These forums are read only, please use our new forums here.

Main :: Spider Valve

2 amps, 1 Cab.
by Krank678 on 2012-09-14 14:33:27.2780

Hi guys,

I already posted this in the L6 Lounge but had 0 replies in the last week. I'm hoping someone here will be able to help with some info.

I have 2 40watt tube heads (4,8 & 16ohm outs) that I want to run through my Line 6 412 VS stereo cab (in stereo mode). I will mostly run A/B between the 2 amps (switching between one or the other) but would also like to blend the two amp signals in A/B/Y mode on occaision too.

SO, we can skip over the obvious issues of impedance matching (done that), and frying my heads (I am running the ABY switcher after the guitar and before my amps, NOT after my amps and before the cab - to maintain an impedance load on the heads and cabs at all times). Also, I know I wont be getting the same stereo spread as I would with 2 2x12 cabs but this setup is geared towards being double mic'd in the studio and on stage.

What I am trying to find out, is what kind of phase issues I may encounter. Does anyone foresee certain frequencies being cancelled out due to phasing, for example, loss of low-end frequencies or muddiness in tone. Also, how would the cab drivers be reacting to having a) 1 amp at a time running, as opposed to b) both amps running together?

Finally, if I ran two different wattage heads in the above configuration (lets say, a 20watt and 40watt simultaneously), how would this affect phasing and cab drivers?

Thanks in advance!

Re: 2 amps, 1 Cab.
by Rowbi on 2012-09-15 23:05:05.6210

It's hard to give you definitive answers and the best advice would be to try it and see how it goes.  You will likely not damage anything whether you get phasing or not, and the difference between 20 and 40 watts is not a lot in Db, so the speakers will cope with that.

Let us know how you get on


Re: 2 amps, 1 Cab.
by Krank678 on 2012-09-16 11:28:18.3140

Thanks Rowbi. I know it is a tough question to answer definitively (especially seeing as you are the only one to chime in on this ). I guess I should read between the lines on this too then... it could mean that this setup is not one that many, if any, people use. That tells me something already, I suppose. Thanks for confirming that I won't damage anything in the process though. Its always nice to get positive reinforcement on that when dealing with expensive boutique heads that I cannot afford to replace!

I was thinking that it (2 amps 1 cab setup) would be a good way to blend two amp tones for one overall tone from one cab. I will definitely be trying it out anyway (and posting feedback here) but the reason I posted the question is that I am waiting for the arrival of my new speakers for the cab so it's sitting empty for another week (should've mentioned that). I was hoping to gain a little insight before that because I do have an opportunity to buy a really nice 2x12 in the meantime, however, I would prefer to just use one cab instead of two because I don't need a wide stereo field and shelling out cash unnecessarily is something I'd like to avoid, if possible.

I am just curious to see if anyone knew, off the top of their heads, of any obvious phase issues that might occur when running 2 heads through a stereo split cab. I'm really hoping that it won't be an issue if the cab is true stereo.

Maybe you could tell me this, Rowbi, could the effects of phasing be lessened or removed entirely by making sure the 2 sides of the cab are completely divided and isolated internally (using a thick ply wood and insulation maybe)? As I understand phasing (laymens terms of course), it is caused by a ever so slight difference between the (in this case) time that the left and right side speakers output the audio signal. Is this correct?

If anyone knows of a good forum that may be more suited for this kind of question, other than Line 6, please pass it my way. It would be greatly appreciated!

Thanks again!

The information above may not be current, and you should direct questions to the current forum or review the manual.