Entropy.

An update on Schiit products for those that are inclined. Most of the below news was provided by the founder of Schiit, Jason Stoddard. 
 
Recap:
-Modi has increased in price.
 
The Schiit Modi (Now dubbed the Modi 3E) has increased in price from $99 USD, to $129 USD. With this change comes a switch in DAC chip, from AKM (who unfortunately suffered a factory fire a while back), to ESS. The specific chip being used here is the ES9018, and measures slightly better than the outgoing modi 3+.
 
On a separate note, the lifespan of the Multibit Modi was extended due to the AKM factory fire. Seeing that Schiit has switched suppliers, expect EOL for the Modi multibit in the first half of 2022.
 
-Silver Schiit products have increased in price.
 
Due to now utilizing a new clear-anodization process, manufacturing silver variants of Schiit products has become more costly. This has resulted in the following price increases:
$10 for small-size units (mani, loki mini (the Magni and Modi are excluded)), $20 for "medi-small" sized units, (Lokius), $30 for medium-sized units, (Asgard, Bifrost, Jotunheim), $50 for "medi-large" sized units, (Freya, Aegir, Vidar), and $100 for large-sized units (Ragnorak). Pricing for the black variants have not changed in price.
 
Note: Jason Stoddard (founder of Schiit) claims that these price increases are not going to become monthly affairs, and that this is a rare, and much-needed price adjustment.
 
-New Schiit coming in hot.
 
Jason has stated that 2021 was a bit of a train wreck, due to supply shortages and component price increases. Many products were pushed back, but this year, he has high hopes. The Tyr, Schiit's monoblockable, soon-to-be TOTL poweramp is slated to launch this year, and has already entered production. A photo of it can be seen on the Loki max product page.
 
The Folkvangr, a 10-tube... Yes, 10. tube. Headphone amp, additionally, has also gone into production. This will likely be Schiit's TOTL headphone amp, with sources claiming that the pricing will be around 10x the vali, or around $1500 USD.
 
To top off the upcoming lineup, we have the Schiit URD: a CD transport that has entered beta production and was shown in a recent Livestream. It is said to have Schiit's unison USB output, optimized for their DACs.
 
Finally, Jason has recently said (Feb 3) that Schiit may be launching some additional, yet-to-be-disclosed products in the near future. And I quote:
 
"1. We still have new products coming, some shockingly good and affordable, some maybe just shocking (or industry-redefining?)
2. The first of the shockingly good stuff is coming soon.
3. The first of the affordable stuff is coming soon.
4. We continue to improve things, and we are seriously working on reducing prices wherever we can."
 
Sources:
https://www.hear.audio/2021/03/22/jason-stoddard-of-schiit-audio-drops-the-list-of-2021-products-going-into-production/
https://www.head-fi.org/threads/schiit-happened-the-story-of-the-worlds-most-improbable-start-up.701900/page-5871#post-16797999

Note as a precaution: Yes, I posted this a little while ago on reddit, this isn't stolen- I'm just trying to spread the information a bit. 

Summary
 
The US is considering processing digital currency in addition to paper money. This isn't crypto related, its about providing a public alternative to debit or credit cards, as they are all run by the private sector. Presumably with no fees.
 
Quotes
 
My thoughts
Why was this not done 20+ years ago? I never understood this. Why does the government manage paper money, but not digital money too? Why am I paying private companies processing fees? Shouldn't it be the government maintaining that? Makes absolutely no sense to me why this wasn't done decades ago. There will be little reason to even use cash once this is implemented, as the only reason I ever use cash is so I can avoid paying fees to private companies to profit off of.
Credit cards will still have use of course. They would still likely have better fraud protection, and of course they help in making large purchases.
 
Sources
https://www.npr.org/2022/02/06/1072406109/digital-dollar-federal-reserve-apple-pay-venmo-cbdc

Watched this earlier today, great watch. Angry Steve is the best Steve

I come from the world of medical acoustics (Audiology) and not from a consumer side, but yes, Bluetooth does cost more. 

The tech / licensing / code compliance side of things all certainly add costs. However, in order to cut the cord it turns out that you actually have to cut the cord, which also removes power. Now the devices have to be independently powered which includes batteries, chargers, and of course more regulatory compliance. 

More points of failure also tend to bring with it more failure, which adds to a companies back end in the form of warranty and support issues. 

