So, this week I received an email from Scott, a WGS
aficionado who was inquiring as to how he should wire his Marshall-style 4-12
cabinet. To be honest, I hadn’t given
that one any thought in a couple of decades, and it made me think. In essence, there are two ways to wire up a 4
speaker cabinet that both wind up with the cabinet having the same impedance as
any one of the individual drivers, or in other words, a cabinet with four 8-ohm
speakers that ends up with a total cabinet impedance of 8-ohms.
The two main methods of arriving at this means are as
Okay, so let’s talk about the difference between the two.
Here is my reply to Scott, which I will … until proven wrong
… stick by:
I opened up a couple of my vintage Marshall cabs (a 4-12 and a 4-10), and both
are wired "series/parallel". I really like these cabs, and so I think I’d
go with that. Plus, if you do it in the "parallel/series" style and one
speaker fails with a full open voice coil, all four speakers will be down, and
your amp will see a no-load impedance. I know this is unlikely with your
ultra low-power amp, but I’d still term it a "consideration".
Scott replied that a fellow by the name of Jim at an amp
shop in his area felt as though "the parallel-series method provides a darker
tone". Hummm ... I had not heard that
before, and I have not been able to substantiate it. So, I’ll stick by my suggestion to go with
the "vintage" Marshall
series-parallel wiring method when wiring a 4-speaker cabinet. However, I am always ready to hear another
point of view. If you have any
experience or input in this, email me, and
I’ll be sure to share the information on this blog! Oh, and as for the modern Marshall mono-stereo switch, well, let’s just
say no to that little bit of absurdity (please)!
Until next week... -Vaughn-
**UPDATE**: Scott has just checked in; he tried the wiring both ways, and could discern no difference in tone - that's kinda what I would have suspected. He went with the series-parallel method for the reasons I described above. Here is a pic of the wiring in his Marshall cab, with the new WGS Green Berets installed. Looks like a good clean wiring job!