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%

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.

Preamp tubes specially designed to prevent microphonic problems. I just installed them in my Mesa Boogie Triple Rectifier and they are very quiet indeed. I'm very satisfied.
As far as I know, these are the only 12AX7 preamp tubes available on the market with a magnetic sheet wrapped around them, but I could be mistaken. It is there to prevent, as much as possible, microphonic squeals and other nasty noises.
These preamp tubes are a little more expensive than the regular 12AX7s but, of course, one pays a little extra for a better product.
So, overall, great quality preamp tubes and the people at Thömann are super fast with the shipping and take great care in packaging the items!