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Tinkerer – Photographer – Enthusiast

[Project] Koss Porta-Pro Wireless Conversion

Koss wireless portapro. Picture: Koss

The Koss Porta-Pro is one of the hidden gems of the budget audiophile world. As a poor person myself, budget audiophilia is incredibly appealing and I love discovering a hidden gem- a device that for very few dollars is the best in a class of devices that goes all the way up to very many dollars. In this case the PortaPro is “the best headphone under $100” clocking in at around $35 depending on sales. Unchanged since its conception in the 80s and retaining an undoubtedly dated aesthetic the Koss PortaPro delivers a very bassy, warm-toned listening experience in a shockingly transparent package. The Porta-Pro disappears on my head after a while, letting in enough of the outside world that I can have conversations easily with the music turned down and then turn it back up and keep jamming.

Aside from the inherent sound leakage of being an on-ear device instead of over-ear (your coworkers will know you like Britney) the only thing that stands in the way of the PortaPro being a device that completely disappears while you’re wearing it is the cable. There are plenty of devices on Amazon and eBay that will plug into the end of the cable and allow wireless connection to your device but that is far too easy, far too bulky, and it costs money.

Koss’ solution is to essentially make the biggest neckbuds ever. Neckbuds are a stopgap between wired earbuds and “truly wireless” (e.g Airpods) earbuds where it simply looks like someone snipped off the cable where it meets below your neck. Two earbuds, wire connecting the two together, and a small control box. Koss simply took a pair of neckbuds and lopped off the earbud parts, instead attaching them to the Portapro’s drivers. Simple. Unfortunately this solution is unsightly and has been reported to have fairly mediocre battery life. On the plus side, it is cheap and required minimal tooling on the part of Koss. So “yay Koss”, I suppose.

As it happened, I have a pair (or two, or three) of PortaPros kicking around. I have replaced the cable three times due to the original being flimsy and the replacements I used being crap. The Portapro comes apart easily, the speaker units simply unsnapping from the headband, and a small cover popping off of the speakers to reveal two enormous solder pads ready for whatever cable you could imagine. There’s even some strain relief built in, for what (very little) that is worth.

Here are my Portapros with poorly-replaced cables and solder points exposed. A tap of the soldering iron frees the wires and I’m left with a pair of acoustic UFOs

Here is the victim. A Taotronics wireless earbuds set. These worked great and had great sound quality and a TON of battery life but met their sad end after a dunk in some water and one of the drivers was never right again.

Not thinking, I immediately hacked off the earbuds with the intention of stripping away the flat cables and soldering the wires to the Portapros. But there was an issue. When I finally got the flat cables stripped, which was a job in and of itself, I found four wires. Red, blue, green, and gold. 

Attacking the earbud itself with some pliers soon revealed the reason and the secret behind the stellar battery life of these ‘buds. Two lithium-ion batteries housed one in each bud.

No problem! The batteries had easy to get to solder pads. I could desolder them from this stringy internal affair and solder them back onto the portion of wire I had stripped back.

Lovely! Red and gold to the battery, green and blue to the speaker pad. I used a high heat setting on the soldering iron to burn back the insulation on the wires and then turned it down a bit to solder them to the pads so I wouldn’t melt the plastic.

Unfortunately I wasn’t able to come up with a cleaner solution for the batteries so for now they will dangle immediately below the driver. I will likely attach them with a dab of hot glue so they don’t wiggle around too much.

At first I thought the batteries could live between the driver and headphone frame but, alas, there isn’t room and I didn’t feel like breaking out the dremel.

“Nice earrings.”

A bit goofy looking, but absolutely glorious to use. Sound quality has not suffered one bit, and the Taotronics chipset is actually able to drive the headphones slightly louder at max volume than I was able to get with them plugged into my phone’s 3.5mm headphone jack (yes, some phones still have them).

In the future I may look at ways to secure the batteries and run the cable up along the headband for a cleaner look. I’ll update this post when I do that, but for now this is a very functional mod and I’m supremely happy with it.

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