16 ohms speakers- 8 ohms output amp

Check out the new Bottlehead Paramount kits (4/8/16 ohm taps) available in both 2A3/300B format.

Less expensive would be the Paramour (2A3) kits with the "iron upgrade". The upgrade iron may be be available (again) in a month, or two.

Imagine many manufacturers/models offer 8-16 ohm versatility.

As far as running 16 ohm drivers off 8 ohm taps I've found the sound to be cleaner (lighter/tighter LF's which highlight the HF's) when compared to the 16 ohm taps on one of my tube amps.

Can't say either way is right as my choice depends upon the specific driver/cabinet being used.

I've gone through more than a dozen different vintage single and coaxial drivers in the past three years.

Cabinet/baffle material & construction will probably alter the sound @ least as much as impedance matching (between 8 & 16 ohms).

Want fuller/looser bass then use less rigid baffle material (just an example).

PS:

Fertin specs the EX20 as an 8 ohm driver, so I assume yours are of special order/production.

Not familiar with field coil drivers, so don't know if you measure the static impedance in the same manner as that of later magnet design cone drivers.

I start by measuring drivers (with a multi-meter) to gauge what I'm starting with.

I've owned 16 ohm "marked" Tru-sonic 80FR's, which measured in the 3-13 ohm range.

Only a few pairs of the vintage drivers I've tried measured within 20% of spec.

My current matched pair of 80FR's come in @ just above 7 ohms and the previous pair @ approx. 13 ohms.

Try searching Fertin @ audioasylum.com as there are a couple of owners/previous owners mentioned.

You may be able to contact them through the Email system.

If you have a scroll and/or keyhole saw and a drill (to cut the holes) you could first experiment with DIY plywood open baffles.

If you have more sophisticated tools, and know how to use them, then all the better.

It's important to use flat wood and to systematically tighten the drivers to the baffles (like an auto's oil pan/valve cover) as to not bend the driver frames, but other than this it's fairly simple.

I've made experimental OB's from scrap ply, a drill/scroll saw and a wood rasp (to bevel the edges of the holes) and I'm officially lame.

Inexpensive DIY OB's approx. 3' x 4' (and larger if possible) will allow you to judge whether added woofers/subs/HF drivers will be needed.

Securely coupling the drivers to a stiff/thick baffle generally offers a cleaner sound/more pronounced HF's.

The distance from the floor to the driver will also affect the bass/mid-bass.

I have not heard much of a difference between centering/offsetting the drivers, but placing them off center seems to be the preferred method of many.

The above variables are why I suggest cheap/DIY in the beginning.

Suggest experimenting with the drivers and various OB/cabinet configurations (with amplification available) before investing in a "long term" amplifier.

May be that you prefer something different than the Fertin's.

I've used gobs of SS & tube amps with many single driver speakers and the amplification choice, though important, is not of a first order priority.

If you like the sound of the speakers, then go from there.