How good is a $3.29 HDMI cable?

Inside our $3.29 HDMI cable we found only 13 wires rather than 19, all surrounded by multiple layers of aluminium foil shielding.

Back in PC User's March 2011 issue, I made the point in the ‘Home entertainment setup guide’ (page 51) that retail HDMI cables are overpriced in Australia and that, in essence, you shouldn’t need to spend more than $10 per metre for a decent cable, provided all 19 pins on the HDMI plugs were wired up and that it had at least AWG28 gauge wire inside. However, a reader letter in the same issue suggested spending $50 to $100 for a cable should be the norm.

If you take a look online at eBay, you’ll find dozens of super-cheap HDMI cables. How cheap? Try $1 for a 2m cable. Frankly, while I’m averse to spending $50 for a basic 1.5m HDMI cable, even I’m a bit sceptical of just how good a $1 HDMI cable can be. Nevertheless, could they be as bad as some people say? So, sparing no expense, I decided to find out and purchased a 2m HDMI 1.3b cable from eBay, spending $1 on the cable and $2.29 on shipping for a grand total of $3.29.

What's that smell?

The cable arrived 10 days later in a small padded bag, but upon opening it, the chemical odour was hard to ignore. Not to put too fine a point on it, the cable reeked. The cable appeared to have fairly decently made male HDMI connectors on both ends, along with end caps, while the cable itself was encased in a plastic mesh sheath. It was quite stiff and didn’t look like the most robust of cables, but since we didn’t plan on flinging it around like a whip, it just needed to work. 

Comparison

We tested the cable between a Panasonic LCD TV and Sony Blu-ray player, with both devices set to use 1080p transfer. We compared it to the original 2m metre cable we purchased for around $50 about three years ago. The original cable was a true 19-pin cable that allowed the Panasonic remote to turn off the TV and the Blu-ray player at the same time using Consumer Electronics Control (CEC), a single-wire communications protocol built into the HDMI cable specification.

With our $3.29 cable in place, we loaded in a 1080p (1,920 x 1,080-pixel) Blu-ray disc and found nothing wrong with the picture quality. Both devices happily negotiated the 1080p handshaking and we had full-definition video and multichannel sound to the TV. No noticeable image problems, no breakups, no dropouts and no failures. As the cable was sold only as a version 1.3 cable, we didn’t test it with Blu-ray 3D, where a 1.4 cable is needed.

However, our first hint that not everything was kosher was when the TV remote no longer turned off the Blu-ray player. That means CEC isn’t implemented and given that CEC wiring is considered mandatory, it’s one area where this cable doesn’t meet the specification.

Inside the cable

While video/audio transfer was a success, we decided to pull the cable apart and see how it was constructed. Under the plastic mesh was a separate full plastic insulating layer. Inside, we found only 13 wires rather than 19, all surrounded by multiple layers of aluminium foil shielding (see 'HDMI connection pin out' below).

The reason the cable still worked is the HDMI standard has six wires that aren’t strictly necessary — four of those are shielding for TMDS Data 0, TMDS Data 1, TMDS Data 2 and TMDS Data Clock. The TMDS (Transition Minimising Differential Signalling) pins already feature differential noise reduction to reduce interference. In practice, 2m is short enough to get away without having those four shielding wires. While we’d be less confident of this cable over runs of more than 3m, it worked as a budget short-length cable.

The fifth ‘optional’ wire is designated Reserved in the HDMI cable standard up to 1.3c and is used as an optional Ethernet connection in 1.4 cables. The sixth missing wire was the CEC wire, something we didn’t expect, especially given its mandatory status in the HDMI spec. But since it isn’t strictly necessary for video/audio transmission, this cable manufacturer decided it was another wire that could be removed, reducing cost.

Is it worth it?

Part of the problem with online shopping is you don’t see the product fully before you buy it. However, we wanted to see just how well a $1 HDMI cable worked. That it did, and had it included the CEC wiring we’d have been happy enough, especially considering the cable cost less than a take-away coffee.

The bottom line is that our $3.29 cable stank, was as stiff as a board and lacked CEC wiring. It did work, though, and next time, I’d probably spend a few more dollars on a full 19-wire cable. What I won’t be doing is spending $50 on one.

HDMI connection pin out

What's in a full 19-wire HDMI cable, compared to what was in the cheapie. (Bold text indicates missing wire in test cable):

Pin 1: TMDS Data2+
Pin 2: TMDS Data2 Shield
Pin 3: TMDS Data2–
Pin 4: TMDS Data1+
Pin 5: TMDS Data1 Shield
Pin 6: TMDS Data1–
Pin 7: TMDS Data0+
Pin 8: TMDS Data0 Shield
Pin 9: TMDS Data0–
Pin 10: TMDS Clock+
Pin 11: TMDS Clock Shield
Pin 12: TMDS Clock–
Pin 13: CEC
Pin 14: Reserved (HDMI 1.0-1.3c)
Pin 15: SCL (I²C Serial Clock for DDC)
Pin 16: SDA (I²C Serial Data Line for DDC)
Pin 17: DDC/CEC Ground
Pin 18: 5VDC Power (50mA max.)
Pin 19: Hot Plug Detect

Note: DDC stands for Display Data Channel, CEC for Consumer Electronics Control.