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This may just be a dumb question, and that’s alright as I’m genuinely curious. In the case of the low gain setting on the “medium gain” amp, wouldn’t an output of 1.0x be equal to the input? Anything times one is equal to itself, right? Now, that could be the case as in no increased levels of volume, but the signal will be stronger and more stable resulting in less noise. So, how exactly does it work when dealing with a factor of 1.0x? On that note, I would be using the desktop amp almost exclusively for IEMs, and all of my current headphones (as well as IEMs) are under 300Ω, but I do plan on getting some high impedance headphones down the road. It’ll probably be a while away before I do go in that direction. Should I opt for the “medium gain” amp now? Keeping in mind my question above, I do like loudness (but when it’s also clean). Will the high gain setting give me a good sense of loudness for most IEMs ($200-ish average)?

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jgillingham
73
Aug 21, 2021
Not a dumb question, and you're right: if gain = 1.0x, then output = input. To be more specific, input voltage = output voltage. In audio, gain usually means voltage gain, and it certainly does in this case. The output current will be equal to the output voltage divided by the impedance of the headphone or IEM. What's the point of an amp that doesn't amplify (also known as a buffer)? If you don't need the gain, the amp will have lower noise and distortion. It will also have the other main advantage of any power amp, regardless of gain: much greater output current than the DAC or preamp, and much greater output power since power = current x voltage. How much gain do you need? Probably 1.0x in your case. Read the following blog post, especially the section called "Gain Details": http://nwavguy.blogspot.com/2011/09/all-about-gain.html
SuperFlyEDSguy
25
Aug 22, 2021
Hey @jgillingham 👋 Thanks for hitting me back up on this. Since the posting, I did incidentally find and read some of NwAvGuy’s blog — and, man, that’s some good stuff! — He missed out on the opportunity to compile it all and publish it as “Audiophilia for Dummies!” 😂 I, like everyone else am curious as to why he stopped posting, but considering that http://nwavguy.com/ (note the .com suffix) still points to his blog, I’m convinced he still wants the world to see it. 🌎 Otherwise, why pay to keep the .com registered and maintain the domain forwarder?! 🤷‍♂️ I didn’t expect an answer, but when I checked the Whois on his domain it comes up as “REDACTED FOR PRIVACY.” What a shock, right?! 😆
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That said, you pretty much confirmed that I was indeed going down the correct path with this! 😃 So, thank you! 👍 I was in fact trying to go through it with the basics of Ohm’s Law, in this case V = IZ and P = IV (of course substituting Z for R here as we’re dealing with wave functions a/k/a audio). The place where I was getting lost was when asking if current(I) is actually increasing, therefore yielding more power(P) at our ratio of 1:1. I arrived at the part explaining how this particular Op Amp circuit is great at matching the input and output impedance(Z), and impedance matching is a great function to have as it will help to eliminate noise by making the circuit ‘cleaner’ if you will, but, I still kept asking myself “Why?!” So, I purchased a couple of books on Op Amp functionality. I had an electronics background, but until recently haven’t used it in over 20 years!!! 😮 I was trained in electronics in the Navy, but to give you an idea how long ago that was, I got out in ‘99! 😮 We did briefly touch on Op Amps, but only the basics, and more-or-less only in passing. It was more about learning that they do exist and what their functions were, and then move on to the next topic (probably 555 timers or something, that was a fun lab though!) I worked in IT for a bit more than a decade, got bored, and worked in finance until my medical retirement a couple years back. Ironically, my son and I got started messing around with circuits a little more than a month ago. I got us enough stuff to entertain us with Arduino circuits for a long while. That’s when the electronics bug bit me again! That’s why I was so obsessed with finding an answer, so I posted. I did purchase the “medium” gain O2 amp as it is a great match with my IEMs. 😃👍 It’s also a great size to keep next to the bed, so you can just lay back, relax, and enjoy your music! So, I am still reading about Op Amps and do have a long way to go before really understanding them, but it’s apparent that NwAvGuy knew them inside and out! What a master! 🤯😂 Op Amps are by far one of the coolest concepts in electronics! I guess in the end is just knowing that they work well for their intended purpose, knowing enough to appreciate it, and just be grateful that it’s just one more small thing that packs a big punch when enjoying our music! 👊 Thanks again, and be well. ✌️