COMPANY: JDS Labs

MODEL: C5D

COST: $250 USD

TYPE: Portable Headphone Amplifier + DAC

WEIGHT: 120g

COLOURS: Black (previously available in Red with Silver End Caps)

INCLUDES:

C5D portable DAC + Amp

4 adhesive rubber feet (note the rubber feet in my pictures are not the original small round included bumpers)

3-foot micro USB cable

User manual

Description:

C5D is a high-performance portable headphone amplifier featuring digital volume control, multi-position bass boost, dual gain, and asynchronous digital-to-analog conversion compatible with iPad, iPhone, and all UAC1 compatible operating systems.

Build Quality, Features, and Aesthetics

All JDS Labs products are designed, prototyped, manufactured and supported in their own USA facility. This is relatively unique in the portable electronics world and speaks directly to the philosophy of the company. I can personally attest that JDS Lab’s customer service is outstanding as well. You can expect to receive same day responses to email inquiries, handled personally and professionally. They clearly care about their customers just as much as they care about their products.

Build quality is always a strength of JDS Labs products, and the care in product design and execution is evident in the C5D. The exterior casing is a minimal and sturdy design of machined aluminum, with a satin matte anodized finish. End plates are aluminum with precisely cut ports and flush, tight and high-quality components and solid feeling switches. Custom engraving is free with any new JDS Labs amplifier or DAC ordered through jdslabs.com. You can submit your own custom artwork to appear in white on the blank case side (the other side has the JDS logo). Engraving image quality is comparable to that of a black and white laser printer.

It is worth discussing the unique digital volume control. For the tech savvy, the workings of the digital volume control can be programmed via Arduino via software made available by JDS. By default, it works by pushing a left or right to decrease or increase the volume by fine steps (63 1-dB attenuation steps + mute). If you hold the volume rocker to the side it increases to full in a few seconds. Additionally the last used volume level is retained every time you switch the amp off. You push the volume rocker in to toggle the gain from 2.3x to 6.5x.

JDS Labs states (in full caps) that the C5D is ASYNCHRONOUS AND GALVANICALLY ISOLATED. I have not noticed any unwanted RF interference (radio frequency interference collected by a cable unintentionally acting as an antenna) nor any other noise issue, so I’ll take their capitalized word for it.

The C5D is a USB Audio Class 1 (UAC1) compatible device, so it is not necessary to install drivers for computer usage, but it does mean that the DAC chip is purposely limited in audio format playback support (maximum 24/96 – no 24/192, 32/384, nor DSD support). However, it means that the C5D is more widely compatible, and having an internal battery (thereby avoiding “connected accessory couldn’t be used because it consumed too much power” error messages) it is usable with iOS devices with the Apple Camera Connection Kit and Android devices using the USB On-The-Go (OTG) feature. Note that the current package lacks any Android OTG or iOS digital cable, so you should include those costs, as well as a few amp bands, into the purchase price for portable usage.

Labels are somewhat sparse on the unit and there are a few things that take time to become familiar. You must remember to change the battery/charge switch to the appropriate setting. Forgetting to select CHG means it will not recharge the battery even when plugged in. The unlabeled (!) bass-boost switch isn’t entirely intuitive either, rather than OFF – MED – HIGH, the switch works (from bottom to top, which in itself isn’t always easy to remember) MED – HIGH – OFF; the only way I know what setting it’s on, is to flip through them and listen. The 1,200 mAh battery capacity is rated for 6-8 hours of playback (depending on volume level) and is certainly not industry leading for portable devices.

Sound Signature and Characteristics

JDS Labs is probably best known for its production of the successful Objective Amplifier (O2) and DAC (ODAC). For many, this was (and continues to be) a gateway into high-end headphone audio and provides clean, accurate sound at a reasonable price/performance ratio. The C5D appears to be an attempt at capturing this success in a more portable package.

Known for a dark, silent background, the C5D makes it easy to enjoy the music you are listening to. Balanced with a focus on accurate and transparent sound, it appears true to the music but is never boring nor sterile. The presentation is slightly warm, with somewhat forward mids and a bit of a punchy upper bass bump. Bass is controlled (except with the MAX bass boost setting enabled – this may prove too much for many headphones and details can easily be lost in the overwhelming mid-bass bloom). Overall, the bass boost gives a bit of additional body to the music (I typically leave it on the MID setting) and I find it slightly less musical and engaging on the OFF position with most headphones.

