Headphone Hybrid Tube Amp (SSMH)

For audiophiles and DIY hobbyists, this amp is the mecca of affordable bang for buck audio awesomeness. This amp can be built for dirt-cheap with great results. Don’t get me wrong, there are better amps out there that are more fine tuned to you and your listening style, but it comes with a very hefty price tag. For those of us still wanting great sounding audio and a low price tag, this is it. Let me introduce you to the "Starving Student Millet Hybrid" tube amp, or abbreviated as the SSMH.

Instructables has very limited information on headphone tube amplifiers. So I have decided to help fill the gap and hopefully inspire some other builders and audiophiles. The build I have chosen is the “Millett Starving Student Hybrid Tube Amp”. Reasons being, it’s cheap (can be easily done for less than $125 for all materials except tools), sounds great, has a simple circuit and has an almost cult like following. Online support for this amp is huge, which makes questions and troubleshooting a lot easier.

There is a surplus of information about the schematic and how to wire the circuit online. So I will attempt to give you the resources about the building process excluding the schematic.

I would like to thank Pete Millett for his development of this amp and schematic. He is a brilliant and generous man and deserves credit.

Important Links:

Pete Millett’s original post:
http://www.pmillett.com/starving.htm

Head-Fi thread:
http://www.head-fi.org/t/319231/millett-starving-student-hybrid-amp

DIY Forums:
http://www.diyforums.org/SSMH/SSMHoverview.php

Bill of Materials:
http://www.diyforums.org/SSMH/SSMHbom.php

Schematic:
http://www.diyforums.org/SSMH/variants/SSMH-12AU7.gif

Step 1: Picking your components.

Pete Millett’s design uses a pair of 19J6 tubes for amplification, however they have since almost disappeared from every retailer and auction site in existence. Don’t even bother trying to find them, people have been trying for years without luck, there’s an easier way. With credit given to Dsavitsk – he slightly modified the schematic to use a pair of 12AU7 tubes that are still readily available all over the place. Here is the schematic: http://www.diyforums.org/SSMH/variants/SSMH-12AU7.gif Also, note the highlighted optional components. They are not essential for a functioning amplifier but will add enhanced audio output and help buffer the pot (volume control).

Now lets look at materials. Here is the standard Bill Of Materials (BOM).

http://www.diyforums.org/SSMH/SSMHbom.php

My amplifier uses the exact same electrical components as above. However, I wanted to go above and beyond for sourcing an enclosure, heat sink, tubes and other materials not involved in the electronics. It was important for me to achieve an overall look that fit my tastes.

While looking at pictures, I became increasingly unimpressed and decided that there had to be a better enclosure option out there. After much distress I found what I finally was looking for. Hammond makes an enclosure designed for DIY guitar pedals that’s already polyester powder painted! It’s perfect. I then moved onto the heat sink and found one that fit the bill. Finally some awesome classic switches, aluminum milled knob and some sweet input/out connectors.

Enclosure:
http://www.hammondmfg.com/dwg_SBVer.htm
Knob:
http://www.mouser.com/Search/ProductDetail.aspx?qs=sGAEpiMZZMuiwDVLTMm01SnXt%252bxMNAYRiE4hqsuOv%2fk%3d
Heat Sink:
http://www.mouser.com/ProductDetail/Wakefield/641K/?qs=sGAEpiMZZMsv9efUTL1hjoRaZH8LLHQ7
Heat Sink Mounting Grommet:
http://www.mouser.com/ProductDetail/Keystone-Electronics/730/?qs=sGAEpiMZZMsQtlBhqKq43fwJXtsOdb9G
This site has some cool connectors and tube sockets:
http://beezar.com/catalog/index.php

Comments

[michaelpless1]

Do you have the exact model number on the Hammond box? It looks like the larger one, but its hard to tell. 1590XXGR maybe? 154x121mm?

[jsapožnikov]

What does the yellow part mean? do they i have to add them to the circuit or i have to change them?

[janw]

Great project! Try to make the links work in your instructable. It makes looking up the extra info so much easier for us lazy people ;)

[wleedham]

Looks like I've found my University 'reading week' project.