The Marshall Shopper’s Guide Part 2: Metal Panel JMP to the JCM 2000

"Vertical Input" Master Volume MarshallsWe love our Marshall amps! The purpose of this article is to recognize the various changes in the amplifiers from the “metal panel” era of the JMPs from to the JCM 2000 series so that the potential buyer can be better educated. Some deliver the goods better than others and I’ve owned many Marshall amps over the years and had to learn the hard way after plenty of dollars spent. Ultimately though — use your own ears and compare. Enjoy the next installment of our Marshall Shopper’s Guide.

The JMP “Metal Panel” Era from 1969-1981

In July 1969, Marshall replaced its gold plexiglass front and back panels on their amplifiers and replaced them with gold aluminum-brushed panels with black-screened lettering. This arrangement continues today.

The mark to the aluminum metal panel Marshalls also marks a significant reduction in comparative value between them and the earlier plexi-paneled Marshalls, though basically by late 1968 into early 1969, the circuit was essentially the same. I say “essentially” because as was often the case, Marshall circuits varied. I’ve played stock plexis from 1969 that didn’t sound like the late plexis and early metal panel amplifiers that are typically associated as having additional gain.

From 1969 through early 1973, the Marshall circuit and construction elements were also essentially the same as the plexis that preceded them, with all hand-wired  circuits with components loaded on turret boards. Again, the additional gain from these amplifiers make them desirable for hard rock applications, but the distortion of course still came from both the preamp and power amp stages, creating a rich tone full of warm tube harmonics and of course a wonderful dynamic sense.

1972 100 Watt Super LeadPlate voltages were reduced during this early metal panel era, resulting in a circuit that was somewhat easier on the power tubes. These amplifiers are also noted for being slightly brighter in tone then plexi amplifiers, making them sonically more aggressive. This trend in added brightness continued as the ‘70s rolled onward – my personal theory behind this refinement is two-fold: 1) There was no such thing as a THD Hot Plate or other type of attenuation device at the time and with added brightening to the circuit came a sense of more gain – certainly desired for the time. 2) The era of the custom pickup or high-output design had begun and was in full swing by the mid ‘70s. I imagine that Marshall based some of its ‘70s designs toward the use of these higher output pickups which by themselves had an emphasis on the lower frequencies. While this is merely speculation on my part, the mid to late ‘70s Marshalls and especially the Master Volume series introduced with the 1976 model tend to sound more balanced with a high output pickup design. This is the opposite case with the first plexi Marshalls which are really tuned to favor PAF-style humbucking pickups that are more tonally balanced.

In 1972, the Marshalls made for export to the U.S.A. became equipped with the more rugged, though sonically different 6550 tube. General consensus is that the EL34-equipped Marshalls were and are thought of more highly, with the added headroom of the 6550 not being as desired in the non-master volume Marshalls of the day.

In 1973, Marshall introduced its printed circuit board (PCB) design to replace the laborious hand-wiring process though some models continued to be handwired until circa ’75.

One debate regarding the shift from handwired turret board to PCB circuits is what, if any, effect was made to the tone of the amps. Early handwired amps are certainly more valued and more expensive. Claims in favor of the handwired amps have been made that not only are they easier to service and work on (certainly a fact!), with PCBs, the signal flowing through the board traces act overall as a capacitor, and this capacitance has an effect on tone in a negative fashion. I suggest that you let your ears decide what sounds best to you. I’ve heard good and bad examples of BOTH types of amps.

The overall benefit of all of these early metal panel Marshalls is that they ALL have very simple circuits and with a few changes to components here and there, can essentially be converted to early plexi circuits or later brighter circuits if desired. In this regard, those that want the tone of a Super Lead or Bass, but don’t want to shell out the collector dollars for a plexi, can be served very well with a ‘70s era JMP variation.

By 1976 and with the introduction of the first Master Volume series marshals, the 2203 (100 watt) and 2204 (50 watt), Marshall had finally brought to market a much-anticipated design. Demands for distortion at lower club-playing volumes was the fuel that made the Master Volume series the company’s most famous and top-selling model certainly through the beginning of the JCM 800 series (which also continued along with these two models).

Part II: Vintage metal panel through JCM 2000 series

The early JMP Master Volume amps achieved their distortion through the preamp stage when played at lower volumes, raising the master volume controlled overall level, but power tube distortion could also be achieved just like with the non-master Super Leads by cranking it up. The sound of these ‘70s JMP master volumes was pure rock. Punchy and full with extra crunch added to the mix when the preamp gain was turned up.

