K5165 • Ultra Low Distortion Mk.3 135W Stereo Amplifier Kit


Cat. Page 221

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Discontinued product
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(Silicon Chip Magazine Mar-May 12) A stunning low distortion, high power stereo amplifier designed for superb performance in any 2 channel audio system. It delivers 135W RMS per channel into 8 ohms (or 200W RMS into 4 ohms). It utilises two of the K 5154 Mk. 3 amplifier module kits, plus power supply board, toroid, speaker protector kit, input and pre-amp boards - all supplied in a stylish 2RU all metal chassis. Silicon Chip have vastly improved the performance of the amplifier modules over the Mk. 2 edition. It features less than half as much distortion at frequencies of 2kHz or above. It also boasts much improved thermal stability & flatter frequency response. Produces incredibly low levels of distortion even at high power outputs. The class AB design runs much cooler than genuine class A amps, without sacrificing performance.

Important Note For Kit Buyers:
This product is supplied in component form and requires soldering, drilling, and assembly. We recommend users are familiar with at least basic electronic principles and have the ability to solder.


  • Professional quality screened front and rear panels
  • Class A-B design with a very low 0.0006% distortion
  • 135 Watts RMS per channel (8Ω)
  • Passive Heatsink cooling for silent operation
  • Heavy duty speaker terminals
  • Speaker protection
  • Case CNC machined and punched for accuracy and finish
  • Tough texture powdercoated chassis
  • Three RCA line inputs
  • Desk or rack mountable with included rack ears and handles
  • LED power meters
  • Toroidal transformer for reliability and performance
  • Internal spade and RCA connections, no need to solder wires
  • AC and DC fuse protection

Why buy an Altronics Kit?
Altronics kits are premium do-it-yourself projects designed to be assembled with ease. However, basic electronics knowledge and soldering skills are essential to construct our kits. A difficulty rating is provided to help determine if your ability is sufficient to build the kit project. Please note, once assembly has been commenced we are unable to honor any warranty claims. Please see the full details here.


  • Output Power (230VAC mains): 200 watts RMS into 4Ω; 135 watts RMS into 8Ω
  • Frequency response: +0, -0.3dB (8Ω); +0, -1.0dB (4Ω) 10Hz-20kHz (see Fig.5)
  • Input sensitivity: 1.26V RMS for 135W into 8Ω; 1.08V RMS for 200W into 4Ω
  • Input Impedance: 12kΩ
  • Rated Harmonic Distortion (8Ω): <0.004% 20Hz-20kHz, typically 0.0006%
  • Rated Harmonic Distortion (4Ω): <0.007% 20Hz-20kHz, typically 0.0006%
  • Signal-to-Noise Ratio: 123dB unweighted with respect to 135W into 8Ω (22Hz to 22kHz)
  • Damping Factor: ~180 with respect to 8Ω at 1kHz & below
  • Stability: unconditionally stable with any nominal speaker load ≥ 4Ω

*Specifications are subject to change without notice.

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  • Can you list all the components involved with the k5165 135watt amplifier. I need to know for my year 12 electronics portfolio.

    Hello Joel, I have emailed you some relevant pages from the instructions for each of the modules in the K5165 - which contain the parts lists. regards-Kits


  • is it possible to incorporate a headphone out to this project
    Derek Marriott

    Hello, Yes - there is a headphone terminal block located close to the speaker-out terminal block. These are in the corner near the inductor L1 on the power amp board (one power amp per channel.) The instructions do not go into details on connecting a headphone socket, however.


  • I would like to know the dimensions of the case used for this amplifier. Thanks
    Ron Ryan

    Hello, The case used has external dimensions of approximately 420mm wide by 423mm deep by 88mm high. I hope that helps.


  • When will this kit be available please?
    David Hanslip

    Hello. I will email you an ET


  • Do you need the toroidal transformer when you make your own version of this kit and if so what is the id tag? Thx I am a yr12 electronics student also doing the major portfolio.

    Hello. If you are building your own version of the amplifier separately from the kit, you will find the specified transformer MC5540 (40V/40V) is no longer available (the last ones were used up in the K5165 kits.) The closest transformer would be the M5535A (35V/35V) but it does not have the extra windings (12/15V) needed for the preamp. If you used the M5535A: your output power will reduce to 148W@4ohms / 100W@8 ohms. And you will need a separate power supply for the preamp. For more info, please contact kits@altronics.com.au