Why are there 4 inputs on a 1959SLP Marshall

Frazer Stockton

Frazer Stockton

New member
I can't figure out for the life of me, why there are 4 input sockets on a Marshall 1959SLP, can someone please explain what the uses of the 4 are, and how they effect each other?

Kind Regards
Frazer


1959slpfeatures.jpg
 
Re: Why are there 4 inputs on a 1959SLP Marshall

There are two different input levels and two different preamp stages.

Last time I checked 2+2 = 4 (Also same system on Blackface and Silverface Fender amps...)
 
Re: Why are there 4 inputs on a 1959SLP Marshall

Right, so one of the inputs is clean and the other dirty? If that's what you mean by pre-amp stages? Or does it vary?
 
Re: Why are there 4 inputs on a 1959SLP Marshall

Frazer Stockton said:
Right, so one of the inputs is clean and the other dirty? If that's what you mean by pre-amp stages? Or does it vary?
Click to expand...

Wrong, one is your normal input and the other is to be used with pedals since it has more resistance built-in.

Wrong, channels are for normal and treble voicing
 
Re: Why are there 4 inputs on a 1959SLP Marshall

Four inputs also facilitate channel jumping, which is really a blending of the two channels (bright and dark) by their respective volume knobs. What you do is plug into the upper left jack (bright sensitive input), and then plug a short cable into the jack just below it. You then plug the other end of the short cable into the upper right jack, or the dark channel sensitive input. You then blend the tones of the two channels to taste using the volume knobs. You can also do it the other way, or in different combinations.

It also facilitates "daisy chaining", or operating two or more heads at once, but without a Y cord or A/B-Y box. You use the extra jack (below or atop the other) to out into another amp. You can do this after jumping channels or only using one channel. Hendrix typically daisy chained at least two or three full stacks together.
 
Re: Why are there 4 inputs on a 1959SLP Marshall

There's four inputs because that's the configuration of a '59 Fender tweed Bassman and the early Marshalls were pretty much a knock-off of that amp, both cosmetically (in terms of the control plate layout, etc.) and circuit wise as well.

In other words, there are four inputs because the Bassman had four inputs.

Any uses such as channel jumping, etc. are all unintentional and unplanned benefits of that design.

Really, there are four inputs in a Bassman because the amp has two channels (one bright and one normal) and each channel has a high input and a low input. That makes for four total.

If you are plugging your electric accordion into a tweed Bassman or plexi Marshall you might want to use the low input (#2) of the normal channel to avoid distortion.

Lew
 
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Re: Why are there 4 inputs on a 1959SLP Marshall

Yep, there's 2 normal inputs and 2 treble inputs. Kind of like how a regular amp would have 2 inputs. You don't always use it, but they have 'em nonetheless.

If you plug straight into the treble input, no jumping, it sounds like crap-ola.

The regular input sounds great alone for cleanish stuff.

Jumped is "that sound," that everyone talks about, but only at higher volumes, in my opinion.
 
Re: Why are there 4 inputs on a 1959SLP Marshall

From the manual: http://www.marshallamps.com/downloads/files/Vint hbk.pdf

Top left: channel 1 high sensitivity
Bottom left: channel 1 low sensitivity
Top right: channel 2 high sensitivity
Bottom right: channel 2 low sensitivity

Channel 1 is the "high treble" channel. Channel 2 is the "normal" channel.

Channel jumping is accomplished by connecting channel 1 low sensitivity to channel 2 high sensitivity.
 
Re: Why are there 4 inputs on a 1959SLP Marshall

ImmortalSix said:
Yep, there's 2 normal inputs and 2 treble inputs. Kind of like how a regular amp would have 2 inputs. You don't always use it, but they have 'em nonetheless.

If you plug straight into the treble input, no jumping, it sounds like crap-ola.

The regular input sounds great alone for cleanish stuff.

Jumped is "that sound," that everyone talks about, but only at higher volumes, in my opinion.
Click to expand...

i actually know people who plug into input 1 on the high treble channel and get great sounds. i totally agree that the real money comes in with channels jumped and the amp up more than halfway but even on a 50w plexi that is freakin loud!
 
Re: Why are there 4 inputs on a 1959SLP Marshall

The reason why the Bassman had that many was so you could plug in a bass and a couple of microphones. Bands used to do this before they found out it sounds like crap for everyone to run into the same amp.

Blending the channels came later, and it serves to make the eq brighter or darker depending on the guitar and room. Plug in a Tele or Strat, and run the normal up and the bright down...plug in a LP and turn up the bright and turn down the normal.
 
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Re: Why are there 4 inputs on a 1959SLP Marshall

I run straight into the high sensitivity treble ch input all the time on JTM45's and it sounds great. This is pretty much the most common procedure with JTM45's. Jumping channels isn't that common on JTM45/Tweed Bassmans.

