Ralph, Thank you for this great post. I enjoy your posts as they are always so informative.
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!
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!
Showing 21 responses by grannyring
Whart is spot on. The sensitivity of the speaker is vitally important and that must be known before picking or considering any amp. For example, a speaker with 89db sensitivity at 8 ohms will require far more power than a speaker with 98db sensitivity at 8 ohms. The first speaker will need at least some 50 watts, while the second will work with perhaps 3-8 watts. As the sensitivity goes down the need for more power goes up significantly. I know you are aware of this due to your seniority and experience here. Knowing how loud you play your music and the type of music played are also important considerations. Can a 30 watt tube drive a 89db sensitive speaker to 75 -78 db comfortably in a modest sized room? Yes most likely. But if you want db levels approaching 90db on average on some listening sessions with orchestral scores, then absolutely not. I have read some great stuff that Ralph at Atma-sphere puts out on the watts and db relationship with tube amps and speaker sensitivity. Perhaps he can repost that here. |
+1 Atmasphere. Great post. I know first hand that distortion always sounds louder and at first can even sound impressive when too few tube watts are trying to drive the wrong speaker too loudly. Well said and very important learning for us all. Helps us pick the right amp/speaker combo based on one's goals and listening habits with a system. |
@blindjim The trying not exceed 20% of an amp's power was specifically mentioned by Ralph for SET tube amps due to their nature in how they distort. As I understand his point, I went back to read it carefully, one must be particularly careful with speaker matching with this type of amp by avoiding higher order harmonics. His statement does not include SS, Class D, OTL and other type amps. