Koss P9 In-Ear Headphones with Volume Control

[image] Audiophiles are no strangers to Koss. After all, the Wisconsin-based company has been at the forefront of audio innovation since developing the world’s first stereo headphone in 1958. Over the years, we’ve sold many of Koss’s flags...

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After endless capacitor changes (SonicCaps) and op-amp rolling (OPA627AU on Brown Dog Adapters), and adding a beefier 9VDC switching power supply, I’d scored a nice STAX 100VAC with North America 120/110VAC Step Down Transformer off of eBay f...

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Given the number of Koss headphones purchased here, a Drop for an upgrade to the energizer would probably have quite a few takers

About a year ago, I shared the story of how I discovered a working set of Koss headphones from the 1960s while I was killing some time in an antique store . https://www.massdrop.com/buy/massdrop-x-koss-porta-pro-x-headphones/talk/1790498 ...

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