Dammit, Pete Millett.

After more rounds of amplifier upgrades and side-grades, I kept hearing about this headphone amplifier that was a giant killer. This mysterious person from the Pacific Northwest designed it to prove a point that super expensive boutique audiophile gear was mostly just hogwash and could be beat, objective performance-wise, by some rather cheap parts and good engineering. It was the Objective 2 and I thought it was so punk rock that I could build my own “better than everything else” amplifier. Super David v. Goliath.

The mystery around the creator – a person who went by NwAvGuy – who posted to a blog for about a year, raised hell, and then disappeared was almost too good.

I spent a few evenings looking at pictures of it and watching videos of folks building it. It looked ridiculously complicated, especially given my only experience thus far was the small Frys kit I built a while back. This was supremely more complicated and involved lots of parts, most of them small and crammed next to each other. It seemed a step past where I was.

Like a lot of folks, I decided it was daunting and I didn’t have time to muck around with it. But, I had to build something now that I had the itch.

On reddit.com/r/headphones someone posted about this amplifier they’d built for their cans. It was called a Butte and I read more about it on this website that looked like it was from 1996. The designer was apparently named Pete and sold stuff on eBay. He said he had a background in electronics and his website seemed like he did. I mean, being so awful looking and full of technical information, he must know his stuff. Honestly, it all seemed sketchy as hell but he had posted stupidly detailed instructions for how to build the Butte and it seemed significantly less complicated than the Objective 2. I figured what the hell – Reddit says other people have done it and that means I can. I ordered the Butte PCB from his eBay page and ordered the pre-configured shopping cart from this weird website called Mouser. I’d never ordered parts like this before, so even that portion was an adventure.

A week later everything arrived.

As usual, I tore it all opened, printed Pete’s assembly instructions, and started on my way inserting resistors where the manual said to and putting on various connectors. After an hour or two I had it assembled and soldered. I decided to power it on with the wall wort that came as part of the preconfigured Mouser shopping cart and hoped for the best.

A little green light lit up and I got excited. A few seconds later I noticed a funny smell. Looking a little closer I noticed something weird, one of the capacitors seemed to be larger than the other. Not in a “good larger” way either. Quickly I unplugged the wall wort.

After some more looking I noticed that in Pete’s pictures the capacitors looked a little different. There are these stripes on them and they went the other way in the pictures. I guess that matters.

This is how I learned about polarity. Turns out polarity is important, folks.

I didn’t really know what a capacitor did, but I did learn that one side is positive and one side is negative. And feeding the wrong side with DC+ isn’t a good idea. I de-soldered the incorrectly placed capacitors and re-soldered them the other way around, though one was bulging out a bit.

Again, I flipped it on, the light turned on, did a quick sniff test for anything smelling funky, and finally connected it to my computer and cheap headphones. Omg it worked. And it sounded good (with super sketchy capacitors in the power supply).

The finished PCB on top the pinnacle of my non-DIY headhone amps, the Audio GD NFB-11

I also noticed that I had a few parts left over. Pete includes an optional CCS circuit that can be installed. I had no idea what this meant or really did, but I decided to install it. Basically, you’re installing a CPC3703 mosfet to make the opamp run at full tilt all the time. Class-A. Moar powwwwa is better than less powwwwa so that was a no brainer. The parts were these small little poopers and I fumbled my way through it. But, it continued to work afterwards and I felt super accomplished.

I even made a 3D printed case for it after some time. Not amazing, but it was fun and cheaper than the $50 or whatever Pete wanted for a really nice aluminum pre-drilled chassis.

Yes, I did replace the capacitors with non-blown up ones. But, wow, I really did think this amp sounded great. It had zero noise and had authority. That’s the best way I can describe it – authoritative. Am I biased because I made it? Probably. But, to this day I still think it’s a damn fine amplifier and for a total cost of less than $100 excluding enclosure, it’s right on the money.

This particular amplifier ended up going to a different home, but I love Pete Millett’s Butte so much I made another one a few years later just because. Well, not completely because – I had started to think about building chassis out of wood and needed an easy project as an excuse to try making a chassis from wood. It turned out alright and is still sitting on my audio rack today.

For a first time DIY audio project, I recommend the Butte big time. And Pete Millett, if you’re reading this, I love you. I really do. I didn’t know it then, but I’d end up building a number of your projects and each and every one is special in different ways. Thank you for being the amazing Colorado guy running a 1996 looking website full of marvelous information that you are.

This project taught me about polarity, AC/DC, and so much more. After almost blowing up (err, really I did) the capacitors and then fixing it, I spent about a week reading and testing various things out. I referenced every single component I put in that PCB and learned that resistors are not polarized, the capacitors were (but not all capacitors are), what a pin out was, where the audio signal went and how it fed into the opamp, what the mosfets I added did, and how a potentiometer is like an adjustable resistor. I feel like I learned so much building, screwing up, and then fixing the Butte that I can’t even express it. I had so much fun.

But, I still wondered about this giant killer – the Objective 2.

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