SET the best?

tubes are all sounding the same- they have similar linearity. But the output transformers vary dramatically!

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I’m  SO

glad you posted this Which confirms my exp in PP amplifaction with various tubes. EL34 KT88 KT120. I mean they might be dif in sound, but not by any significant margin,, l

ets just say a miniscule nuance..and this applies also to KT150 KT170 Nuance,, but with the wrong speake, all squashed to zero nunaces. I figured all SET tubes are only going to be variations on a SET theme. = nuance dif. Nada mas.

My frends pure cobalt trans, adds something special. But again, out of production and very expensive,, = not doable/practical.

Back to reality.

Z6/Z11. Not bad. So where does this lead us, if we can’t get the real deal Cobalt Dream Trans??? Speakers. Here’s where we can pick up ,,or lets say,, here is where we can elevate the SET amplifiaction to its magical pure linear Powers. Which is why I hammer non stop about the super high value of a FR (= Full MidRange Speaker) assist system. Why assist? WEll as we all know well, SETs tend to roll off both ends the spectrum,, No big deal.. **whaaaaaa???* you demand to know. WEll yes, No big deal. I am not going to explain why its no big deal as I have already explined no less than a dozen X’s around here,,and I want to get back to my music in the other room. btw I may pass on the Beta.s had you said, a pair of Beta 8 in good condition,,yeah I’d take you up, Those go for $2k a pair in excellent condition.. But I kknow the DLVX8 match if not pass up the Coral Beta 8.

To say 845 sounds similar to 300b or any other SET is nonsense. 845 plate voltage nearly 1000V vs 350v with 300B means everything. Power supply 845 massive, 300b baby in comparison. Certainly, transformers extremely important, but these two tubes and amps very different animals. Both 845 amps I've been running for many years sound similar and unlike my 300B or 2a3 I ran some years ago. 845 tube has unique requirements, results is unique sound qualities.

ahh yes, the magisterial  845 tube, has held me facinated for decades, 

Now afforadble, with the newer chinese designs,  still its the weight factor, as you mention. Getting up in age limits mobility.

+ one must consider heat factor, which if I did remain here in New Orleans, in a  small room, get the idea....heater in 100++ degree heat???

= Your *special requirements*

Hi @mozartfan ,

845 tube needs ~10KOhm output transformer that has more narrow bandwidth compared to 3.5K transformer for 300B, 5K transformer for 45 or 2.5K transformer for 2A3 tube. 

So, if you have high sensitive speakers in a small room I don't see any reason for 845 amplifier. Not just because price.

845 not for you, heat, weight, and reliability factors in as well. Heat is enemy of reliability, these things run hot, hot, hot, they have no soft start circuit so wear out tubes more quickly. I wouldn't trust just anyone with nearly 1000v running through these things, not sure I'd trust these rather unknown Chinese 845. Line Magnetic is one of better ones, although I've seen propensity to burn out certain boutique power tubes, which tells me they run them hard.

This is issue I see today with SET in general, some of these guys run higher plate voltage then output tubes can handle, too many instances of premature tube failure. People too often blaming tube manufacturers. Prior to purchasing any SET, I'd research this aspect of that particular amp, know what your in for.