Headphone amp section, integraded or seperate ?

[Jean]

Hello !

I would like to hear what you all think about building a headphone amplifier section and putting it into amplifier case ? I use my headphones alot, sometimes for 6 hours at a time so good headphone output is a must for me. Would you guys rather build it as a seperate unit ?

I am using sony mdr 7506 (v6) if it matters, and plan on building Aksa and Leach amps.

Jean.

[paulb]

Either. Both. It depends.
I put a headphone amp in my last power amp, but running from a separate power supply. It is a Class-A "Szekeres" design, similar to the Zen amps (see www.headwize.com for it and other projects). I had the right power supply already for this.
My current project is refurbishing a set of biamped speakers. The headphone amp will be added later as a separate box that also has a common volume control for both speakers and a differential input (I run differential audio through the house). I'll probably use a high-quality opamp design here for the headphone driver because it makes for a smaller enclosure and matches the power supply I need for the control sections.
The ultimate headphone amps are always built in a separate box with their own power supply because they are complicated and/or use up a lot of power (relatively). Again, see Headwize for a good selection.
You can even use vacuum tubes to see them little filaments a-glowin' in the dark. Probably adds to the headphone experience. Would probably make a great tube starter project.

[Jean]

Paulb,

Thank you for your explanation. I am not ready to build a tube amplifier just yet, they do look beautiful though

I am looking at class a Doz headphone amplifier on Rod Elliotts website http://sound.westhost.com/project70.htm . I am having trouble finding bd139 in Mouser and Digikey catalogs

If anybody who is reading would like to comment on this particular project please do

Thanks again.
Jean.

[audiorasp]

Hi Jean,

Take alook at Futurlec at

http://www.futurlec.com/index.shtml

for the BD139

http://www.futurlec.com/TransPower.html#BDSeries

George

[Jean]

Hello George!

I found some NTE and MJE substitutes but way more expensive. Thanks for the link, great pricing !

Jean.

[paulb]

I used a 2N4923. I bet an MJE340 would work as well.

[Jean]

I found all the components, just finished my order with futurlec and mouser. Enough parts to get the headphone amp going and project 3a amplifier. Just need to order 3 transformers and power supply caps.

[paulb]

Please let us know how the DoZ headphone amp works out. My original plan was to use complementary versions (+ supply and - supply) for left and right channels. I've only built up one channel so far, but am diverted onto something else at the moment.
You'll be happy with the 3A, I know I am.

[morsel]

I realize it may be too late for input, but you can do so much better than the Doz. HeadWize and Head-Fi are overflowing with various designs. The META42 is a really good, currently popular design for which boards are available. There are plenty of others to choose from, but please, go do some research on HeadWize and Head-Fi. They are at the cutting edge of headphone technology.

[paulb]

DoZ should be pretty good. Bipolars are supposed to be inherently more linear than FETs and I know the FET-based Szekeres sounds good. Some folks make disparaging remarks about op amps, so it could be an interesting comparison.
I'm sure the META42 represents the state of the art in op-amp headphone amps. I've been meaning to order one of those boards.
Then I'll cut up my headphone cord and try a Pass BoSoZ.

Jean, make sure the power to the DoZ is clean. It will make a big difference. Look at Rod's cap multiplier circuit.