I am sure there are some additional complications that I am not covering, but this should roughly answer the question. 

I'm a similar case to you and shear. Oftentimes I just listen late into the night with apple earpods, pretty close to sleep and with no distractions in my room. Even with a suuper unresolving setup, I often find myself picking up cues that I don't hear in my headphone or speaker setups. 

I like to blow up said audio device with a HV pulse generator. Something capable of outputting 15 - 20 kV in less than 5 us does the trick. By the time I've got that particular audio device back up and running, I'll know more than I ever wanted to know about it. 
 
In all seriousness, I usually listen to it carefully in a dedicated session. I prefer to do it in a pitch-black room to minimize distractions (I'm a highly distractable person). After a while, I'll turn the lights back on and write down anything I noticed, then spend a few hours studying the schematics (if available) or taking some measurements to try and quantify what I'm hearing..

Audio naps are the only way I've found as well. Gotta turn off all your other senses to heighten what your brain can pick out of those squishy transducers.

It's really going to come down to what you try to use with the motherboard. Most gaming and "consumer" (think wired sony wh-1000xm4's and the like) headphones should be fine- albeit most of them aren't really recommended. 

Deva pro came out for $30 extra pretty recently. Improved dac module (and it's r2r for some reason..), smaller form factor, headphone can be used with single/double 3.5mm cables, the deva now has the stealth magnets, ect. No power specs on the bt module now, though, would assume it's lower.

A decent option that may actually be an upgrade would be the Hifiman HE400SE.

Deva pro came out for $30 extra pretty recently. Improved dac module (and it's r2r for some reason..), smaller form factor, headphone can be used with single/double 3.5mm cables, the deva now has the stealth magnets, ect. No power specs on the bt module now, though, would assume it's lower.

The Hifiman Deva Wireless is ~$300. At a much lower price point, the KSC35 wireless is cheaper and good-sounding but the battery life and interface aren't very good.
 
If you plan on gaming, none of these will be sufficient. Bluetooth latency is usually 100-200ms. You'd have to look for aptX-LL or a proprietary wireless standard.
 
Sennheiser used to make wireless open backs for movie watching (RS120, for instance), which should have reasonably low latency, though I can't comment on how good they are.
 
 

TLDR: You'll usually get better quality from USB. Optical specifically is often best avoided.
The 'bits are bits' argument is not true in audio as it ignores some aspects specific to digital audio transmission protocols.

Long Version:
So there is a lot of misunderstanding surrounding digital audio. With the 'bits are bits' argument often being used.

It's true in the sense that the actual CONTENT of the signal, the audio data itself, the 1's and 0's will either reach the DAC intact, or they will not.
There are no 'audiophile bits' and as far as data integrity goes, optical SPDIF, coaxial SPDIF, AES, USB, I2S or anything else will be able to get the exact same data to the DAC.

BUT, the issue with audio is that it is not purely about data integrity. TIMING is important too. If you have exactly the same audio content, (ie: Exactly the same PCM samples) but they are converted at different times, you'll get distortion.
This is called jitter.
 

 
USB is an 'asynchronous' protocol.
This means that the timing is actually controlled by the DAC.
A super simplified explanation is that audio data from your PC is sent to your DAC, often in chunks at a time.
This is put into a buffer on the USB receiver of the DAC, and then the DAC uses it's own internal clock (crystal oscillator) to determine when to convert these samples.

When the buffer is getting low the DAC instructs the PC to hand it some more data and it sends more to put into the buffer ready for conversion.

The DAC is dependent on its own clocks for timing accuracy, and whether you plug this DAC into a Mac, a PC, a Pi, or any other device, the jitter performance will be absolutely the same. The timing with which the source device sends data to the DAC makes absolutely no difference so long as the DAC always has the next sample in the buffer ready to convert.


SPDIF is a 'synchronous' protocol. And unlike USB, the source you use DOES have a direct impact on the quality of the output of the DAC, even if the data itself is completely identical.
Why? Because with SPDIF, the clock signal is actually sent by the source device (PC), NOT the DAC's own clocks.

Data is sent in a constant stream, accompanied by the clock signal, and so if there is additional jitter on that given clock signal, the DAC itself will be converting samples with less accurate timing and the analog output will be less accurate.

