ok so basically as the title says i need help with the output jacks of my JCM900 4101 model.

i m concerned about two things.

one is the loudspeaker outputs: it has two loudspeaker outputs which are in parallel and a selector for the impedance which is weirdly 8 and 16(4). this is what i dont get tho. why is the 4 in the parenthesis? right now i have the impedance on 8 ohm on the switch and i have the G12-100 celestion( 8 ohm) connected to one of the jacks. this gives me an 8 ohm load in total. if i wanted to connect a cabinet to the other speaker jack (say a 8 ohm cab) i would result in 8 ohm in one and 8 in the other so that gives me 16 cause its in parallel...but what the hell is the 4 doing in the parenthesis cause thats really confusing me:S explanation?

what i m trying to achieve is to have sound coming from the combo speaker AND an external cab(prolly a 4x12 to get an 8 ohm impedance(four 8 ohm speakers in series-parallel right?)

thats one. the other question is easier. there are two outputs in the back which are line-outs. one says recording compensated and the other says direct line out. which is best for headphone use at night and which one would i connect to the PA or to my computer for mixing and so on?

i know this is alot but yeah i hope i get an answer from some people who know!
thanks in advance
Well if its an 8 ohm speaker on the inside and a 8 ohm cab then you have to set the switch to series, and 16 ohms to hook it up to the 4x12 and have the stock speaker all together, because the cab is 8 and the celestion is 8 so in series it would be 16

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DUDE i just read that the combos have a 8 or 4 ohm selection and its always in parallel...so that explains alot
btw impedance is the resistance of the speaker. in series two speakers ohm-age is added( ex two 8 ohm speakers make one 16 ohm load) in parallel its halved( two 8 ohm speakers make a 4 ohm load). always remember to have equal load speakers.
so for me if i wanna connect another cab ( 8 ohm) to the second output AND have the internal speaker (8 ohm) connected...it would result in a total load of 4 ohm ( 8 and 8 in parallel) btw its always only parallel....u cant put them in series

phew that solves alot

anyone have suggestions on the line outs? direct line out and recording compensated?
Quote by georgakis187
anyone have suggestions on the line outs? direct line out and recording compensated?
Use them to make a W/D/W rig! Go on, you know you want to.
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In a nutshel, an expensive rig. Consisting of a totally dry (no effects) cabinet in the middle (can be a combo) and a stereo effects (W/W) rig fed by the line out on your amp with it's own stereo poweramp, a left cabinet and a right cabinet. Preserves the original uneffected tone of the amp in the "D" part and sounds massive in the "W/W part. Also costs an arm and a leg. I will do this one day.
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hmmm enticing....of course for it to work my question needs to be answered when i use the line out (which of the two?) will the speaker in my combo be silenced?
Shouldn't do, but if you'd like to mute the speaker while using them, just turn the master volume down I guess.
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hey i just checked now with both outputs( Direct line out and Recording compensated) and neither work with my headphones....the headphones work perfectly with my stereo system....the headphones have a 1/4" jack thingie and its stereo...does that have anything to do with it? if i plug it into effects send i can get a bit of sound on only one phone of the headphones. any ideas? i know if its stereo and the amps outputs are mono that the sound will not be stereo but shouldnt i be getting sound from one of the phones when i m using the line outs?
All the outputs and the FX Send are mono, it's simply grounding one side of your headphones. They aren't really designed for headphones, it's a professional gigging amp. You should possibly get something from the line outs, especially the emulated one, even if it's mono.
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well ok i m just anxious to get my vox amplug they say those are like pretty good tone for headphones and i ll just be using it when i m playing at night so...
BUT what if i used the outputs on my amp to send a signal to my stereo ( a rack type cd player------> stereo power amp) and from the stereo to my headphones? i d have to use a 1/4 jack to those two red/white cables...would that work?