ALO have long been known for their interconnects and amplifiers so it’s fair to expect that the v5 (as in version 5) of their Continental amplifier might just be pretty good. Many thanks to Mark from The Sound Freq for lending me his personal unit (and for far longer than I would usually take to complete a review)! One of the reasons for the delay is that this marks (no pun intended) the first ever video review for Passion for Sound. The video content is different from the text below so you might find it helpful to consume both. Obviously my conclusions and opinion remain the same, but the details in what I say and focus on might vary slightly. Please comment here or on the video to let me know if you prefer written or video reviews for audio gear – it would help a lot!

Overview

The Continental v5 is a portable amplifier with a hybrid design combining both solid state and tube circuitry. In the case of the c5, the tube is in the input circuit running in a Class A setup while the output stage is solid state in a Class AB setup. In layman’s terms, a Class A setup is preferable for pure quality, but is inefficient in terms of power consumption. Class B amplifier circuits swing the other way, prioritising power efficiency over sound quality due to higher distortion. As you might expect, a Class AB circuit merges the benefits of both and delivers the power efficiency of Class B combined with the sound quality of a Class A (almost). The power efficiency also keeps heat to a minimum which is important for a portable amp too if it’s in your pocket, bag, or resting on your lap.

According to ALO, the Continental v5 is a combination of some of their best technologies from a variety of their amplifiers so it should play a bit like a greatest hits. Its compact design and relatively light weight belie the power and technology packed into the single-piece aluminium case.

Specifications

• Dimensions:  92.5mm x 58mm x 20mm (H x W x D)
• Frequency range: 10 – 300,000 Hz (+/- 0.1DB)
• Input impedance:  110K (low gain) / 10K (high gain)
• Output impedance: <0.5 ohm
• Gain: -10 dB (low) / +10 dB (high)
• Output power: 325 mW per channel (RMS into 32 ohms)

Key features

• Premium low ESR audio-grade power supply capacitors
• High / low gain switch
• 1 x 6111 dual triode tube, user changeable
• 16V power supply (+/- 8V)
• 20-second mute circuit for tube warm-up
• Low output noise and microphonics
• Up to 9 hour play time
• Charging time ~4 hours
• Low voltage warning
• Charging LED (orange = charging, green = charged)
• High-grade CNC billet aluminum enclosure with CNC machined markings

Design & Accessories

First up, the Continental V5 is beautifully made. It is machined from a single piece of aluminium so there are absolutely no seams anywhere on the casing – everything is smooth and sleek with beautifully rounded corners. There are grill holes machined into the top and side of the amp which allow you to see through to the tube inside and show off the blue light which indicates the tube warm-up mute circuit as well as the orange tube-glow-simulating light that’s on all the time when the amp is powered up. The grill isn’t required for heat dispersion as the tubes in the V5 don’t generate much heat – they get warm to the touch, but not super hot.

In terms of size and weight, the V5 is solid, but not too heavy and its footprint is tiny. It is dwarfed by both my phone and my E12DIY amp. It’s quite a bit thicker than both though so I guess it depends on whether you prefer a broader, flatter profile or a more compact footprint with some extra depth. As you’ll see shortly, I look at the V5 as a portable desktop-type solution so the exact dimensions aren’t particularly important because

Accessories

The V5 comes with a micro-USB charger, elastic band and manuals. There’s nothing extra in the box, but there’s nothing wanting that I can think of, except perhaps a nice quality interconnect cable. Mark included the leather case and a fabric pouch in the bundle he sent me so I am assuming that one or both of those were also a part of the original package. All-in-all though, accessories aren’t nearly as important with portable amplifiers as they are with something like earphones.

Sound Quality

The sound from the Continental V5 is nothing short of excellent. It’s tonality is just on the warm side of neutral, or perhaps it’s truly neutral. All I know for sure is that it’s great and not at all analytical or cold. The stock tube (a Philips 6111) in the input stage of the amplifier imparts a nice organic / natural tone to the sound, but the amp doesn’t sound “tubey”. The quality of sound is much more akin to the very transparent Bottlehead Mainline amp rather than the creamy and warm setup I ran with my old Bottlehead Crack amp. Changing tubes to the optional 6832 tube (available separately from ALO) introduced some of the thickness that many equate with tube amplifiers, but it’s still well-balanced overall to be articulate and clean – just a touch warmer and fuller. I can imagine the 6832 pairing really nicely with cooler headphones like HD800s whereas those with warmer headphones like NightHawks will probably want to stick with the stock 6111 tube.

Regardless of which tube you choose, the overall sound quality remains pretty much the same thanks to the V5’s wonderfully black background. This is due to the power supply technology carried forward from ALO’s own Rx amplifier. Sounds come out of nowhere and it helps to create a realism and engaging nature to the sound that’s very enjoyable. Compared to the FiiO E12DIY amp that I use as my reference for portable amps, the V5 was consistently better. They are close enough to require focussed listening to separate, but I definitely always found the V5 to present a more engaging overall sound.

Headphones vs Earphones

There’s no doubt in my mind that the V5 is more a headphone amp than earphone amp. It sounds fine with earphones, but there is a little bit of hiss that is noticeable in everyday listening environments. This does dampen that wonderful black background and although it mostly disappears behind the music, I found myself enjoying the amplifier less with earphones. With headphones, though, this is a completely different beast. This might be the perfect portable headphone amplifier in terms of sound quality, power output and size – it’s tiny, sounds amazing and will drive anything I could find to try it with (easy-to-drive dynamics through to planar magnetics). The question remains for me though, is there any need for a portable headphone at this price level that is best suited to flagship headphones that you’re likely not taking out and about. In the office or around the house it’s a great option, but is it worth spending $800 USD for a portable solution when you can probably get more for your money with a compact desktop amp?

Interference

When I first tried the V5 with earphones I heard a lot of noise from the circuit – not the hiss, but a rhythmic electronic noise. Some research on ALO’s site explained why. You see, the tube circuit in the V5 is prone to picking up mobile / cellular and wi-fi noise like an antenna (a common issue with many tube setups). If I left my phone in the other room I had no issues with noise, but I often use my phone (via AudioQuest DragonFly DAC) as a source and that poses an issue if you want to use the phone and the V5 together. Sure, you can switch off communications (i.e. activate flight mode), but what if you want to stream music? Not a chance. It’s important to note that this noise wasn’t powerful enough to impact the larger, harder-to-move drivers on headphones, but it will prevent earphone usage, even with less-sensitive earphones (e.g. Shozy Zero).

Summary

Overall, I really like the Continental V5. It is a superb sounding amplifier and has me totally hooked on the idea of buying an ALO Rx amplifier for my IEMs, but it didn’t quite win a place in my heart because of the hiss with earphones and the noise issues. I love the fact that you can tube roll even though the 6111 sounded pretty much perfect to my ears and the design and build quality are absolutely top-notch. If you are looking for a headphone predominantly for headphones you should definitely check out the V5, but do be mindful of the potential noise issues and think about how you are likely to use the amp. If you’re like me you might want a more versatile offering, but if you’re all about the headphones and non-cellular sources you might have found your perfect amp!

If the Continental V5 sounds like your kind of amp and you’d also like to support this blog to continue providing plenty of reviews, please check out the following link to Amazon – it really helps me and costs you nothing! 🙂