Vocals are presented naturally with extension and detail. Overall the C5D has a smooth presentation, very pleasing and musical, and isn’t sterile nor grainy. While it isn’t perhaps the most detailed nor revealing, the full impactful sound signature remains fatigue-free even over long listening sessions. As a whole, the soundstage is engaging, remaining intimate but reasonably spacious.

While the low gain setting works fantastically with IEMs and reasonably efficient full-sized headphones, the higher gain setting does have enough power to drive less efficient headphones such as the HD650. The sound with these higher impedance headphones is clear but a bit lacking in dynamics – but then again I’m used to the legendary pairing with a Bottlehead Crack OTL desktop amplifier, so I likely have unfair expectations.

Conclusion

One of the best purchases I made early in this crazy obsessive hobby was the JDS Labs C5D. It still sounds great and meets all my portable needs, even after many headphone changes and auditioning and owning arguably “better” gear. I didn’t realize at the time of purchase that they offered free laser engraving, so over a year after purchase, I exchanged a few emails, and sent it back to them. At the same time, I had the headphone amplifier input changed to be a DAC line out, so I could use it that way as well (as I typically only use Android USB OTG). Of note, I’ve been slightly disappointed in the sound quality of the DAC only output connected between a Windows 10 tablet and desktop headphone amplifier, and prefer using an Audioquest Dragonfly Black for that single purpose.

I’ve owned it almost 2.5 years, so you can consider this an extended test and review. It’s played countless hours of music for me and still works just as well as when it was brand new. Plain and simple, I love this thing!

Technical Specs

AMPLIFIER PERFORMANCE

Frequency Response +/- 0.1 dB (20Hz-20kHz) THD+N (20-20kHz, 150 Ω) 0.0015% THD+N (20-20kHz, 32 Ω) 0.0045% Noise -105 dBu Crosstalk @ 150 Ω -67 dB Inter-channel Phase @ 1kHz +/- 0.01° Channel Balance +/- 0.55 dB, all volume positions Max Output @ 600Ω 4.146 VRMS Max Output @ 150Ω 3.580 VRMS Max Output @ 32Ω 1.182 VRMS Power Supply 14.0 Vpp Output Impedance 0.62 Ω Battery Run Time 6-8 Hours* Charge Time 2-4 Hours*

FEATURE CHARACTERISTICS

Digital Stepped Attenuation 63 steps + mute Dual Gain 2.3x and 6.5x Bass Boost Off / Med / High Low Battery Indication @ 20 Minutes Thin Film Resistors 0.1% Tolerance Battery 1200mAh, 3.7V Li-Ion

CONNECTIVITY

Analog Input 3.5mm Digital Input USB Output 3.5mm Charging USB

DAC PERFORMANCE

Frequency Response +/- 0.14 dB THD+N 100 Hz 0.0014% THD+N 20 Hz 0.0015% THD+N 10 kHz 0.0025% IMD CCIF 19/20 Khz 0.0015% Noise A-Weighted -103 dBu Dynamic Range > 109 dB A-Weighted Linearity Error -90 dBFS 24/96 0.2 dB Crosstalk -10dBFS -80 dB Sum of Jitter Components @ 11025 Hz -112 dB PCB Stackup 4 Layers Maximum Output Line Out 100K 2.0 VRMS

DATA SUPPORT

Audio Formats 16/44, 16/48, 16/88, 16/96, 24/44, 24/48, 24/88, 24/96 Interface USB, Audio Class 1 Native Driver OS Support Windows XP & Later, OS X x86, Linux, iOS 7 DAC

COMPATIBILITY

iPhone YES: Requires iOS7+ and CCK iPad YES: Requires CCK Windows YES Linux YES Android YES: Requires v5.0+ and OTG Cable OS X YES

DIMENSIONS

Case Dimensions (mm) 99.5 x 61.5 x 14.0 Weight 4.2oz