Mason Fleck
Published © GPL3+

2x260W@4ohm Audio Amplifier

A class D audio amplifier based around a TPA3255 board with features that include preamps as well as balanced and unbalanced inputs.

AdvancedWork in progress10 hours169
2x260W@4ohm Audio Amplifier

Things used in this project

Hardware components

3e Audio TPA3255 2x260W Amplifier
This was purchased through a group buy on www.diyaudio.com. It might not be available on eBay now, depending on when you're reading this.
×1
Connex Electronic SMPS600RS
This is the main power supply. Connex Electronic sells this power supply in 120V or 230V AC versions and with many different output voltages. The 48V output version is closest to the 50V the main amp can accept.
×1
Mean Well PD-2515 +/-15VDC Power Supply
This is the secondary power supply for the preamps.
×1
Douk Audio NE5532 Preamp
This is the preamp for unbalanced input.
×1
AD828 Preamp
These are preamps for balanced inputs.
×2
Texas Instruments LM4562 OpAmp
This OpAmp replaces the NE5532 OpAmp.
×1
HiLetgo 12V 8 Channel Relay Module
This is a relay module for the balanced inputs.
×1
HiLetgo 12V 4 Channel Relay Module
This is a relay module for the unbalanced inputs.
×1
10 Position Screw Terminal Strip (45A)
This is a terminal strip for the power side
×1
12 Position Screw Terminal Strip
This is a terminal strip for the signal side. FYI this is a pack of 5 strips. I only used one.
×1
NKK HS12 2N Rotary Switch
I did not include a buy link for this because it is no longer available from the seller I bought it off of on eBay, and because I really do not recommend using it in this project. See my notes for details.
×1
NKK Switch Knob (AT431)
This is the knob I used for the rotary switch. Anything much smaller would be very difficult to turn.
×1
10mm M3 Standoffs (100 Pack)
You might want to use slightly shorter standoffs, but it's really up to you.
×1
M3 Washers (100 Pack)
Here are washers for the standoffs.
×1
M3 Screw (Kit of Assorted Lengths)
The length you use will depend on the thickness of the bottom and side panels of the case.
×1
Hook Up Wire Kit, 22 AWG
Hook Up Wire Kit, 22 AWG
These are for signal side. I highly recommend using multiple colors of wire and keeping the purpose of each color decently consistent.
×1
Hook Up Wire Kit, 18 AWG
Hook Up Wire Kit, 18 AWG
These are for power side. I highly recommend using multiple colors of wire and keeping the purpose of each color decently consistent.
×1
Rocker Switch, SPST
Rocker Switch, SPST
Any SPST switch will work as long as it can handle ~6-8A @ 120VAC or ~3-4A @240VAC (if don't live in North America).
×1
Power Entry Connector, IEC Appliance Inlet C14 with Fuseholder
Power Entry Connector, IEC Appliance Inlet C14 with Fuseholder
This is a power socket with a fuse holder.
×1
Mains Power Cord, 16 AWG
Mains Power Cord, 16 AWG
Any C14 Power cable works.
×1
FUSE, QUICK BLOW, 8A
Any 8A, 5x20mm, quick blow fuse will work.
×1
Speaker / Loudspeaker Audio Connector, Chassis Mount
Speaker / Loudspeaker Audio Connector, Chassis Mount
Any 2x sets of binding posts work.
×2
Speakon Connector 4-pole
Any 3x 4-pole Speakons would work.
×3
Rotary potentiometer (generic)
Rotary potentiometer (generic)
3 total pots are needed: 1x 100 Ohm Linear taper, single pole AND 2x 1 kOhm Audio/log taper, two pole.
×3
Axial Fan, 12 VDC
Axial Fan, 12 VDC
This may not be needed unless you intend to run the amp at full power for long periods of time in small spaces. Any 12VDC fan will work. I used a 120mm, but you could probably use a smaller one.
×1
Through Hole Resistor, 33 ohm
Through Hole Resistor, 33 ohm
This is to tone down the fan's power consumption.
×1
XLR Connector, Chassis Mount
XLR Connector, Chassis Mount
Use 2x XLR's for the balanced inputs.
×2
3.5mm TRS Chassis Connector
Any 3.5mm (1/8") TRS chassis connector will do.
×1
1/4" Shaft knob
Any 3x 1/4" shaft knobs will work. I have 3 of the same for the 2x balanced pots and the fan control pot.
×3
6mm Shaft Knob
Any 6mm shaft knob will work. This is for the unbalanced preamp.
×1
3PDT On-On Toggle Switch
A 3PDT on-on toggle switch for switching between balanced and unbalanced. FYI the toggle in the picture on Newark is wrong (It shows a DPDT).
×1
Female/Female Jumper Wires
Female/Female Jumper Wires
These are optional, but they can be helpful with connecting some of the boards.
×1
2x6 Pin Header (5-pack)
Digilent 2x6 Pin Header (5-pack)
These are optional, but they can be helpful with connecting some of the boards.
×1
Quick Disconnect Terminal, Female Quick Disconnect
Quick Disconnect Terminal, Female Quick Disconnect
These are optional, but they can be helpful with connecting some of the boards.
×10
Ring Tongue Terminal, M6
Ring Tongue Terminal, M6
These are optional, but they can be helpful with connecting some of the boards.
×24

Hand tools and fabrication machines

Soldering iron (generic)
Soldering iron (generic)
Wire Stripper & Cutter, 30-10 AWG Solid & Stranded Wires
Wire Stripper & Cutter, 30-10 AWG Solid & Stranded Wires
Any wire strip/crimp/cut tool will work as long as it can handle 18 AWG and 22 AWG.
Multitool, Screwdriver
Multitool, Screwdriver
Any screwdriver will work, assuming you have the correct bit.
Mastech MS8217 Autorange Digital Multimeter
Digilent Mastech MS8217 Autorange Digital Multimeter
Any voltmeter/ammeter will work.

Story

Read more

Schematics

Diagram/Layout

I'll add a better diagram in the future. I had already made this diagram.

Credits

Mason Fleck

Mason Fleck

1 project • 2 followers
I enjoy building electronics such as computers, audio amps/systems, and some random projects. I am currently majoring in CE & EE at Mizzou.

Comments

Add projectSign up / Login