I managed to upgrade the best-selling Koss PortaPro headphones using a couple of items I’ve bought on eBay. The headphones are some ten years old now, yet sturdy and rocking, and now have become even better:
I managed to upgrade the best-selling Koss PortaPro headphones using a couple of items I’ve bought on eBay. The headphones are some ten years old now, yet sturdy and rocking, and now have become even better: