Need help with speaker wiring in series

[Speeddemon]

Here's the story:
I got an Engl Savage 60 head which only has 2 speaker outputs; an 8 Ohm and a 16 Ohm.
Now all of my 2x12 cabs are 8 Ohm (with each one having 2x 16 Ohm speakers in parallel).

So I figured, with a speaker jack plate like this, I could potentially make one cab in a sort of 'stand-alone 8 Ohm' or 'serial output to a 2nd cab to make a 16 Ohm total load.

But, I followed this wiring schematic (found here: http://www.danbecker.info/guitars/20170312SpeakerCabExt/index.html

and before hooking it up to an amp, I measured it as a single 8 Ohm cab, but once I hooked up the 2nd 8 Ohm cab, instead of 16 Ohm, it became 4 Ohm total load!


So it looks that the wiring schematic may be wrong and still creating a parallel wiring, possibly with one cab inverted phase-wise.
What's your take on it and how should I wire my jack plate so that it has 1 8 Ohm input, and a serial output?

 

[8len8]

Year, you’re still parallel. You need to route like this:

Main input + > cab 1 +
Cab 1 - > cab 2 +
Cab 2 - > Main input -

 

[mcstinger]

You can solve this easily by using switched jack. I have found this schematic and modified it for your required wiring of two 16Ohm speakers in one cab. You must use upper jack to connect the first cab to the amp. Lower jack is for connecting the slave/extension. In that case don't forget to use correct amp output.

 

[Speeddemon]

@mcstinger

Would this switching also be possible with a jack like this? (one side of the legs are disconnected once a plug is inserted )

together with a standard Switchcraft/REAN like:

I'm trying to wrap my head around how the wiring would need to look like...

 

[mcstinger]

@Speeddemon
Of course, you can use any jack with a switching contact. My nice drawing here below

 

[Speeddemon]

Thanks! I was in the process of drawing something similar....
But as it looks, the Main jack can be a standard, non-switching jack with just Tip and Sleeve contacts, right?

Also, I wonder if another loop between the T and S on the switching side of the Slave/Extension jack is necessary or even helpful, since when the Extension is not in use, it will properly connect the 2 closed switching contacts, right?

Mind you, I do have a way to overthink this... ;-) (Always have, math in highschool was a torture... teachers: "Yes young Speed, you *did* manage to find the right answer, but man, did you take a shitload of de-tours to get there." XD )

Like this:

 

[mcstinger]

But as it looks, the Main jack can be a standard, non-switching jack with just Tip and Sleeve contacts, right?
Yes, of course

Also, I wonder if another loop between the T and S on the switching side of the Slave/Extension jack is necessary or even helpful, since when the Extension is not in use, it will properly connect the 2 closed switching contacts, right?
This will work of course, disconnection of the contacts is more reliable, if there is a problem with one of those contacts. However, each contact has its resistance, in your wiring you are doubling it. And in a guitar cab wiring we want to get rid of any unnecessary resistances, so I would prefer the wiring below. Of course, reliability of this kind of wiring of the slave cab is dependent on the quality of the slave jack. If the contact is defective and slave is not connected, speakers in the main cab will have no signal, thus amp no load. In you wiring you are doubling the chance of such a failure by using two contacts in series. So anyway, need to be careful when turning the amp on, make sure there is a load by turning the volume up slowly. Also must be careful with not plugging the amp to the slave jack, the same would happen, no load.

 

[Speeddemon]

Thanks @mcstinger , I did it your way, measured it and it works.

Only 'negative' I can find now, is because of my speaker matchings, the top 2x12 sounds a tad more 'screechy' or crunchy/mid-forward than the bottom one, which sounds huge, especially considering its size (24" x 24" x 12").
Top one has 1x G12-65 (original vintage '81) and a '71 pre-Rola G12H30 55Hz.
Bottom cab has 1x Mesa V30 + beamblocker and the cab's original '86 G12T75.

Both cabs have added dampening material inside and closed backs. This weekend I have to play on one of the bigger European metal festivals (GMM) and I'm considering schlepping both cabs with either the Savage 60 or the EVH 5150III 50W, but maybe I leave them both at home and just bring the Mesa vertical 2x12, which always delivers. Due to some transportation limitations I can't bring the Engl 4x12.
Interestingly enough, both Marshall 2x12 cabs upright take up less space combined than 1 4x12 cab in my car.

 

[mcstinger]

Graspop in Belgium? Band?

 

[Speeddemon]

Yep. I pm'd you.