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View Full Version : Marshall Plexi 1986 Bass vs 1987 Lead?


lzstones
01-17-2013, 09:24 AM
Hey guys,

I have never owned a Marshall and really want to get a plexi('68 Bass or '68 Lead), or some clone(Germino Club 40 or Lead 55LV)

For those of you that have had experience with these amps, which did you like better. I know they are quite similar and only varying in a few components, but I was wondering what the differences in tone there are. I'm looking for the usual classic rock sound: Page, Clapton(Cream), Bolan, Kossoff. I don't need the gain that EVH uses, as I'm not really a fan of his sound. I really like that honk that Bolan and Kossof get. I've heard people have said that the Leads can be a little harsh. I'm currently leaning towards the Bass spec, but am I little worried it'll be too bassy and low range driven.

So what do you guys think would be best for late 60s/early 70s classic rock/blues stuff? Thanks a bunch in advance.

Trebor Renkluaf
01-17-2013, 09:50 AM
I'm no Marshall expert but I do have some experience here. I have a 1969 model 1986 that when I first bought it was modified to 1987 specs. I sent it to Victor at the Plexi Palace for some restoration work and he noted it was really a bass head (1986) and suggested restoring it to it's original specs. He said the 1986 circuit is basically the same as the JTM-45 albeit with el34 tubes and a solid state rectifier. I had Victor restore it to 1986 specs and I'm glad I did. Before the mod, I always felt I had to jumper the channels to control the brightness/in-your-face sound of the bright channel. It sounded great but it was always a balancing act between the two channels to get the tone I wanted. Now I can just plug right into the bright channel (don't need to jumper them) and dial in the tone I want right away. There's a hair less gain now, so the amp stays clean a little longer before breaking up. I seem to remember the 1987 coming on at pretty much full volume and then just adding gain from there. The 1986 comes on a little slower and you can turn the volume up a bit before it starts to break up. The 1986 also takes pedals very, very well. The tone is still all Marshall, but I feel it is more versatile now.

Both are great amps and will get you vintage Marshall tones in spades. My feeling are this: if you want aggressive, in-your-face rock tones, then get the model 1987. If you want a more versatile sound that can still rock hard but is also capable of some lovely cleans/crunches and is an excellent pedal platform then get the 1986.

big mike
01-17-2013, 10:06 AM
I'm no Marshall expert but I do have some experience here. I have a 1969 model 1986 that when I first bought it was modified to 1987 specs. I sent it to Victor at the Plexi Palace for some restoration work and he noted it was really a bass head (1986) and suggested restoring it to it's original specs. He said the 1986 circuit is basically the same as the JTM-45 albeit with el34 tubes and a solid state rectifier. I had Victor restore it to 1986 specs and I'm glad I did. Before the mod, I always felt I had to jumper the channels to control the brightness/in-your-face sound of the bright channel. It sounded great but it was always a balancing act between the two channels to get the tone I wanted. Now I can just plug right into the bright channel (don't need to jumper them) and dial in the tone I want right away. There's a hair less gain now, so the amp stays clean a little longer before breaking up. I seem to remember the 1987 coming on at pretty much full volume and then just adding gain from there. The 1986 comes on a little slower and you can turn the volume up a bit before it starts to break up. The 1986 also takes pedals very, very well. The tone is still all Marshall, but I feel it is more versatile now.

Both are great amps and will get you vintage Marshall tones in spades. My feeling are this: if you want aggressive, in-your-face rock tones, then get the model 1987. If you want a more versatile sound that can still rock hard but is also capable of some lovely cleans/crunches and is an excellent pedal platform then get the 1986.

Excellent post.

I agree. If you want more Kossoff, and a less aggressive tone, go bass spec. If you want more amp gain, crunch and in your face (not quite EVH but closer) go lead spec.

The rest of your rig is very important in this equation as well.

Plus a good tech can modify either to become the other spec with the flip of two switches.

lzstones
01-17-2013, 10:28 AM
Thanks guys. Sounds like the Bass is the one for me.

For what it's worth, Im looking at just playing a Les Paul straight into the amp through a 4x12 cab with V30/G12H30 mix.

Sirloin
01-17-2013, 10:42 AM
Thanks guys. Sounds like the Bass is the one for me.

For what it's worth, Im looking at just playing a Les Paul straight into the amp through a 4x12 cab with V30/G12H30 mix.

You had me at "Hello"....you lost me at "V30/G12H30 mix". Those circuits, IMHO, will sound best with an M type speaker, maybe mixed with an H type, but in a closed 412 I would go all M Greenbacks or some clone of that speaker.

big mike
01-17-2013, 10:42 AM
It'll get you Koss for sure.

Add a boost if you want to kick it over the top.
Gonna be loud though :D

Germino Club40 would be an excellent choice.

big mike
01-17-2013, 10:43 AM
You had me at "Hello"....you lost me at "V30/G12H30 mix". Those circuits, IMHO, will sound best with an M type speaker, maybe mixed with an H type, but in a closed 412 I would go all M Greenbacks or some clone of that speaker.

I agree. But rock what you got in the mean time. :)

TonyBony
01-17-2013, 03:39 PM
You had me at "Hello"....you lost me at "V30/G12H30 mix". Those circuits, IMHO, will sound best with an M type speaker, maybe mixed with an H type, but in a closed 412 I would go all M Greenbacks or some clone of that speaker.

I would second that. There is nothing wrong with V30's, they are a great speaker,but for an amp without a master volume, Greenbacks seem to bring the volume of an amp like that down to a more manageable level. Plus they sound better :stir Bass circuit Marshalls are awesome.