We can show this quite easily by measuring the output of the DAC.
This for example is the Schiit Yggdrasil, playing a 'J-Test' file, when fed SPDIF from a good source:


 
And then this is that same DAC, playing EXACTLY the same file, with no data integrity issues, but with a poorer quality SPDIF source that has higher jitter:


 
These are not digital simulations or readings, these are measurements of the actual XLR analog output of this DAC.
 
Many DACs will have methods of attempting to get rid of jitter from a poor source device.
One common method is a PLL, however a PLL does not eliminate jitter, it's more accurate to describe it as jitter attenuation. The level at which it can do so is dependent on both the design of the PLL itself (performance of PLLs varies MASSIVELY), and the reference clock used. As the PLL can only ever be as accurate as the clock you're using as a reference.

So unfortunately, in audio, bits are not always bits. And other aspects of the digital source can absolutely make a difference in quality even if the 1's and 0's themselves are no different.
This is why there is an entire product category called 'digital to digital converters' which take audio data from your PC, and output over I2S, AES, SPDIF etc, with exceptionally low levels of jitter. The idea being that you can use these to gain an improvement in jitter performance over your DACs internal clocks when using USB. And in many cases these work quite well.

An example being the singxer SU-6: https://shenzhenaudio.com/products/singxer-su-6-xmos-xu208-cpld-femtosecond-clock-usb-digital-interface

And the last thing to mention would be noise. As @H713 mentioned, optical offers galvanic isolation, meaning there is no actual electrical connection between the source and DAC (cause it's just light). This prevents any sort of noise being conducted from the noisy, beefy gaming PC to the DAC which can degrade performance.

Some DACs will have this internally but typically only at the higher end of things.
But DDCs like the singxer SU-6 will almost always include this feature as well so they can provide an exceptionally low noise output on SPDIF/AES/I2S even if your PC is horrifically noisy.
There are also products to do this on USB such as the Intona 7055-C https://intona.eu/en/products/7055-c

Generally though the noise advantage of optical is not worth the often drastic hit to jitter performance. ESPECIALLY if you're using a PC. Seriously most motherboard optical outs that I've tested were beyond awful it's a miracle some dacs can even successfully lock to them.
 
 
 

The impedance itself doesn't dictate how hard a headphone is to drive. The sensitivity is actually more important, and both have to be considered.

You can have a very high sensitivity high impedance headphone that'd take almost no power at all, or a very low impedance, low sensitivity headphone that requires a ton (such as the infamously hard to drive Hifiman HE-6)

It's very likely that trying to construct a dual-impedance design would inherently cause challenges for sound quality generally. And it'd make more sense to just have a more sensitive headphone that won't require too much power and therefore can be used wirelessly for long periods

Yes, the stock cooler for i5-10400f is suitable. Your cpu might run a little toasty, and might not look the best, but It should absolutely be fine. Usually for a 10400 build I'd actually reccomend the stock cooler most of the time. 

the issue with a lot of sub $200 DAC/amps and  older $100 DACS is the amplifier stage and some older DACS are their DAC implementation is usually bad. the e10k has a bad sounding Amp while for the budget and AGE the DAC sounds bad its basically bottlenecked by the amp. These days most companies Nail both the amp stage and DAC implementation especially with sigma delta DACS so its really hard to tell the difference between most Affordable DACS. there are slight differences but are much less noticeable than say the differences between amplifiers. to the point where they are near insignificant for the most part. 

I'm the same. I'll almost always avoid EQ other than in some cases a very small bass increase.
But pretty much never do EQ other than that on headphones.

Tbh nowadays most amps are practically the same as well even between different manufacturers.

TI6120A2 or OPA564 opamp based amps include pretty much the entirety of the 'affordable' headphone amp market and even some much more expensive ones:

Schiit Magnius
Basically all topping amps (A90, L50, L30 etc)
Basically all SMSL amps (HO200, SH-9, SP400 etc)
Any THX headamp (THX 789, Benchmark HPA4 etc)

To find a notably different sounding (and differently built) amp you actually have to look pretty hard in most cases. Though there are some gems available like the Asgard 3 and Singxer SA-1
 

yeah I've experienced this as well. and pretty much avoid opamp based amp for this reason. I love my asgard 3 and is currently my Daily driver due to its performance and great pairing with my dt 880 600 ohm, and it's excellent performance for sensitive gear like IEMS. I like the sound of these vs any of the amps you've listed with teh exception of the singxer which I've heard praised by my audio circle but have yet to hear myself. other amps I love in the sub $700 range are the lake people G103 s, G111, and the Rebel amp. the RNHP deserves a mention I just dont love it because it doesn't fit my personal preference. 

