Recent content by TzeYang
1. ### New Stoner Acoustics Ruby Portable Amplifier

https://www.facebook.com/StonerAcoustics/posts/1197085356973008 Seems like they are having a sales for the holidays...

Justin, I don't own your products because I'm too poor to afford them, but from an engineer's point of view, I really admire your work. Pure curiosity, how do you deal with the unbalanced 2x 9V batteries causing dc offset issues when they drop low? Does the amp cut off the batteries...
3. ### Post pics of your builds....

I LOVE what you did to the USB connector.
4. ### Oh how I hate Eagle PCB - Any help with A47 upgrade?

try diptrace if eagle is too hard to use.
5. ### 2 or 3 Channel, Single Ended Class "A" Design Thread

if you're going to add an opamp anyway, why not simply build PRR's MOSFET + OPAMP combo with two rails? There's an elegance of using output caps when your circuit is that simple but if you have something that controls the output, having output caps is counter-intuitive.
6. ### General design theory help

been busy with school. but here's a quickie. Generally, you want to have the input impedance of the non-inverting input and the inverting input to be the same. Hence, R1 || R2 = R3 || R4. This applies greatly to BJT input opamps where there is enough base current to cause dc errors.
7. ### General design theory help

Quote:   ACTUALLY, the calculation is the same. The input differential stage is self biased. Meaning that input stage current depends on how much voltage you drop across the source resistors and the IDSS curve of the device itself (this varies between devices). The VR1 is there to set...
8. ### General design theory help

cant be sure, but here goes. correct me if i'm wrong.   input impedance is dominated by R1 and R2. The input impedance of the direct input is usually VERY large, depending on the types of input transistors. In an ideal case, it is assumed to be infinity. You don't really have to look at this...
9. ### Hakko 936 discontinued, viable replacements?

the only problem you'll probably get is the stupid plastic knob that breaks down after 2 years. Replace with aluminum knob and pretend it's hi-fi.
10. ### [No title]

1269220705465.png
11. ### Would 1.5v battery kill a headphone driver testing polarity?

but are you not heating up the drivers by applying DC across it?
12. ### M3 with Monster beats

ground the pot shaft.
13. ### Good amplifier theory/practicum book

look for research papers on specific things you want to learn. There is rarely a one kind of book that does everything for you. I find microelectronics circuit analysis and design from Neaman good though But abit of maths so it might be kinda annoying. I use it for my course. Best...
14. ### RSA Tomahawk Bass lite?

use line out. Burn in is super irrelevant.
15. ### Blochead Diamond Buffer + Gain Stage

^P devices will always be mismatched from N devices. They are not perfect. And there are plentiful other of parameters to match other than just BETA alone.