Phil M
01-30-2013, 11:14 AM
Is it possible to have an amp or a mod where you can flip a switch to go between 1986 and 1987 specs?

I'm not sure if something like this exists or if it's not even possible due to the differences in circuitry.

man_mars
01-30-2013, 11:18 AM
You had me at "Hello"....you lost me at "V30/G12H30 mix". Those circuits, IMHO, will sound best with an M type speaker, maybe mixed with an H type, but in a closed 412 I would go all M Greenbacks or some clone of that speaker.

+1 to this :aok

fusionbear
01-30-2013, 01:41 PM
Is it possible to have an amp or a mod where you can flip a switch to go between 1986 and 1987 specs?

I'm not sure if something like this exists or if it's not even possible due to the differences in circuitry.

Too much difference between circuits IMO. Here is a basic list:

1986: V1 shared cathodes 820.320uf 1987: V1 Split cathodes V1a 820/330uf, V1b 2.7K/.68 uf

1986: No bright cap 1987: 470pf Bright cap

1986: Mixers 270k 1987: 470K with a 560pf across lead channel mixer

1986: V2a 820, no cap 1987: V2a 1K-1.5K/.68uf (on most of them)

1986: PI Couplers .1 1987: Pi Couplers .022


Get the picture?

Geetarpicker
01-30-2013, 01:55 PM
Too much difference between circuits IMO. Here is a basic list:

1986: V1 shared cathodes 820.320uf 1987: V1 Split cathodes V1a 820/330uf, V1b 2.7K/.68 uf

1986: No bright cap 1987: 470pf Bright cap

1986: Mixers 270k 1987: 470K with a 560pf across lead channel mixer

1986: V2a 820, no cap 1987: V2a 1K-1.5K/.68uf (on most of them)

1986: PI Couplers .1 1987: Pi Couplers .022


Get the picture?

Agreed.

And most bass spec Marshalls have a 27k negative feedback resistor, as the lead spec typically have a 47k, or even 100k FB resistor. This is another important part that helps make the bass spec amps cleaner and less gainy.

wyatt
01-30-2013, 01:55 PM
Can you easily and completely toggle switch between 1986/1987 models? No. But boutique builders and DIY'er's are commonly adding switching to change between 2 for 3 or more cathode-bypass caps for V1 and/or V2. You'll see this with "Decade," "'60/'70/'80," and Modern/Vintage" switching on a lot of Plexi- and JCM-style amps.

It doesn't change a 1986 into a 1987 or vice-versa but it does allow so variety in preamp voicing. Add to that some negative-feedback switching, and you have some options. BUT, to really compare the gain and personality of one amp or the other, you really need to pick one and stick to it.

fusionbear
01-30-2013, 01:56 PM
And most bass spec Marshalls have a 27k negative feedback resistor, and the lead spec typically have a 47k, or even 100k. This is another important part that helps make the bass spec amps cleaner and less gainy.

Aah yes, I had the privilege on converting your former 1986 to lead just recently.

Well done Sir!

skhan007
01-30-2013, 01:59 PM
I think there's a push/pull pot mod you can do to go between split and shared cathode. I think that may account for a good deal of the difference you might hear. The rest, I'm sure, will have some difference, but I've read perhaps not as much as the split/shared cathode- anybody know for sure? Getting rid of the bright cap made a tremendous difference for me on my 1987 plexi.

ScienceFriction
01-30-2013, 02:22 PM
You should go check out the metroamp forum, especially the 50 watt amp kits and Do It Yourself Amp Builds sections. You can find a lot of info there about mods you can do so you can have both 1986 and 1987 flavors in your amp. I think the most common are the split/shared cathode switch, negative feedback knob, and tone stack switch. I prefer the bass spec myself, but I love the lead spec too. You can get a lot of the best of both worlds with the mods above, and just change component values until you have the overall sound that you like. I'm sure you can find an amp builder who builds something that has options like this, or find someone who can if you really want to have both lead and bass flavors.

I'd also recommend you look more into the specific gear each of your favorite musicians used, and when, as well as speakers. You can't forget speakers in the mix. One guy might have been using an early Marshall cab with paper voice coil lead spec Greenbacks, where another might have been using bass spec Greenbacks (ala Hendrix). The guys you named used a lot of different amps and gear. Page for example is more often associated with Hiwatt and Orange than Marshall I believe. I hope this helps.

rykus
01-30-2013, 05:47 PM
I have a plexi bass and metal face super bass and prefer them to my metal face lead as well.

The Lead is great and I can get the same tones jumping the inputs then using the 2 volumes to blend the tone till I find a sweet spot. I like on the Bass models that I can crank all the pre amp for more gain with out the extreme treble of the Lead where I usually run them a bit lower and the presence back at 5 r so.

both are great, My plexi bass is my fav, but the 100's sound crazy if you can crank em up to 7 r 8... something different with the extra tubes!
Also FWIW the bass models changed very little between the JTM and when they went to printed boards in '74 while the lead went through quite a few changes in specs.

sickboy79
01-30-2013, 08:22 PM
Agree with the above assessments of the Bass bs Lead circuits. Bass circuits are warmer, fatter, and more headroom. Leads are brighter and more aggressive. Both are fantastic.

SlyStrat
01-30-2013, 09:10 PM
To me there's not that much difference in tone. 1986 is a little darker.
Snip the bright cap on the 1987 and turn down the presence and treble. Now you have a 1986.