It’s not easy to narrow down the sound characteristics of AMP module alone because what we hear is a synergy of pair up between the DAP, the module, and the headphones. Thus, in theory I’m describing the sound of headphones and their synergy with a source. For this testing, I choose three pairs: iBasso own IT03, Campfire Audio VEGA, and Beyerdynamic full size Tesla driver T5p 2nd gen. I also noted which cable was used in each pair up and the “v” volume level to get an idea of a relative output power comparison between the modules.
Another thing I noticed, while AMP1 is more plug’n’play friendly, higher voltage/current AMP3/4/5 will require you to power down DX200 before plugging in the next module. Otherwise, it creates some in-rush condition during hot-plug which shuts down the DAP.
Last, but not least, in addition to sound description with AMP3/4/5 modules, for the baseline reference I also describe the sound with a stock AMP1 module.
AMP1 (v53) – wide soundstage; more reference sound with a brighter, more revealing, colder tonality; good dynamic expansion, good layering and separation, great transparency; nice sub-bass rumble and fast mid-bass, neutral revealing mids, sparkly airy controlled treble.
AMP3 (v56) – wider soundstage; the sound is still revealing with an excellent retrieval of details, but I hear sub-bass going deeper with a little more weight, mid-bass being a little tighter, mids a little more micro-detailed, and treble having more energy with additional crunch. Overall sound feels a little tighter and more transparent.
AMP4 (v53) – very wide holographic soundstage; the sound is still revealing and detailed, now being a little more natural without any additional warmth; sub-bass is deep and textured, mid-bass impact has good authority, mids have a little more body, still micro-detailed but just a touch smoother, treble has plenty of energy with enough sparkle and crunch without being splashy. One very noticeable difference here, besides 3D soundstage, is a very dark background with notes popping out with a fast-transient response.
AMP5 (v63) – wide soundstage, its SE output is on par with BAL of AMP1 and even close to AMP3; excellent retrieval of details, but the sound is smoother and with more body; still a deep sub-bass and nice mid-bass impact, mids are detailed but a little smoother and with more body, and treble also well-defined and crisp, but not as vivid or as crunchy. Here, the sound is being a little more organic.
VEGA w/ALO SPC.
AMP1 (v53) – wide soundstage; leaner sound with a more balanced signature; in some pair ups VEGA bass can be overwhelming while treble a little harsh, but not in this case. Sub-bass has a good extension though not as much weight, mid-bass impact is big and hits hard, lower mids are neutral, giving enough room for bass/mids separation without muddying the sound, upper mids are a little colder and thinner, detailed, and treble is crisp and well controlled.
AMP3 (v53) – wider soundstage; the sound has more natural body without sacrificing retrieval of details; sub-bass comes alive with more textured rumble and higher quantity, mid-bass has the same authorative impact, but overall the bass sounds tighter and more controlled, lower mids are a little north of neutral and upper mids are more organic with a little smoother retrieval of details, very natural but a little pushed back due to low end impact; treble is crisp and detailed, but not harsh or splashy. This amp module really pushed VEGA bass performance to the next level in comparison to AMP1 pair up, with a sound leaning a little more toward L-shaped signature.
AMP4 (v53) – very wide holographic soundstage; in this pair-up the sound is more balanced and natural, with bass under more control without overwhelming impact. Sub-bass has a great extension but not as much weight as with AMP3, and the same with mid-bass impact being more balanced; lower mids have plenty of body without muddying the sound, with a linear transition from lows into mids, upper mids are smooth, detailed, organic, very natural; treble is well defined but not too crisp or bright, more toward the smoother side. The bass in this pair up still hits with an authority, but relative to mids and treble it’s less overwhelming. Also, blacker background of AMP4 helps to give the sound a little more transparency and definition.
AMP5 (v60) – wide soundstage; the sound signature is close to being balanced, but the sound itself is more congested and less resolving due to a smoother nature of this amp which doesn’t pair up as well with a signature of VEGA. I’m not necessary saying it’s a bad pair up because here it sounds like VEGA is going through a tube amp which some might enjoy, but it’s not my cup of tea. Bass has a good sub-bass extension and you still get a powerful mid-bass impact, but bass is not as tight and spills into lower mids which have too much body as a result, upper mids are also too smooth and warm and not as layered or detailed; treble is well defined, not rolled, and not as crisp or airy.
T5p2 w/TWag v3:
AMP1 (v75) – wide soundstage; a nicely balanced signature with a good sound transparency, but I’m sensing a bit of a lower treble sheen; deep sub-bass extension with a more neutral rumble, while mid-bass has a nice fast impact and overall bass is tight and well controlled; neutral lower mids and smooth detailed upper mids with natural tonality; treble is well defined but not very crisp or too bright, nicely extended and airy, but has a very faint hint of sheen.
AMP3 (v75) – wide soundstage; still a balanced signature, dynamic sound expansion, nice level of sound transparency, with overall sound being a little tighter and more natural; sub-bass gets a little more rumble and mid-bass has a little stronger impact; neutral lower mids and detailed organic upper mids with a little more natural tonality; treble has a good definition, extension, and sounds a little crisper and still with a good level of airiness.
AMP4 (v74) – wider soundstage; still a balanced signature and dynamic sound expansion, but the sound itself is more transparent, more revealing, more micro-detailed while still being natural; deep sub-bass rumble and articulate mid-bass impact, with bass being tight and well controlled; neutral leaner lower mids and detailed revealing upper mids, not as smooth as other amps but more revealing and micro-detailed, though not harsh or analytical; treble is crisp and airy, well defined, not peaky, great extension. Typical of AMP4 performance, the background is black, making note transient faster and tighter, the sound is still natural but not as smooth.
AMP5 (v84) – wide soundstage; balanced signature with a dynamic sound expansion, and natural revealing tonality; nice extension of sub-bass with a more neutral warm rumble, fast mid-bass impact with a little slower decay, but overall bass is still well controlled; neutral lower mids and natural detailed upper mids, having a perfect balance between smooth natural tonality and revealing retrieval of details; treble is well defined, crisp, airy, extended, not too peaky.
You can’t assume that each of these amp modules will have the same pair-up synergy with every IEMs or full-size headphones, but I found some common characteristics where:
AMP1 has a distinct reference quality signature with a more revealing transparent sound, wide soundstage (BAL output), articulate bass, brighter micro-detailed mids, and crisp airy treble extension.
AMP3 widens the soundstage, tightens overall sound, extends sub-bass with more rumble, gives a little more body to the mids with smoother more natural details, and gives treble a little crisper definition without being splashy.
AMP4 has the widest holographic soundstage with the blackest background and more transparency which makes sound pop out with the faster transient of notes on/off; improved sub-bass rumble and mid-bass impact, and more revealing upper mids and lower treble tonality without being cold or analytical.
AMP5 has a wide soundstage which is on par with AMP1 BAL output, and a more natural tonality with more organic body added to the sound which makes upper mids and lower treble smoother without losing details.
It’s not an easy decision to pick just one amp for your DX200. But at the same time, each of these modules offer something unique to help you decide if it’s the right update for you. But regardless of your choice, the fact still remains that you don’t need to buy a new DAP and can fine-tune your listening experience with just a module update. That’s a big plus of DX200 modular design.