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Sonic qualities of SET output tubes?

Can you readily identify a 300B, 2A3, 805, 211, etc., amp’s sound with your eyes closed most of the time?


If so, I’sure would like to hear from you.


Amplifier design and the technology utilized within its confines decides the ‘voice’ or influence it will yield as much or more so than merely the output tubes the designer has chosen to use.


I get that part emphatically. One must hear the amp regardless the type of output tube technology on hand.


And yes, some Pentodes and Tetrodes are used as Triodes but are not indeed triodes by their specific architecture. That’s OK, just focus on their use as Triodes herein, please.


There are however certain tube types, irrespective of vintage which have basic undeniable sonic colors or characteristics, apart from their electrical aspects which keep attracting people to amps which use this or that tube in its output stage.


Some love 211s. some adore 300Bs. Some love EL34s configured to run as Triodes. I have an affinity for the latter. So far anyway. This topic could change my mind.


Has your own experience informed you what this or that output tube’s natural flavor regularly announces itself to be so you can have a reasonable expectation of its general presentation?


What sonic attribute continually attracts you to a particular SET tube design, 300B or some others?


Or, conversely, what is it about the sound that would bring you to covet a 211 amp over a 2A3, for example.


Why as another example, would you pick a 2A3 amp over one using 805s or 300B, 211, etc. or vice versa?


Removing ‘vintages’ and electronic or electrical qualities from the argument, what sonic attributes for the more popular S.E.T. amp output tubes have you determined seem to persist in their particular DNA?


I’m asking for input from those SET tube devotees to lend their experiences and knowledge on the subject of what tube sounds like what irrespective of the SET application, generally speaking.


My goal is to try getting a better feel for which SET Tube amp design, if any, I’d want to pursue and possibly invest heavily into going forward as the soul of a new system.


Tremendous thanks to all!

blindjim
grannyring's avatar
grannyring
4,637 posts
 
This is such a great thread and I now better understand, technical reasons,  why I have been so frustrated in the past with some wonderful SET amps. The music was wonderful at lower volumes, and they did drive my speakers to go very " loud " I was initially impressed, only to find the sound not to my overall liking longer term.

It was this whole issue of sounding "loud" when a system should not sound loud when turned up. Rather, the performance should simply swell and grow with greater impact etc....

My mistake was not the particular SET amp, but pairing the amp with a 4-8 ohm speakers with sensitivities ranging from 89-93db.  My 8-20 watt SET amps, while playing these speakers loud, always fell a little short of greatness. Greatness at low, moderate, and higher volume levels.


kdude66
1,198 posts
 
atamasphere,

Very nice information,thank you.

I quess in the golden days of audio weren't most speakers 16 ohm to be more tube friendly in that respect.

Kenny
charles1dad's avatar
charles1dad
6,996 posts
 
The irony is that the vast majority of high End speakers are in the 4 ohm range. This  suggests that either, 
1 4 ohm load impedance speakers are easier to design/build.
2  An assumption that the majority of buyers plan to use solid state amplification. 
3  The designers/builders simply believe that the speakers sound better with the lower 4 ohm impedance. 

My SET and 2 push pull amplifiers all mate beautifully with my 14  ohm speakers. I do believe Ralph's assertion that higher speaker impedance is beneficial to all amplifier topologies.  It seems many speaker builders would disagree with him given the predominance of 4 ohm speakers in the marketplace. 
Charles 
wolf_garcia
4,650 posts
 
I've returned to using my Silverline Preludes (allegedly 91 db) as they sound astonishingly good with the Fire Bottle HO (the HO…it's a HO)…along with 2 REL subs. I understand completely about the obvious benefits of higher efficiency speakers with lower power amps, so I was surprised at how well the Preludes are working…absolute clarity at the levels I choose to listen, and I'm very picky about noise and distortion. You can simply turn the amp up to test the limits (at a certain point it just loses it's mind), and at my normal listening levels which are plenty loud at times, the little amp works splendidly with surprisingly clean dynamic punch . Note that I've been using the Preludes for years, and with this amp listening at low levels (late at night generally) is far more detailed and enjoyable than before the HO was installed. Dennis Had claims that pretty much any great speaker will work with this amp, the only limiting factor being ultimate level constraint due to efficiency. 
atmasphere's avatar
atmasphere
7,068 posts
 
I guess in the golden days of audio weren't most speakers 16 ohm to be more tube friendly in that respect.
Of course!

1 4 ohm load impedance speakers are easier to design/build.
2  An assumption that the majority of buyers plan to use solid state amplification.
3  The designers/builders simply believe that the speakers sound better with the lower 4 ohm impedance.

My SET and 2 push pull amplifiers all mate beautifully with my 14  ohm speakers. I do believe Ralph's assertion that higher speaker impedance is beneficial to all amplifier topologies.  It seems many speaker builders would disagree with him given the predominance of 4 ohm speakers in the marketplace.

The vast majority of amplifiers are solid state. These days most of them are safe with 4 ohms, and further many of them can double power into 4 ohms. In this regard, many speaker manufacturers are seeking to make (under a false impression) to make their speakers more compatible with solid state and thus secure a greater market. Its a good example of dollars being the goal rather than the ultimate in sound reproduction.

If they were to simply raise the speaker's impedance and keep all other things the same (which in many cases would be a bit of a trick) they would find that their speaker is sounding smoother and more transparent, regardless of the amp they use.

There really isn't any point in making a speaker that is 'difficult to drive' as the result will be more distortion, of a type that will cause the amp to be harsher and less detailed. You can see it in the specs.
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