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

Showing 7 responses by wolf_garcia

Blindjim…there’s an interesting Youtube video of Had talking about his amps with a little tour of his shop, and a several hundred page discussion of his "post Cary Audio" builds on Audioaficianado.org. He sells his stuff exclusively on Ebay (or you can order things directly from him by contacting him through his Ebay address, although he’s pretty busy so good luck with that..) although he does build headphone amps sold through Moon Audio (recently positively reviewed by Absolute Sound). You also can look up his sales history on Ebay to see what he’s sold recently. Otherwise he’s a small potato in the current audio geek component manufacturing  scene (I assume, having no idea how many amps for example Atmosphere sells) , but I personally think his amps are an utter bargain in the world of hand made sonic excellence…Shindo Schmindo!
My HO (Dennis Had "Inspire" Fire Bottle SEP HO, or High Output) has seen various tubes in the recent few months as it uses only 4 of them (great for rolling), and my most recent new issue Tung Sol 6SN7GTB rates only a "meh" although it does look cool. Back in went the supplied Amperex 6SN7GTB which imparts clarity in the treble which the Tung Sol doesn’t so much. It’s also interesting how much influence the rectifier tubes have on the HO…my current fave being a Shuguang 274B, and although it sounds very similar to a new Gold Lion GZ34/U77 (!), the 274B just looks cooler so it earns its place due to esthetics in the HO (also Gold Lion KT88s won out over KT77s and whatever else I had around here to try). Differences…YUGE.
I tried dumping the output transformers and the amp exploded and nearly destroyed my double wide. Lesson learned.
Stfoth…Mine came with the Gold Lion KT88s, an Amperex USA 6SN7GTB from some NOS vintage, and a JJ 5Y3S rectifier. I've since bought another Amperex that sounds identical to the supplied one (different getters, but labeled a USA tube), a new issue Gold Lion GZ34/U77 rectifier which works great with the 88s, and the 274B which sounds like the GZ34 but looks cooler. I also have a set of JJ KT77s but they lack the resolution and sparkle of the 88s in this amp. Note that none of these tubes are particularly expensive (the Shuguang 274B was 18 bucks shipped from China), and you need less of 'em for this amp anyway.
I have no idea how many watts my HO generates, although as a recent one it’s maybe 17 watts (it’s not a "Hot Rod", although those claim about the same wattage as mine), but at least 12…I currently prefer it with KT88s and  a Shuguang 274b rectifier (I mean really…a cool looking tube), and these amps come with zero published specs other than what can be gleaned from forum conversations and Had’s comments (and a published log book page  of Hads with various parameters noted in pencil…great stuff…), a somewhat unique thing with no warranty or anything other than good faith from Dennis. Also it wasn’t expensive…relatively...
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. 
A couple of months ago I bought a Dennis Had Inspire SE "Fire Bottle" HO (high output) pentode based amp of recent vintage, and have been rolling various tubes through it…note that this sort of amp has only 4 tubes so rolling is el-cheapo. So far I've noticed differences between rectifiers…234B, GZ34, and a 5Y3S…interesting…more bass, less bass, soundstage changes, etc., and output tubes including KT88, KT77, KT150, 6550, and parts of an old toaster (not really, but uh…). The amp came with a NOS Amperex 6SN7GTB, and I tried another of the same type of Amperex of a different design (getters on the side or top or something) and those sounded identical. Everything seems to change a little or more than a little, and all of it is fun. Note this amp has lots of dynamic juice in its massive 12 watts per side, sounds better than any amp I've owned in over 5 decades of gear silliness, and proves once again that "everything I know is wrong."