Switchable series to series-parallel

Wouldn't something like this be more appropriate with 4 ohm drivers? But I must admit I tend to the general opinion its an undesirable complication. If my amp required 4 ohm I'd wire it for 4 ohms, and if 16 ohms 16, and live without the switch. I can too easily image some careless 'helper' knocking the damn switch off during the load in.

 

There companies that make this sort of product.
Palmer CAB M | Signal Splitter & Switcher | Palmer (palmer-germany.com)
Cab-Link - Radial Engineering

Check the specs if they are posted. I don't think these are really designed for a 800W bass amp. They will work fine at a modest power level.

I have a wiring diagram that does series parallel (I think). I believe this is how my Hiwatt DR201 was originally wired.



Here are the proofs I worked through...let me know if I missed something.



When no speaker is attached, I believe this configuration shorts out the output. This would be very bad for a solid state amp, but it's desirable for a tube amp. By bad I mean possible destruction of the amp.

 

Old Ampeg tube amp with a 16ohm output -- sounds like a B-25-B to me.

 

Beware of those switch boxes where there is a connection to the enclosure, on a bridged amp this will place the box enclosure at above ground, so if the box touches ground, 1/2 of the amp will be shorted and damage can occur.

I do not recommend using anything like this with most class D amps since they are usually internally bridged.

 

SIMPLE Parallel/Series Select Switch
Make each load a series pair of speakers and you are done.

 

FWIW, every time I've contacted Eminence directly regarding replacement drivers I've been happy with their recommendations.

 

So......

if the speaker out is requires 16 ohm, and there's an extension speaker output available that is also 16 ohm... the amp is good with 8 ohms?

Last pic above

 

Woah! That thing is made for some serious abuse dude.

600w, tilt back stand, and 122lbs

My God, you're going to love everything but moving it. Especially since it's so low to the ground.


I would simply take one set of leads going to the second input on the cab. Wire them in reverse order. Top, - +. Then, you'd have yourself one parallel port, and one series port. You would need to run in to that cab from the parallel out on another cab.


That's my guess. I've never done it. Never needed to anyway. But, it makes sense right? That is how I would try it.

Now, my question is...wouldn't that just put the entire cab out of phase?

When one speaker is out of phase, you fix it by reversing the leads. If you have a whole cabinet taking a signal in reverse, wouldn't the whole cab just immediately be out of phase with the other cab?

 

I believe the speaker out is for a 16 ohm cab,
and the “ext” speaker out and speaker out are wired in series — you would use two 8 ohm cabs and the amp would make 16 ohms.

 

Possibly, some amps switch impedance automatically when an extension jack is plugged in. I have a peavey deuce guitar amp that does that between 8 and 4.
That particular amp I have no idea about though.

 

It looks that way to me, too.

 

Doesn’t work that way unless I’m missing something.

 

When I built my first speaker cabinet back in the late 60's with a pair of Altec 421As, I worked out a series/parallel switch so I could use my only bass amp at the time, a B-15, with it, using the 16 Ohm capability. When I bought a dedicated head (a Super Beatle 1143) I used it in the 4 Ohm position.

By the way, there is only a very small SPL difference when you switch it from 4 to 16 Ohms, but there is some tonality change.

 

Okay.

My thought was that the 8ohm cabinet, with all the speakers wired in parallel, would be the same as adding 1 8ohm speaker in series, if you were to reverse the input leads. Made sense to me. Just like, purchasing a "series wired cable"

Except that the cable would just simply be the other input jack. Know what I mean?

 

I don’t think so.

 

rockness monsta Do a search here on this forum using the term 'B-25B Dummy Plug'