Some thoughts about the Beyerdynamic A20 amp

The Beyerdynamic A20 is a straightforward headphone amp with RCA in, and 2 1/4 inch Neutrik headphone jacks out. It has a very clean Teutonic design reminiscent of the Beyerdynamic A1, features quality components (with a very smooth Alps pot) and has RCA out that is hot (when the input is active) even when the device is turned off.

It puts out 170 mW at 250 ohms and 100 mW at 600 ohm, so not a slouch powering higher impedance headphones. It is worth noting though that the rated output impedance is a whopping 100 ohms.

Looks wise, it is very pretty, and reminds me a lot of the Burson Soloist (in terms of the quality of construction and the solidly manufactured aluminum enclosure.)

What does it sound like?

Sound wise, it is transparent and neutral. A great pairing with Beyer headphones (after all Beyer designed the amp), but it does struggle with power hungry planars. I did not have the opportunity to hear the A20 with IEMs but from what I have read the pairing is hit-or-miss.

What's the competition?

The Burson Soloist SL has a brighter, more forceful sound overall, and also has gain selection. Keep in mind that the Soloist SL puts out 2W at 16 ohms, so it is much more suited for higher end orthos. In the head-to-head between the two the Soloist SL wins, unless you are looking for a transparent amp.

The Schiit Asgard 2 isn't in the same league, and at its usual $250 price point, is clearly the more value-rich selection from a price-performance perspective.

The most favorable matchup for the A20 is the Violectric V90. Both have pre outs, dual headphone jacks, and similar sound profiles. The V90 does have a price disadvantage, though, compared to the A20 on sale.

The best way to think of the A20 is probably to consider it to be a sophisticated version of the Objective O2 amp. Is it worth the money over the O2? It depends if you have the discretionary income to throw on an amp that isn't feature rich. In sum, if you are assembling a neutral setup you need to take a look at the A20, especially if it is on sale. But from a purely price-performance perspective, you may want to take an equally close look at the O2.

Some thoughts about the Little Dot Mk IV SE, and how it compares to the Mk III

How does the Little Dot Mk IV SE differ from the Little Dot Mk III? 

Well, both are OTL (output transformer-less) tube amps, made by Little Dot in China. The Mk IV SE is supposed to be an upgraded version of the Mk III, with a premium price. So what are the differences?

[1] upgraded tubes - instead of stock GE5654s, you get a pair of Mullard M8100s, and also updated 6H30P-i power tubes. It should be noted that my LD Mk III came with stock RCA EF95 tubes (which was a pleasant surprise, because they were 70s vintage. I might have lucked out).

[2] The 1/4 plug on the SE is a Neutrik

[3] The SE has "upgraded" RCA connectors

[4] The SE has pretty gold tube protectors

[5] The SE has a different volume knob

In theory the Mk IV SE is supposed to have a different ALPS pot than the Mk III, but every internal shot I have seen of the SE has the same pot as my Mk III.

David ZheZhe (Little Dot seller) claims the SE has "premium circuit component upgrades in key signal path locations". As to what these upgrades actually are (apart from the ones I noted above), your guess is as good as mine.

So are the differences worth the extra money?

As you start going up the Little Dot product ladder, you begin to slowly start losing the price-performance advantage you have with the Mk III.

You can get M8100s in abundance on ebay for $20-40 for the pair. The upgrade to the Elektro-harmonix 6H30P-i isn't really a deal unless you get a NOS Elektro-harmonix, since the new "reissued" EH 6H30P from the Reflektor plant are, well, reissues.

If you are upgrading power tubes you might as well get a couple of Novosibirsk Gold Grid 6N6P-i from the 70s/80s (before the Wall came down!) for $10-15 for a pair (keep in mind that driver tubes typically last longer than power tubes, and the Gold Grids with the "OTK" quality symbol were engineered to last a while).

Who should get this? 

Those that want to experience OTL tube sound, and don't have the money to get a Woo Audio WA3, a Woo Audio WA2 or an Eddie Current Zana Deux.

Also those who own a Sennheiser HD600 or HD650, the pairing is excellent.

Keep in mind that the Little Dot Mk III is a better bang for your buck than the Mk IV SE. Also keep some money aside for tube rolling.

