Op amp: upgraded to the MUSES02. I'll include the stock. Tubes: All the best, including a pair of each for: Voskhods (6Ж1П-ЕВ), the stocks, the Sylvania (GB-408A), and 5x GE (5654W). How much? Only $140 + shipping and paypal fees. I ship via USPS priority mail for this package. Sounds amazing with Grados. And it actually has plenty of power to drive many high-impedance headphones. Thanks!