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Are you aware of the relatively rare and not widely used 200w Marshall Major? This was a production amp between 1967 and 1974 (first called the Marshall 200 then the Major starting in 1968) which had four KT88 tubes – giving it 200w of brain-pounding power.
Or actually, more like 140w. John “Dawk” Stillwell, Ritchie Blackmore’s tech and the guy who modified Ritchie’s Majors, says on his forum that “the spec of maximum output rating on a KT88 is only really 35 watts RMS.”
(Btw, according to the book “Jim Marshall: The Father of Loud,” Jimmy Page had his stage Super Leads modded to run four KT88s for 200w!)
Apparently Blackmore was the one who pushed Jim Marshall into 200w territory, but Marshall couldn’t design a 200w amp that wouldn’t quickly fry itself. So Marshall asked the Genelec tube company to design the amp.
What they got was an amp that by all accounts was sensitive, eats tubes and can’t take distortion boxes thanks to something having to do with an “ultra-linear” output transformer. (I’m not an amp tech by any means, so if I’ve botched any of that explanation please let me know!)
Major History
Anyhow, here’s what Dawk says about the Major on his forum (all info is his, edited):
> Some of the history of this came from Marshall’s own Ken Bran and the rest is from my years of experience of working on [Majors]. It all started when Deep Purple went from playing clubs to 20,000-seaters. Many prototypes of a 200-watt amp were built by Marshall, they all failed. So they had GEC design one for them. It’s the company that made the famous Gold Lion KT-88 tubes.
> To get the 200w RMS rating, GEC had to boost the b+ [plate voltage] to 650 volts dc. The maximum designed rating for a KT-88 is 450 volts plate voltage. Then to top that off they used an ultra-linear-designed output transformer. It’s basically designed like a hi-fi amp. The Major has a very clean sound and low gain when compared to the rest of the Marshall line. That’s why Blackmore’s sound on Made in Japan sounds so good.
> Those people at Marshall back in the day didn’t know what rock and rollers were going to do to that amp. When a booster or some kind of other pedal was used to make some distortion, the 650 volts of b+ would jump to 1,800 volts – that’s called “prv” voltage. The optx [output transformer] is working sort of like a fly-back transformer in a TV set. That’s what’s producing that high prv voltage.
> Then the b+ at 1,800 volts would arc over to the closest ground, usually between pins 2 and 3 on the output tubes, causing a lot of smoke, burning of the tube socket and a real bad smell…leaving a big black carbon mark inside the chassis where it arced. This would happen so fast that it didn’t have time to blow the fuse…blam! Sometimes the fuse holder itself would explode. [This what Dawk calls "the Smoke on the Water effect."]
> [Because of] the cost of warranty repairs on these amps, Marshall took some steps like covering the primary leads with extra insulation and changing the tube sockets to ceramic. Then the prv would arc over in other places like on top of the tube socket or inside the tube base – the worst being inside the output transformer itself. The transformer could test good, but then only to arc over again when the first hard chord was played. Most of all the original Dagnall output [transformers] are damaged in this way. The amp will play okay until it gets a loud signal, and then blam! Because there no signs of an arc over in the chassis, you’re not realizing that the arc over was inside the optx itself.
> At that time Marshall couldn’t keep up with production let along sending parts to America. So they (Unicord) hired this old guy Otto to make transformers in a back room in their warehouse on Long Island. I had Otto wind a lot of mylar insulation between the primary and secondary in the new output transformers he was making. Dagnall had used masking tape for this – masking tape! What a piece of crap that transformer was. The Majors that are not blowing up when pushed hard (now) probably have that upgraded Otto transformer in them.
> The warranty replacement got very costly for Marshall…new optx and new KT-88s as well. So that was the main reason for this amp to be discontinued by 1974 [though] there were many more reasons for this decision…. Lack of sales and their high price also played a part.
> Ken told me once that all the parts [would] be installed by the girls [in the Marshall shop and] only then would the heavy transformers go on the chassis. This made the amps too heavy for the girls to pick up and move around on their benches. [Ken said] “We here at Marshall were loaded with back orders,” [and] the girls doing the assembly could be making three 50-watters and two 100-watters in the same time it took to build a 200w Marshall Major. So case closed on the 200w Majors.
The Players
Blackmore and Paul Kossoff are the most famous Major users, along with Mick Ronson of David Bowie’s band who called his Major “the Pig.”
A lot of mods were done to everything back in those days. Not sure about Koss’ and Mick’s amps, but Blackmore’s majors were messed with quite a bit to keep them stable and to help get Ritchie where he wanted to go tone-wise. Apparently Dawk added an extra gain stage (preamp tube) to help that along, and did who knows what else.
Ritchie boosted his signal with a Hornby Skewes treble booster and in the studio with an Aiwa reel-to-reel tape recorder, among other items. His guitars were anything but stock. So while the Majors contributed to his tone, it certainly didn’t end there – which I know for a fact because I had the opportunity to play through one of his actual Majors recently!
However, the head in question had had the Blackmore mods removed, so the Blackmore gain wasn’t happening. The head was run through an old Marshall 4×12 and an old Marshall 4×15 (which I believe were recommended for the Majors). It sounded GOOD, and actually started to break up halfway up even with the 4×15 cab.
Was it loud? Heck yeah, with two cabs especially. But just remember that 200w (or 140w) is not twice as loud as 100w.
