Made to order
DIY kit
For those comfortable with soldering and using a multimeter. Includes the PCB, components, heatsink, mounting hardware and instructions.
Choose a DIY kit βAmplifier
AMP-KIT 4330
MK II
A proven circuit, built in Russia
A DIY kit or ready-adjusted amplifier module based on Alexey Nikitin's circuit.
An open schematic, clear instructions, tested components and support for your first power-up. Build your amplifier yourself or choose a module we assemble and adjust before shipping.
- Warm sound MOSFET transistors
- Class AB push-pull output stage
- Protected soft start + DC protection
- Build it yourself or order it assembled
Heatsinkβ€ 1.5 Β°C/W Β· thermal paste included
Short signal pathTL074 op-amp Β· no unnecessary signal stages
Output stageN-channel MOSFETs Β· IRL540 / IRL2910
Power supply filter13,200 Β΅F per channel
Protection Β· relaysoft start + DC protection
Delivery and payment terms are confirmed before orderingComponent compatibility consultationAssembled modules tested before shippingSupport for your first power-up
Gallery
Explore the PCB and assembled module
Actual photographs of the AMP-KIT 4330 MK II
Build options
Choose your format
Build your amplifier yourself or receive an assembled and adjusted module.
Preorder
Assembled and adjusted module
For those who want to get straight to connecting and listening. We assemble the module, set the bias current and test the amplifier and protection circuits.
Choose an assembled module βWhat you will need
What is included and what to buy separately
AMP KIT is an amplifier module or a kit to build one. A complete amplifier also needs a transformer, enclosure, volume control or preamplifier, input connectors and speaker terminals.
β Included with AMP KIT
- Amplifier PCB
- Components for your selected version
- Aluminium heatsink
- Mounting hardware and thermal paste
- Documentation: schematic, instructions and parts list
- Speaker protection and power supply already on the PCB
Required separately
Transformerrequired
Toroidal, 2Γ25β30 V, 120β150 W. We recommend Torel.
Volume control
47β50 kΞ© potentiometer (Alps), Nikitin's volume control or your preamplifier.
Terminals
RCA input connectors and speaker output terminals.
Enclosure
Ventilated aluminium enclosure. Do not use a sealed enclosure without ventilation.
Configurator
Configure your kit
Choose the build option, output transistors and power supply capacitors. The summary shows your configuration and total price.
1Build option
2Output transistors
3Power supply capacitors
Documentation
Read the schematic and instructions before buying
Review the PCB, schematic and guide in advance to assess the assembly difficulty and see which extra parts you will need.
Assembly guide, PDF Assembly steps, parts checklist and bias current adjustment.
Download the PDF guide Why this circuit
The proven AMP-KIT 4330 MK II circuit, ready to build
A two-channel Class AB MOSFET amplifier with no unnecessary signal stages, carefully laid out PCB, speaker protection and straightforward adjustment. The mk II revision improves thermal stability and bass performance for DIY builds and assembled modules alike.
MOSFET output with current headroom
MOSFETs provide a smooth presentation and good load control. The sound also depends on the speakers, power supply, enclosure and grounding.
Short signal path
No unnecessary stages in the signal path, keeping potential sources of distortion to a minimum.
The mk II version
The mk II revision improves the output stage and thermal stability for more stable operation and tighter bass, while retaining the original's characteristic tube-like presentation.
Character
Sound character
Sound depends on the speakers, power supply, enclosure, preamplifier and grounding as well as the PCB. Your configuration makes a difference.
Soundstage Opens up with a suitable power supply and correct grounding
Dynamics Current headroom helps control the load
Vocals Presentation depends on the speakers, enclosure and preamplifier
Bass Low frequencies benefit from the right transformer and power supply filter
AMP-KIT 4330 MK II
Technical specifications
Output power and distortion
Output power (8 Ξ©)40 W
Output power (4 Ξ©)65β70 W
Distortion (0.1 Ξ©, bias current 100 mA)< 0,05 %
Frequency range3 Hz β 25,000 Hz, β1 dB
Channel separation> 60 dB
Signal-to-noise ratio> 100 dB
Output impedanceβ 0.1 Ξ©
Input impedance47 kΞ©
Input sensitivity400 mV for 40 W
Output stage operating mode
Amplifier classAB/A push-pull
Recommended bias current70β100 mA
Peak current> 18 A
Power supply
Supply voltage (AC)Β±25β¦Β±35 V
Transformer power120 W (for 2 channels)
Filter capacitance (per channel)13,200 Β΅F
Heatsink and cooling
Heatsink thermal resistanceβ€ 1β1.5 Β°C/W
Output transistor insulationceramic pads
Thermal pasteon both sides (included)
MountingM4 screw with an insulating sleeve
Dimensions, mm
Printed circuit board172 Γ 115 Γ 1,5
Heatsink172 Γ 40 Γ 50
Assembled unit172 Γ 155 Γ 50
Additional features
Soft start (turn-on delay)included
Protectionagainst DC at the output
Operational amplifierTL074
Output transistorsIRL540PBF (Vishay) / IRL2910PBF (Infineon)
Before the first power-up
DIY kit or assembled module β what to check
The kit has an intermediate difficulty level. If you are comfortable soldering and using a multimeter, follow the guide to assemble it. Choose the ready-made module to get to listening sooner: we handle adjustment and testing.
