Shortest Way 51 Amp Impressions (Only)

Thanks man! I’m basically trying to get more dynamics and less veil with my HD650s than the Vali 2 is giving me with the stock tube - I assume a tube upgrade in the Vali would help, but I feel not likely enough of an uptick. Seems like SW51+ may be an answer.

 

I may not be the best person to ask about the Vali 2, but I just do not believe a tube swap will get you close to SW51+ with HD6XX. SW51+ is just on a different level, and it almost kills the veil on HD6XX, while keeping the pluses of the SW51+ (SS type sound without the standard SS stereotypical faults).

 

I can say for me it did help. I swapped in a Phillips PCC88, which is a bit more forward and punchy, with a bit more of that upper shimmer. Just a little expansion on both ends of the spectrum. Vali 2 can actually have some of that layering of fine upper-mid/treble information with the right tube matched for those headphones. Definitely. I wouldn't ask for miracles. It won't breathe new life into your HD650's, but it can help. I wouldn't spend too much. I think I got mine for ~$20 and wouldn't have spent more, knowing what I know now.

It was enough for me to get a few years of enjoyment out... I say as I wait on my SW51+ to be completed

 

I have enjoyed listening to the SW51+ so much in the last few weeks that I felt compelled to post impressions. This is one amp worth considering for best value amp for the budget conscious audiophile*.

Listening chain - Tidal > Pi2AES (Volumio) > BF2 > SW51+, Jot (Balanced), Liquid Carbon (Balanced) > HD800 (SDR Mod), HD6XX, TH-X00 (Purpleheart)**

To my ears, amp sounded U-shaped. Bass is meaty with more emphasis on sub-bass over mid-bass. Mids sounded distant , slightly grainy and affected by a bit of bass-bleed. Treble is quite smooth, detailed and non-fatiguing. Despite a narrow soundstage, positional cues are easy to pick out across a 3D-like stage. Overall sound had great detail, dynamics and timbre and totally excels in these areas when compared to the other amps below. Being a soundstagehead, I thought this would be too claustrophobic for my taste but I quite enjoyed it. To me it sounded like being dead center in a snow globe and is a good contrast for the wide speaker/out of head experience I am usually chasing.

vs Schiit Jotunheim (balanced)

The amount of bass I heard from SW51+ on the HD6XX and TH-X00 made me think this was similar sounding to the Jot but with more microdetail. In comparison, Jot is more prominent in the mid bass and felt like it had more slam. Mids sounds quite clear and present but offset by bright and glare-y treble. Sounded quite one dimensional. I would choose SW51+ over Jot to pair the HD6XX. Although the treble still sounds a bit veiled, I prefer the laid-back presentation whilst softening the mid-bass emphasis.

vs Cavalli Audio Liquid Carbon 1st edition (balanced)

The LC has more treble detail but poorer low bass extension and a variable yet underwhelming mid-range response (either too soft and distant on low z output and too up front and grainy at high z output). However, I was hoping that the SW51+ would be a better pairing with HD800 but unfortunately the pairing sounded quite cool with anemic bass and slightly harsh treble still prominent.

Conclusion

It is not the perfect amp (small bass bleed in the mids, small soundstage) but provides a very addictive and musical listening experience. It is significantly better than similar-priced amps I own.

* Assuming high-Z Sennheiser headphones where matching is important rather than the next flavor of the month items.
** Listening was on low-Z output and without any extra anti-vibration pads. With pads it helped alleviate bass bleed in mids (made male and female vocals sound more natural and clear) and lessen HD6XX veil. High-Z output also performed similarly but to a much lesser effect. But YMMV and not recommending buying peripherals over better headphones/amps/dacs/source etc.