12ax7 vs 5751

Grayf I am fairly new to tubes also and enjoy tube rolling a lot. Friday night I had a real big problem. One of my Gec CV6091/A2900's went out and took a Ei KT90 with it (but didn't know it right away). So I replaced the Gec with my Brimar yellow T's and the KT90's with my Tung Sol 6550 black plates. Sat morning I decided to verify the KT90's and sure enough 1 was bad. I didn't know it at the time but when I put the 6550's back in and damn the Brimar took out 1 of my 6550's (all in the same positions). I never thought anything like this could happen. But it did. I have all stock tubes back in now except for my Rca 5751 triple mica black plate. So it was a very sad and more important very expensive weekend for me. I'm still confused because I have had output tubes go before and that was it. Anyhow be careful should an input or driver tube go.

Forgot to mention the lesson I learned is in the future if I have any input or driver tubes go bad to have them checked out with any output tubes in the channel.

Yes, as a general observation, British tubes do deliver a warmer sound. There are makes of other nationalities that will also do the same. For a warmer sound, I like Amperex Bugle Boys (Netherlands). These tend to work reasonably well in all applications.

Yes Mcpherson, I found the Focals very bright and somewhat over analytical when I first bought them. In the store, I was dazzled by all that detail and transparency. Wouldn't you know, it I had auditioned them by letting the store choose the amplification and source, of course it was all tube! Well, I got them and I had a really nice Musical Fidelity SS integrated amp, and was I in for a surprise. It took a complete system overhaul, but I stuck with them tinkering until I got them to sound the way I knew they could. Now they astonish and delight me ever single time I hear them.
I disagree with those who think that any high caliber equipment, when well implemented, works with all speakers. The real trick BTW was the use of tube power amps, not just the tube pre. Together the all tube system is incredible. The quick fix is prolly using Mullard NOS/OS tubes and getting Cardas cabling. However, I almost guarantee that you will find tube power amplification to be the ultimate answer and I bet you will be deeply pleased with the result.

Mechans
What type amp/preamp are you using? I will probably trying to get the Thor amps to compliment the pre once the smoke clears from the preamp purchase. My wife is tolerant but not quite as excited about audio as I am!
I am gonna order a replacement tweeter and then start trying some different tubes and see what happens.
Thanks jayson