I’m a long-time fan of Pete Millett’s circuits—particularly his Wheatfield HA-2, which was my introduction to tube audio when I bought one from Headroom nearly 20 years ago. Although I’ve owned (and sold) lots of equipment since then, I still think of the HA-2 as the single best audio purchase I ever made. And I’ve made plenty.
A few years ago, I gave my HA-2 to a young, budding audiophile who still uses it, and I set out to build my own version of the circuit using a bigger enclosure and some upgraded parts (beefier PT, stepped attenuator, some oil motor run caps, better output caps). It didn’t sound dramatically better than the original, but it was an upgrade. I was pleased.
Until, that is, a few months ago when I happened upon a Head-Fi thread from 2008 started by n_maher:
https://www.head-fi.org/threads/pete-milletts-menace.320365/#post-4135125
Maher is also a HA-2 fan, and he worked with Pete Millett to re-imagine the OTL HA-2 circuit so it could drive low-impedance headphones. The result, the Millett “Menace,” was a 2 chassis tribute to glorious excess: it featured a 50 lb. power supply with two tube rectifiers, dual output tubes, and oil motor run caps used throughout, including a pair of paralleled 100uF caps used in the output.
I immediately wanted to build my own Menace, but I don’t have room for a 2 chassis headphone amp, and my favorite headphones are Sennheiser HD800s, so I didn’t need all of the steroidal enhancements of the Menace. A single rectifier and output tube were enough, and I didn't need parallel 100uF output caps
.
I had a couple of Hammond chasses sitting around from projects that never got started, and their sizes suggested that I could bolt them together as a kind of “pseudo”- 2 chassis build. So I built a scaled down Menace, a kind of "Minor Menace."
OK, some caveats: I’m a hobbyist with modest building skills, and I only know enough about electricity to build relatively simple circuits. My goals were to make a quieter, better sounding HA-2 using the “Menace” as a guide. To cut down hum, I used a Hammond PT with an electrostatic shield and I put the PS in one chassis and the signal circuit in the other. I bolted the two together using non-ferrous hardware, some damping material, and a sheet of copper. Wiring between the two chasses go though holes I drilled that ended up too thick for normal grommets, so I used rubber tubing instead.
Some pictures:
I had no idea what to expect when I first plugged my HD800s into it, but the sound exceeded my hopes. There is the barest hint of hum, ever so slightly above (my) hearing threshold. Sonically, the lushness and musicality of the original HA-2 is retained, but the sound is bigger, richer, more relaxed and assured.
In short, I'm a proud papa. I now have 4 headphone amps but, geez, I'm thinking that HD800s through this amp is my audio nirvana.
I don't know what interest there is in such a project, but I'm happy to answer any questions anyone has.
LarryM
A few years ago, I gave my HA-2 to a young, budding audiophile who still uses it, and I set out to build my own version of the circuit using a bigger enclosure and some upgraded parts (beefier PT, stepped attenuator, some oil motor run caps, better output caps). It didn’t sound dramatically better than the original, but it was an upgrade. I was pleased.
Until, that is, a few months ago when I happened upon a Head-Fi thread from 2008 started by n_maher:
https://www.head-fi.org/threads/pete-milletts-menace.320365/#post-4135125
Maher is also a HA-2 fan, and he worked with Pete Millett to re-imagine the OTL HA-2 circuit so it could drive low-impedance headphones. The result, the Millett “Menace,” was a 2 chassis tribute to glorious excess: it featured a 50 lb. power supply with two tube rectifiers, dual output tubes, and oil motor run caps used throughout, including a pair of paralleled 100uF caps used in the output.
I immediately wanted to build my own Menace, but I don’t have room for a 2 chassis headphone amp, and my favorite headphones are Sennheiser HD800s, so I didn’t need all of the steroidal enhancements of the Menace. A single rectifier and output tube were enough, and I didn't need parallel 100uF output caps
.
I had a couple of Hammond chasses sitting around from projects that never got started, and their sizes suggested that I could bolt them together as a kind of “pseudo”- 2 chassis build. So I built a scaled down Menace, a kind of "Minor Menace."
OK, some caveats: I’m a hobbyist with modest building skills, and I only know enough about electricity to build relatively simple circuits. My goals were to make a quieter, better sounding HA-2 using the “Menace” as a guide. To cut down hum, I used a Hammond PT with an electrostatic shield and I put the PS in one chassis and the signal circuit in the other. I bolted the two together using non-ferrous hardware, some damping material, and a sheet of copper. Wiring between the two chasses go though holes I drilled that ended up too thick for normal grommets, so I used rubber tubing instead.
Some pictures:
I had no idea what to expect when I first plugged my HD800s into it, but the sound exceeded my hopes. There is the barest hint of hum, ever so slightly above (my) hearing threshold. Sonically, the lushness and musicality of the original HA-2 is retained, but the sound is bigger, richer, more relaxed and assured.
In short, I'm a proud papa. I now have 4 headphone amps but, geez, I'm thinking that HD800s through this amp is my audio nirvana.
I don't know what interest there is in such a project, but I'm happy to answer any questions anyone has.
LarryM
Last edited:
