May I introduce to you one of the first mechanically customizable headphones ever. At least that’s what Koss says. Regardless, I’m fairly certain very few of the people reading this website have but a clue that this headphone even exists, but it had been on my “must own” list for a while–ever since I had come across a seller with two pairs that quickly sold for over $50, which was how much my most expensive headphones cost. Strangely enough, a few months ago, I managed to snipe a pair for $16. Fairly good deal I must say. Heck, it cost me 50% less than my Portapros.

Some advertising:
“Technician/VFR with variable frequency characteristic. The Technician/VFR is the first headphones of the world, to which the possibility offers of changing the process of the frequency response of the two transducers. If one places the automatic controllers into the upper position, then an increase of the bass range takes place, whereby one and effect of a small group of presentations volumes can increase. In contrast the large orchestra with its many different instruments stands on relatively small area. If one places the VFR automatic controllers now into the lower position, then the acoustic rendition reaches one more linear outline, which affects itself particularly favourably with classical music or organ music.” –Koss

They were released around 1974, and sold for $75, which when inflation is calculated, is about $300.

The stock sound is…exactly what I expected it to be. It’s incredibly bright, with graininess in the mids and bass that isn’t well defined or detailed, and average detail. Happily, the variable frequency response works, well, worked. How does it work? Well, additional pressure is placed on the driver if you turn the dial up, and vice versa if you turn it down, sadly, the system is comprised of foam, and after almost 40 years, it starts to really wear down, which it has on my right cup. It’s now stuck on the bassy setting.

The VFR is made of metal and plastic. The plastic is of the durable sort, and reminds me of Beyerdynamic DT770Pro plastic. The pads are filled with air and can get mighty uncomfortable after a while.

Now, if you knew me at all, you’d know I’ve opened up every headphone I’ve ever had. Which I did here with the Kosses, to restore them.

I added tack to both the baffle and the cup to stabilize backwaves, replaced the rotten foams with felt, removed the screen in front of the driver, and put polyfill in the cups to increase soundstage, which was incredibly lacking. The last part was probably dumb, because it was a low pass filter, but I assumed my mods would add bass, so I took a gamble and ripped the cloth out in hopes that it set the mids free. It didn’t as much as I hoped, if at all. And it’s brighter. But more detailed, so I kept it as is.

Here’s a bit on the sound, because any information at all about these is incredibly scant. These impressions were made before the foam-decomposing tragedy:

The overall sound signature is decidedly dark. The bass is tipped up in respect to the mids and treble.

The bass in the VFR’s is okay. It’s not the most detailed, nor the most deep or tight, but it isn’t offensive, and is decently fast. In the extra bass mode, the bass muddies up, but is increased a good bit. If you don’t mind the bass loosens up in exchange for a extra few decibels of it, then it would suffice most people. They still aren’t bass monsters with the shift.

The mids are also just okay. Vocals can sound grainy at times, guitars sound mechanical, and brass sounds too metallic, but I’ve heard worse. The other mode veils the mids too much for my liking. At its worst, the mids can sound echoey and hollow.

The treble is a bit artificial, even with all the tweaks. It isn’t bad, but it’s far from smooth and get can sibilant. The other mode recesses the treble a good bit.

The soundstage is pretty in your face, which isn’t surprising considering it’s a closed headphone. It has decent placement though.

The VFR is decent in and of itself, but don’t get it expecting amazingness. It’s good for what it is, but that’s it. Then again, I’m probably spoiled with my other gear. The VFR is probably the coolest dynamic headphone I have, other than the K4, but it’s a hybrid, so it’s different. I’d say for the $16+shipping I paid for it, it’s impressive. My only qualms are sibilance and mediocrity in mids, and that’s not bad at all in the grand scheme of things. Although the sound’s only around low-fi level (I prefer my Portapro for its airier sound) it’s certainly not bad enough to avoid–get it if you can find one and are even considering one for cheap, since you’ll have a heck of a time finding another. This is the best looking pair I’ve seen for sale, ever. I recently saw one in worse condition (missing a sticker) sell for over $100. It had a case and paperwork, but who needs papers?

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