Mesa Boogie Tube SPAX 12AX7

These tubes are just unbelievable. I used it to replace the preamp tube on my Marshall valvestate 8240 stereo. I replaced the original one with a JJ tesla tube a while ago and it was good, I liked it, but it is nothing compared to these. The sound is thick, warm with massive low end. It sounds very solid, consistent. I don't really know how to describe it. Well I love Metallica and metal music though I don't always play that kind of music. I think this is the closest to THAT sound I have ever heard my amp when you turn on the distortion. When you turn it up is when you can hear the massive difference there is no loss of tone all harmonics are there...

I have owned this amp for more than ten years and It never sounded like this. I was a bit sceptical about the price at first because I thought they were all the same and it was just all about electronics. I also read some reviews saying that Mesa tubes are just JJ tesla tubes with a printed Mesa Logo... well all I can say is that I recommend these tubes 100%

cold, bright, empty, dark , hollow, unpleasent, sceptic dead sound, I ve tried this with various amps. Great colour with Engl, Peavey, Mesa amps. Quite cold and unpersonal touch when used with more clasic amps like VOX, Fender, .....
This walve has its own metal armour shielding around , ao its well suitable for big heads with big Watts as well :)

For me ? Tung Sol products fits better my needs. More colour, more worm, more thick......iven in dropped B ;)

I was so very disappointed in these valves. I bought a complete set for my mesa boogie mk iV that is approx 12 years old, thinking that they would be more reliable, and that they would bring the amp sound quality back to almost as it was when it was new (or even better?) - how very wrong I was.
The clean channel and the crunch channel volumes dropped away significantly, and the sustain channel sounded so brittle it was painful. Certainly not the warm gutsy sound the amplifier had when I bought it, so I have reverted back to my old valves and the sound I love is back.
I played one gig with these SPAX valves and spent the whole night fighting with the amplifier to get any sort of decent sound - they are absolute rubbish and I am sooooooo disappointed to put it mildly.
The end result is that I now have around £200 worth of useless valves that I cannot return, and the only option is to maybe try and sell them on ebay. It may be that these weren't right for my amp, but might be OK for another , but since they bear the name mesa boogie I expected so much better - poor quality product.