The Introduction For Luxman LXV-OT7 Clone

For more than two months, I never listen the music on my system anymore. This simply because all of my amplifier was sold. They had moved to their new house, of course with the new satisfy owners. One-by-one are gone until I realized, I've sold all my amplifier.

If I count, it is all gone started from my simple LM3875 gainclone amplifier, Mauro Penasa design LM3886 amplifier, Elekit TU-8900 amplifier, and Parasound HCA-1206.

So, I don't have anything to powering up my speakers right now.

Of course, I always have a plan, but sometimes the plan is not run as expected. My new amplifier project is delayed due to the imported parts is not delivered yet. I still have to wait a month for the parts to come, not to count the making process for the new amplifier project yet. So, maybe I should be waiting for the next 3 month until the new amplifier project finished. And right now, no amplifier = no music.

I only browsing from the internet, reading some reviews and looking to beautiful audio photos. Until one day, I saw the Luxman kit that sold many years ago in Japan, I got my interest on it.

The photo above is not the actual Luxman LXV-OT7. It is my clone for the same amplifier, but with many improvements.

You can start browsing this Luxman LXV-OT7 and the news is everywhere. But seems you cannot buy it now since this unit was sold as a kit in Japan, many years ago. This Luxman LXV is sold as magazine along with the kit, so you can read all the idea behind the unit and assembly the kit as working unit later. They are actually coming with several series such as: vacuum tube harmonizer (OT6), hybrid vacuum tube amplifier (OT7), vacuum tube FM stereo tuner (OT8), tube 5-band graphic equalizer (OT9), and phono equalizer (OT10).

In this build, I just focus on the Luxman LXV-OT7, the hybrid vacuum tube amplifier.

Fortunately, the Luxman LXV-OT7 schematic can be found online, so it made my day easy to did this clone.

I found the original kit using the switch-mode power supply. This is for cost and weight saving, but big no for audio because they are noisy. Other than that, the power supply lines are all combine with single 15-volt DC same from the switch-mode power supply, including for the tube filament power supply as well. Speaking for the tube itself, the original kit is using 12AU7 tube which in my opinion, 6DJ8 or equivalent tube like this is more suitable for audio.

So, I made this Luxman LXV OT-7 clone with that improvement, using linear power supply, regulated the DC and separate the tube filament supply, using 6DJ8 tube and all this built into small thick aluminum amplifier chassis.

I can now start listen to my favorite music on my audio system after I finished this amplifier build.

This amplifier is not 100% complete because the parts needed is still on the same batch with the delivery imported parts. I still need the potentiometer and RCA plugs. I will be using APLS RK27 and CMC RCA plugs. Those are minor parts but at least this amplifier can work now.

For the sound quality, I think if the power output is not an issue, this amplifier is solved all my amplifier needed. The 3 watt per channel is tiny, but it drive my 86 dB sensitivity speakers with ease. Of course, you cannot expect huge dynamic range with hard bass slam.

But it is more than enough for great music presentation.

For now, the great photos of this Luxman LXV-OT7 clone taken with my old and trusted Fujifilm X-T10 can be enjoy.

Of course, on the next post, I will share the original schematic, together with the improvements I made and the build process of this amplifier.

Until then, see you.

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