https://www.facebook.com/StonerAcoustics/photos/a.689220487759500.1073741826.426811050667113/1342274039120805/?type=3&theater

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...

I LOVE what you did to the USB connector.

try diptrace if eagle is too hard to use.  

is there noise at the first place?

just so you know, these ideas are all discussed and done thoroughly before here and on headwize. Eventually, you'll end up with a PRR like MOSFET amplifier with two rails.You could add complexity to the output stage by adding a CFP, add some FETs to the rails, cap multiplier, small shunt regs to...

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.

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.

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...

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...

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.  

but are you not heating up the drivers by applying DC across it?

With a circuit this symmetric, consider using thicker traces and a star ground.

lower the resistor between the buffer and the output of the opamp to about 100 ohms.

^you mean an open loop diamond buffer? They don't like driving low impedance loads and IMO if you were to trim a diamond buffer the only way to do it is to introduce an offset error to the CCS to nullify the differences between NPN and PNP complementary parts. You can introduce the offset...

transportable jisbos

ground the pot shaft.

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...

use line out. Burn in is super irrelevant.

Quote: Originally Posted by Currawong Years of hi-fi experience and research? It's very simple: If you introduce a component that changes the frequency response of the signal, you are introducing distortion. A good recent example has been the HD-800s, with a number of owners, myself...

^where did you pull that one out of?

lol^

excellent! Now I won't even bother with other formats if this becomes accessible.

^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.