Hello all, soon to build my first headphone amp, and have a question about the power source.
I really want to be able to use this with my portable and with my computer, and I was just thinking about using one of these instead of adding a 'wall wart' female plug. I am assuming this will work out fine . . . but just want to double check.
This got me to thinking though, I know that the power supply effects sound quality in a direct way, but how? Also, what would the sonic differences be between 2x 9V battiers and the trusty old wall wart?
Not all wallwarts are regulated. Personally, I would go for regulated ones. There are one available from RadioShack. I use one for charging my portable CDP. I used to use it for my Szkeres amp. It has 800mA capability and 2.5V~12V output (adjustable). Last I checked they are available.
Note, however, that the effects that PSUs have amps are highly depended on the design. Opamps comes with ripple regulation by default. Therefore, sometimes, opamp based amps can go without regulation. However, for descrete designs with no ripple regulation implemented such as Szkeres amp, the sound quality is almost equal to the quality of PSU.
I know that people has been very picky on PSU designs and methods. But you shouldn't feel obliged to hype up your PSU. In some cases, that might be simply overkill.
In absolute sense, batteries make better power supplies. It is free from AC completely. If you use batteries, no part of your circuit needs to be effected by AC. The PSUs that plugs in always have some residual ripples however small they may be.
In practical sense, batteries aren't so much better solution. You have to replace or recharge your batteries pretty frequently. (At least once a month or so.) Also, for class-A amplifiers which eats electrocity "by a cart load," battery consumption is simply staggering. The outlet PSU does not need recharging or replacing. It can output specified voltage constantly and can support large current needs.
Some mentions that Beefy outlet power supplies are good. But in absolute sense, Beefy battery array offer much better sound quality although recharging and battery maintainance is nuiscence.
Let us put aside battery solution for a min and talk about the quality of outlet PSU. In my experience, generally Beefy outlet power supplies perform much better than cheap outlet PSU. Bass is stronger noticeably. Also, you get higher accuracy. (Note I say generally, "Beefiness" is depended on designs ... You have to look for "good" and "beefy" supplies.)
Now to the battery solution. Many people has misconception that when I say it, they imagine a 9V battery or a pair of AA batteries. That are what I call ... cheapo battery supplies. Conveniently small and light, but hardly "beefy" or good for that matter.
I would use couple lead batteries and design a special charger for them. If I were to build decent battery PSU, it would be about a size of your computer case. (Ok ok maybe couple inches smaller than that.)