How do I connect speakers with different configurations with an amp?

[Sune Andersson]

I have a tube amp with two parallel output Jacks (marked Högtalare) and an impedance switch (4/8/16 or 100 ohms) marked Omkopplare. See images!



I also have two 2x12” (8 ohms each speaker) cabs, that I want to be able to use either as one cab or two cabs together with this amp.

Each cab can be used either in mono (speakers in parallel) which makes them a 4 ohms cab, or in stereo and that makes each speaker separate with 8 ohms each.



So my ways to connect my cabs are:

1. One cab with two parallel connected speakers (2x8 ohms) connected with one speaker cable and setting the impedance switch to 4 ohms on the amp.
2. One cab in “stereo” mode with each speaker (8 ohms each) connected with two cables into the amp’s two output jacks (they are in coupled in parallel inside the amp) and also setting the impedance switch on the amp to 4 ohms.

I can off course stop here and be satisfied but... I want to be able to use two cabs, but if I use mono mode as they are set up right now, the switch on the amp has to be set to 2 ohms and that is not possible.


QUESTION

Is there a way to change the speaker cables in each cab so that the mono mode is serial (8 ohms each speaker = 16 ohms/cab) and the stereo mode is still functioning too?


That way TWO cabs could be connected to the amp (setting the impedance switch on the amp to 8 ohms) or ONE cab connected in mono, one cable (setting the impedance switch on the amp to 16 ohms) and ONE cab in stereo mode, two cables (setting the impedance switch on the amp to 4 ohms).


Is that possible?

 

[Jon Snell]

I would use each cabinet with speakers wired in parallel giving 4 Ohms each 'box', mono input socket. Set the amp for 4 Ohms load to use them separately.
If you wish to use them together wire the 'boxes' in series with a series socket box, using just the mono inputs and set the amp to 8 Ohms load.

 

[Sune Andersson]

I would use each cabinet with speakers wired in parallel giving 4 Ohms each 'box', mono input socket. Set the amp for 4 Ohms load to use them separately.
If you wish to use them together wire the 'boxes' in series with a series socket box, using just the mono inputs and set the amp to 8 Ohms load.

That sounds like one way to do it...

 

[Sune Andersson]

Will this work?

 

[schmee]

Will this work?

That looks right. Basically you are doing this to create a Series Adaptor:

 

[Jon Snell]

Don't use metal switchcraft type sockets! Use isolated jacks or you will get a short circuit on the right hand socket and no sound from that one.

 

[5595bassman]

Don't use metal switchcraft type sockets! Use isolated jacks or you will get a short circuit on the right hand socket and no sound from that one.

Or use a plastic box with metal switchcraft type jacks.

 

[ArcticWhite]

That looks right. Basically you are doing this to create a Series Adaptor:

This schematic looks like a melancholy dentist, staring out of a window.

 

[Sune Andersson]

This schematic looks like a melancholy dentist, staring out of a window.

Hahaha... a good one!

 

[schmee]

WINNER! It IS a melancholy dentist!