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Gear Spotlight: Mesa Boogie Strategy 400 Power Amp

Updated: Mar 30, 2022

When guitarists speak of “the Metallica sound,” there are a few iconic pieces of gear that always seem to dominate the conversation - Mesa Boogie Mark IIC+ amps, Gibson and ESP guitars, EMG pickups, etc. While that gear undoubtedly deserves a place at the forefront of any Metallica tone discussion, there’s another piece of gear that‘s oftentimes overlooked, but no less critical to some of the most recognized tones of the band - the Mesa Boogie Strategy 400 Power Amp.

In this Gear Spotlight, we’ll examine what the Strategy 400 is, how it’s related to the band, and discuss the “not talked about enough” impact this power amp had on the Metallica sound for over 20 years.

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The Mesa Boogie Strategy 400 Power Amp


In the spring of 1987, Mesa Boogie released a pair of power amps that gained widespread acclaim in the audio industry - the Strategy 400 and the Stereo Simul-Class 295. Audiophiles were quick to adopt and praise the clean, forceful power section of the Strategy 400, heralding the clarity as unrivaled and essential in their high-end home stereo systems. Pushing a massive 200W from each channel, the Strategy 400 could rattle walls, enhance the sound of any source put through it, and had the ability to do one thing not many other power amps could claim - it cleanly reproduced the source material in a transparent fashion. Essentially, you got out what you put in with minimal coloration allowing your stereo (or guitar amp) to be heard the way it was designed.

The introduction of a massive, all-tube power amp was particularly striking during this era of the 1980s and not without criticism, as solid state, transistor and MOSFET technology threatened to dethrone tube gear in the audio world. These ‘80s favorites were cheaper, efficient, and becoming more prevalent in gear that would not have been feasible to produce in massive quantities with tubes for the prices offered. To some critics, tube technology was archaic, and the 1980s would be the death knell. To the discerning ear of musicians, however, nothing would replace the magical quality of vacuum tubes.

How many Strategy 400s were made?

The Strategy 400 was produced in small quantities starting in the spring of 1987 and continued on the market until mid-1991. Here is where the water gets muddy. The Strategy 400 and concurrently released Stereo Simul-Class 295 unfortunately used the same serial number format. Due to this, it is impossible to determine exactly how many were made. However, we can make educated assumptions.

The serial number format used by the Strategy 400 and Stereo Simul-Class 295 was an “S” followed by the serial number. For example, the 375th unit produced would be serial number “S-375.” These two power amps collectively went from serial number S-001 to S-2673. Given that the 295s more practical power application was likely more marketable, they were assumed to have been produced in slightly higher quantities than the Strategy 400. By using a conservative 60/40 production split in favor of the 295, we can take an educated assumption that around 1000-1100 Strategy 400s were produced.



Looking at the history and production of the Strategy 400, we can break them down into 3 different versions that were produced based on the options that came with them.

Version 1 (1987)

The original Version 1 of the Strategy 400 released in 1987 seemed to be geared mostly toward high-end audiophiles and their massive home stereo systems. This model had a sleek and clean front panel layout with no front mounted controls other than on/off and standby/on rocker switches.

These earliest Strategy 400 amps had the serial number etched into the chassis as opposed to being located on the back with a sticker. Below is an early example, serial number S-190.

Serial number S-190

These models had a fixed presence value with a relatively flat EQ that was intended to cleanly amplify the signal put into and reproduce it with surgical precision. There was no tonal degradation or coloration of the signal from the power amp itself. This is partly why the Strategy 400 was so beloved by audiophiles.

The early production Version 1 models had additional XLR jacks on the back for connection, though these were removed on the later Version 1 models.

XLR Jacks on Version 1

Version 1, although heavily geared toward audiophiles and home stereo environments, immediately received notice from guitarists for their massive sound and power. Despite pushing more air and wattage than any other offering from Mesa (like having 2 Coliseum power amps built into 4 rack spaces with extra wattage to spare!), the amp has an exceptionally smooth volume taper that makes it equally adept for playing at low volumes with a thick and full sound.

