My tube headphone amp
I spent some time this weekend testing a few different tube types in my Little Dot MkIII tube based headphone amp. This system is the only way I can focus these days when at work.
My work system is made up of:
Since I started using my Little Dot amp I have been very happy with the audio quality. That is up until this weekend when I decided to try some other tube manufacturers which was driven by my recent reading about “Tube Rolling” an amp.
The Little Dot came with 5654 driver tubes and 6N6 power tubes. The 5654 is basically the equivalent of a 6AK5 which has many different manufacturers. After digging through my tube collection I came up with Sylvania 6AK5 and a Motorola 6AK5. Although you would normally used matched pairs of tunes I notices that the internal construction of these tubes was exactly the same down to the smaller detail. They were effectively the same except the name printed on the glass. After testing the mutual conductance of each on my B&K 707 tube tester I found that one measured 78 and the other 81. Close enough for my testing.
After installing these newly found beauties I was struggling with what I was hearing and after switching back and forth between the tubes a few time finally called my wife Debra as a second opinion. She confirmed that what I had thought was a wonderful soundstage and fidelity The original tubes were in fact flat and sounded a little like it was in a tin can. How could their be such a difference? The new 6AK5s were wider, larger, clearer and made me feel like the vocalist was in the room!
Next I replaced the power output tubes. The Little Dot standard 6N6 were replaced with a pair of 6H30PI tubes made by Electro Harmonix with gold pins. These tubes gave tighter bass and just seemed to give everything a more airy feeling.
These tubes were a major step up from the stock options. I’m now waiting for a vintage set of Mullard M8100 driver tubes I found on EBay. These are on their way from England and should be another step up from the 6AK5s found in my old spare parts box.
I no longer get an office at work, so I just create my own little world of wonder.
My work system is made up of:
- Audioengine D1 96k DAC
- Little Dot MkIII Tube Amp
- AKG K702 anniversary edition headphones
- Decibel player on my Macbook Pro
- My music collection (Cds and Vinyl) ripped to .flac format
Since I started using my Little Dot amp I have been very happy with the audio quality. That is up until this weekend when I decided to try some other tube manufacturers which was driven by my recent reading about “Tube Rolling” an amp.
The Little Dot came with 5654 driver tubes and 6N6 power tubes. The 5654 is basically the equivalent of a 6AK5 which has many different manufacturers. After digging through my tube collection I came up with Sylvania 6AK5 and a Motorola 6AK5. Although you would normally used matched pairs of tunes I notices that the internal construction of these tubes was exactly the same down to the smaller detail. They were effectively the same except the name printed on the glass. After testing the mutual conductance of each on my B&K 707 tube tester I found that one measured 78 and the other 81. Close enough for my testing.
After installing these newly found beauties I was struggling with what I was hearing and after switching back and forth between the tubes a few time finally called my wife Debra as a second opinion. She confirmed that what I had thought was a wonderful soundstage and fidelity The original tubes were in fact flat and sounded a little like it was in a tin can. How could their be such a difference? The new 6AK5s were wider, larger, clearer and made me feel like the vocalist was in the room!
Next I replaced the power output tubes. The Little Dot standard 6N6 were replaced with a pair of 6H30PI tubes made by Electro Harmonix with gold pins. These tubes gave tighter bass and just seemed to give everything a more airy feeling.
These tubes were a major step up from the stock options. I’m now waiting for a vintage set of Mullard M8100 driver tubes I found on EBay. These are on their way from England and should be another step up from the 6AK5s found in my old spare parts box.
I no longer get an office at work, so I just create my own little world of wonder.