Who should not get this? 

Folks getting their first amp (get a solid state amp!) or those who run orthodynamic headphones as their primary headphone (bad pairing, as are the Beyerdynamic T90 and T1).

Also folks whose budget will not extend to tube rolling.

And this certainly isn't "endgame" material, if that is your goal.

Folks wanting the ultimate price performance ratio should probably look at the Little Dot Mk III. And those who want a transparent amp without coloration or distortion should not touch this with a 10 foot pole.

Who are the competitors? 

The Bottlehead Crack, of course, although the Crack is a DIY OTL tube amp. And the Valhalla 2 is a serious competitor (gain switch, preamp out) especially if you are looking for a more transparent sound, as is the Woo Audio WA3 (although that costs about 2x the cose of the Mk IV SE).

What you need to know about the Beyerdynamic DT990 Premium (600 ohm version)

The build

The DT990 Premium features impeccable build quality, and superb comfort, especially for extended listening sessions. They look and feel like high-end headphones.


The sound


These are open headphones, and leak sound significantly. All Beyers have a V-shaped frequency response curve. In general, the DT990 has the most V-shaped curve when compared to the DT770 and 880, with prominent bass and a somewhat bright treble.

The 600 ohm version of the 990 Premium follows the same general rules, but its bass is a little less prominent, most likely because of the reduced clamping force. The low end is controlled, and if you amp them appropriately, nice and tight.

Mids are neutral, vocals are well represented without tonal distortions or coloration.

It has the same 9000 Hz spike as the Pro version, and so if you are not a fan of tinkly treble then most likely the 990 premium will disappoint.


FAQs


Q: Does the Dt990 600 ohm premium need an amp?

A: Yes, it will benefit from an amp. You don't need a monster like the Schiit Lyr to power it, though. The most noticeable difference with a good amp will be tighter bass. Some mobile devices like phones and tablets will struggle to run the 600 ohm DT990


Q: Whats the difference between Pro and premium DT 990 versions?

A: Materials (more metal in the Premium version, more plastic in the Pro), and clamping force (less in the Premium).


Beyerdynamic DT880 vs DT990 Premium versions: The 880 is a lot more neutral. The DT880 does not have the sparkly highs that are so forward on the 990s. DT 880 bass is more linear when compared to the rest of the frequency profile.


AKG Q701 vs Beyerdynamic DT990 Premium: If you are a fan of the Beyer sound profile with its V shaped emphasis on the bass as well as the highs, you may find that the bass and treble are both going to be lacking somewhat with the Q701.


HiFiman HE400 vs DT990 Premium: The 990 premium has better build quality. HE400s have a flatter frequency curve. You'll notice the mids coming forward compared to the 990. A lot. HE400 bass is tighter and more controlled than the DT990. The bass isn't as prominent as the DT990, but "punchier". HE400 treble is harsher and more sibilant than the 990. Cymbals and hi hats go into "attack mode". The HE400s are heavier and a lot less comfortable than the 990s.


Sennheiser HD598 vs DT990 Premium: 990s have much better build quality. The 598s are much warmer and smoother. Mids are more pronounced with the 698s.

DAC vs DAC

Q: Do DACs really sound that different from each other? I thought all DAC chips sounded pretty much the same

A: Most DAC chips are indistinguishable from each other, but keep in mind that DACs have analog circuitry too, which changes the sound to a lesser or greater degree.

So for example I cannot tell the difference between Modi and ODAC most of the time but I can tell the difference between my NOS DAC and ODAC every time!

And between my Cambridge Audio DacMagic 100 and Modi every time (different analog circuitry specifically tuned by Cambridge Audio to sound warm for classical music)

What makes really expensive headphones so expensive?

Q: What makes really expensive headphones so expensive?

A: Essentially there are 4 aspects to the cost of any product [1] R&D [2] materials [3] manufacturing and [4] marketing. These costs may be either fixed (eg payroll) or variable (eg sourcing raw materials).

