Plexi style amps are deceptively simple to dial in

[What?]

I have had my plexi clone (Plexi 51, 1987 circuit) for I guess a couple of years now, and I'm still figuring out how ways to dial it in. It's just a handful of knobs, but I have spent more time learning this amp than any other amp I have owned. There have been times when I have hated it, loved it, and been indifferent to it. Any of you found any tricks to dialing in plexi style amps?

One of mine. I have bounced back and forth between switchable bright caps, 1000pF (hella bright!), none, and 100pF. I figured out that when set to 1000pF, treble and presence knobs down to about 2, bass at 6, mids at 5, treble channel at 2 and bass channel a little higher, and the tone knob on the guitar down to taste (4 on my les paul), it responds in a very different way than 100pF or no bright cap. I mean to say, brightness being about equal by changing other settings for the bright cap switch positions, the 1000pF position is crunchier, has more springy give in picking attack, and just sounds better and is more fun to play for crunchy rock n roll stuff than no bright cap or 100pF bright cap. With everything set as mentioned, this amp is addictive play.

 

[Gene Ballzz]

Anyone who thinks that even a standard, stock Marshall Plexi is a "one trick pony" simply doesn't get it! There are so many subtle nuances that can be squeezed out that I find them to be one of the most versatile amp designs on the planet! Of course, once I find "that magic spot" I tend to never touch the knobs on the amp, but find myself able to access most of those nuances from the guitar, either through adjusting the controls on the guitar and/or my playing technique! We don't even need to get into what can be accomplished with foot/stomp/pedal/thingies!!
Simply Crankin'
Gene

 

[Smellytele]

It really depends on what I'm going for tone wise. But in my limited experience, I found the fastest way to get into tones I dig was to use a y-splitter into the top of each "channel" and bring up volume 2 first, which will be kinda dull (though it can be a cool sound) Then start bringing up volume 1, which brings in the "ah, oh, yes, goodness, nice, there it is" tones.

 

[What?]

Anyone who thinks that even a standard, stock Marshall Plexi is a "one trick pony" simply doesn't get it! There are so many subtle nuances that can be squeezed out that I find them to be one of the most versatile amp designs on the planet! Of course, once I find "that magic spot" I tend to never touch the knobs on the amp, but find myself able to access most of those nuances from the guitar, either through adjusting the controls on the guitar and/or my playing technique! We don't even need to get into what can be accomplished with foot/stomp/pedal/thingies!!
Simply Crankin'
Gene

Yea, it has a good range of sounds to be dialed in that I have found so far. But man, it takes some work finding them for sure.

 

[Eric'45]

As a general baseline that should more or less work for Plexi style Amps (that can mean a lot of different Amps, an early JTM45 is not a late Super Lead) I would say, first of all, the "everything on 10" setting is nonsense. YMMV, but for me it has never worked.
Something like Presence and Treble at noon, Bass dialed back, Mids dialed up, and the Channel Volumes anywhere between 4 and 8 should work.
My Personal Favourite JTM45 Reissue is set up like:
Presence: 5
Bass: 1
Mids: 9
Treble: 5
High Treble Vol: 7
Normal Vol: 4

 

[TonalEuphoria]

I like an amp easy to dial in and not a million controls. Knobs and faders always get bumped and I have to return them to the exact spot or the tone isn't the same. And knobs and fader extremely sensitive to me means they need to be basically in that exact spot I spent my time squeezing the exact tone I like out of them with minor adjustments for the gig/room I take it to at any particular day. Another reason, I'm considering getting rid of my Mark V 25 rig and turning the money over on another Marshall. And now that I'm back to playing Marshall's again with the little DSL20CR combo I have bought and modded to my taste for a covenient combo to have around, I am starting to like the Mesa tone less and less. And starting to think the Marshall is much more of my prefered tone. Damn.

I use an HX Effects for my main effects with maybe a pedal or two thrown in. And this where I can program and have solid presets modding the tone from what I keep consistent on my amps so there are no knobs or faders to mess with or get hit. And I can change those presets and snapshots with a click of a button or two. And that's what I prefer. So.,,,,,,,,I see more Marshall's and easy to dial in amps in my future. And less million knobs and fader amps becoming history for me.

 

[dro]

It really depends on what I'm going for tone wise. But in my limited experience, I found the fastest way to get into tones I dig was to use a y-splitter into the top of each "channel" and bring up volume 2 first, which will be kinda dull (though it can be a cool sound) Then start bringing up volume 1, which brings in the "ah, oh, yes, goodness, nice, there it is" tones.

Only played a couple 1987's not my cup of tea.
The JTM45 on the other hand. Jump the channels. Use the two volumes to dial in the room.
I can find the sweet spot fairly quickly. Much faster than amps with more controls.

 

[What?]

Presence high makes a huge difference. Maybe a bright cap isn't needed after all. Roll the guitar volume back a bit to tame it, and it's a crunch fest.

 

[79 2203]

I have had my plexi clone (Plexi 51, 1987 circuit) for I guess a couple of years now, and I'm still figuring out how ways to dial it in. It's just a handful of knobs, but I have spent more time learning this amp than any other amp I have owned. There have been times when I have hated it, loved it, and been indifferent to it. Any of you found any tricks to dialing in plexi style amps?

