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April the first, but this article is for real as I really lack the creativity to throw a successful April Fool. Now let’s get on to the review. I have mixed feelings about the new C5 amplifier. While there are improvements, going from the older C421, my ears still find the more laid back sound of the C421 to be more preferable. Though that may just be a personal thing. Anyway plus and minuses are normal in a review, so let’s get into the details to get a better picture of the new amplifier from JDSLabs.
A Digital Volume Control
Apparently one of the aspects about the C421′s performance is that the analog pot is not ideal for tracking stereo channel in low volume levels. Well, what analog pot is? The solution has always been to either use a different headphone/IEM that’s less sensitive, lower the gain of the amp, or switch to a stepped attenuator. Recently portable amp manufacturers tend to prefer digital volume controls, first seen in Ray Samuels’ The Shadow.
The digital volume control implemented in the C5 eliminates not only the channel tracking problem, but also the sound is noticeably cleaner, less grainy, and with a tad larger soundstage. I didn’t really feel that the jump in technicalities to be huge over the C421, but they’re there on careful listening. A word on the soundstage, despite the C5′s being a little bigger, the more forward sound of the amplifier does sort of mask that fact. On the C421 with its more laid back sound, it’s easier for me to pick up an impression of a big soundstage, whereas the C5′s more forward midrange sort of put everything into a more focused stance and so I don’t usually associate the C5 as being large sounding.
The sound is more forward, but not Apex Glacier or Fiio E12 forward. This is one of the more forward sounding amps in the market, and a slight departure from the JDSLabs sound signature that I’ve heard on the CmoyBB and the C421. Upper midrange is definitely more relaxed on the C5 than compared to the Fiio and the Apex. However compared to the C421, the entire midrange is pushed more front and the resulting sound that you get is more upfront and with a slightly faster pace than the C421. It does make for a generally wider bandwith sound, as I can play faster-paced music better with the C5 even with something laid back like the HD650, than I can with the C421. Though the presentation is forward and the pace faster, the C5 maintains its composure well. The amp never gets shouty, honky, harsh, or bright in its presentation. At really loud volume levels, however, the amp does lose a significant bit of its composure. It loses control on the dynamics, and the upper mid starts to break lose, even as I’m using a relatively normal 300Ω Sennheiser HD650. For reference the C421 holds things better than the C5 at really loud volume levels. This sorts of puzzled me as the C5 is supposed to have the same power output as the C421.
I noticed some parts of John’s C5 blog writing about the fantastic THD+N numbers of the C5 when compared to the C421 and even to the Objective 2 amp. I really don’t know how superior THD+N numbers are supposed to translate to the audio waves picked up by my ears, but I don’t think that the C5, as much as I dislike the O2, can compete with the clean black background sound I hear on the O2 amplifier. The C5 is more musical to my ears, that’s for sure, but I wouldn’t really compare its technicalities to the O2. Likewise in reference to the C421, yes there are slight improvements on the technicalities as I’ve written earlier: slightly cleaner and less grainy, but it really is not a big jump over the C421.
A New Bass Boost
In between these mixed feelings, I do have a big crush on the C5′s bass boost toggle. This is not the average bass boost switch. What I’m hearing is a big gain in bass levels, yet with things still well in control and with the bass boost extending quite low to almost sub-bass region. It’s an extremely nice bass boost, easily the best in sub $200 amplifiers. What it does is not just bass quantity, but rather an extra HD650 effect to the already weighty HD650. You get an even fuller sounding lows, adding weight and bass fun into the sound, without the clouding of the midrange section. Again, even with the HD650, I keep the bass boost switch on, all the time. Music is so much more fun that way.
The biggest upgrade, I feel, is the enclosure which is now extremely solid and refined. Even with the red color far from being my favorite red color, I still dig the look of the amplifier tremendously. That thick machined faceplate really screams premium, and I wouldn’t be surprised if JDSLabs was to price this upwards of $220 (the C5 sells for $189). It really is a big step up in terms of build, and that is a big deal with portable amps, as much as you want your smartphone to have a great build quality.
However, spending time with the C5, I really haven’t been able to really blend with the sound, as much as I did with the C421. I know the sound direction that it’s going for, and it’s done a pretty good job with the tuning. More forward, slightly faster pace, wider genre bandwith. It just didn’t hit the homerun for me, though I’m not so sure if that’s John’s fault as the amplifier designer or it’s just my ears that prefer more laid back sound. I do think that if the C5 is going to be a more forward sounding amp, it needs a faster, tighter, and punchier bass section. Perhaps an AD8066 or an AD797 type of a sound. As you read through the review, you should be able to pick up positive points about the C5. Had I created a positive/negative checklist, the C5 should be a clear winner over the C421.