Prefered load alternatives vta m-125

I have different load alternatives to choose from since I'm using
six drivers for the work at hand. I have the possibility to connect
them as 2x8/3=5,33ohm or 3x8/2=12 ohm.
The first alternative will have a smaller missmatch to the 4ohm
output tap (1,33ohm) but the 12ohm load will be equally missmatched
to either the 8 or 16ohm tap (4ohm).

Any thougths on this ?

Well I already have the active filter    The M-125 amps will be used for
midbass (50-350hz). There are six Seas "8" inch drivers in the midbass panels.

This filter is up for a rebuild with all tube outputs (John Broskies "Unballancer").



The active part comes from "WAF-audio" it's called Najda and I'm using
half of it, the dsp resources only (the wiring looks better now than in this picture).



Most of the set-up.



It's quite a task to rewire the speakers, that's why I'm asking

That looks like a system with incredible potential! Do us all a favor and publish some more details, please.
The article(s) from Bob make abundantly clear how complex impedance matching is, among other things. My limited experience, backed up incidently by a major independent speaker builder, is that one is generally both better off sound-wise AND safer using taps that are somewhat less in impedance rating than the nominal rating of the speaker, rather than the other way around. This seems to increase "tightness" of sound perhaps by influencing the damping factor favorably. It is safer, presumably because there should be less chance of current over-draw on the amp. Now, what with your using active crossovers, one problem is eliminated - the impedance swings around passive crossover points. But speaker impedance is a complicated matter. Take a look at real-time impedance curves of any model speaker out there - they're all over the place. Nominal ratings are somewhat arbitrary.
In fact, Bob is correct - in the real world, the only way to determine the "best" loading is by careful experimentation. I imagine the Seas are already wired up at 5.33 ohms. Should be quite satisfactory on the 4 ohm taps as is. I know I wouldn't wish to open up those towers and rewire them. Not today or any other day.

Dahlberg wrote:I have different load alternatives to choose from since I'm using
six drivers for the work at hand. I have the possibility to connect
them as 2x8/3=5,33ohm or 3x8/2=12 ohm.
The first alternative will have a smaller missmatch to the 4ohm
output tap (1,33ohm) but the 12ohm load will be equally missmatched
to either the 8 or 16ohm tap (4ohm).

Any thougths on this ?

Who designed this speaker?

Thanks for the input on wiring. Seems that 5,33 connected to 4ohm or 12
connected to the 8ohm tap is what should be tried then.
The speakers are my own design with a ribbon driver fairly simular to the
ones described at my homepage. And no, they are not for sale    .
These ribbon drivers are supplied with even more powerfull neo magnets
(magnetic assembly weight 40kg). They are driven by a pair of
C3m/KR300b xls/Hashimoto amplifiers.
Midbass drivers comes from Seas and are modyfied by removing the dustcap
and instead adding a solid aluminum fase plug. Subs are a cross from
AudioArtistry Bethoven and the "Ripole idea", Dayton "15" inch drivers (4/ch)
wired as 16ohm driven by A pair of Hypex ucd2K/regulated psu +/-90v.
Got some of the inspiration from Monte Kay's subwoofer towers but 12x15   x2  
Everything gets their signal from the dsp in the first picture.
It has 2ch (hardwired) John Broskie "Unballancer" and one balanced output from "Twisted Pear".

I'm rebuilding the dsp with 3 new pcb's from John soo there will be tube outputs for all channels soon (I hope).

I can't ad any links yet but you will probably find most of what's mentioned with a quick search anyway.

This is the simulated (close enough) impedance curve. Resistance drops to 4,8 ohm but
is never above 10 ohms in the 65-400hz region. Speakers are actively crossed over 2/order
at 65 and 350hz today and I will most likely not change that.

This is a P.S. to my post here of Oct. 3 concerning preferred impedance taps.
As my new Tyler Acoustics speakers have continued to settle in and blossom, I thought I'd once again test the 8 ohm taps of my ST-120. Lo and behold, now they sound much better - more open sound with no hint of the out-of-control quality I had first experienced. Response at the extremes of low and high is improved. So I guess the message is - Don't stop experimenting. Things change over time, whether it's the equipment or simply the ears!

So I have tried the 4 and 8ohm taps with speakers still wired as 5,33ohm
and the 4ohm tap came up a clear winner. If we round it of to 6ohm there
is a 50% higher nominal speaker impedance than the tap used says.
There would be the same ratio if I would rewire the speakers to 12 ohm
and then use the 8ohm tap.

Question, would this load draw less current from the output tubes ?

Next question, is the 16ohm tap dedicated for feedback only or is it
possible to use that for speaker connection as well ?

Sorry but I belive that I was a bit unclear about what the two alternatives are .

Alt 1: Speakers wired as 6 ohm connected to the 4 ohm tap.

Alt 2: Speakers wired as 12 ohm connected to the 8 ohm tap.

And wish one of these would draw more or less current ? (if there is a difference).

Thanks for clearing up about the 16 ohm tap