R&D is variable, so calculating the cost of R&D for an individual headphone model is difficult. Newer models still haven't seen a return on ROI costs, while older models (for example HD600) have probably recouped their R&D costs, and then some. R&D costs may be hard to figure out accurately because one technology may be used in multiple products, or may be responsible for the development of other innovations, for example the design of the HD580 enclosure and drivers directly influenced the design of the HD600 and 650 enclosures and drivers. Another great example is the Q701 -- it is in essence a K701 with modest changes. Most of the R&D cost was for the K701, and the Q701 reaped much of the benefit.

Material costs vary over time, often wildly, and are subject to supply and demand constraints. For example the price of copper, used in headphone voice coils and wires, has changed dramatically over the last few decades, and copper futures are still often volatile.

Production costs also vary, for example Q701s were made in Austria, but AKG wanted to save costs and moved production to China. But moving production to China does not necessarily make things cheaper, for example some Audio Gd amps probably cost more to make than equivalent Schiit amps, even though Schiit makes its stuff in the US and Audio Gd in China.

Many companies OEM some or all of production, which again affects costs depending on who they OEM to. And it's not just a case of folks using cheap Chinese OEMs -- some Denons for example were OEMd by Fostex, for example. And keep in mind that OEM companies typically conduct their own R&D, have their own design costs, have to retool equipment for specific products, etc, which changes cost calculations.

And finally marketing: some companies spend more on marketing (e.g. Apple, Nike, Beats) and make huge profits, while others spend very little on traditional marketing and still manage to do very well for themselves. One way to get around substantial marketing costs is to engage in direct marketing (eg Emotiva, Schiit) or to depend on word of mouth (like HiFiMan depends on HeadFi).

But eventually, keep in mind that companies will try to make as much profit as they can, so the price may be determined by what the market can support. For audiophile products, there may be a substantial markup in price just because companies know they can get away with it. A classical example of this is the Grado RA1, which has been substantially marked up when you take into account its design and materials/manufacturing cost.

Burson Soloist SL vs Schiit Asgard 2 for the HiFiMan HE500

Q: I own the HifiMan HE500. Which is a better amp for it, the Burson Soloist SL or would a cheaper amp like the Schiit Asgard 2 get the job done?

A: I would pick the Soloist SL over the Asgard2. Mainly because it puts out 2W at low resistance, as opposed to the Asgard's 1W, which would be better for the HE500. But also from a purely subjective perspective, really. I just like the design, execution and sound of the Soloist SL better than Asgard2. The variable output stage is IMO particularly well done. Plus the Soloist SL just looks better.

Now I see it, now I don't....

Q: Do different DACs sound different? What kind of DAC should I get?

A: In theory the DAC should generate the exact identical analog version of the digital source, i.e. the sound is faithfully transmitted to the next link in the chain without any additions or subtractions. This is my definition of a transparent DAC --- a DAC that behaves "like it's not there".

But in reality that's not what happens, since the additional components that make up the DAC add their own "voices" to the signal, as does the DAC chip itself.

Having said this, most DAC chips use the same digital processing method (delta-sigma) and so sound remarkably similar to each other, whether they are made by Sabre or Wolfson or Cirrus Logic or Analog Devices, or any of the other slew of DAC manufacturers. There are some exceptions, for example old-style NOS (non oversampling) DACs sound different than their delta-sigma brethren, because they operate under entirely different principles.  But by and large when you read reviews that wax eloquent about the significant and substantial differences in the sound from one DAC chip or another, you are being subjected to, well, bullshit.

Why then is there so much variation recorded between DACs? Why are some dacs felt to be "warm" and others to be "cold"?  Well, the biggest reason is that it is a matter of perception: if you approach DAC transparency from an objectivist position, then for you a transparent DAC is ideal and if you are a subjectivist listener then the same DAC is "cold" or "boring".

If you are an objectivist, you want the faithful transmission of a signal, then the coloration imparted by the analog component fo a DAC like the Cambridge Audio DacMAgic 100 is anathema.

And if you are a subjectivist, the coloring of the sound excites you just as much as the faithful transmission of the signal, and the transparent output of a DAC like the ODAC might be "bland" or "cold" or "not energetic" to you. I would argue that for such a subjectivist listener, the tonal variations offered by a tube DAC might actually be more pleasing than "the truth the whole truth and nothing but the truth" offered by a transparent DAC. If you don't believe me, ask anyone with a Grado.

