This is gonna be bit of a rant here but I feel it needs to be done. If your easily offended leave now or just skip the rant section.
Trying for yourself is not always possible, although its the most desirable situation. This is aimed to guide people along what lines they must think to find a suitable amp. IF you do want to give a recommendation please compare the amp to the other amps you own, and list your source components. For all intensive purposes since the previous Denon Dx000 series was made by Fostex(Foster) and the new Fostex phones are very similar with improvements, and judging from the feedback, the same type of amps will work and suit both ranges.
Warning: Rant (Click to show)
I have decided its time to upgrade my amp (running from an ASUS STX with THS4032 opamps and a faux impedance decreasing adapter.) And as any good head-fier I read and read and read some more first, and I can't help but look at the recommendations people give others, without having the headphones, or the amp or understanding at all what makes a good pairing. Often just spewing out there favourite brands and models in completely inappropriate times.
It really is sickening, how some people recommend to others to buy $500~$1000 amps that just WILL NOT MAKE THE BEST OF THE HEADPHONES!
For instance, with the Denon Dx000 series (and newer Fostex headphones) there is very important criteria, and firstly they don't need an amp, but they do benefit from one, and there are are these mindless zealots that recommend the Fiio E6 when the person is looking to spend $1000 stating it won't benefit, which is utter crap.
Then you get the brand monkeys (not looking to insult the brand here but these are examples) that say "get the Schiit Lyr for the Denons" for example, another tell tail sign that they know nothing.
Impedance matching is one of the most important things with the Denons/Fosters, there is no point buying an expensive OTL if the output impedance causes your bass to muddy and bloat, and the microdetail you paid so much for to disappear.
So either know exactly what you are talking about, or please just don't say anything because if I see another monkey recommend a completely inappropriate amp I may just flip my waffles.
If your one of these zealots time to attone for your sins, if you feel you have a valid and experienced point feel free to debate, please do note the debate may get heated, so those of you who can't take criticism should not bother posting. Do not take this personally or make this personal.
I'm going to say this plainly: here is the criteria for a Denon/Fostex amp
1) low output impedance on the amp: <1ohm!!!! (if your spending so much you really don't want to lose your money due to menial factors)
2)Solid state not tube, solid state preferred because of the strong sonic characteristics of the Denons/Fosters which tend to mask whatever its plugged into, versus AKGs which sound a lot like whatever you plug them into.
3)High current, the Denons/Fosters are low impedance and if you know anything it doesn't mean they are easy to drive (although that is how they are, but it is of no consequence) but it does mean that they use a lot more current then voltage. Which means high voltage swing amps will be wasted if they can only output a little bit of current.
Amps that do work for Denons/Fosters at any price range
Now to put an end to these threads especially for the Denons/Fosters, post amps that you have used that have great synergy with the Denons/Fosters, here is the culmination of my research from people who actually know what they are talking about, feel free to prove me wrong any particular one because I haven't used any (yes I know the irony.)
- AudioGD all (except SA series) - (No complaints, at all)
- AMB labs Beta 22 (slight analogue sound, very good detail, impression)
- Benchmark DAC1
- Burson HA160 (always a safe bet, noted for its bass)
- Fiio E10, E11 (good bang for buck)
- Fostex HP-P1
- Fostex HP-A8 (expected great pairing, but better then the TOTL amps?, undecided feedback?)
- Gilmore Dynalo (Sheer Audio HA++, Headamp Gilmore lite) (trademark wire-with-gain)
- Kao Audio UD2C-HP (Project86 review)
- Lehman Black Cube Linear (Overpriced but still a great performer)
- Matrix M-stage (One of the most recommended Denon amps, more coloured sound)
- Meier Corda Arietta (apparently an improvement over the O2 in every field)
- Musical Fidelity X-can (And all its revisions, another often recommended amp)
- O2 (a bit clinical, but good value)
- Schiit Asgard
- Yulong D100 (mainly because of its DAC, a dedicated amp can still be beneficial)
TOTL (Top of the line - Best of the Best) amps for Denons/Fosters
(please note that depending on your preferences others may qualify aswell, I'm trying to keep this list short.)
- AudioGD Master 5 (and most probably other Masters) (Ruthless but detailed and clear. well suited to a forgiving source eg Yulong D18)
- Eddie Current Zana Deux SE (OTL) (Low output impedance) AppleheadMay Review
- Grace m902 (and by extension the m901, m903) (The m903 has light/tight bass and is perfect for those who think the stock bass is too much in QUANTITY, a quality increase in expected anyway)
- Violectric V200 (Well liked across the board, no particular strengths or weaknesses)
- Woo Audio WA6SE (a rare tube exception, highly musical)
- Yulong A18 (More forgiving Vinyl sound)
Tentative (more feedback needed)
- AudioGD SA-31
- DACport products
- Gilmore Dynahi, Dynamite (could have too much power, but depending on gain expected to be good)
- Headroom Buda
- KICAS (non-caliente)
- Lake People (all products are suspected to be good, G100 confirmed good)
- Matrix CUBE
- Musical Fidelity M1HPA (High current, low output impedance, good specs)
- Red Wine Audio Corvina
- Schiit Lyr (1 for, 1 against: audible noise)
- Violectric (all are expected to be good, V200 confirmed great.)
- Yulong A100
Amps that DONT work
- All OTL tube amps (with more then 3ohm output impedance): Decaware CSP-2
- All Amps with higher then 2 ohm output impedance (3 ohm maximum for tubes)
- ASUS Xonar Essence ST/X (Only those who don't know any better like it.)
- BottleHead Crack (OTL)
- DarkVoice 336 (OTL)
- Fiio E7 (Does not provide enough current)
- Fiio E9 (1 for, many against)
- Little Dot (MKI+ [32 ohm output impedance] ...)
- Nuforce anything (all 10ohm and coloured)
- Schiit Valhalla (Tubes)
- SPL Auditor (made for High Voltage)
- Woo Audio WA22, WA2, WA6 (Tubes)
Amps that should work but just are not phenominal
- Apex Peak
- Meier Corda Concerto
The Advanced Talk
Ok this sections is right at the bottom for a reason, most people should avoid this, as it may just confuse you, but it aims to explain why I have been so stringent on some of the rules. - As I figure out how to phrase stuff I will rewrite it.
Warning: Contradictory stuff (Click to show)
As Songmic pointed out, output impedance doesn't actually matter as much as I made it out to, so then why did I? I did because it still matters, and most probably always will, but not always negatively, but more importantly because its an indicator of how adept the amp is at driving high current / low impedance loads.
Tubes colour the sound, and as I have stated before Denons are already coloured, and those that buy them, buy them for there colour. SO why would you want to alter it? If anything you want to protect it, and keep it whilst enhancing clarity. But having said that the WA6SE is an example of how you can alter its colour for the better, and there is probably another example of this, but the odds are very very very low that any given tube amp will do that. So stay away, unless your a real gambler because 98% of the time you will be disappointed.
Output - transformerless amps are Satan spawn because most of them have high output impedance and really do struggle with low impedance loads, it could even be harmful to some amps. There are exceptions, like the Zana Duex, which is mind boggling with an output impedance of 3 ohms. If you find any other example, then let me know, because it join the short list of 2 tube amps that do suit the Denons.
Edited by WiR3D - 1/21/13 at 12:31pm