What do you know about Marshall JCM 800 MKII Lead?

[Madsakre]

Im talking with a guy who has this one for sale. Its 50 watts which, for me is AWESOME because i dont need to punish everyone just as hard to get awesome tone out of it.

The thing is that theres a billion 800's out there and i barely know the difference between them all.

Heres a couple of things im curious about.
1. Will this amp generate enough Gain to make Morbid angel'ish Sound along with a Tubescreamer?
2. Does this amp drive pedals really well?
3. there are four inputs on it. I see people use a jumper cable between them. What does this do?
4. Which tubes does it use?


Its for sale for 600€ - So its cheap.. Atleast here :)

[Dmoney]

Is that pretty much the same as the 1959 JCM800 super lead? closer to a super lead than a 2204, but not identical to the 1959?
If it's what I think it is, it doesn't have a master volume... so you're going to need to put one in it or use an attenuator to get the gain you want out of it without blowing your balls off with volume.
Jumpering the inputs runs two gain stages ("channels") in parallel for more gain, however this is still less gain than one of the more usual JCM800s (2203,2204) that has the stages in series. the Randy Rhoads mod on the 1959 put these stages in series for more gain, closer to a 2203 or 2204.
Tubes? probably 6550's or EL34's. I imagine it will take pedals well.

I might be wrong though.!

[Madsakre]

Here's a couple of pics:

[Dmoney]

ah right!
the volume I and volume II on the front are the 'gain' controls for the two channels.
BUT
that chicken head knob on the back MIGHT be a master volume mod. It's out of place.

right to left, looks like IEC, the mains + HT fuse, then the voltage and impedance selector, then two speaker outputs... so the chickenhead knob looks like a mod. It could be anything though... Depth control for example... but a master volume is probably more likely.

I'd ask if it's been modded and if so, what has been done.
If it has a master volume mod then you'll be able to overdrive the preamp without cranking the volume level of the output, but without the series gain stages I doubt you'd get into that 2 input JCM800 gain territory without a serious boost. I don't know much about boosts or distortion pedals so it might be possible to get there while relying on a pedal.

[Madsakre]

its also a 1987 if that helps?

[Madsakre]

The chickenknob is a master volume. its made where the old DI sat

[Dmoney]

i think the 87 and the 59 have the same preamp.
there is just the master volume control issue and 87 and its 50watt.

If it has a MV then that has done you a favour.
try finding some high gain clips of the 59 or 87 with the channels jumpered on youtube.
Then maybe find a clip of the Randy Rhoads Marshall and see what you think of that, since that has a modded version of the same preamp for more gain.
Stock, It's going to have less gain than a 2203 or 2204, but you could mod it... depends on what you'd rather do.
Lots of possibilities
more research needed

[Telerocker]

Found this:

Superleads (Marshall Mk II, heads):
1959 (100W) and 1987 (50W) are the two different "superlead" models. They were introduced in 1965 and are still being made as ’69 reissues. Originally made with KT66 power tubes (1965) but soon they were replaced by EL34s (1966). The superleads are easy to recognize with their four input-/no master volume-design. The amps feature two channels (two inputs for each, the inputs are wired so that they can be used to connect both channels, thus giving you two different sounds in one, and the level of each controllable with a volume), bright and normal, individual volumes for each channel and a standard 4-band EQ. The sound is very "rock", and very wanted. With the lack of a master volume, the amps rely on power tube distortion. This phenomenon comes with a price, and the price is volume. And when I say volume, I mean volume. A cranked 100W amp is VERY LOUD, therefore power attenuators are often used to reduce the level from stupidly loud to extremely loud. An original 1965-68 "plexi" (the term "plexi" is used due to the fact that the amps had gold-painted plexiglas panels during that era) head might not be very easy to find, and if you find one don’t expect it to be cheap, but superleads were made both as JMPs (in the 70s), JCM800s (in the 80s) and reissues (today) and you should be able to find one used.

Plexi Information:
Years are 1965 to 1969, later in Europe. Three phases within the Plexi era: (dates are approximate)
(mid 65-66) - block-lettered Marshall logo, JTM45/Mk II front panel legend, aluminum chassis, KT66/640vA, 3" power transformer, 2" output transformer, no external filter caps. (67-mid 68) - gold script Marshall logo, reverse JTM front panel legend, steel chassis, EL34/460vA, 2" or 3" power transformer, 1.75" output transformer, one external filter cap. (mid 68-mid 69) - gold script Marshall logo, JMP front panel legend, steel chassis, EL34/500vA, 2" power transformer, 1.75" output transformer, six external filter caps.

JMP series (heads and 2x12" combos):
In 1976 Marshall introduced the master volume amps (2203 (100W) and 2204 (50W)). With the master volume, the amps no longer had to be cranked to distort. However, no tube amp will sound good at low volumes and these ones are certainly no exceptions. The amps feature two inputs (high/low), preamp- and master volume controls plus the standard Marshall 4-band EQ (treble, middle, bass, presence). The superleads (1959 and 1987) were also made in the JMP series. Identical to the originals except for the cabinet. All four models (2203, 2204, 1959 and 1987) were also made as 2x12" combos (2103, 2104, 2159 and 2187). The sound is still classic rock and with a humbucker loaded guitar and one of these, you’ll have no problem grinding like a demon.

