Well, goodbye ADA4075 in my O2's voltage gain, hello OPA1692. Just wow.
dat AD8022 bass, though, gotta love dat bipolar midrange, too
Have not tried nor used the O2 design by this is what the designer said is THE best for voltage Stage is to use the NJM 4556. I love to try this op amp.
Apparently all the NJM Audio engineers made some pretty great op amps designed for audio with high current and low distortion that the unknown creator of the O2 is high on. The best part is they are dirt cheap!
It’s also important to note that a lot of the MUSES are fancied up NJM designs so I’ve read.
"NJM4556 OP AMPS: The NJM4556 op amps, by far, work the best in this design. No other dual DIP8 op amp can deliver even close to as much current at as low of distortion. Few op amps are made for driving headphones but the NJM4556 is. It also works well paralleled and not all op amps do. The TLC2062 is an acceptable substitute for headphones 32 ohms or higher and also provides about 3 times longer battery life. See: Low Power Option. The RC4580 is a very distant third if have no other choice.”
I’ve often seen this from some Diyers on this thread about gain settings and in turn become enraged by their blind arrogance to the said info. I don’t believe in pure gain as a panacea.
O2 designer also says this which I happen to agree with as a rule of thumb in regards to gain. You can ALWAYS use a DAW limiter to your mod you files which essentially doesn’t the same thing and is safer. One word of causation anytime you use a limiter you are essentially compressing your files. But you can alway lower the dbs and double the tracks to make them fuller. This is also true when you want to add more fullness to crappy mp3. Some programs and apps can to this in real time with meta-data.
Here’s what O2 designer says:
“THE GAIN RESISTORS: Before you solder in the four gain resistors by the gain switch, you might want to consider different gains than the approximately 2.5X and 6.5X default values. You want just enough gain so typical music plays loudly enough with your headphones and source and not much more. Extra gain means using less of the volume control’s range, more noise, more distortion, and makes accidental headphone damage more likely. Here’s what you need to know about calculating gain:
Lower Is Safer - Lower gain settings make the amp less likely to damage headphones by limiting the maximum output voltage to only approximately what’s needed.
Lower is Cleaner – As shown in the first article, there’s a slight increase in distortion, especially at high frequencies at higher gain settings. Lower gains also result in lower noise.“
