Tannoy Westminster amp matching question.

Borg,
Phaelon makes a good point. If the MK II version is that much improved(transformer quality is crucial for great SET sound) I`d exercise some patience and get the better Solista amp. Your speakers deserve the best quality amp you can afford.My SET has double C-Core transformers custom built in japan.I believe that plays a 'major' role in the superb sound they make.I`d not compromise transformer or power supply quality in an SET amplifier.
Regards,

Borg7x9, unless you are in a small room listen to what Bvdiman is saying, or you could be making an expensive mistake.

SETs have certain properties. One is that they essentially make no distortion at low power levels. This is unusual- most amps have **increasing** distortion below a certain power level. This is why they have that 'inner detail' that is part of the description of any SET.

The 2nd thing about SETs is the lushness. This comes at slightly higher power levels and has everything to do with the 2nd harmonic distortion that appears at moderate levels. As we can see, the human ears does not mind too much about this distortion.

The final aspect of all SETs is what happens above about 1/4 to 1/3 power. The higher ordered distortion components begin to appear. If the speaker has enough efficiency, this will only occur on louder transients. However, on these transients are also the higher ordered harmonics, which, it happens, that the ear uses to determine how loud a sound is.

The result here is that the SET appears to have far more 'dynamics' because of these loudness cues than it should for such a small amp. You will hear people talking about this all the time.

However, as you can see this is all based on how the amp distorts. The problem you are up against is that you actually need some power. The speaker you have has got bandwidth, and that is something that higher power SETs don't have. To be really successful with an SET you need a horn-loaded speaker with about 103 db at a minimum! That way you have a moderately-powered amp (12 watts, no more) that might still have some bandwidth. Its a trick!

However, SETs are not the only amps that have distortion going to unmeasurable as power is decreased. There is at least one OTL that does that as well. I think there are a few push-pull triode amps as well. The trick here is how the driver circuit is designed. This is a feature you want, because its that first watt that gets you that 'inner detail'. The issue is you need power and bandwidth too (if you really want to hear what the speaker can really do).

I agree with Charles1dad:

Your speakers deserve the best quality amp you can afford.

There are very few SETs that will fill the bill- you can count them on one hand. OTOH there are a number of push-pull amps (including at least one OTL) that will suit that will give the the inner detail, power and bandwidth. BTW all of the ones I am thinking of are zero feedback.

Everyone has an opinion about what amplifier type is better than others.You could find many sucessful and talented builders of SET amplifiers who would disagree with atamaphere`s viewpoint and in fact make a very compelling case opposite of his.Borg,you`ve used SET amps and obviously came to your own conclusions based on actual listening experiences.SET amps have flaws and so do OTL, push-pull tube and any other amp topology you can mention.

I believe a variety of amps could work well with the Tannoys,Borg you like SET amps for one very good reason,they sound fantastic and really involved you with your music.I`ve heard OTL amps,they were good, but I find SET more realistic and natural to my ears. Others will hear things differently and that`s to be expected.

Borg, I hope you can hear the Atmasphere OTL amp and a good PP tube amp and compare to a good SET amp. I don`t believe the Viva Solista is a potential mistake at all. Listening will settle this as it always does.
Charles,

I've heard the Solista in a number of systems, including with Avantgarde Duos and a custom horn system (105 db/w efficient), and thought that it sounds pretty good. The Solista is not that far off from the sound of a 45 tube amp, so it should be to your liking. If you can get that anywhere near the price range you specified, that would be quite a miracle, given how expensive these amps are.

Keep in mind that the replacement tubes for that amp will not be cheap. In addition to the 845 output tube, that amp uses 211s or 845s as rectifiers. In that application, the tube might last a long time, but, if that is not the case, the cost of replacing the rectifiers would be pretty high.

I also agree that you should, if possible, hear a good OTL amp. The immediacy and "jump" factor with an OTL is pretty exciting and hard to duplicate with other types of amps. One can get similar results with the low powered SET amps (e.g., a 2a3 amp), but, usually that involves very efficient speakers and quite expensive amps.

Charles1dad, I think you might misunderstand me on something. Although what I said about distortion in the SET is perfectly true and should not be a matter of debate, it is incorrect to assume that I don't appreciate what a good SET can do.

However I am of the opinion that people try to get away with using SETs on speakers that are not efficient enough! The result of this is that they never find out what the amp was capable of nor what the speaker could do. If you have a speaker that has the right efficiency, SETs offer some of the more transparent and musical setups around. **But the speaker must have the efficiency.**

This is why horns have become more popular in the last 20 years. The Tannoy of the OP, IMO, does not have the efficiency to allow most SETs to strut their stuff. IMO/IME The JOTA (not sure if that one is made anymore; might be available through the UK designer) and the VIVA are good choices of higher power SETs. But in general the idea of a 'high power SET' is nearly oxymoronic although there are a few out there. None of them IMO have the 'magic' of a 45 or 2A3, which require 6-10 db more efficiency than the Tannoy has.

'high power' SETs are expensive! That is why I have been recommending something that offers as much of the 'magic' of an SET, but will also have enough power to do the job.