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Just bought a Spider Valve Mk2 from GC

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So, it was time to upgrade.  I had a Spider2-150 for what seems like a decade.  I wanted to do more with my amp and get tube distortion, possibly even sell my Peavey 6505 now that I have a tube from Line6.


So, my questions:


#1 - I kept my 4x12 Spider2 slant cabinet.  It looks like I can set the amp to 8 ohms stereo and use the existing Line6 cab just like I did with the Spider2?  I run 2 speaker cables (1/4) from the left and right outs on the amp to the left and right 8 ohm in's on the cabinet?  This seem correct?  I think the cabinet is rated at 320 watts, and the output of the valve is rated 240w, so I should not blow anything up?


#2 - So, if I want to go FULL STACK, I could put the amp output to 4ohms, and run 1 cable to the Line6 slant cab as 4ohm mono and use the left-mono plug.  I also have a Peavey 5150 cab with 4 x 16ohm speakers in that.  I think that cab has, or can be wired as 4 ohm input by running the speakers in parallel?  Basically, I would split the input signal 4 ways, one + and one - to each speaker so that the 4 ohm signal is sent to each of the speakers?


Does this sound correct?  Or, does the 4ohm incoming to the cabinet get broken down to 1 ohm per speaker?  I always though if you put 4 speakers in parallel, then the speakers would each run at 25% of the rated ohm;  if you ran 2 in parallel, then 50%, etc?


If it works like I remember (been years since I had to rewire any cabinets), then I can practice with my slant, and switch to full when I go to jam with friends.


Replies appreciated, the 5150 cab has celestions (the British ones), I also think the line6 cab has Celestions as well, but some special Line6 variant of their speakers.


Replies appreciated.




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Most speakers are wired in parallel, but check your manual or open those cabs..

Here's some general Ohm impedance formulas:

Series:    A Ohm + B Ohm = Total Ohm
Parallel (common Ohms):  Common Ohm / # of speakers = Total Ohm
Parallel (uncommon Ohms 2 speakers): A Ohm X B Ohm / A + B = Total Ohm
Parallel (uncommon Ohms 3 speakers): 1 / (1/A + 1/B + 1/C) = Total Ohm
Series+Parallel: Use above formulas together, compute series first as one speaker load, then do parallel formula.

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Thank you for your reply.


Even thought it was kinda-generic.  I say this because I don't think Peavey ever released a cabinet with multiple speakers of different ohms, it is a 4x12 with all speakers of 16 ohms.


It seems like I will use the 4ohm out with left and right going to top and bottom cabs.  When I practice at home, I will switch to 8 ohms stereo and plug both outputs to the Line6 cab.


Thanks for the clarity, should get the amp today or tomorrow.







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OK, I can't do what I thought I could.  The Spider Valve Mk2 will only allow pairs of 8-Ohm or 16-Oms, no 4-Ohm pairs.  You can go single with 4, 8, or 16-Ohms it seems.


So, I have a straight cab that is 16-Ohm, and my Line6 Spider2 slant cab is either 4-Ohm Mono, or using 2 plugs it will do a pair of 8-Ohms stereo.


But, I think I have an idea:  I can rewire the Slant cab from the spider 2 to series-parallel to get it to do 16-ohm mono.  I researched and it seems it has 4 x 16-Ohm speakers, so doing a re-wire to series-parallel will get me to 16-ohm in a single 1/4" input.  This sound right?


I wish there was a plug that would allow me to switch between an 8-Ohm pair for practice at home on the 1/2 stack, the allow me to switch to the series-parallel wiring to run a full 16-ohm stack when I go practice with the band.  Anyone know of this?  But sicne I can run a single 16-Ohm out from the Spider Valve Mk2 head, I will just run it as mono on the 1/2 stack, then switch to the 16-Ohm pair output to go full stack?


The straight cab is a Peavey with 4 x 12" 16-Ohm speakers, and I guess they are already in the series-parallel wiring, so now I just have to do the same with the top slant cab?


So, the back of the amp has 3 output combos, being:


Output=A : Single 16-Ohm output <--- will use this with rewired L6 Slant in Series-Parallel


Output=B : Single 8-Ohm OR 16-Ohm pair   <--- Will use this to go full stack with Rewired L6 slant and Peavey


Output=C : Single 4-Ohm OR 8-Ohm pair  <--- Using this now with non-rewired L6 Slant as 8-Ohm stereo pair





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