I'm generally not a fan of opamp based headphone amps either. They're not necessarily 'bad' but I've never heard one that I went 'WOW!' with.
Though to be fair they have gotten a lot better. I got the SMSL HO200 in for review recently and it's miles better than earlier 'nested feedback' opamp based amps such as the THX 789 or Topping A90 were. Though they're also doing a sort of hybrid discrete approach by doing the 'OP' stage discretely, and the amplification via the opamp itself. And that may be contributing to the improvement. It's a nice amp for the price.


(SMSL HO200 internal. This approach to my knowledge was actually first done by chord, and is used in products like the DAVE DAC)

My favourite products are all discrete, though there are certainly plenty of bad discrete designs. It's not a guarantee of quality at all. Just that IMO the majority of the best designs are discrete. But not all discrete designs are good.

I remember I noticed a nice difference which I like. I had the Asus portable monitor with the ESS built-in DAC and I liked the sound. I had the Fiio E10K and this crap is identical to my onboard audio but I needed it as a starter and to feed my DT880 250ohm. The hardware may be the same, I guess it's how the manufacters set up their configs? 
 
I don't like to use any EQ otherwise it's a bad headphone, but that's my honest opinion tho.

Just a warning from somebody who repairs this stuff, i have seen a lot of KRK loudspeakers die quite early.
They for example had the "black goo of death" problem, but even the ones, that were bought after that, seem to die far too easy and repair of them often is more expensive than they are worth.
 
Be aware this is only the experience of one repair guy and maybe the KRK at the moment just are by far the most common loudspeakers in my area, but they really are by far the most common brand of powered speakers, i get for repair.
 
Oh and please dont buy Behringer... They sometimes have products that work quite well, until they dont anymore, because all the mechanical parts usually are just the cheapest avaiable fail really fast and are really hard to replace.
 
Now to my tech-tip: If you are really on a budget, there are a lot of loudspeakers from the 80s and 90s that sound really well and are very cheap. The same applies to amplifiers. I personally am a fan of older Sony, Harman Kardon etc... The only problem with this is, the amplifiers are old and might need service by now. But most loudspekers, if they work and dont have foam surrounds that deteriorate over time, they usually are just fine.

I used to be pretty much a non believer as well. Thinking most differences only came from the output stage of the dac and how well implemented it is and if it measured well. That's all the mattered. Until I started borrowing friend's bifrost2 and ares 2. I borrowed several sub $500 sigma delta DACs as well and really couldn't tell much of a difference vs my current sigma delta DACs. But the r2r DACs sounded great and had a actual noticable difference like the bifrost made things sound more fun and had better timbre and the ares 2 had better staging and better timbre. A few months later when I had the chance I picked up the bifrost for myself. 

Yep a LOT of delta sigma dacs are practically the same product.

Look at practically any <$1000 DAC and there's a damn good chance that it's an ESS9038, meanwell switchmode PSU, XMOS USB receiver, and one of a small handful of TI opamps.
They all sound incredibly similar because...well they are.

That's not to say there aren't differences. A D1SE which has a much nicer power supply, clocking, and output stage design than say a Topping E30, does indeed sound better and objectively performs better.
But the differences between most of these similarly designed dacs are very small compared to the difference between something like a Topping D90SE and a dac with a fundamentally different design like as you mentioned a denafrips ares 2. Or other delta sigma dacs with quite different designs such as something using a burr-brown DAC chip (ifi uses these in most of their products). Or higher end discrete delta sigma stuff like esoteric/dCS/chord

So I've been fortunate to have the opportunity to try quite a lot of high end audio gear. Though I primarily focus on headphone listening as whilst I enjoy speakers, I don't currently have the space to make them worthwhile and also do not wish to disturb my housemate or those in neighbouring apartments. In future though I'll move more into that.

