumption, automatic: | < 0.2VA |
| Power consumption, idle: | approx. 50W |
| Power consumption, maximum: | approx. 750W |
| RMS | -Performance per Channel: |
| approx. 300W at 4Ohm | Music performance per channel: |
| approx. 350W at 4Ohm | Loading capacity: |