Power and performance
The SP200 is no slouch in the power stakes. In fact, with 6 watts on tap at 16 ohms, and 3 watts at 32 ohms this basically equates to near-limitless reserves of power for just about every current, and likely any future headphone pairing. Those of you on a budget who are concerned about the need for a future power ‘upgrade’ need not be concerned here – the SP200 has oodles of drive. Despite power rating dropping down to 440mW at 300 ohms and 220mW at 600 ohms, this is still ample power to drive higher-impedance cans to their full potential, very quickly and very capably.
There SP200 has two gain settings – ‘low’ adds 6dB of gain, whilst ‘high’ increases gain by 18dB. The highest I ever set the volume pot was to 10 o’clock for the hardest-to-drive headphones I have on hand, the 600-ohm Beyerdynamic T1’s – and that is in low gain.
What’s remarkable about THX’s AAA amplifier technology is its ability to deliver this kind of power and drive with the complete absence of any perceivable distortion, background noise or hiss – even with sensitive IEMs.
The given power ratings are identical for both balanced XLR and single-ended outputs on the SP200, unlike the Drop THX amp which outputs considerably less power to its single-ended headphones. Swapping out single-ended for XLR cables on the MrSpeakers Aeon Flow Open does indeed prove that the sound pressure levels are identical for both XLR and 6.3mm connections, implying that the topology of the SP200 is not fully balanced from end to end. This being the case, the provision of the four-pin XLR output is there for convenience and compatibility more than anything else. But, it does mean that the SP200’s single-ended performance is markedly stronger than its competitors, and worth noting if you plan on using single-ended headphones.
The SP200’s output impedance of ‘near 0ohm’ helps to add to its versatility and ability to play nicely with headphones of varying impedances without unduly affecting their frequency response.
If there’s one weak spot to the SP200, it’s the implementation of the volume pot. Whilst it’s built from metal, it’s pretty light and floaty and lacks tactile feedback that allows for precise levelling. If you do plan on having an SP200 take pride of place on your desktop, just be mindful that the volume pot does feel pretty cheap, and does detract from the overall product experience. But then again, to deliver a product at this price does require sacrifices somewhere…right?
The SP200 I tested also had some clear problems with channel imbalance at lower levels. This was less evident with full-sized headphones, but testing with the 5-ohm Audio Technica ATH-IEX1 IEMs showed some significant imbalance at low levels, requiring my DAC’s source volume to be lowered to ensure I could get proper level matching between channels.
Trying to describe how the SP200 ‘sounds’ is a somewhat abstract task, as it becomes immediately clear that it performs its given task with absolute stone-cold precision: it amplifies headphones without distortion, colouration, nor artifice. The SP200 is an absolutely transparent look into your music, your source material, and of absolute importance for Headfonia readers – your headphones themselves. With its linear power delivery, low output impedance and absolutely imperceivable distortion levels, the SP200 plays back nothing except the innate characteristics of your headphones, unleashing their dynamic capabilities and individual traits in their purest form.
Don’t expect to hear adjectives like warmth or lushness when it comes to describing the SP200, because it adds nothing of the sort. Nor is it appropriate to describe what the ‘bass’, ‘mids’ and ‘treble’ sound like on the SP200, because it doesn’t have any colour to speak of – you inevitably start to describe your headphones instead of the amplifier itself. Many amplifiers create tangible differences when paired with certain headphones, the SP200 does not.
Now from what I’ve just described, you might be mistaken that I think the SP200 is ‘boring’ – it is not. It sounds absolutely killer. The overwhelming feeling you get from listening to headphones on the SP200 is one of energy. Familiar micro details hidden inside your favourite tracks are extracted and delivered front-and-centre. Bass and percussion hits are delivered with speed and slam. You feel like you want to continually turn-up the volume pot to add more of that addictive sense of energy, but then you realize that you’re able to enjoy all the dynamic swings and detail of your favourite music at comfortable listening levels on the SP200.
Click-over to page 4 to hear about listening tests, comparisons, and our final conclusions.