Yesterday I auditioned some new reissue Tung-Sol 6L6GC STR tubes in the 6L6 “Spalted Alder” amp. I was quite surprised at the results.

Long time readers will know that I typically lean toward JJ power tubes when looking for new production tubes. However, a recent series of JJ power tube failures have pushed me into trying some other options. So a while back I ordered a pair of new production Tung-Sol 6L6GC STR power tubes. Yesterday I installed them in the 6L6 “Spalted Alder” amp and settled in for a listening session.

The first thing to know is that Tung-Sol is currently owned by Electro-Harmonix. But these tubes are not simple rebrands of the Electro-Harmonix 6L6GC. They are actually a slightly different tube built to different specifications. Tung-Sol describes them thus:

The Tung-Sol legacy continues with the introduction of the new 6L6GC STR. The ultimate in musical tone and smooth overdrive, the STR delivers the sound that established Tung-Sol as the benchmark of quality. Built to the same “Special Tube Request” specs of leading amplifier manufacturers of the 1960s, the 6L6GC STR is a rugged and reliable power tube for use in the most demanding guitar amplifier circuits.

This explains the “STR” after the name. Here are the tubes I received from my supplier.

And here they are installed in the Spalted Alder.

These came with a November 2023 manufacturing date stamp.

As I said above, I was surprised; pleasantly so. These tubes have a magnificent sound in this amplifier. They are rich and full in a way that the JJs never were. Don’t get me wrong, I really like the performance of the JJs. But I would describe the JJs as fairly neutral in the Spalted Alder amplifier. These Tung-Sol 6L6s are anything but neutral. The best description I can give is very full.

These tubes really let the amp come alive. They provide a color and tonal shaping in the Spalted Alder that the JJs don’t. It almost sounds like a different amplifier. The biggest difference was in the low end. These tubes delivered big powerful bass without sacrificing the upper end. Solo bass lines and floor tom drum beats came through smooth and crisp just like being in the room with the musicians.

Some of my favorites selections for bass lines like Bachman-Turner Overdrive’s “Not Fragile”, Humble Pie’s “99 Pounds”, and Norah Jones’ “Cold Cold Heart” really came alive. Even deep vocals and bass beats such as in Avi Kaplan’s “Change on the Rise” found new life and fullness with these new Tung-Sol 6L6GC STRs.

If you have built a Spalted Alder, I highly recommend a set of these Tung-Sol power tubes.

As always, questions and comments are welcome.