If you build it yourself
- βComponent values
- βElectrolytic capacitor and diode polarity
- βTransistor insulation from the heatsink
- βSpeaker output jumpers
- βTransformer supply
- βBias current
- βDC voltage at the output
If you choose an assembled module
- βVisual soldering inspection
- βPower supply check
- βBias current adjustment
- βSpeaker protection check
- βDC voltage at the output
- βHum check
- βShort functional test
Why AMP KIT
How AMP KIT compares with an unknown PCB or sourcing parts yourself
Review the schematic, kit contents and instructions before you buy. Components are selected for this amplifier circuit, and you can check compatibility before paying.
Unknown assembled module
- βUnknown circuit
- βComponent quality is hard to assess
- βNo clear support channel
- βPower supply, protection and enclosure often need reworking
Sourcing parts yourself
- βFind the PCB and components yourself
- βRisk of choosing incorrect component values
- βMore time spent selecting and checking parts
- βNo complete kit
AMP KIT
- βKnown circuit
- βComplete component kit
- βFreely available instructions
- βChoose DIY or an assembled module
- βSupport and delivery
Reviews Β· since 2013
What builders say
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Built it myself
Assembly took a few hours. The parts were sorted and the instructions helped me work through the process smoothly.
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Arrived quickly and safely
The kit arrived well packaged, with components organised into groups.
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Assembled module without hum
After connecting it with correct power and ground wiring, the module operates steadily with no noticeable hum.
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Help with the first start
If something does not look right, advice is available on connecting and adjusting the module.
Original customer review screenshots Β· Avito, Ozon and direct messages
Common concerns
Does the kit contain everything for a complete amplifier?
No. AMP KIT is an amplifier module or a kit to build one. The transformer, enclosure, volume control and terminals are selected separately.
Can I use any output transistors?
We recommend the tested IRL540 or IRL2910 options, as they affect the circuit's stability and operation.
Does the circuit need modifications to sound good?
No. The base circuit is already balanced. Modifications change the design and do not always produce predictable results.
Will there be hum?
Hum usually comes from the power supply, enclosure, grounding or input wiring rather than the PCB itself. We test assembled modules before shipping.
Should I choose a DIY kit or an assembled module?
Choose the kit if you are comfortable soldering and using a multimeter. For a quicker start with less assembly risk, choose the adjusted module.
Delivery, payment and support
Clear and predictable
Before you order, we will confirm the kit contents, component compatibility, delivery availability and the payment method available for your country.
Delivery
Contact us before ordering so we can check delivery availability and calculate the cost for your country.
Payment
Available payment methods depend on the country. We will confirm the options during a consultation before you order.
Support
We test assembled modules before shipping. For DIY kits, we help with assembly and the first power-up.
FAQ
Frequently asked questions
Can I build this if I have never assembled an amplifier before?
Yes, if you are comfortable soldering and using a multimeter. If you have little experience, choose the assembled and adjusted module.
What tools do I need?
A soldering iron, solder, a multimeter, side cutters and a screwdriver. Take care when mounting the transistors on the heatsink.
What else do I need to buy?
A 2Γ25β30 V, 120β150 W transformer, enclosure, input and speaker terminals, and a volume control or preamplifier.
Why is the transformer not included?
The transformer and enclosure depend on your layout, dimensions and mounting method. We provide the specifications and can suggest a suitable option.
What does adjustment of the assembled module include?
Checking the power supply, setting the bias current, testing speaker protection, checking output DC voltage and testing general operation.
Can I ask for advice before ordering?
Yes. We can help check transformer, enclosure and volume control compatibility, and explain the wiring.
How many channels are on the PCB?
Two channels on one PCB, with the power supply and protection on the same board.
Why use N-channel MOSFETs?
The N-channel MOSFET output stage uses local negative feedback for symmetrical control with opposite gate voltages. The symmetrical push-pull stage can operate in class B, AB or A.
Can I replace the output transistors?
We do not recommend substitutions. Requirements include a low gate threshold (logic level), at least 120 W power rating and at least 20β25 A maximum current. The kit offers IRL540 or IRL2910; the latter has a slightly higher power rating and price.
How can I check delivery and payment terms for my country?
Contact us before ordering. We will check delivery availability, its cost and the payment method available for your country.
Build the AMP-KIT 4330 MK II your way
Choose a kit to enjoy the assembly yourself. Choose an assembled module for a tested PCB and a quicker start.
The AMP KIT range
Other models
AMP-KIT 4330 MK II is available to order. For other projects, we can help select a format, enclosure and compatible components.
Assembled modulePreorder
AMP-KIT 4330 MK II MONO
A ready-assembled and adjusted mono module. Preorders are open β reserve yours.
Assembled modulePreorder
AMP-KIT 5350
A more powerful model in the AMP KIT range. Preorders are open β reserve yours.
Keep me informed about new models
We will let you know when new models, versions and accessories are available.
Any questions?
We will help you choose and check compatibility
Tell us about your build β we can advise on the transformer, enclosure, volume control and compatible parts before you order.