Author Topic: 1972 Koss HV-1's.  (Read 5881 times)

SunnyDaze

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1972 Koss HV-1's.
« on: July 26, 2010, 01:13:00 AM »
After buying 3 broken pairs of these puppies including two on eBay for parts at .99 cents each, I've finally been able to put together one fully functional and splendidly clean set of Koss HV-1's. Originally, I came across a set of these on CL for $20. I offered the chap $10 after they'd been online for almost a month. He accepted. He claimed that they were in perfect working order. This is probably why he had his wife meet me with them at Giant Eagle. I took them home, and only one side worked, and barely.

At least he gave me the original packaging.
 
Me, being what I am, took the non-functional side apart. I found that the magnet had accumulated rust around the diaphragm voice coil. The only thing I could do was attempt to disassemble the driver unit and clean out the rust. I popped the diaphragm off oh-so gently, and one of the coil leads broke off at the connector. Great. At least I could solder that side, or so I thought. I get the rust cleaned out of the coil by sliding sandpaper in the coil gap and running it around in circles. As I went to solder the coil lead back onto the terminal... guess what? It melted clear down to the coil. Then I disassemble the somewhat-functional side. The entire coil is oxidized and green. Great. Just great. Strike one.

I search and search eBay and CL for a set to use for parts, more specifically, to recycle the drivers. After two months of nothing, I find two sets by the same seller for .99 cents a pop. I spring for both of them. He claimed that each had one side that didn't work. The first pair showed up and were CLEAN. I took them apart to find that the drivers inside were not the Koss High Velocity drivers at all. They were indeed Koss, but they were made entirely of plastic and were not serviceable, as the HV units are all metal and are completely serviceable. Strike two.

The second pair arrived on Saturday. I pulled them out of the box to much disappointment. They looked as if they'd been left in a trench near Cologne since 1917. They were covered in a black muck, and plain ol' brown mud. I thought to myself... there's no way in hell that the drivers inside of these puppies are going to be remotely usable. I scrape and scrape the front surface until I can finally see the 4mm bolts. I fuss with them for a good hour. The entire time, I'm thinking to myself... back to the drawing board. I even checked eBay in the process!

I get the left side open. The driver inside is IMMACULATE. I threw the multimeter on it. 151.4 ohms. PERFECT! I hurry the right side open. Again, the driver is spotless, and guess what.. 151.4 ohms! I mounted the drivers inside of the ultra-clean set. I plugged them in. I haven't listened to my sr325is's since.

Here's a picture. They'll be at the meeting on the 31st. Someone, please, bring a headphone amp.



« Last Edit: July 26, 2010, 01:21:15 AM by SunnyDaze »

Offline MasterBlaster

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Re: 1972 Koss HV-1's.
« Reply #1 on: July 26, 2010, 05:44:00 PM »
I'll bring in the FUBAR IV.
HT: Audiocontrol Maestro M3, Sunfire 5*200,  Tannoy Mercury MX , SVS PB-12 Sub

Head-Fi: FUBAR IV Plus DAC, Grado SR225

Living Room: Dynaco ST-70 (R&R work done by NATOE), Dynaco PAS Preamp, Jamo C607 towers, MCS 6710 Turntable

SunnyDaze

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Re: 1972 Koss HV-1's.
« Reply #2 on: July 26, 2010, 06:31:13 PM »
Excellent.

Offline gdv

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Re: 1972 Koss HV-1's.
« Reply #3 on: July 27, 2010, 10:14:45 PM »
Glad you got the Koss headphones working...

I remember once in downtown Pittsburgh, seeing a person with small speakers attached to his head...  Bigger than STAX!!!
5 out of 4 people have trouble with fractions...

SunnyDaze

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Re: 1972 Koss HV-1's.
« Reply #4 on: July 30, 2010, 04:41:03 AM »
I'll bring in the FUBAR IV.

Actually, don't sweat it, unless you want to bring it for your own liking. The onboard HP amp on my DX 708 is plenty powerful enough. It had the HV's singing tonight. Thanks!