With the Strategy 400 quickly getting integrated into the rigs of professional guitarists, the amp started to undergo slight revisions to help provide a few additional options for tone shaping.

Version 2 (1988-1989) Version 2 was produced starting in 1988, though some early ones seem to date back to late 1987. Version 2 was very similar to Version 1 with one primary addition: a presence switch on the back for each channel that shifts the top end and changes the attack, feel, and response of the power amp. With the switch turned off (pushed in on the bottom), the amp sounds, feels, and reacts identical to Version 1. With the switch engaged (pushed in on the top as pictured below), the top end becomes more percussive and the upper mids have the “feel” of additional gain. It is the equivalent in response to using some of the pull switches found on the Mesa Mark II/III/IV amps.

Presence switch on Version 2

The presence switch was eventually removed and one final change was made that lasted until the Strategy 400 was discontinued.

Version 3 (1989-1991)

The final version of the Strategy 400 removed the presence switch and added a presence knob, all while moving the control knobs to the front panel. This was to provide guitarists more flexibility over the previously set presence value and afford control quickly from the front panel to avoid having to reach behind the amp and rack.

Version 3 with front panel controls

Unfortunately, the presence switch and presence knob serve different functions, forcing a choice between the models for tailoring your tone. Version 2 with the presence switch can bring an additional cap into the signal path, altering the top end and “feel“ while having a fixed presence value. Version 3 does not have the switch for a change ala the Mark series push/pull knobs, but has a presence knob to alter the value that is fixed on Version 2.



The Strategy 400 was designed around and originally shipped with Mesa labeled, Made in the USA Sylvania power tubes - the Mesa STR 415 6L6 and Mesa STR 416 6CA7/EL34. The inner 8 sockets accept 6L6s only, whereas the 4 outer sockets were configured to use either 6L6s or EL34s. Therefore, some amps shipped stock with all STR 415s, and others shipped with STR 415s in the inner 8 sockets and 4 STR 416s in the outer 4 sockets.

The STR 415s and 416s were screened in two different colors - green or blue - to allow musicians to quickly match tubes in Mesa amps without needing to rebias the amp.

Mesa STR 415 (Left) & Mesa STR 416 (Right)

By the later editions of Version 2, Sylvania‘s had slowly started to phase out in favor of Beijing-issued Chinese power tubes. These tubes would become known as the Mesa STR 420 6L6 when relabeled by Mesa Boogie. The original black base STR 420 started being used in some Mesa amps without a label (pictured far left below) and had a straight bottle. These quickly transitioned into “coke bottle” shaped editions which Mesa labeled with colored dots for matching (pictured second from the left). As opposed to the 2 color scheme of the STR 415/416s, the STR 420s expanded to red, blue, green, yellow, grey, and white.

The evolution of the Mesa STR 420 6L6

Mesa later changed to a sticker label that was applied to the base of the tube (second from the right above), but the multiple color codes that originated with the colored dots remained in place and continues to this day. The final version was a return to the straight bottle format with a slightly thinner base (pictured far right). This base came in both brown and black versions until the tube was discontinued.

How different are STR 415s & 420s?

There is a dramatic difference in feel, response, and tone between STR 415s and STR 420s. The STR 415s are a very robust tube, having a defined bottom end that thumps, low mids that bloom with volume, and a top end that is punchy but not bright. They have an almost hi-fi, 3D texture to them that enhances anything put through them.

The STR 420 has a more subdued low end, dialing back the low frequencies which makes it suited especially well for bass heavy amps/circuits to keep them tight. They have a nice top end, neutral mids, and work fantastic in many Mesa amps, particularly in the Rectifier series. Compared to the STR 415s which are built to withstand a beating, the STR 420s are a notoriously fragile tube. Heat from prolonged use can force the glue to loosen on the base causing the glass tube to shift around and wiggle loose. This can be glued back into place, or oftentimes a well placed and gentle twist can safely secure the tube back into the base. However, if you are inexperienced or uncertain, please do not attempt this at home unless you’re willing to risk damaging the tube or making it unusable.

Do the STR 420 versions sound different?