U.S.A. export versions of these amps continued to use the 6550 tubes, while all of Europe and Canada retained the use of EL34 tubes. Interestingly enough, and again in my opinion, the 6550 tube is my favorite when used in the master volume circuit. The tube helps contribute to a much “fatter” tone with better bottom end response. My favorite JMP series master volume amplifiers were made in 1977 and 1978. These featured the first full integration of the bolder-look cabinet. Elephant grain tolex replaced the smoother levant, white piping/trim replaced the gold, the Marshall logo was enlarged, illuminated square red power rocker and black rocker switches replaced the toggle switches and small square lamp, and plastic corner protectors as well as plastic ventilation (for 100 watt models) was implemented. The first of the Master Volume series from 1976, retained the earlier cosmetics, though transition to elephant grain tolex was made before the series introduction.

1976 Marshall 2203Further brightening of the circuits occurred in the 1979-1981 JMP master volume models in addition to the non- master volume models. I believe this is due to the incorporation of a new style of capacitor which was now a square plastic cap. Again, in stock configuration, the higher-output pickups which inherently have emphasized bass but reduced highs seem to balance out the circuit. The ’79-’81 models are easily identifiable since they marked the beginning of Marshall adding its serial numbers on the amplifier front panels beneath the power and standby switches. Even with the minor circuit tweaks that only amount to a personal preference toward the ’77-’78 models, the ’79-81 amps were still punchy, and great all around rock and roll amplifiers. Combo versions in 2 x 12 and 1 x 12 versions also gained popularity during this era.

From the late ‘70s, the Canadian (CSA) models reverted to an interesting arrangement cosmetically and can be identified by their use of small metal toggles (different from those used in earlier standard-issue JMPs) as well as a similar square LED pilot lamp. Rather unusual in appearance on the bold-look (and later JCM 800 models), these amplifiers also retained the use of EL34s like the European versions. From circa ’79, CSA models incorporated additional circuit fusing under the hood as well as an output transformer tap for 8 and 4 ohms only with the 16 ohm tap removed. It is unclear to me as to why these various changes were made only to the Canadian models, but one has to suspect that much of it is due in part to stricter Canadian electrical regulations.

General Value Scale of 1969-81 JMP Models and Some Purchase Recommendations

The most desirable and costly of the 1969-1981 era of amps are the earliest Point to Point Amplifiers from 1969-1973, with the 1974-to early 1976 amplifiers available for several hundred dollars less due to the PCB-circuit, extra brightening, and perhaps somewhat to the “older is better” mentality of shoppers. The best value amplifiers from this series if you’re looking for the original Super Lead tone are clearly the ’76-’81 models with the bold look. These make great player-grade amps and though collectors turn typically turn their noses up in the air with regard to these models, with a little bit of circuit tweaking and change to EL34 tubes (assuming you have a 6550-equipped U.S.A. export model), these can be made to sound very good indeed. Also since they aren’t currently as collectable, prices remain the lowest out of the entire era. Slightly more valued are the master volume series from this same era, with the early ’76 version having a bit more value perhaps due only to the retention of the classic cosmetics. For the first-time Marshall player who wants to have a taste of this tone, or for the player on a budget, look into the ‘70s era as the amps of choice.

The JCM 800 series 1981-1990

There remains a lot of hype surrounding the JCM 800 series and the market value of them has been driven up as a result. The notion is basically this: JCM 800’s are ALL great and the JCM 900’s that follow are bad. As with any rumors/hype there ARE some elements of truth within the statements, but it is NOT always so clear-cut.

The JCM 800 series marked a very unique time in Marshall history. Marshall was free from a contractual distribution deal and in essence celebrated its independence with the introduction of the JCM 800 series. Cosmetically now changed with front and rear panels and chasis that extended all the way across the bottom of the amplifier heads, and its larger logo now put onto a fabric backing piece, this is the basic Marshall look that continues today.

"Vertical Input" Master Volume MarshallsInside the circuit, the early master volume and non-master volume models continued and were essentially the same as the JMPs that preceded them. To my ears however, I hear just a slight bit more gain and brightness from the circa ’81-’83 JCM 800 master volumes. These were and are aggressive rock amplifiers and sound great. Unfortunately, with the hype surrounding the master volume models, especially the strength of the 100 watt 2203, its value has eclipsed the earlier JMP variations. Whether this will continue remains to be seen, but with Marshall recently reissuing its 2203 model as well as bringing out the limited Zakk Wylde (Ozzy Osbourne) model also based on the 2203, the 2203 buzz is currently hot!

