i'm currently using svetlana's in a cayin a-50t with excellent results in an office system using a quad cdp player and kef 101's and an audio pro ace bass sub woofer.

I had a Cayin A50-T for over a year now. Truly a wonderful amplifier, and undiscovered gem. Recently I replaced all my tubes. I bought Mullard re-issue EL-34's and gold plated Electroharmonics for the preamp stage. The amp was good as it was, but with these tubes it seems to sculpt the mids very nicelly and achieves such silky smoothness in the high end, it makes me melt when I listen to some of my faves. The difference is subtle, but audible and enjoyable. Purists will tell you that Mullard re-issue are not as good as the original Mullards, but purist always say things like that, that's why they are purists. Mullards are now made by New Sensor company which is based in New York, manufactures in Russia and has bought most of the tube producing companies around. I paid ~150 USD for a set of 4 EL-34's and a set of 4 gold plated pre-amp tubes including shipping. Other components in my system are B&W 604 S3, CambridgeAudio 640C, Thorens TD-160. Hope this helps.