After owning and testing hundreds of Mesa STR 420s - original run, coke bottle, straight bottle, black base, brown base, etc - we have found no discernible sonic difference among the versions. No two sets of tubes will sound the same and all will age differently, but the inherent, core sound of all versions of the STR 420 is the same.



Metallica originally acquired Mesa Strategy 400 power amps in late 1987 prior to the recording of …And Justice for All. These power amps would become the backbone of Metallica’s live tone for 20 years, from 1988 - 2008.

Starting on the “Damaged Justice” tour in 1988, both James Hetfield and Kirk Hammett relied on the Mesa Strategy 400 exclusively to power their live sound. All amps and preamps were slaved into these power amps for live use. This included Hetfield’s Mesa Mark IIC+ heads, Kirk’s later Mesa Dual Rectifiers, the Mesa Triaxis preamps and more. The only noted exception to this is when Kirk used a VHT power amp for one leg of the tour for the Black Album in the early 1990s.

Is the Strategy 400 on the albums?

Yes, the Strategy 400 was used extensively on the albums from the late 1980s until the recording of St Anger. It can - confirmed - be heard prominently on the following albums:

And Justice for All, Load, Reload, Garage Inc, S&M, St. Anger, Death Magnetic, and Hardwired (limited, see below)

There is also a possibility that the Strategy 400 was used during the recording of the Black Album, but we have found no confirmation of it. It was used on the main studio floor by both James and Kirk during drum tracking, and James did have a Strategy 400 in his recording rack in the control room. Because we cannot confirm it’s use, we currently mark the Strategy 400 as “possible” of being on the Black Album.

Floor rack for drum tracking during TBA

The Strategy 400 was only used in a limited capacity during the recording of Death Magnetic and Hardwired. Although it was not a part of the primary recording setup, the Strategy 400 was used on the floor during jams and writing sessions. Death Magnetic featured a wide array of gear and each track contained an assortment of amps, including the Mesa rack. Hardwired had some tracks with guitars lifted directly from floor rehearsals which would contain the Strategy 400, such as “Now That We’re Dead.”



With the history of the Strategy 400 and Metallica’s use of it established, which model(s) and options did they use?

Based upon photographs, videos, and discussions with those close to the gear, the Strategy 400s used by Metallica throughout the years are:

Model: Version 1 & Version 2

Tubes: Mesa STR 415 & 416

Metallica acquired their Strategy 400s during the late Version 1 era and look to have a mix of Version 1 and 2 in racks dating all the way through to the Death Magnetic era (when they were replaced by Mesa Simul-Class 2:90 power amps to reduce the rack space being used). There has never been documentation of Metallica using Version 3.

1 of 2 racks assembled during the Load era

Contrary to some artists that frequently change tubes, Metallica appears to change tubes only as necessary. One infamous story is when Van Halen’s techs were changing tubes and throwing away vintage Sylvania tubes after every show! Metallica has been seen still using Mesa STR 415 (and possibly STR 416) tubes in the Strategy 400 into the 2000s. This is also a testament to the longevity and durability of the old Sylvania tubes!

Strategy 400s in use during the St. Anger era

The Strategy 400 may not be the most glamorous or talked about piece of gear in Metallica circles, but it’s use on a majority of the bands albums and as the central backbone of James and Kirk’s live rig for over 20 years easily make it one of the most essential pieces of gear that has shaped the “Metallica sound.”

If there are aspects of Strategy 400 not covered here that you’re curious about, please leave a comment or send a message. We can edit the article to include additional information if there is a demand for it.

Also, please check out our other articles for a detailed analysis on other Metallica gear, album breakdowns, and more. Thanks for reading!

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1 Comment

Jun 25, 2023

Awesome information over here!!! Like you have said "may not be the most glamorous or talked about piece of gear" but it deserves better; a long time ago I couldn't afford a rectifier and knowing nothing about amps went for a strategy 400 (if it's good enough for Metallica, it's good enough for me) later on the rectifier couldn't touch the magic of the 400. One thing I have always wondered is if James/Kirk run all 6L6 (x12) or 6L6 (x8) mixed with EL34 (x4) in their Strategys.

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