However, during circa 1985, the design of the 100 watt JCM 800 series changed in order to cut costs. The age of the vertical input style of inputs as used on 2203s and 2204s for years had ended. A new horizontal input configuration began and this in itself only meant that the potentiometers and input jacks were now mounted directly to the printed circuit boards rather than being wired up with flying lead wires. This obviously simplified construction and in itself was NOT such a big deal, but what WAS a big deal was the change in the filtering and power supply structure of the 2203 (but NOT the 2204 – which remained unchanged) that took place later in l986 – this was also designed to reduce costs. Unfortunately, this latter change altered the tone of the amp. When looking at a vertical input JCM 800 2203 (or earlier JMP 100 watt for that matter) at the chassis, a total of six filter capacitors (those large blue cans that look like tubes) were previously present. The first of the horizontal input models were basically unaffected and examples such as the one pictured below show a design with five filter caps rather than the previous six. The primary four caps grouped together that ran as two pairs in series, was still part of the design and corresponded to Marshall’s early power supply design. The circa late-1986 2203’s, to reduce costs further, incorporated reduced power supply requirements and specifications and was able to eliminate one pair of the series-run caps, reducing the number to three filter caps total. Unfortunately these new 2203’s just didn’t have the same punch or power levels. Sure, they were still loud, but were much more grainy and thin-sounding as they were turned up. It did NOT help that at around the same time, the U.S.A. versions of the JCM 800 series began to re-adopt the EL34 tubes, which otherwise could’ve been a blessing. For Marshall’s best-selling 2203 and 2204 single-channel master volume heads, the switch in tubes actually limited the tone further since the 6550 – while not as quick to break up – still provided a fuller tonal range in this particular configuration. In essence, the three-capacitor-equipped 100 watt JCM 800 was the first Marshall that did NOT necessarily sound better as the volume went up – in fact, it began to sound worse – more grainy, thin, and muddy as the volume increased. REMEMBER: THIS is simply MY opinion represented above – you may prefer the later JCM 800’s as is your right to do so!

Full Powered "Horizontal Input" 2203During the JCM 800 series, Marshall introduced its first channel-switching amps that also included reverb with the 2210 and 2205 (100 and 50 watt models respectively) heads (combos were available as well) and these quickly became the best sellers in the range. What made these popular besides the benefit of a separate clean (really, more semi-clean) and distortion channel was the fact that the distortion channel had a bit more preamp gain built in that could be dialed in with an additional knob. As a previous owner of a 2210, I felt it was an o.k. amplifier but two things bothered me about it. 1) the clean channel would sometimes bleed into the distorted channel and produce weird overtones. The bleedover problem was a well-known occurrence and was a design-fault issue. 2) The overall distortion tone lacked the fullness and punch of the earlier single-channel vertical input models. Yes, more preamp gain was on tap with the dual-channel Marshall, but it was just typically a bit thinner overall. All said, these amps could still produce some desirable tones, especially in a studio environment where volume could be controlled and reduced – a pleasant irony for Marshall since they were known as the amps you had to crank up!

Silver JubileeIn 1987 Marshall brought out its Silver Jubilee series for its 25th anniversary. In the ‘80s, the hot-rodded Marshall was all the craze, with Marshalls being modified in all kinds of ways around the world for more preamp-gain as well as options such as direct outs and effects loops. Again, the desire has always been and continued to be to get more distortion at lower levels and this was before the era of the THD Hot Plate, which in my mind, really revitalized and revolutionized the vintage amp market as it is today (read the review in the amp section). In anycase, Marshall set out to produce its own hot-rodded from the factory amplifier and the various 50 and 100 watt Silver Jubilee amps were born. They looked cool as well with chrome mirrored panels and unique silver tolex.

These amps have their own unique sonic structure and are rather versatile. The tone circuits worked much more dramatically when one would turn up or down the e.q. controls. More gain was also produced, thanks to a diode circuit that provided additional distortion from one of the gain stages. Tube purists have criticized this circuit saying it is lacking due to not being a pure tube circuit. However, because of the design of the amp itself which really has a well-designed preamp tone stage in particular, the Jubilee amps enjoy widespread popularity and have become rather collectable today.

The modern features such as an effects loop, direct out, a channel switching modes brought further versatility to the amp and in all fairness in my experience, this series does a great job of capturing the essence of the earlier Marshall tones as well as doing the best of the modern higher-gain sounds. Diodes or not, Marshall did a nice job refining this preamp circuit and the design but also still incorporated the cost-reducing elements that occurred about a year earlier (reduced power supply filtering along with PCB-mounted pots and jacks). Since the Jubilee series were newly-tuned circuits, Marshall seemed to put more care into the final tone and design of these models than they did with the regular JCM 800 line when the cost-cutting went into effect!

The Jubilee 2555 100 watt head continued after 1987 as the “Custom series 25/50 2555” and was produced in standard black trim. Later, the amp would be reborn again as the Slash Signature amp.

The last of the JCM 800s were produced in 1990.

JCM 900/JCM 2000 series

When the JCM 900’s were introduced, they offered more features and corrected channel-switching capabilities. JCM 900’s, while more versatile in features then ever before, have been stigmatized by being the dogs of the Marshall lot and are typically held in low esteem. However, this isn’t an entirely fair position, but as was the case with the JCM 800s, not all JCM 900’s were created equal.

