I was the first to review the Butte on the Canadian leg of its loaner program. Unlike most reviews, I'm just going to start off with my blunt and final impressions. Do I think this amp is worth the money? Nope.
Now that I've got that out of the way, read on for why. I will try to keep my writing concise and point form where possible. I will note that I was in the middle of doing my portables shootout (link) when I had the Butte, so they formed the majority of my listening time. However, I did spend time with more equipment and also organized a meet while I had the Butte so I could gather more impressions and try a broader range of equipment. For sources, I primarily used the lineout from an iBasso D10 fed via optical.
Warning: Spoiler! (Click to show)
Not a complete list...
AKG K240 Sextett
Audio Technica A900
Sennheiser HD25-1-ii, HD25-13-ii, HD600
Beyerdynamic DT880/250, DT250/250, DT1350, T50p
orthos: Fostex T40v1 transplant, Yamaha HP3, SFI transplant, Realistic Pro30
Turtle Beach Audio Advantage Micro II (mostly used as usb/optical converter)
Esoteric transport & dac
Form and construction
- surprisingly small: 135 x 109 x 51 mm
- lightweight - I forget to write down the exact weight, but when it was all packed up for shipping it came in at 1.06kg (and that's counting the box and power adapter)
- has a good solid feel to it
- a set of RCA and 3.5mm inputs on the back, with a button switch on the front
- one 6.35mm headphone jack on the front
- button power switch on the front
- standard barrel plug for power on the back
- inputs do not seem to be fully isolated from one another; signals may bleed over
A very plain looking amp, rather unassuming. Buttons and knobs are all in plain site and easily accessible. Along with the big rubber feet (which are bit oversized I think, but that's a minor aesthetic quip), there's enough heft to it to keep it from sliding around too much if you're prone to jacking in different headphones frequently.
- the included wallwart was an AC-AC adapter
- wallwart seemed generic, outputs 12V AC
I was a little surprised to find that the wallwart supplied in AC, which means the DC conversion takes place inside the amp. From a design perspective, it's a halfway point between doing all your power management in the same chassis, or taking the entire thing out. I guess it makes sense to at the very least take the big noisy transformer out and do all the fine detail work in the chassis.
- feels like slightly better control in the low end, but also a little dryer
- bass rolloff slightly around 40Hz, seems more noticeable than the Bottlehead Crack
- gain is much too high for most iems
- performs better with high impedance headphones and orthos
- very slight channel imbalance at the very lowest volumes, also doesn't attenuate all the way
- bass rolloff seems to come slightly quicker than the Crack and D10
Well here's where things get a bit finicky. I was not blown away but this amp. If anything, I was a little underwhelmed. Sonically I didn't hear anything wrong per se. Sound across the bass/mids/treble felt relatively consistent. Staging was decent, though at times felt a little recessed.
When comparing a bunch of the portable headphones, my overall impressions were “it's ok”. Nothing really stood out, I didn't feel much energy, and I was bothered by many of the noise issues (see below). At times I also felt like my frequency responses were slightly wobblier than usual. With the high impedance and/or lower sensitivity cans, performance improved. Headphone response felt tighter, like the notes were hitting harder and with more definition. With orthos, performance was actually quite good, solid power and impact, and noise was negligible.
Considering the high gain and overall performance, I would say the Butte is geared more for the heftier non-portable cans. Having an adjustable gain would have been nice and would make it easier to use sensitive headphones, but that would be a design decision and I'm sure it doesn't have one for a reason.
- background is not fully black, even when sourced from a portable player (with negligible dc offset)
- inputs do not seem to be fully isolated from one another; there is bleedover
- cannot have one input plugged in at the back but nothing on the other; generates noise, even if “off”
- two types of noise: a static white noise, and another that sounded like faint blowing wind
- also highly susceptible to grounding issues
- low impedance/high efficiency headphones were most susceptible (T50p)
- sensitive iems were almost unbearable
This here was one of my main issues with the Butte. Sometimes it worked very well, but oftentimes I had serious noise problems. I've run through my fair share of amps and organized several meets, and I have never had the issues that I had with the Butte.
I could use the same source and one day it would be fine, and the next day (nothing touched) it would be incredibly noisy. In some cases, noise could be heard with softer music playing and volume at approximately 50%.
The inputs seemed to not be fully isolated from each other. Say you had your sourced plugged into input 1 but had your switch set to input 2; turn up the volume and you can still hear input 1.
There was also a very large amount of noise if one input was left hanging free. I suppose this could have been an electromagnetic interference issue, but the surroundings were exactly the same as when I've A/B'd other amps and I've never heard interference to such a large degree. Best case for reducing noise was to only have one cable and source plugged in at a time. Even with a second source connected but turned off, there seemed to be ground loops present.
I'm not sure how the shielding is configured in the Butte, but I wonder if somehow it winds up amplifying interference. On a couple occasions (and with different sources) I had noise so bad that it was impossible to listen to music, but moving or touching various components or the Butte would alleviate it. I was unable to fully isolate or identify this problem as it was not consistent.
- inconsistent noise from iBasso D10
- caused errors in the Esoteric DAC
At a meet we had an Esoteric cd transport and dac, a rather large double box affair. For some reason, it simply could not get along with the Butte. Every few seconds it would trigger some sort of click in the Esoteric and the music would briefly cut out. This did not happen with any of our other amps, and according to the owner of the Esoteric he had never seen that happen before either.
Performance with my other sources was spotty at best, as noted in the noise section above.
vs Bottlehead Crack+Speedball
- limited my comparison to high impedance cans
- Butte had better stage width but all the sound was pushed back further; Crack had a more forward but narrower stage
- Crack tonality felt richer, stronger treble, bass extension seemed lower
- Butte had a more resonant midrange
vs Audio-gd Sparrow (fed via optical)
- bearing in mind that the Sparrow used its own dac
- these honestly seemed very comparable and I had a lot of trouble telling any difference
- at times I felt the Sparrow even edged it out slightly in terms of instrument separation
- the Sparrow is slightly larger, but significantly cheaper and includes a dac
vs iBasso D10
- the D10 and feels veiled and lacks the headroom to play with the heavier cans compared to the Butte
- but I felt it handled the portable cans better and had a more dynamic and energetic feel to the music
vs Ortofon HD-Q7 (from memory)
- Ortofon brighter, much more upper energy, induced a Grado-esque love it or hate it feeling
- Butte trumps it for gain, solid if somewhat boring presentation
Overall I feel that the Butte is rather expensive for what you get. Even ignoring the issues I encountered (which could entirely be due to factors on my end... though I experimented with quite a range of equipment to try to minimize that), I did not feel that the sound quality alone would be worth the $500. The compact form is quite nice, but within that size and price bracket I'm now at the top end of the portable amp list.
Butte, Bottlehead Crack, Esoteric CD transport and DAC
Apex Butte and iBasso D10
RMAA comparative results vs iBasso D10
Draw your own conclusions, or not, whatever.
frequency response (swept)
frequency response (multitone)
intermodular distortion (swept)
total harmonic distortion