Bottlehead Crack Headphones Amplifier (Part 1) Introduction

This Bottlehead Crack headphones amplifier is not a new news but still hot for sure.

For some reason, this amplifier is always praised by DIY'ers as the best headphones amplifier kit available so far. Not just because it is using vacuum tube, but it is sound good.

This Bottlehead Crack headphones amplifier is sell in a kit and luckily for you living in States, this kit can be obtain with the ease. But not for me living in Asia, the delivery cost for this amplifier will high and takes so much time. This Bottlehead Crack amplifier in this post here is lend by my friend. He bought it in used condition and he is willing to bring it to my house yesterday to let me check it first.

My quick inspection, this unit is all original component, nice layout, simple design, and quite dirty for sure.

I will cleaning it up in return and maybe some cosmetic upgrade later on.

I am new to the vacuum tube amplifier and having this in my table is something that I could say, rare.

As usual, the tube amplifier have a common looks, they exposed the vacuum tube itself. It is beautiful for sure, but with a purpose. It is just like a heat-sink on the solid state amplifier, the vacuum tube exposed it to release the heat as well.

This Bottlehead Crack amplifier is overall have a very simple presentation. Only a power tube and a driver tube along with the power transformer and all input output connector on the top chassis.

I do some quick test with a simple setup.

I am using iPod as source and Sennheiser HD600 headphones.

Once I turn it ON, the vacuum tube start to glow. It will reach the optimal temperature about 5 minute, then I start to play the music.

My initial impression with this amplifier is the sweet sound. Very dynamic and rich sound on overall music frequency. I loved the midrange sound. It is very live and intimate.

After I spent about an hour in this listening session, it is time for me to disassembly all components and start to clean it up.

As you can see, the top plate is quite dirty. The transformer cap has some rust on it. But overall still in maintained condition.

The wood panel on side is loose to the top plate, means no any screws locking to both parts together. I also don't have any idea what should I do to attach them. I guess using glue will help.

Here in the internal components from today quick inspection. It is all tidy, it is all original except the potentiometer has been upgrade to ALPS blue.

I see some additional resistor after the potentiometer. It is 1 kilo ohm, usually for improve amplifier input stability. I will try to remove it later and return to it's original as per schematic.

Here is the original schematic.

And here are another photos that I was taken during this inspection.

Please continue to the Part-2.

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