Gold Lion AX7 in tube preamp

Check with your manufacturer if trying 5751

If your talking 12ax7’s I believe they make one from Mexico and one from Russia. The Russians being the better of the 2 I’ve heard.  I had some Russian ones that came stock with an amp I bought. They were pretty good for new production.

They tend to share sonics with Telefunkens not as good but resemble each other. When I pulled the gold lions and put in the Telefunkens that’s when you see the big difference. First thing I noticed was sound stage then how much more natural the Telefunkens were and I’ve never thought of Teles being relaxed and natural. 
 

You really notice a difference when you compare the GL to the Mazda, mullards, RCA’s, Tungsram and others but you would expect this comparing new production to vintage. For a new tube I think they are pretty good but there not cheap either. You can buy used vintage 12ax7 that test new for the price of the Gold Lion.

It’s not a race run it in when you get back. Odds are nothing will happen but if it red plates it could smoke your amp and worse smoke your house.

When you get back run it 100-200 hours see what happens. It’s a very detailed tube and should smooth out. If your looking for a clean and detailed tube the GL is it, if you want a Mullard sound you will never get that.
 

if  you are looking for Goldie locks tube the RCA may be it even though it’s more of a guitar amp tube. It falls between the Mullard and Telefunkens Everybody’s taste is different.