RTA001

This usually is the first thing I ask a customer when they’re bringing their amp in to be looked at, and that’s where I start. If it’s a heavy-metal player I’d set the amp up differently than say for a country picker…
For example due to it’s extremely low residual noise we use the JJ ECC83S (12AX7) the most here at Thermal Relief… Most Marshall and Peavey 5150’s/ 6505’s get JJ’s in their pre-amps but for Fenders, I prefer the Russian Tung-Sol reissue 12AX7. With Mesa’s I stick with the old axiom of “Mesa tubes in a Mesa amp “… they just sound and work best that way. The JJ’s sound and work the best for the hi-gain and metal crowd but you must audition each one as some end up being too noisy in the V1 position but can be used with no problems farther down the signal chain as phase inverters and reverb/tremolo drivers.

For really stubborn noisey hi-gain amps like Peavey 5150’s, a little secret is to find a 12AX7 Chinese tube, with the red writing where it says “China” in a little white sticker… this really helps tame that old 5150 that sounds like it’s raining when the gains cranked and you stop playing. Otherwise I may grab an occasional Mesa SPAX7A, this is the specially selected 12AX7 tube with a piece of heat shrink tubing on it. Sometimes it’s the only hope of killing that gain noise. And to help with microphonics, I sometimes put my own heat shrink on a tube, stretch the tube shield spring and then push it down tight over the tube. In the new Marshall JVM’s, I’ve been putting a JJ ECC81(12AT7) in V1, which brings down the overall noise in the amp, but retains that great old rock sound these amps have. I really think this is Marshall’s best amp lately… they don’t have the huge metal palm muting gain that a Boogie or a Peavey 5150 has but they’ll tear you in half with that original solid Marshall rock tone we all are searching for and the JJ ECC81 (12AT7) really hits the mark there.


Now for the country picker, I want to give them tons of headroom with a clean swirly tone and the Russian Tung-Sol reissue 12AX7 is a little bomber for that “vintage-y” Fender clean tube sound. The current Fender DeVille’s and Deluxe’s come stock with cheap pre-amp tubes and even cheaper speakers. A new set of the Russian Tung-Sol’s really makes these amps happy!
The best of these new Fender’s is the reissue Blues DeVille 4X10. I really want one of these … In my opinion, Fender seems to have 3 grades , made in Mexico, made in USA, and the Blues DeVille 4X10. But no matter which one, I say Tung-Sol’s all around for Fenders!!! As I just mentioned above the Fender DeVille and Deluxe really suffer from cheap speakers. I personally have stuffed stuffed everything from Celestion Vintage 30’s (yay!) to Weber’s into these baby’s. They really seem to come alive with just a simple pre-amp tube change and speakers. Also they bias these cold from the factory, I suppose to keep the tubes lasting through the warranty period, but a quick bias and there on their way. Recently I’ve also been sneaking the new JJ 6L6GC double mica power tube into all these combos, it’s a sweet tube with extra top mica installed, cushioning the inner works from the glass so it won’t get rattled about like most combo amps do to tubes.

Any of the Groove Tubes are great tubes too, however Aspen recently sold the company to Fender and there’s a back order on just about everything now, so i’m waiting for the new shipment to come in. They changed the look of the tube from a neat orange silk screen to a little sticker.
I used to be able to use the silk screen as a guage on how much abuse the tubes have taken… we’ll have to see about the little sticker. I’m hoping they won’t sell the Groove Tube Silver Series to the public anymore, as they don’t really test these tubes properly, but they sell them as such. At one time Guitar Center bought a bunch of them and were selling them. I’d stay away from the Silver Series as every time I find them in an amp they are usually the problem.

I love setting up an Ampeg SVT with a sextet of GT-6550R. Expensive but amazing tones!!! And I also love the Groove Tubes GT-EL-34M. A great sounding tube. I had a quad of them in my ’73 Suzi Quatro Marshall Super Lead for the past year. Groove Tubes also makes an amazing “matched phase inverter” but for extra money I can get the JJ’s like that also!


Before they stopped selling them I used to get these EI tubes and I put them in everything. I think the chrome plate 12AX7’s they made sounded a lot like an old Mullard… the only problem was microphonics. A tube can quickly be tested for microphonics by tapping it with a “Sharpie” while the amp is turned on and plugged into a speaker with the back off. A loud tap when struck is OK but if the amp starts ringing or feeding back the tube is microphonic. Those EI’s I used were almost all microphonic but the tone was amazing… it really cut through and had lots of bottom end. I still have a stash of them, I like to put in my Twins and mess around with. Yea I have 2 Fender Twins and a Musicman RP100… I love my clean tone as much as I love my metal!!!