Fostex back loaded horn, need advices...

Greetings to all music lovers out there.

I appreciate very much if more experienced people can solve some doubts of mine about the loudspeakers that i'm planning to build.

It's a back loaded horn with a 8" Fostex full range driver and super horn tweeter, I will build their recommended enclosure.

Enclosure:
https://www.fostexinternational.com/docs/speaker_components/pdf/recom_enclose/208ez_enclrev.pdf

Full Range Driver:
https://www.fostexinternational.com/docs/speaker_components/pdf/fe208ez.pdf

Super Horn Tweeter:
https://www.fostexinternational.com/docs/speaker_components/pdf/t900a.pdf

I decided to use tube amplification, it will be my first tube amplifier too.

Some people tells me that is vital, an tube amplifier with high output impedance, also knows as low damping factor, so that's why SET amps are a classic match for this kind of speakers? mostly because of their high output impedance?

Meanwhile some amplifiers dealers are telling me that this is not a important factor when considering this particular loudspeakers...

Appreciate all the thoughts and elaborations about this subject.

Also, appreciate very much any other relevant infos about tube amplification with a back loaded horn similar to this design, thoughts from owners of this particular design are also very welcome.

Many thanks, best regards to all!

 

Here's a possibility, via an tube amplifier builder, that I'm discussing the possibilities of build the amp with appropriated output impedance for my loudspeakers.

I explained to him that is important the amp to have a high output impedance, showed to him the driver's specs and etc...

Here's one option the he provided me:

OTOMON Laboratory　(音門ラボ) / Special order made 2A3PP amplifier with all HIrata TANGO transformer * Excellent !!!

His my question to him and his reply:

Me:
Let me ask you about an important spec for me, it's possible for you to provide the output impedance (damping factor) about the amps?

Amp Builder:
It is not fixed number but it is about 6-8 due to tube and schematic you use. Generally, damping factor should be higher than 5 with SE amplifier.

What you guys think about this values for my speakers?

Many thanks!