Mesa Boogie Strategy 400 Power Amp Retube Kits

The Mesa Boogie Strategy 400 Power Amps. Every kit is configured to provide a specific sound/experience.

All our Mesa Strategy 400 Power Amp Retube Kits include power tubes that are hand selected to run perfectly in Mesa amps. We have extensive hands-on experience measuring the fixed bias points in these amps and what grade of tubes will achieve optimal performance.

The default power tubes for these Retube Kits is a Matched octet of the JJ 6L6GC’s (installed in the outside four sockets on each side, see image below) and a Matched quad of the JJ E34L’s (installed in the middle four sockets). The 6L6GC tubes follow the classic sonic archetype with big lows, smooth mids and crystalline highs. What sets them apart is their low end clarity, mid-range detail and very clear highs without being overbearing or harsh. You can also use an octet of the JJ 5881’s. The JJ 5881’s are a Classic 23 watt 5881 in a traditional stubby bottle. “Jangle” for days and a very warm full tone. Right in-between the JJ 6L6GC and the JJ 6V6S in power. If you’re looking for that early-breakup “tweed” era character these are it. You can also use an octet of the JJ KT66’s in the outside four sockets on each side. The JJ KT66’s are one of our favorite tubes here at Eurotubes. These tubes have a clean low end response with a forward mid-range and articulate highs. When overdriven these tubes crunch up early in the upper mids and highs resulting in an incredibly complex tone that retains excellent low end clarity (just like the originals).

Other options for use in the middle four sockets include quads of the JJ EL34’s, the JJ EL34II’s, the Big Bottle JJ 6CA7’s, the JJ KT77’s and even the JJ KT88’s! Thru the years the JJ E34L’s with their added punch and articulation have become a favorite here at Eurotubes and with our customers. They are very tight with an extended low end over a standard EL34. However you can use the Power Tube drop down to select the JJ EL34’s, the JJ EL34II’s, the JJ KT77’s or the JJ 6CA7’s. The JJ EL34’s are known for their mid range bloom and have a slightly looser feel when compared to the E34L’s. The JJ EL34II’s are not as aggressive as the E34L, but they are a little fuller in the lows and low mids than the EL34’s. The JJ KT77’s have an extended frequency response with big/chunky lows (even deeper than the E34L’s) and chimey/present highs. The mids are very smooth for an EL34 type tube and when driven they’re extremely rich and complex. The JJ Big Bottle 6CA7’s have big lows (on par with the KT77’s), an emphasis in the lows mids, and very round/natural highs. This gives the tube a very thick and round character that’s as close to crossing a standard EL34 with a 6L6 as you can get. The JJ KT88’s are a replacement for all standard KT88 and most 6550 applications. These are a higher power tube with lots of headroom, thunderous lows and thick/aggressive mids.

The Standard Retube Kit is as close to OEM as possible. Maintaining the amps stock level of headroom and gain while providing a warm but even handed overall sound. The kit includes one Matched octet of JJ 6L6GC’s and a Matched quad of the JJ E34L’s by default and four Matched and Balanced JJ ECC83S’s.

The Gold Pin Retube Kit uses the JJ ECC83S Gold Pin variants to provide a smoother, creamier, and more singing overall sound. This option is less aggressive and has less “teeth” when driven hard. If you like a classic raunchy gritty overdriven tone, we recommend looking to the Standard or High Gain option. If sweet, open, and more refined is what you’re after this kit will do it. The kit includes one matched octet of JJ 6L6GC’s and a Matched quad of the JJ E34L’s by default and four Matched and Balanced JJ Gold Pin ECC83S’s.

Below is a visual guide showing all of the different combinations of Matched quads of tubes we have run in the Strategy 400.