JCM 800 master volume:
The JCM 800 master volume heads also have the model numbers 2203 and 2204 but are not identical to the JMPs. These amps have more gain than the JMPs and this is partially due to a solid state clipping-circuit that was added for this sole purpose. Some tube-fanatics consider this to be a work of Satan and refuse to play JCM 800s. Being a work of Satan or not, the Mk II master volumes still provide a sound that lots of people love. The sound is quite dark and barky with an accentuated upper midrange, so if you're looking for the scooped-mid Metallica sound, look elsewhere or buy an EQ and a distortion pedal. These are no-nonsense machines for more classic rock sounds. They can indeed be criticized for having basically just one sound, but what a sound! Lots of people consider that sound to be THE sound...

JCM 800 superleads:
Basically identical to the original superleads but fitted in the modern bold cabinets.

JCM 800 split channels:
Being the first Marshall with channel switching capabilities, the split channel amps (heads: 2205 (50W) and 2210 (100W)) became very popular for their versatility. The clean channel is by no means clean in the real essence of the word, but to the early 80s Marshall devotees it was something completely new. The overdrive channel sounds a lot like the master volumes’ and is clearly where these amps excel. Also fitted with a reverb (not indiviual for each channel) and an FX loop, the split channels were Marshall’s first hi-tech amps. The split channels are a little harder to find used than the master volumes, but you should be able to find one. It sounds quite like its brother, the master volume, but with some (limited) channel switching capabilities.

General JCM 800 info:
Introduced in 1981 (split channel amps in 1982) and discontinued in 1989. Superleads are available as heads only, 50W split channel and master volume amps available as heads, 1x12" and 2x12" combos, while 100W split channel and master volume amps were available as heads and 1x12" combos. Pre-1984 JCM 800s for the American market were shipped with 6550 power tubes and sounds a lot different from the EL34-equipped "standard" ones. Converting an originally 6550-equipped amp to accept EL34s is a minor mod and should cost you more than £30. The 2203 was reissued in 1995 as a special limited edition amp in red tolex, with matching 4x12" cabs.

[Blackcaster]

Yep, it's a 1987 circuit, you have to know that this amp is pretty loud not really ok for bedroom level ! For instance there is only 6db between a 50w and a 100w

1. Will this amp generate enough Gain to make Morbid angel'ish Sound along with a Tubescreamer?
even with a TS it'll be difficult to rise the sound you're after, only 3 gain stages and it appears you need 5 preamp gain stages

2. Does this amp drive pedals really well?
yes the 1987 accept very well pedals in front to convert it in distorsion machine
 
3. there are four inputs on it. I see people use a jumper cable between them. What does this do?
jumper is there to cascade gain stages, you can swap the jumper for an AB/Y switcher for more versatility, it's a good upgrade

4. Which tubes does it use?
6550 or EL34 tubes, depends if it is an export model or not

b.

[Madsakre]

Yep, it's a 1987 circuit, you have to know that this amp is pretty loud not really ok for bedroom level ! For instance there is only 6db between a 50w and a 100w

1. Will this amp generate enough Gain to make Morbid angel'ish Sound along with a Tubescreamer?
even with a TS it'll be difficult to rise the sound you're after, only 3 gain stages and it appears you need 5 preamp gain stages

2. Does this amp drive pedals really well?
yes the 1987 accept very well pedals in front to convert it in distorsion machine
 
3. there are four inputs on it. I see people use a jumper cable between them. What does this do?
jumper is there to cascade gain stages, you can swap the jumper for an AB/Y switcher for more versatility, it's a good upgrade

4. Which tubes does it use?
6550 or EL34 tubes, depends if it is an export model or not

b.

Hey

It will stand at my bands practice space, so no bedroom levels :P

5 preamp stages? are there some kind of scale that im unaware of? Good old they uses a Jcm900 with a rat infront of it. Along with some eq i cant remember the name of.

its actually a british amp, because it was bought in london back in 89 :)

[Dmoney]

The jumper does not cascade the stages. It runs them in parallel.
Jumpered, you get 2 stages in parallel, into the cathode follower gain stage, the cathode follower itself adds no gain, then you have your phase inverter, which adds a fair bit of drive.

The JCM800 2203/2204 has the stages 'cascaded'... input stage > 10K cathode stage > CF driver stage... so a 2203/4 is really only 3 gain stages before the phase inverter. a 2203/4 with a little boost would probably get you heavy enough so I doubt you'd need excessive gain stage to get the sound you want.

the Randy Rhoads mod is what cascades the first stages in the 4 input 1959 etc heads.
50watt is 3dB lower than 100watt. 10watts is half as loud as 100watts.

If its really cheap, you have a lot of scope for mods to get more gain. just depends if you want to go that route.

[Madsakre]

Well lets see how much i need to mod it. I dont use ridiculous amounts of gain. Think Kill em all, thats around as much as i need when not using my HM-2

[Dmoney]

if you have an HM-2 It'll probably do you well!
Just try it. don't worry about how many gain stages it has and be glad it has a master volume.

[Madsakre]

if you have an HM-2 It'll probably do you well!
Just try it. don't worry about how many gain stages it has and be glad it has a master volume.

My thoughts exactly :P I guess im just excited to try it

[HTH AMPS]

those are nice amps - I always find the JCM800-era of 1987 and 1959 model amps to sound the most AC/DC out of all the non-master amps.

even with a master volume, gain levels without any pedals is gonna be AC/DC.

they DO like pedals though, so bash that HM-2 in the front, get yer spandex on and rock like it's 1983 and Metallica are still a club act.