Here's a brief summary of my experiences with various bits and pieces (I'll add more to this list later):

(I also have reviews of some of these on my youtube channel https://youtube.com/goldensound and also post objective measurements and testing of dacs/amps on my website https://goldensound.audio)

HEADPHONES:

Hifiman Susvara: These are to date my all-time favourite headphone. They RRP for $6000, but if you ask dealers nicely you can usually get them for about $4500 as hifiman gives dealers large margins.
These are without a doubt the most convincing headphone I've heard with an immense sense of realism and presence. Detail retrieval is amazing, timbre is staggeringly good, and whilst the soundstage isn't necessarily as 'expansive' as something like an HD800, the quality of it is stunning in that the positioning and imaging of stuff is just spot on. It's not 'huge', but the 3d presentation is brilliant.
These need ridiculous amplification though. I actually run mine on a speaker amp and I've only heard one 'headphone' amp that actually drives them properly. You can get them loud on plenty of stuff, but if spending this much on the Susvara, get a speaker amp to get the most out of them.


Abyss 1266 Phi TC: Perhaps the most fun headphone you can get. These are far from a 'normal' headphone in many ways. Firstly in aesthetics and build quality (you can literally run these over with a car and they'll work fine, abyss actually did that). But also in sound and how you use them. These are not intended to fully seal against your head like most headphones, and the frame has an adjustable joint at the top that allows you to space and adjust the fit to tune the seal and get your ideal bass response.
These headphones are not a 'natural' or realistic sound, but they are incredibly energetic, forceful, detail-forward, and stage is monsterous.
These things put such a smile on my face.


Stax (Various Models): Estats are an interesting group of headphones. They have a key advantage in that the resolution and detail retrieval of them is in many cases absolutely insane. I owned a pair of Stax Lambda Signature (released in 1987) which are to date the thinnest driver Stax ever made at about 1 micron thick, and also the most resolving headphone I've ever heard including compared to other estats.
BUT, whilst detail is amazing, I have never heard an estat that does everything else particularly well. Bass response feels thin and lightweight, staging can often be quite wide but with no frontal depth at all on the 'Lambda' series stax, and timbre of both vocals and instruments can come across etchy and unnatural even though there is immense amounts of detail.
I ended up selling mine. I'd recommend people try estats, but don't buy them until you've actually spent 30-60 minutes straight listening to one. They're a huge 'WOW!' moment when you first put them on, but as you listen more you start to go "ehhh actually it doesn't do X, Y and Z very well".
Totally get why some people love stax/estats, but they aren't for me.


Sennheiser HD800S: This is a headphone that gets a lot of praise, hate, debate and there's a lot to say about it.
Firstly, there are a few versions of the HD800; the original HD800, a 'late revision' original HD800, the HD800S, and then the HD800 'SDR' which is a user-performed mod. The HD800S is actually pretty much sennheisers own take on the SDR mod after it became massively popular among original HD800 owners.
(There's also the HD820 but we don't talk about that...if you want to know how that sounds, imagine listening to music with your head underwater in a bathtub. And then anytime there's supposed to be bass, you just whack your head against the bottom of the tub instead).
I've heard them all and whilst a lot of people swear by the HD800 with SDR mod, honestly I'd say that either the HD800 SDR or HD800S are the ones to go for and the HD800S has a slightly more agreeable tuning to most people. 
The stock HD800 is too aggressive and sharp for most music, and the HD820 is a complete and utter mess so just avoid those.

The HD800 is a headphone that I would describe as incredibly picky both with the sources/amps you use it on, and the genres you listen to. I use mine mayyybe 2% of the time, but I could never bring myself to sell them because quite frankly, for those 2% of songs, nothing else quite does it like HD800 does.
The HD800 is a unique sounding headphone, and nothing else sounds like it. It's a headphone that could almost be described as bright and warm at the same time. With a pushed back subbass and upper midrange dip, and this results in an incredibly technical, 'matter of fact' sound that will absolutely shove any sort of mastering flaws down your throat. This thing is a microscope for music and if you listen to even 'not so great' produced tracks, the HD800 will not be enjoyable. But then you listen to a beautifully recorded track like Grissini Project's 'Merry go round of life' ( https://song.link/gb/i/1463873106 ) and wow....
The technical capability of this headphone shines through like nothing else on well produced tracks, and the famously huge staging makes orchestral music in particular quite an experience.
Many people also enjoy using the HD800S on tube amps, as the high output impedance of tube amps will lift the bass response and create an overall warmer and more full sound on the HD800 than most solid state amps and it really does go well. The HD800 is a headphone that I wouldn't recommend getting as your main/daily driver as it's NOT a good all-rounder. But there's good reason why you'll see it sitting happily, and deservedly alongside $5000+ headphones in many collections.