They did however all incorporate the diode-clipping circuit as the Jubilee amps did and received fair criticism for again not having a pure tube circuit. Another change occurred when the JCM 900’s were produced using 5881 (a.k.a. 6L6) rather than the classic EL34s. 5881 tubes were more commonly available, rugged and less costly. Again, critics were quick to talk about the JCM 900’s departure from the classic EL34 tube and the amp’s reputation was further tarnished.

The bottom line with these amps or any amps for that matter is to try before you buy and then you can ultimately be the judge for what sounds good to you. I’ve played some JCM 900s that sounded horrible and others that sound pretty good. Same thing with the JCM 800 series. One of the frustrations about Marshall and owning a Marshall amp is the fact that changes have been made through the years and unless you are hip to those changes, you may wonder why your selected amp may sound poor while a buddy’s sounds better. Remember, I was one of those people and the degree in variance between models and years is the reason why I decided to write this article in the first place – so hopefully others could avoid the trappings of buying the wrong amp and understanding what to look for.

With the JCM 2000 series, the general consensus is that the tone of these amplifiers are rather improved over the JCM 900 line. I would tend to agree with that for the most part. Dual and Triple channel Super Lead amps make up the top end of the tube amp line. My personal sonic preferences are with the DSL rather than the TSL versions as they appear to have a smoother drive characteristic.

These days with the current Marshall JCM 2000 series, because they are high-gain amplifiers with an emphasis on the preamp-gain structure, the guitar type, pickups and speakers are a bit less critical since the amplifier is supplying the majority of the gain and tonal structure. For this reason, those players looking for a good basic rock tone without worry or need to think too heavily into other elements, will be served well with the JCM 2000 series. While I think they are fine-sounding amplifiers and certainly fulfill today’s market requests for a number of features, the best Marshall tones I’ve heard are from the more simple circuits in the older amplifiers. That said, people who want loads of features and with footswitchable access will certainly enjoy the options provided by Marshall’s latest.

One note: If you’re a guitarist interesting in getting the classic Marshall sound used in rock, regardless of what marketing you hear, that tone is achieved through the harmonics and complexities and dynamics provided from overdriving the power tube stage. It is not going to be the same type of sound regardless of what era of Master Volume amp you choose, whether a JMP from the ’70s or a JCM 2000.

Again, the JCM 900 and JCM 2000 series with their reduced filtering make it so that they are not as effective when used as cranked-up amps and the power tube distortion is often muddied sounding at best — As a result, these amps really sound best when used at lower and moderate volume levels. All said though, Marshall’s newest amps certainly are designed to satisfy the requirements of the majority of guitarists that want footswitchability and added features for a wide range of uses.

I hope this two-part series was useful – and while I did not cover every model specifically, it is simply again meant as a general guide to help you the shopper decide between the various models made and to cover the pros and cons between them. Obviously, the overall trend with Marshall production through the years has been to add additional features as well as more gain, while at the same time reducing costs and keeping prices somewhat in line with what musicians can afford. This is not an easy thing to do and while it is easy to personally criticize the company for cheapening out over the years, the simple fact of the matter is that if Marshall were to attempt to build an all point-to-point hand-wired amp in quantities that would fulfill demand, it would be a VERY costly proposition and Marshall would become an elite high-end boutique company that would only be able to cater its products to the wealthiest few. Marshall’s philosophy has never been that – in fact, quite the opposite; Marshall’s beginnings served as a way to provide an alternative to the very costly Fender amps of the day for the local British musicians that couldn’t afford to absorb not only the costs of the Fender amps being imported but having to pay the taxes and overseas shipping costs as well. Marshall’s working class approach continues today.

Don’t Forget the Speakers!

The Celestions used throughout the years will make a tremendous difference on the amp you use. The G12M-25, G12-H30, G12-65, G12-70 (Stay away!), G12T-75 and Vintage 30 Celestions all exhibit different characteristics for different tones. Read about many of these speakers here.

A final note: The views in here in particular when referencing the tone of a given amplifier are the author’s (David Szabados) opinion. What I may view as thin and grainy may be exactly what someone else may want and enjoy. It is for this reason that the most important thing to do when shopping for your Marshall is just to have some of these ideas and differences in your head and then PLAY the amps! When you hear one sounding different from another in the same series, now you can have a handle on potentially why. Also, my intent is not to insult your particular amplifier if you happen to have a model that I believe is not as good. Again, it’s my opinion, and trust me, I’ve owned plenty of Marshalls through the years that I felt were not quite up to par – If you may have one of those and Love it to death, than ultimately my opinion shouldn’t matter. With all said here, again, I hope you’ve found this useful and informative. Ultimately it’s all about music so find the amp that works for YOU!