However, it's quite common on the later model plexi's that have been re-designed with "split cathodes" especially to better facilitate channel jumping. Indeed the split cathode plexi's treble channel is bright enough that you almost need to jump channels. The dark channel on a split cathode plexi isn't as woofy as on a JTM45 either.
 
Re: Why are there 4 inputs on a 1959SLP Marshall

Thank you very much for the prompt replies, I'm starting to get this now, however putting two amp heads together was mentioned, how exactly would this work?

I think ive got a picture of the wiring setup (below) for the front of the amp (minus the guitar input) but how would the amps then be hooked up to the cabinet(s)?

For what purpose would there be two amps hooked together like this? Im guessing its due to the lack of ability to switch channels between clean and dirty, seeing as the way you input your guitar determines the channel you play through? (However the picture below shows the amps connected both in the same channels)


Many thanks
Frazer
 
Re: Why are there 4 inputs on a 1959SLP Marshall

On both amps (in the photo) the guitar signal is running directly into the dark channel low sensitivity input from somewhere else (probably a preamp).

When daisy chaining two or more amps, you would usually plug directly into one of the high sensitivity inputs, and then take a cable from the input directly below that one (because this signal is slightly padded) over to the next amp and plug it into one of the four inputs.

On edit: Oh... and each amp will have it's own speaker cab with its own speaker cable (or set of speakers within a stereo cab)
 
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Re: Why are there 4 inputs on a 1959SLP Marshall

Guitfiddle has it, back in the day the whole band would plug into one amp. Even in the mid 70's in my first band me and the bass player both plugged into his Selmer amp. Not too many bands could could afford an amp each.
 
Re: Why are there 4 inputs on a 1959SLP Marshall

Ahh I see, would it still be possible to get a clean sound out of this amp though, without having to roll off on the volume pot? Or by switching the wires at the front, mid song.

Many Thanks
 
Re: Why are there 4 inputs on a 1959SLP Marshall

A 1959 (or any stock 4 input Marshall for that matter) is a 2 channel (one bright one normal) each with a volume control. You can play it clean or you can crank it for distortion...there is no master volume so by the time you get it crunchy it is REALLY loud but thats how these amps sound best!

As for getting back to a clean tone you roll the volume control down and pick lighter and the tone gets cleaner.

Another thing to do, which some guys have been doing a lot lately is to use custom built "volume box" or an EQ of some kind with a level fader...

The "volume box" is just a volume control, like the one in your guitar but in a box with a bypass switch...you set the volume control on the box to say 4 and then when you step on the box the signal drops, just like if you had rolled your guitars volume down to 4 and the tone is cleaner.

The EQ deal is like what Paul Gilbert is doign these days...it's an EQ and you run the level fader (or knob) way down so that just like the "volume box" when you kick the EQ on the signal dropps...

But what I think you are asking about is like channel switching or switchable master volumes and, no...these amps simply are not built like that.

Also, be warned...a 1959 cranked to the point of distortion is more than enough amp to play stadiums so if you're at home or in a club you will not be able to use these amps like that.

You're only other choice is to use a distortion pedal and set the amp clean but in most cases that sounds pretty bad.
 
Re: Why are there 4 inputs on a 1959SLP Marshall

Frazer Stockton said:
Thank you very much for the prompt replies, I'm starting to get this now, however putting two amp heads together was mentioned, how exactly would this work?

I think ive got a picture of the wiring setup (below) for the front of the amp (minus the guitar input) but how would the amps then be hooked up to the cabinet(s)?

For what purpose would there be two amps hooked together like this? Im guessing its due to the lack of ability to switch channels between clean and dirty, seeing as the way you input your guitar determines the channel you play through? (However the picture below shows the amps connected both in the same channels)


Many thanks
Frazer
Click to expand...

I'm not convinced the amps in that pic are directly hooked together. Check out the color of the tape around those cables - it's not the same.

A lot of big time touring pros have a backup amp at the ready in case something goes wrong. My guess is that's what we're actually seeing here.
 
Re: Why are there 4 inputs on a 1959SLP Marshall

First things first...Billy's Marshalls are modded PLUS he uses a rack mount preamp with the Marshalls to make the set up more versitile.
 
Re: Why are there 4 inputs on a 1959SLP Marshall

According to the company that modded it, the mod (Pre-amp Crunch) "is $350.00. It includes a master volume installation and tonal shaping with some internal parts changes."

Thats all straight forward but as for the rack mounted pre-amp .... This is where im confused, how does this all hook up? Is the rack mounted pre-amp connected via the Send and Recieve effects loops at the back of the amp?
 
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