Vox speaker out on a AC15C2 using speaker cable, to a Fender Frontman 212R Combo

[ctguy1955]

   So I double checked the way I wired the fender and the amp power white went to the left speaker white and then to all of the other ones
in the proper order.  I did the 9 volt battery test and the right speaker moved where you could see it, but the left speaker did not seem to
move at all.  I put my finger gently on the cone and I could feel it going IN when power was given, and out when power was turned off, and it
felt the same on both speakers. They both went in and then out.   I saw the right speaker seem to move to the left slightly, but the left speaker
did not appear to move at all. 

I have learned so much here, and its so nice to be able to come to a website for information and get really good info and facts.

  Thank You all so much for all of your help, It is so much appreciated  !!!!!!!!!!!!

Mike

[juanjosebh]

Hey guys, jumping in. Im interested in doing this to run a Epi Valve jr into a Frontman, my question is, in doing this would i be just pluggin in the speaker 4 ohm out into the switch and that would immediatly disconect the Fender and just work as a cab right? this seems a lot simpler than other solutions I have seen. thanks!

[phatt]

Hey guys, jumping in. Im interested in doing this to run a Epi Valve jr into a Frontman, my question is, in doing this would i be just pluggin in the speaker 4 ohm out into the switch and that would immediatly disconect the Fender and just work as a cab right? this seems a lot simpler than other solutions I have seen. thanks!

Sorry it not clear what you mean?
But if you disconnect the speaker from the Frontman Amp (at the Terminals on the speaker basket) then you can drive it with the Epi Amp.
Your suggestion sounds like you may end up connecting 2 Amp outputs which would cause a total failure of both amps. 

Also Watch your impedance, if 2 8 Ohm speakers then the total is 4 Ohms.

Phil.

[ctguy1955]

 It's been awhile, and I just remember
That my vox and my orange micro
Have a 4 ohm out jack, and that
is why I rewired the frontman speakers
from parellel to series, to make them
4 ohms.
  When using the cliff jack, you never
Have the frontman turned on, nor plugged
in, for that matter. It works great, with
no danger to either system.

[J M Fahey]

It's been awhile, and I just remember That my vox and my orange micro
Have a 4 ohm out jack, and that is why I rewired the frontman speakers
from parellel to series, to make them 4 ohms.
  When using the cliff jack, you never Have the frontman turned on, nor plugged in, for that matter. It works great, with no danger to either system.

What you write is not clear but sounds wrong.
You seem to be connecting your Orange or Vox output into the Frontman back panel jack so sound travels down to the speakers through the internal wiring.
That is plain WRONG and your amp is alive just by Miracle.
Turning off or unplugging the Frontman does not remove its transistors from the speaker wiring.

The proper way to do it is to disconnect the speaker terminals and rewire them to *another* cable where the external amp is connected.

And you are also mixing series with parallel.
Your speakers now give 16 ohms, go figure.

[ctguy1955]

  Im sorry that you dont understand what Im saying, but I dont think you know what a cliff jack does ?

You cut the wires from the amp and install them on the right side of the cliff jack. Now you run the speaker
wires to the left side of the cliff jack that has leaves that lift up when you insert the speaker cable from
the Vox or the Orange amp out jack.  When you insert the speaker jack, the entire amp system is
taken off the grid totally, and only the speakers get used.   I used a 9 volt battery to make sure
that both speakers are in phase and it works perfectly, so I dont know why you keep returning
with negative answers.   I dont use it with the Vox much any more, but I do use it a lot
with the Micro terror as it fits into the back bottom of the 212R with the speaker cord and
everything really well and its nice to get different sounds.
  I unplug the 212r as Im not using it, only the two speakers.

  It is totally ok to run a 4ohm amp into a 16 ohm cab. The rule is that you can mismatch ohms as long as you mismatch lower rather than higher

[J M Fahey]

It is totally ok to run a 4ohm amp into a 16 ohm cab. The rule is that you can mismatch ohms as long as you mismatch lower rather than higher

That's NOT what you said.
Which actually was:

I rewired the frontman speakers
from parellel to series, to make them
4 ohms.

Well, that's plain WRONG.

[Roly]

I rewired the frontman speakers from parellel to series, to make them 4 ohms.

So the speakers are 2 ohms each?  That's extremely unlikely.  Wired in parallel that would present only 1 ohm to the amplifier which is unheard of in guitar amps.

The 212R specs on the Fender site;

Wattage:    100 Watts into 4 Ohms

Speaker:    Two - 12" Fender® Special Design
Impedance:    4 ohms

The latter figure is the total, not individual speaker impedance that I would expect to be quoted under "speaker", which would make them 8 ohms each, and therefore 16 ohms total in series.

I dont think you know what a cliff jack does ?

I'm sure @JM knows very well what a switching jack can do, and about permissible load mismatch, but as he said "What you write is not clear but sounds wrong"; however what you wrote about rewiring your speakers "to series, to make them 4 ohms" is clear, and wrong.

[g1]

1)  A switching jack (cliff) was wired in SERIES between the Fender combo amp and it's speakers.  It was wired up to be an input to the speakers, NOT an output from the Fender amp.
  This enabled the Fender combo's speakers to be used as if they were a separate speaker cab.
2)  The Fender speakers were re-wired so they would be in SERIES (16 ohm).  The stock wiring had been parallel (4 ohm).
This was because the Vox amp had an extension speaker jack that was rated for 16 ohms, and the Fender speakers were to be used as an ext.spkr. for the Vox amp.

[Roly]

Quite so.

I'll just note here that if you try this trick on a valve/tube amp you a skating one shaved inch from disaster.

Drive a valve amp with the load accidentally disconnected and you can generally kiss goodbye to the output transformer, one of the most serious and expensive failures you can suffer.  A valve/tube amp must never be operated with a load securely attached.