Hi Triode- I've only ever used them in my JoLida 502B. I was suprised to hear an improvement - more detail & spaciousness, I'd say. I really didn't expect to be able to hear a change. Didn't think my system or ears were "resolving" enough. But I thought they did. Proof came when a tube went and took the HiFi fuse. I replaced with a cheap Radio Shack substitute until a replacement arrived. I heard the "loss" when running the RS replacement. It's a minimal investment given the dollars some have in their systems. Worth a try. The Cable Co. is running a special during the Christmas season (I don't work for the Cable Co. - they are just a convenient retailer for me). Search HiFi Tuning Fuses...there have been some recent threads on this topic.