#1
hi there, sorry to bother people with a question that probably gets asked a lot but ive just got a marshall jcm 2000 dsl50 and a jcm 900 lead 1960a 4X12 cab and having always being a user of combos im confused as to how to hook them up as there seems to be a few options (mono,stereo etc) ive included photos of the backs of them both.any help would be much appreciated (the simpler the better haha) ive tried the head at both 4 and 8 ohms with the cable on either side selected as mono but im getting nothing from the cab, do i have to have 2 cables for it to work or should it still work with the 1 cable? https://goo.gl/photos/R351rUU2ngv6Jcb28
#2
First thing, make sure you're using a speaker cable, not an instrument cable. They look identical, but most will have writing on the cable, near the tips, that says if it's a speaker or instrument cable.

Once you know you've got a speaker cable, just use it in 16 ohm mono. The 16 ohm output on the head is the lone one on the left. 16 ohm input is the one on the right on the cab, with the switch set to mono. That is, on the right from your point of view looking at the input jacks. It's actually labeled as "left" because that would be the left side input if you were running stereo. The mono/stereo switch on the head shouldn't matter of you're using the 16 ohm output. If you hook it up that way and aren't getting sound from the speaker, something's broken.
Guitars
Schecter Hellraiser C-1FR, C-1 Classic, and Hellraiser Hybrid Solo-II
Orange Rockerverb 50 212
Basses
Yamaha RBX374 and Washburn MB-6
GK 400RB w/Ampeg 4x10 Cab
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Last edited by the_bi99man at Nov 1, 2016,
#3
yeah its a brand new boss speaker cable. i thought the 16ohm was for stereo? what load will i set the head to as its only got 4/8 ? thanks
#4
Quote by riccosuabe
yeah its a brand new boss speaker cable. i thought the 16ohm was for stereo? what load will i set the head to as its only got 4/8 ? thanks


Its only stereo if youre using both inputs.
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#5
SHOULD BE: Plug into the 16 ohm output jack of the amp, use the 16 ohm input of the amp with the switch set to mono. Someone else double check behind me.
#6
The amp jacks are pretty self explanitory a single 16ohm and two 4 or 8 ohm depending on how you set the switch.

As for the cab, the two ohm ratings on the upper side of the plate (4 ohm and 16ohm) are impedance values when the cab is in the MONO configuration, the different values are due to different wiring, either all 4 16ohm speakers in parallel or two speaker in series in parallel with another two speakers in series. You don't necessarily need to understand that - the point is teh 4 and 16ohm ratings are for when the cab is in MONO mode, For your setup you the 16ohm output on the amp and connect it to the 16ohm input on the cab with the switch set to mono.

The 8ohm right and 8 ohm left refer to the impedance if you are running the cab in STEREO, in this case you would switch the amp impedance selector to 8 ohm, then use two cables to connect the parallel outputs from the amp to the two inputs on the cab, with the cab set to STEREO.

Either one of those configurations will work, if you aren't getting any sound then something else is wrong, or turned down, or maybe you are still in standby.