One of mine. I have bounced back and forth between switchable bright caps, 1000pF (hella bright!), none, and 100pF. I figured out that when set to 1000pF, treble and presence knobs down to about 2, bass at 6, mids at 5, treble channel at 2 and bass channel a little higher, and the tone knob on the guitar down to taste (4 on my les paul), it responds in a very different way than 100pF or no bright cap. I mean to say, brightness being about equal by changing other settings for the bright cap switch positions, the 1000pF position is crunchier, has more springy give in picking attack, and just sounds better and is more fun to play for crunchy rock n roll stuff than no bright cap or 100pF bright cap. With everything set as mentioned, this amp is addictive play.

No wonder it’s bright !! The bright vol on 2 means the bright cap is in full force. The more you turn it up, the less bright it will be.
That would have to be pretty clean at those settings too. I mean my stock 71 1987 is abit of a fire breather, but bright vol 2, jumpered, normal vol on 3 would be edge of breakup.

But yeah, in regards to dialing in a ‘Plexi’, it did take me a long time to bond with mine. I go for a low-med gain ACDC tone and like you I struggled with the stock brightcap in that 4-6 range of the bright channel vol(where ACDC lives)
And before I got an attenuator I struggled with the volume. The attenuator mostly solved both issues and learning to jump channels was the icing on the cake.

Of course then there’s also which input to use or wether or not blending channels is necessary depend on the input and where the volumes are set. Over the years I’ve used just about every option the 4 inputs and 2 volumes allows and lately I’ve settled on…..
Straight into top left input, vol 6, jumpered normal vol 2.
Pres 3
Bass 5
Mid 4
Treb 5
Hotplate -8db, Deep/Bright off.
68 straight cab with Pulsonic 25 watt Greenbacks.

OTOH my recently acquired stock 70 Super Bass was relatively quick to dial in. There’s no bright cap and I did my research on how the EQ works so I pretty much nailed it first play through.
Straight into top left, vol 6, Pres 8, Bass 0, Mid 7, Treb 10.
Hotplate -8db, Deep/Bright off, but I think I’m gonna have to go -12db because the Super Bass is so much louder than the 1987.

 

[What?]

Lately I'm pretty sure that I want to change the 1000pF bright cap to 4700pF. I'm not running the channel volume over 8 (usually 4-7), and I'm looking for more crunch in the mids and tighter bass.

 

[Matthews Guitars]

To me, a stock NMV Marshall is a one trick pony, but in the sense that that trick is to be a blank canvas for you to paint your own sonic art on. While its own range of tonal options via twisting knobs is somewhat limited, it gives you the whole (usable) spectrum of sound that a guitar player is likely to want. By means of his pedal board, guitar choices, speaker/cabinet selection, maybe an effects loop added in, or a master volume, or various mods, the player can take a Marshall into any sonic territory he wants.

Even those tone controls, while being fairly subtle in their range and effect, can dramatically change the resultant tone. I think we've all found this out pretty quickly once we got our hands on a Superlead. In truth it doesn't take a BIG change in the frequency response of the amp to have a very noticeable change in perceived tonality.

What makes a Superlead so intimidating, and to some extent a hard amp to play, is that it is both very loud and very honest. What you play, will be heard, with clarity and very much "LOUD AND CLEAR". It'll reward the proficient player, by making him sound great, and send the less than ready player back to the practice room with his tail tucked between his legs. Because if you suck, you WILL suck out LOUD.

 

[Stefan_E]

It depends a lot on what pickups you use. With weaker single coils you get less overdrive, with hotter ones like Burstbuckers there's a ton of distortion.

 

[What?]

It depends a lot on what pickups you use. With weaker single coils you get less overdrive, with hotter ones like Burstbuckers there's a ton of distortion.

Burstbuckers are pretty low output PAF style. I guess there are lower output pickups, PAF's are about the typical lower output range of humbuckers. With similar output 57's I get more than enough gain for the stuff I play.

 

[EndGame00]

I modded my 68 Plexi clone with no cap /4700pf cap mini toggle switch... I usually go for no bright cap if I'm using a distortion pedal, then bright cap if I want all the dirt from the amp...

I usually keep the presence at 4.5, mids dimed, treb at 4, bass at 5 with bright cap on....

Bright cap off, would be presence at 5, bass at 5, mids at 7, teb at 6...

 

[X2203xman]

I use mine very close to that .I use the big bright cap as well.The biggest difference would be my vol#1.I keep it around 5 or 6 and the #2 around 2.I'been setting the ppimv at noon.Turning down the guitar gives a decent clean.I boost it with a 10 band eq with super bright guitars like a tele.My SG really dosn't need anything,and goes straight in.I think mine is sounding better and better,but taming the volume and finding the best sounding compimise of volume and tone takes some playing around.

 

[purpleplexi]

Plexis. You get them perfect then you bend over to scratch your ass and when you stand up they sound completely different. You'll never stop fiddling with it.