Hifiman Arya: Have to mention this one as this is probably the headphone I would recommend to most people as an absolutely amazing main/all-rounder headphone.
There are two versions, the stealth and the V2. (As well as the 'OG' or 'V1' which you can only find used). I've heard all three and would say that most people are going to prefer the stealth but they're all great.
They're great from a practical standpoint as they're probably the most comfy headphone I've tried, and also they are not ridiculously hard to drive like their big brother the susvara. Though you're still going to want a decently powerful amp for them.

The aryas are a headphone that boasts impressively large soundstage, and to back it up, absolutely spectacular layering and 3d presentation. The Stealth is a bit smaller sounding than the V2, but in exchange is more resolving and the low-end is quite a bit more forceful and punchy.

Aryas are a neutral to slightly bright tuning with impressive technical capability and a sense of space, realism and immersion not offered by many other headphones at or below this pricepoint.

ZMF Verite Closed: These are a very warm, beautifully vivid and coloured sound which unlike many other warmer headphones, retains exceptional detail retrieval.
Timbre of vocals and instruments is lush, rich, and these can be described best by imagining that someone turned up the saturation dial on real life sound. They're beautiful.
Oh, and they're absolute works of art. The 'stabilised' ones sell pretty much instantaneously, but if you CAN get your hands on one, you'll have an incredibly unique headphone.


 
I've heard and own a lot of other headphones, but those were some of my favourites.


Amplifiers:

Amplifiers are always going to be a bit situational. Different headphones need different things and work best on different amps. There isn't a single 'best' amp. But here's some that I particularly like:

Benchmark AHB2: This is technically a speaker amp, but it's one of the objectively highest performing speaker amps in the world (in fact I think it's THE highest performing amp unless something has beaten it recently). And to the point where it actually offers more dynamic range and better performance than a lot of headphone amps do. Even though it has immensely more power at 100w @ 8 ohm (25w @ 32 ohm).
I originally bought this specifically for the Susvara, and it sounds absolutely amazing. But I also have since begun to use it as my reference amp for headphones generally because...well..it's fantastic. It's one of if not the most resolving amps I've tried, the things it does with bass and lowend are incredible. Bottomless subbass and ridiculous levels of control especially with planars, and it also offers some of the most impressive representations of subtle spatial cues I've heard. The clarity of space between instruments and the recording environment is scarily good.
In terms of tuning/tonality it's absolutely neutral in my opinion. Not THX 789 'neutral' (that thing sounded glary and harsh), but ACTUALLY neutral done right. It's an incredibly impressive amp and I doubt I'll be getting rid of it for a LONG time.
It's also quite compact for a speaker amp so sits on a desk nicely. 


Ferrum OOR: This is likely my favourite dedicated headphone amp currently. It comes standalone but can also be purchased with their 'HYPSOS' power supply which offers transient current correction and some other nice features which to put it simply give the amp more 'oomph'.
This is a massively detailed amp with a tuning juuuust slightly bright leaning. But not too much. It's also impressively powerful with 9.5w @ 32 ohm (spec says 8w @ 50 ohm but I measured slightly higher than that on my unit).
This thing can power the hardest to drive headphones with ease, it's the only 'headphone' amp I've heard that does Susvara justice, and all the while you can run sensitive IEMs on it without issue too.
Objectively it's very high performing, and subjectively it's an energetic, detail-forward sound that will satisfy those wanting something of an analytical signature but does not go too far as to become what some would describe as 'sterile' or 'clinical'. Bass speed and impact on this amp is amazing.

Singxer SA-1: Easily my favourite <$500 amp. Objectively one of the highest performing headphone amps available. Fully discrete design, with a sound that leans just a notch warm of neutral.
It's an amazing all rounder, with 6w @ 32 ohm so will happily power most headphones without a problem, and offers technical performance in terms of detail, soundstage, accuracy of timbre and separation that punches FAR above its pricepoint. 
The only issue is that some people might find it to be juuuust a touch too soft sounding. It's detailed, but some people might want something that's a little bit more forward/in-your-face with stuff.

