CLASS A HYBRID - tube/fet AMPLIFIER
Heros is a very unusual hybrid amplifier marrying old concepts with the latest technology.
Tube amplifier architecture with the simplest signal path
Transformer coupled input and output
MOSFET output devices
Silicon Carbide diodes in power supply
Silver input transformer
Presettable speaker impedance
Our favourite 6N6P tube used
Fully balanced differential operation
RCA and XLR inputs
Compact chassis built like a tank
100W Class A power output
DC-coupled, no capacitors in signal path
Choke filtered power supply
Heros is like no other amplifier ever made as it has a single differential DC coupled FET/Tube stage working like a single super tube. This DC coupled cell is loaded by a low impedance push-pull transformer helping improve the efficiency to almost double that of a normal Solid State Class A designs. The output transformer blocks DC on the output and presents many other benefits by isolating EMI/RFI, scaling down the output voltage (reducing residual noise) and protecting the output from any power supply noise by canceling it by the nature of it's differential operation.
Тo guarantee a fully differential architecture we split the phase with the input transformer and sum it back up with the push-pull output transformer. This solution completely floats the the gain cell between the two transformers isolating it from any external influences making Heros immune to the influences of its environment.
The power supply uses high voltage Silicon Carbide diodes followed by a filter choke preventing any switching noise from reaching the output stage. The result is an amplifier free of grain and fizziness or screaming intermodulation, giving new meaning to transparency and tone density. We use our beloved 6N6P as the base for the proprietary DC gain cell, a recognised audiophile performance tube. To keep all at this level we chose a silver wire permalloy input transformer and the highest grade custom toroidal output and power transformers.
Operating all devices in class 'A' produces a fair amount of heat, so to handle that the Heros' chassis itself is a heat sink. It is still the most compact 100-watt class A solid state amplifier available today.The chassis is designed not only to cope with the heat produced by the components but to provide a vibration-free structure to house them. Heros shares it's chassis design with our other hybrid power amplifiers - Teres, but all similarity ends there. Heros can handle any speaker giving it a new voice.
SILVER ANODIZED ALUMINUM
BLACK ANODIZED ALUMINUM
First introduced in 2012 as the market demanded a no glass tube power amplifier the Heros was designed as a direct alternative to the emblematic Spartacus. Same form factor and aesthetic values. It featured a 5687 input tube driving a cascoded FET follower via capacitive coupling with stacked power supplies.
Essentially an exemplary differential tube amplifier with solid state pentodes.
While working on the move to the Teres size chassis our new DC coupled circuit was developed and implemented taking the 2020 Heros Mk2 to a completely new level.
The original Heros still holds its ground and should be a tasty grab if it ever reaches the second hand market.