Bear62 wrote:I may have missed this, Brad can you tell me what tubes you use in the SMS. Thanks
For about a year or more I've been using the premium selected Shuguang series 9 12AX7's. These are chinese tubes. I never thought I'd allow it, but after years of testing and returning literally hundreds of european tubes for failure or bad microphonic issues, I finally took the cues from audiophiles and boutique amp makers such as VHT/Fryette, Fuchs, and others and gave these a shot. They're actually quite good, they have a good and solid clean tone, and generally have been holding up better than the JJ's and the Soviet tubes (Sovtek, EH, Tung-Sol reissue, Mullard reissue, etc.). These premium Shuguang tubes are also marketed under the brands Ruby, Groove Tubes, Tube Amp Doctor, Penta, and a few others. The chinese Shuguang factory has been refining their 12AX7 since the '80s, and now on their 9th generation of refinements and tweaks, it's become a pretty well respected new tube. You will surely find people who will automatically dis these tubes because they're Chinese, as I did for years. But in reality, they're good.
Now when it comes to use in preamps designed for overdrive, I can't make any claims about these tubes. My intended use is for clean with high headroom, and NOT delving into the issues of tone and harmonics when clipped and overdriven. That's a whole other realm.
Now that being said, I think it's always a nice idea to consider an upgrade to a good old or NOS (new old stock) 12AX7 by RCA, GE, Sylvania, Tung-Sol, Mullard, Telefunken, etc. Lots of really great tubes out there from the old era of when tubes were really made to last. They're pricier, but can be found. Personally, in my rigs, I'm using these Shuguangs and amp perfectly happy with them.