I replaced the stock/original tubes in my Fender Hot Rod Deluxe Amp with these to try them. I personally didn't like the high gain and more highs that they give, otherwise they're a great tube. I ended up replacing them with the Sovtek 12AX7WA which are the same as the original tubes (except no Fender logo on the tube). If your looking for more gain/highs, this is the tube for you. It just depends on the sound you prefer.

Harmonically rich, good value BUT DO NOT USE IN MESA. I've had about 5 go microphonic or dead in various positions both in my Rectoverb and Express 5/50, @large shows (w/tubes only months old). No problem in my other amps BUT I now gig exclusively w/Mesa Boogie.

These tubes are more musical than sovteks,jj's,or eh. The consistency,durability is about as good as sovteks. Harmonics much better than sovtek,similar to jj's. Rich and balanced with good top-end but not piercing. Best preamp tube for the money imho.

I picked up this tube to replace the stock Fender in my Super Champ XD. My main goal was to give this little amp more of a bite to it. This tube did the trick. Not only does it make the amp louder but it adds a more gain as well. The tone seems a brighter as well.I'm currently using a 1x12 cabinet stocked with a Celestion g12m70. This tube gives my setup a nice crunching low end. For the price its worth giving it a shot.

I purchased 4 of these and had to return three. Two of the tubes intermittently lost volume and signal after 10 minutes of playing. One tube was low output, as in 25% of your average 12ax7. The other tube was as advertised, a high output fantastic sounding tube. Playing through a tele the cleans were very articulate and 3 dimensional sounding, with some shimmer that made me check to see if I hadn't accidentally left a little bit of chorus in the signal chain. Switching to 4 stages of high gain the I noted that the distortion had a lot of depth and layers to it. This tube won out over the Ei and electro harmonix 12ax7eh I had because of its ability to span the range from great sounding cleans to killer wall of sound distortion. I own some NOS telefunken, amperex, JAN phillips and would say that this preamp tube has the potential to compete with them once quality control at new sensor is able to produce some consistentcy.