Woo WA33: An immensely impressive (and unfortunately ridiculously expensive) tube amp. For those who are under the impression that tube amps are warm/soft/not high performing and people just like them because they're smooth, one listen to this will change your mind in an instant.
This is a massively incisive and detailed amp, with immense amounts of power at upto 10w@32 ohm. It has absolutely incredible definition of lowend, delivered with force and impact that few amps can rival, and a timbral quality that whilst slightly more 'rich' than real life would be, is beautifully incisive and transparent. This amp completely changed my mind about tube amps in general and I'm sad that I've only got one here for a short period of time. It's absolutely incredible and I'd love to keep it.
Also, it looks fantastic:



Will add more amps to this list later, I've got quite frankly a silly number of them here currently so can't put them all on the list yet 😛

DACs:

Dacs are a category that seems to needlessly stir up arguments. With many arguing that 'it's just 1's and 0's!' or that DACs should not sound different at all.
When this is simply not the case. DACs might be RECEIVING digital data, but they are still an analog component and the way in which dacs operate can vary hugely, and as a result, so can the sound. In fact there are often larger objective differences between DACs than there are between amps. And also some measurements and factors that affect DACs (such as jitter) which do not affect amps at all.
So to preface this section, yes, DACs do sound different. Though worth noting that the differences between various lower cost dacs (Under $1000 especially) are usually much smaller as many of them are incredibly similar in design. If you look at most DACs on the market at affordable prices they'll nearly all be a meanwell PSU, XMOS usb receiver, ESS DAC chip and TI opamps.
Whereas at the higher end, different companies offer various discrete, proprietary designs with in some cases some REALLY clever solutions to problems facing D-A converters. And this is where most of the differences and upgrades will unfortunately be found.

SU9n - Best affordable DAC: Won't say too much about this one other than that it's one of the best DACs you can buy without spending around $700. Objectively fantastic, subjectively fantastic and better than most competitors I've tried. Highly recommend to just about anyone.

dCS Bartok - Most disappointing DAC: This DAC costs about $15,000, and it sounds quite frankly mediocre. I was really excited to try this and so disaappointed when I did. It's too smoothed over, lacks any real sort of incisiveness, impact, or engagement, and the good stuff about it like detail retrieval or soundstage doesn't really beat MUCH cheaper stuff like the Gustard X26 Pro ($1500). 
Objective performance is also 'fine' with nothing particularly impressive about it either.

Holo Audio May - Best DAC I've heard (so far): This is currently my main DAC, and even after having heard some incredibly expensive (and impressive) options like the $20,000 rockna wavedream signature, I still feel that the may is the most impressive DAC I've tried, and is one of the few components I've tried that actually brought me to tears. 
Objectively, it's using a design called 'R2R'. Most DACs nowadays use a different approach called 'Delta-Sigma' which is a lot easier to get good performance out of and can be made much more affordably. Building an R2R dac with good objective accuracy is very difficult, and some in the past have argued that you CANNOT get the same level of performance from an R2R dac as you can from delta sigma. (Though many people subjectively prefer R2R to DS even though objectively they're usually poorer performing).
Well, Holo showed that that isn't the case. Building a DAC with THD+N performance that rivals some of the highest performing delta sigma dacs, and the highest dynamic range (140.5dB) of any DAC currently available.
Couple that with other over-engineered features like full laser diode galvanic isolation on the USB connection to prevent any noise or ground loop issues from the PC impacting the DAC (and a fully proprietary USB receiver design that boasts some of the lowest jitter and highest sample rate support I've seen), or a separate chassis, dual mono, multi-stage regulation PSU, a fully discrete, Class-A output stage, the most powerful PLL (jitter attenuation) implementation of any DAC, and you're left with something that is from an engineering standpoint, quite frankly incredible. Not to mention visually stunning. This is just the main converter chassis:


And subjectively, well, it's amazing. The most resolving DAC I've heard, the most realistic timbre and spatial presentation of any DAC I've tried, its, honestly hard to describe the 'sound' of this DAC because it's simply the closest I've heard to being 'there'. The closest I've heard to real life. 
As mentioned previously, this product on many occasions brought me to tears with how beautiful, immersive, and the sense of utter realism that this DAC provides.