3M Dual Lock and Attaching Your Player to a Portable Headphone Amp

No Easy Solution
I've been thinking about how attach headphone amps to portable players for 20 years. There's simply no really good solution. Using Velcro means semi-permanently sticking something to your iPhone ... which verges on blasphemy for some folks. The Velcro also doesn't last forever; it slowly "fuzzes out," which causes it to lose holding power and lets the player and amp wiggle relative to each other. 3m_duallock_photo_SiBurningUsing large rubber bands works, but the size and shape of all the electronic components have to be the same as the iPhone (or player) or you will end up covering buttons with the bands. Using small camera bags works rather well, but it means hunting down a bag that just happens to be perfectly right for your needs, and in the end your phone won't fit into your shirt pocket any more. At HeadRoom, we custom made bags and rubber bits to accomplish the task, but it was enormously expensive to ramp up a fabric manufacturing capability, and to develop and make the rubber parts. They're no longer made due to the expense.

The perfect solution, of course, would be if portable players had great headphone amps built into them --- over time they've gotten better, but there will never be "great amps" in mass market portable players and smartphones (though the iPhone is quite good). I'm afraid enthusiasts will forever have to be a little creative with the tools and techniques available when assembling their portable rigs.

Fortunately there's a relatively new, and very cool product available that may help quite a bit.

3M Dual Lock
Dual Lock works a lot like Velcro, except both sides are the same. Think of it as a field of tall mushrooms closely spaced together. When you attach the material together, the round tops slide past each other and then hook together under the caps. Once locked together, the material has a surprisingly strong hold, which has very little give in any direction. It lasts about 3 times longer than Velcro, providing 1000 open/close cycles (100 for the low profile material).

On the downside, it does leave about a 6mm gap (0.24") between devices. (There is a low profile version available that leaves only a 2.3mm gap (0.09").) This gap can be to your advantage in some cases; I'll show you about that in a moment.

Dual Lock can also leave adhesives on your portable gear when removed. Dual Lock comes with both acrylic and rubber based glues; I like using the rubber-based glue as it seems to come off more easily with a bit of Goo-Gone.

A full selection of 3M Dual Lock is available by the yard at iTapeStore here. Small 1"x3" strips under the Scotch brand --- usually in clear with acrylic adhesive --- is likely available at your local Staples or other stationary store (Scotch part no. RFD7090); and in black from Radio Shack under the brand name Superlock (part# 64-2360).

Let's have a look at Dual Lock in action ...

3M Center
St. Paul, MN 55144-1000

4nradio's picture

Thanks for these do-it-yourself tips, Tyll.

I wasn't aware of the 3m Dual Lock product but have used Radioshack "Superlock" strips for years. It is very similar to 3M's offering and may be easier for some folks to find. It is RS catalog #64-2360 and costs $3.99 for two 1" x 3" strips. You certainly don't need to use much due to its high tensile stength. Like with 3M it is also best to let the sticky-backed adhesive set for a couple of days before pulling the gear apart.

13mh13's picture

Luv da way TH *strains* to SNAP the DualLock'd pieces apart. Good thing he has those $$$ OtterBox ... uh ... "strain reliefs" LOL!!!

I have a horror story about using the death-grip-like DualLock (Radio Shack variety) ... resulted in cracking an iPod PERMANENTLY out of commission. But that gave the person an excuse to buy a HiFi-Man DAP. The 3M-HiFIMan conspiracy! LOL!!!!!!!!!!!!!

But Descarte's Evil Demon would wear the High-end-audio-journalist's horned baseball cap ... and say:
"Highly Recommended"


"Be of Sound Mind", folks.

metalsonata's picture

I wanna know what all that stuff is strapped to the poor bloke above. Looks like some sort of cyberpunk nightmare.

Tyll Hertsens's picture
That's Si Burning, and yes he did regularly wear that rig around Manhattan. Left to right is: a gel cell battery pack; the gray tube is spare batteries for the CD player; the CD player above; then a pouch holding an iRiver IHP hard drive player with digital out; then I think he has a HeadRoom Portable Micro Amp w/DAC under the player in the bag. The iRiver remote is clipped to the strap.
metalsonata's picture

...pretty much the only thing I can say about that rig. Imagine trying to get something that looks like that through airport security today.

13mh13's picture

Some of the now-CLASSIC Stereophile ads -- ca. early/mid 90s -- were not much ... uh ... "worse". BETTER IMHO ... those had character.
Now ... yawnsville and totally UNmemorable.
Technological "improvements" = miniaturization + form-factor-"improvement". Now, folks can stick their iPods in their Fruit-of-the-Loom DRAFTS ... and walk around LOOKING totally normal ;)
No more individuality -- everybody's off the same assembly line. Same song, different day. Work with me on this, folks.
Speaking of underwear + normal ... how far would YOU go to for your company ...

Merck's picture

Wow that stuff really seems to work very well. I will definitely keep this article in mind when I build an awesome portable rig with the CLAS.

CarlSeibert's picture

They marketed this stuff to photographers as far back as the eighties. I have strobes from back then with patches of "PhotoLok" to hold slaves and they still work fine.

My laptop dock at work is held together with about 2 square inches of it and it's not going anywhere.

Believe Tyll when he says you have to plan for the thickness.

allmotor91's picture

Did you make those short iPhone to amp connectors or can you buy them? Awesome write up about it. Love the DIY stuff.

mikemercer's picture

You can buy those LOD cables (cables coming from the iPod/iPhone) from ALO, or Moon Audio, Whiplash Audio makes them as well!

GREAT write-up as always Mr. Hertsens!!