Mentor Monoblock 300B (Quad C-Core) Coming Soon!


The new Legend series: modestly priced, exceptional value & loaded with quality.

SKU: 300B-INT-MONO-1 Categories: , , ,


The new Mentor  Series Monoblock: modestly priced, exceptional value and loaded with quality. The sound is reserved for customers seeking zero feedback, single ended triode amplification! With both 8.5W and 20W versions available this product

ANK Audiokits

Birth of the Mentor MonoBlocks SET

The Mentor Series Monoblock Single Ended amplifiers employ a 6SH7 driver tube wired in a pentode configuration to successfully drive a Parallel or Single Triode 300B.

  • Single 300B Amplification 8.5W Single Ended
  • Parallel 300B Amplification 18W Single Ended

The sound of SET in a compact chassis

The Mentor Monos  deliver that gorgeous zero feedback Single Ended triode sound. Simplicity is the key to the circuit of the amps and targeted at higher efficiency speakers they provide remarkable sound quality to rival the best of SET amplifiers yet do this at a real world price. A remarkable achievement!

. They are a pure power amp with approximately 2V sensitivity and ideal when mated with our L3 L4 L5 Pre-amplifiers. The classic 5U4G rectifier tube smooths the AC for the power supply. DC filaments and a large 300MA power supply choke installed inside the chassis assures dead quiet operation!

Copper insert plates

The Legend Monoblocks now ship with the new copper insert plates for both single and parallel 300B configurations! In addition we have an option in silver which also looks great.

Along with that, we have standardized on the new high quality black teflon valve bases for both 4 and 8 pin. The sockets are the same physical size and are keyed so that the tubes can only be inserted the correct way.

The Audio Note traditional venting pattern is used. The plates are coated in a high gloss clear coating so they are protected from scratches and will never change color.

Building your Legends in easy to follow steps

We provide easy to follow, step-by-step wiring instructions with our assembly manuals. Our kits come with everything you need to produce a fully working Legend SET amplifier that will provide year of musical enjoyment Just a soldering iron and a table, and you are ready! Below is an overview of the Legend assembly process.

Mentor Monoblock_5small

The Choke and Heat Sinks

Start by mounting the CHOKE inside the unit and use countersunk screws to secure to the chassis. Once mounted you then will install the Filament board heat sink and power supply ceramic tag strip inside the chassis.

Mounting the Transformers

Install the large grommets for the chassis and mount the Mains and Output transformers on the top of the chassis. You will start to see the amplifier taking shape! Once the mechanical install is completed you install the power supply valve base & external capacitor 100+100. The IEC section is nice and easy with pre made twisted cables – follow the expert wiring diagrams to layout your power supply wiring.

Mentor Monoblock_5small

The Filament Board

Then you start working on the Filament Board – this section takes AC from the Mains and converts to DC for the 300B filaments! Finally you can start working on the Front insert plate that you can do outside of the amplifier – once this is complete, you install the insert plate inside the chassis mounted on the tang strips and prepare for the final inter-wiring steps – connecting Filament and grounds & HT!

Circuit Testing

We do a series of ohm checks to make sure all the wiring checks out. Follow our power up guide which takes you step by step through the process and ensures filaments start and HT voltage check out. With a few DC voltage checks followed by an AC signal amplification test you can be assured your amplifier is ready to go. Any problems during the build and you can contact us for support and debug assistance.

The Circuit

The Legend Power Supply has been designed for ultimate sonics – lightweight and snappy! Our new T-195 Mains transformer supports taps for both single and parallel configurations.

The classic 5U4G tube rectifier circuit sees a 30uf Mundorf PS cap mounted inside the chassis along with a monster 300ma choke to smooth the rectified AC. A single 100+100uf (35mm diameter) Mundorf capacitor stands solo at the back of the chassis and steps the voltage down for the 6SH7 driver tube – the ultimate in simplicity!

Two .47uf film caps are installed inside the chassis along with about 12 resistors. The 6SH7 is configured in a pentode configuration in the Legend Monoblock. Our Expert Wiring Guide shows you how to build your Legend like a pro!


Power 8.5 Watts Class A (Single 300B)
18-20 Watts Class A (Parallel 300B)
3.5 Watts Class A (Single 2A3)
18-20 Watts Class A (Parallel 2A3)
Output Tubes 2 x 300B or 4 x 300B
1st Stage Gain 6SH7
Rectifier Tube 5U4GB
Front Insert Plate Solid Copper
Inputs 1
Outputs 1 x Stereo Pair 4, 8 ohms
Recommended Speakers min 88dB
Width 24.5cm
Height 20.5cm
Depth 38cm
Weight 25kg
Chassis 3mm Aluminum with Black Powder Coat

Parts Compliment includes:

  • TAKMAN 1W Resistors
  • Mundorf 100+100 & 30uf 600v Power Supply Capacitors
  • Panasonic FC series cathode caps
  • PTFE Silver Plated Hookup Wire
  • Shuguang 300B Tubes
  • Audio Note Speaker Posts & RCA’s
  • Ceramic Hard-wiring Posts
  • Solid Copper Insert Plate

Additional information

Mentor 300B Monoblock

Mentor SET MB 8.5W (Pair), Mentor PSE MB 18W (Pair)