For what you're using headphone wise 18v might be a little excessive. It will give you a heavier unit and I do believe it actually decreases the run time because twice as many volts sent through the same resistance means twice the current. To support that current load you would want to configure it with the two rail-splitters instead of one as well (u2&u3) instead of just using u2. This is just a guestimate, but that much current/voltage would probably not be worth it except for insensitive or high-impedence headphones. If you aren't turning the volume knob up a fair amount, you are wasting energy by boosting the signal unnecisarily.
Hey, that's even better, less to worry about. But a straight usb as a power source is only 5v right? The dac's gonna run off the usb and I think I'll get a wallwart for the amp. the wallwart they recommend is a xicon 12vdc with actual output at 16~18v.
JDS guideline gives: gain suggestion
• 8-32 ohms: Av = 2-4 (U3 and C5 recommended)
• 33-80 ohms: Av = 5-6
should I go with 6x gain or 4x since the wallwart is a higher voltage? the T50RP is damn hard to drive though.
I'm also thinking of using the low gain for the Bass Boost, although I doubt I'll use it at all.
The BOM doesn't have a link to the R1: 47Ω - 1/8W, 5% metal film resistor, but this is it right?
http://www.mouser.com/Search/ProductDetail.aspx?R=299-47-RCvirtualkey21980000virtualkey299-47-RC
and what resistor should I use if I want the LED dimmer? this pic is from headphiles and it looks way too bright. should I go for double-ish 51Ω?
http://i55.tinypic.com/2zrj4g9.jpg
and last question, when it says 'generic 3mm led' it really doesn't matter? v, mA? I have no idea.
haha, lot's of questions. thanks dude.
Edited by randomZash - 11/16/11 at 1:49pm