Further, a DAC can pick up floor noise -- hiss from, say a laptop via the USB port, that the muddies the sound profile a ta. But the same DAC may be deathly silent when plugged into a desktop USB. Does that mean that the DAC is transparent when it's connected to a desktop but not to a laptop? By my definition, yes.

You can get around noisy USB by including a good power transformer with the DAC itself. But these are expensive, and can drive up the price of the DAC. One DAC brand that has been touted for its sonic neutrality, to the point of becoming a standard reference whenever the term "transparent DAC" rears its head, is the Bench mark DAC1, which is an expensive option.

So from price-performance perspective, does buying a DAC1 make sense? Probably not. You can get a relatively transparent DAC as cheaply as $100 - the Schiit Modi (which uses a wallwart for power), or alternatively the ODAC (which uses USB power, and is priced at $150) and these are perfectly acceptable price-performance options to something like the DAC1.

Tube versus solid state amps (the cheap ones!)

Q: How does a cheap tube amp like the Darkvoice 336SE compare to a cheap solid state amp like the Schiit Magni?

A: You cant really compare solid state and tube amps, since their sound profiles are entirely different.

If you want neutral sound (or relatively neutral sound), reliability, and true value for money I would say always go with solid state  (Magni, O2, etc.) over a tube amp.

If you want the warm tubey sound at a budget, then before you pull the trigger on a budget tube amp, you should probably also think about how much you will need to factor in for tube rolling. DarkVoice tubes are cheaper than, say those for McIntoshes, but keep in mind that something like a Shuguang Treasure CV181 will cost you upwards of $100 so after swapping the stock tubes you may be really looking at closer to $350-500 than $250. At that price point, Magni isn't really a comparable amp anymore from a price perspective, IMO you should now be looking at a totally different tier of solid state amps.

If you just want to get into tube amps for the rolling experience more than anything else, tube rolling for a Little Dot mk3 works out better than a DarkVoice 336SE because tubes are relatively cheaper and you have more variety.

Q: But doesn't a tube amp better than a solid state amp? After all, tube amps have variations in their sound when you put in different tubes but all solid state amps pretty much sound the same?

A: I don't know if tube amps are better or worse than solid state amps, just that they are different.

There is a lot to be said for solid state amps, for example: quality solid state components cost much less than quality tube components, solid state components are more reliable than tubes, and they are more efficient. If you are buying your first amp, you should probably get a solid state instead of a tube amp unless you are very sure that you want tube sound.

If you are a "purist", i.e. what you want to hear is the source file without coloration or added tonality, then you should not go down the tube route since you are sure to be disappointed. If you want the coloration, tubes give you pleasing distortion and the ability to "tune" that distortion by swapping tubes.

"Better solid state" is not necessarily "the same sound, just better". The quality of solid state components do make a difference acoustically, to some degree (like noise floor, THD, etc.) But you are right that the difference between, say a Magni and an O2 is not as vast as the difference between, say a Schiit Valhalla and a Little Dot.

Q: Can DAC s power headphones?

A: Some DACs have circuits on their output side that can run most headphones without issues -- for example the Benchmark DAC1 is a reference DAC that also has a high current, low impedance headphone amp. Now you can use it as a DAC with fixed output to a standalone amp, but in reality you could use it as the only equipment you will ever need, if you wanted to. The HPA2 on the DAC1 is very capable of powering 2 headphones on its dual outputs, including most higher impedance headphones. The volume knob allows you to easily adjust the level of the output, and so you can set your source volume at 100% and use the DAC1 to pretty much manage your entire personal audio experience.

In contrast, you have the Schiit Modi, which outputs a line-level signal via the RCA jacks on the back. The Modi output may not be powerful enough to power many headphones, and you have no way of adjusting output volume unless you modify the source level (which is typically not the best thing to do since the sound quality can degrade).

So the trick, if you want a single unit solution, is to find a DAC/amp combo, or a DAC that has a headphone amplifier circuit built in. Keep in mind that some lower-end DACs don't really splurge on the quality of the built-in headphone amp since they don't see the need (many of their customers will be using standalone amps anyway).