Tenor OTL 75wi vs 175s

I just bought a pair of Tenor OTL 75wi. I use it with a Lamm preamp. I do not know how exactly put it in words, this is the finest amplifier I have ever heard and that too by miles. It is unbelievably realistic sounding. The only little issue is, my Tannoy Turnberry SE seems to make this amp run out of gas for some kinds of music and at certain SPLs (not head banging SPLs). I cannot imagine letting go this amp. But I was wondering if it was worth saving up for the Tenor 175s which would give me all the headroom I would ever need but then the output stage is solid state and I do not know whether it can match up to the magic of all tube OTL 75. Has anyone heard the 175s and OTL 75 to give me an idea about how they compare ?

Changing the speaker is another option but I have kept it to the last because I absolutely love the Tannoys.
Some obvious speaker recommendations are the Classic Audio Loudspeakers, also Audiokinesis. We've used both at shows with our OTLs of similar power to excellent effect!

Any speaker that is at least 8 ohms in the bass region (without dips below 6 ohms) and otherwise at least 93 db 1 watt/1 meter should do the job.

However looking at the specs of the speaker, it sounds to me like the amplifier has a malfunction- weak tubes, bad sockets, something like that. The speaker looks like it would be no problem for an OTL.
Hi Atmasphere,
Thanks for the suggestion. By weak tubes, are you indicating at the driver tubes or the output tubes ?

Secondly, do you have any recommendation on what kind of speaker cables should be used between a typical speaker and an OTL for a good match ? I currently use a 3 meter biwiring set of Auditorium23 speaker cables. Do you think shortening the speaker cable to less than 2 meters can actually improve the amp's response ?
I also owned a pair of Tenor 75WI around the same time that Mike owned his. I actually spoke with him prior to buying mine. They were "magical" but didn't really work well with my speakers either. Mine ran out of gas just as yours do. I was concerned that they really limited the speakers that paired well with them but boy, when they were playing the right type of music in the ranges they excelled in, they were really something and they were damn pretty to look at with all those tubes glowing. I moved on to a Boulder 1060 and ultimately paired that with an Aesthetix Janus which suits my needs better. I do miss those Tenors, but like Mike, mine had some problems that were repaired under warranty. I didn't want to have to deal with long-term reliability issues and the replacement tube sets would have also been expensive.
My Tannoys are not exactly a bad match. For at least 75% of the music I listen, I do not have the trouble in getting the desired SPLs. Only with stuff like Michael Jackson where you really would like to crank it up and swing, you kind feel shortchanged for the SPLs. These well recorded pop numbers have great punch and dynamics with lots of instruments playing simultaneously at various SPLs, so to resolve all that at high DBs is not always easy. Good SS amps can do it well (like my FM Acoustics F10 does), high powered push-pull tube amps also do it well (may be not nearly as good as SS) but SET and OTLs would only do it with the best matched speakers. I am thinking of getting an Avant Garde when I have a bigger room to play music. My heart though skips a beat whenever I see/hear a nicely driven pair of Tannoy Canterburry.
Pani, based on your post above I think the problem is you just don't have enough power.

So you might want to consider a more efficient loudspeaker or a more powerful amplifier. The problem is that you have heard what OTLs do and you are not going to be satisfied by a solid state amp, which might have plenty of power but really just won't have the finesse.

There are larger OTLs available.

plan B: get a set of speakers that are more efficient. I use the Classic Audio Loudspeakers mode T-3.4, which are about 98 db and 16 ohms (both the efficiency and the impedance are a boon!). With our M-60 OTLs I have to put on earplugs to actually be able to clip the amps as they can make 110db at the listening chair. My room is 17' x 21' 21'. I play all sorts of stuff including electronic music with plenty of thump- my speakers go down to 20Hz and I can literally shake my house with them. They are very satisfying, very detailed and very smooth, image beautifully and I've no complaints.

The only thing is they are not cheap. I think if you do the math and you are happy with your speakers that a more powerful OTL will be less expensive and will very likely sound even better.