Why are there 4 inputs on a 1959SLP Marshall

[the guy who invented fire]

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?

Yes...becasue the Marshall head has a preamp out/power amps in set up Billy can use the rack mount pre amp and use the Marshalls power section to power it all.

What he does is his cleans and his mid gain sounds come from the rack preamp but powered by the Marshalls power amp...the heavy crunch is all the Marshall, no rack preamp...

Back in the day he ran JUST the Marshall(s) and no rack preamp...those modded Marshall are really the key to the Green Day sound and if you wanted to the Marshall plus the mods and a 4x12 woudl get you really close but it's gonna be ear splitting loud.

 

[Frazer Stockton]

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

Ahhhh thanks so much for the help clearing this up =D

 

[the guy who invented fire]

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

Ahhhh thanks so much for the help clearing this up =D

Dealing with modded amps and MIDI rack systems is a little hard to follow!

No worries, if you need more help feel free to ask!

 

[RLee]

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

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

Electric accordion into a 100w plexi... that gives me a headache just thinking about it! :approve:

 

[pinto79]

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

Just a note of possible interest, my 1959RR has a cascaded gain stage in V1 that is also known as the "One Wire Mod" which turns the right-most inputs to have significantly more gain than stock. When plugged into either Channel 2 input, it uses the channel 2 volume control as a gain control and the Channel 1 as a crude Master Volume.

Using this setup, I can use an A/B/Y box to select one channel, the other or both combined.

I've used the Channel 1 Low as a Rhythm volume and Channel 2 High as a Gain/Volume boost for lead work.

 

[Frazer Stockton]

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

Just a note of possible interest, my 1959RR has a cascaded gain stage in V1 that is also known as the "One Wire Mod" which turns the right-most inputs to have significantly more gain than stock. When plugged into either Channel 2 input, it uses the channel 2 volume control as a gain control and the Channel 1 as a crude Master Volume.

Using this setup, I can use an A/B/Y box to select one channel, the other or both combined.

I've used the Channel 1 Low as a Rhythm volume and Channel 2 High as a Gain/Volume boost for lead work.

Thats a really interesting concept, is it hard to modify?

 

[shredaholic]

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

Its pretty easy to do yourself if you've worked on an amp before. Better yet, you can make it totally switchable so when using a push-pull pot on the volume control, the amp goes back to stock form!

http://home.comcast.net/~mamp17/Misc Mods and Info.html

 

[pinto79]

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

Thats a really interesting concept, is it hard to modify?

I've heard that it's a very simple mod, as it is simple one wire moved...

The 1959RR came with the mod from the factory so I didn't have it modded. Visit the Marshall forum (www.marshallforum.com) There's guys there who know how to do it.

I was playing my RR today and really digging the tone. It's so raw and naked that it forces you to play better as it won't hide anything.

 

[wosinek]

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

working on my son's 1974 excellent Marshall Super Lead Mark II 1959~ head and have a question.
I dont have a jumper installed but the 2 volume controls are interacting and I'm trying to
see if that is normal or the amp was modded... ( first time to look at a Marshall)
He gets a wonderful Marshall tone with the guitar plugged into Channel I High and
Channel I volume is set to level 5 and Channel II is then set lower around 3 or
whatever volume level desired. Is this because the two volume controls interact
and essentially short some of the input signal to ground when turned down
or am I missing something on the schematic or a mod has been done that I dont see?

Everything works great but I have an operational questions about inputs.

Channel I High is cleaner and has more gain/treble expected.
Channel I Low is clean but signal level is lower as expected.
Channel II High has less treble and gain is ok but somewhat lower as expected.
Channel II Low is same as II High but is lower as expected.

Input channels all have the expected resistances between each other when
tested with an ohmmeter... i.e. 136K between Channel I High and Channel I Low,
and 1 meg to ground on High inputs of both channels.

thanks a bunch.

 

[esandes]

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

with these 4 input marshalls, two guitarists can play through one amp. i had to resort to this when my other guitarists amp fizzed out.

 

[glassman]

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

Some interaction is normal.

Normal interaction: plugged into channel 1 only with volume 1 up half way; if you rotate the channel 2 volume, there will be some high frequency attenuation as you roll back toward zero. Vise versa is also true.

Abnormal interaction: plugged into channel 1, volume 1 all the way down; if you rotate the channel 2 volume up and get appreciable sound...something ain't right or the inputs are tandemed. Vise versa is also true. Replace V1 and see it it affects the behavior. Non-Super Lead amps may have some interaction due to the common cathode on the input stages.

Hope this helps.