SET the best?

All I was trying to say is that the 845 hasa good reputation for delivering the goods.

My tech points in the 845 direction for what he feels will give me best bang.

He also likes most other SET tubes.

Liking a tube is very different from how it can be made to perform 😁

The simple fact is the more power the SET has, the more limited its bandwidth. This is because the higher the power the output transformers designed for SETs are, the more limited their bandwidth. Its inescapable (except in marketing literature).

The more limited the bandwidth, the more phase shift is introduced (unless you have a mess of feedback to control it; not possible with a tube amp). Phase shift messes with the soundstage; not saying you won't have one, but it will be more palpable if the phase shift isn't there.

That is why the 300b was King 30 years ago, why the 2A3 supplanted it 20 years ago and why the type 45 is reigning now. So we went from 7  watts to 4 and from 4 to 0.75Watts. Compared to these tubes in terms of the sound quality you get, the 845 is fun but not in the running.

I'm with Atmasphere on the choice of tube.  I prefer the lower-powered tubes for SET amps, and I like the tubes in the order he presented--from 300b to 45 (the 45 sounds great if you can get by with a very low amount of power.  My own SET runs parallel 2a3 tubes; I wish it was set up to run 45s instead (some others I know who own the same model of amp run 45s in place of the 2a3, but, the tubes don't last very long).  

My Dennis Had SEP (pentode) is plenty loud and clear into my alleged 99db rated Heresy III speakers, enhanced by a couple of RELs. I simply don’t care much about opinions of others regarding things they haven’t heard (i.e. my system), although some here have garnered my respect generally...I’ve owned a couple of these Had Firebottle HOs ("high output" or "prostitute" depending of who you believe) and the one I kept sounded best and is a bit louder than the rejected one (a newer version, but still...outta here!). Suffice to say that after many decades of enjoying various well designed SS amps, the single ended tubester stays right where it sits. That said, I might try a Pass XA 25 someday since I can.

I was a die hard SET guy for decades.

And 45s are the best. The lower the power, the more the magic.

However, I now have my destination amps-AGD Audion mono blocks.

I do not miss SETs at all. The AGDs are like a great SET combined with a great SS. They give an “open window” into the sound and make even the best SET dull.

mglik614 posts 12-01-2021 5:32pm I was a die hard SET guy for decades. And 45s are the best. The lower the power, the more the magic. However, I now have my destination amps-AGD Audion mono blocks. I do not miss SETs at all. The AGDs are like a great SET combined with a great SS. They give an “open window” into the sound and make even the best SET dull. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Well its now beena few more days of listening to various recordings,,, now moved into big symphonic works,,, hummm, , well initially I was captivated completely by the magic of the UX250 SET amplifier ina dual Full-Midrange-Speaker system... Got to rethink this before I click BUY NOW on the 845 amplifer I am looking at. 1st i need to get some new KT88's in the Defy. Its possible I may be missing some of the dynamics and power of the Defy in symphonic works. Just waiting on my tech to get back with me, before I make any final decisions. Although it would not be til July when I had the cash for the 845,,I just like to know if the plan is scraped or still on the planning table... **lower the power , more the magic.** 'No you see I need MORE power to deliver symphonic works with dynamnics and more weight in bass, better extrention in highs. Got to think this through and proceed with caution. Actually I have no issues with the Defy, other than, with the excessive power, limits the abibilty to empoy more gain on the linestage vol pot. My room is 10x15,,, 60 db SPL is where I am confortable. This is the issue, I want more freedom on the vol pot, which the UX250 allows, But the more gain, does not deliver more dynamics. Seems a SET and PP amplifier operates under dif parimeters of power/gain from linestage. New tubes janurary, I will let you know how the speaker respond with new tubes on my new dual Full-Midrange-speaker system. The older tubes had 4k+ hours So some of the upper sheen had worn off. If the new tubes add some sparkles, I may pass on adding a 2nd amplifier.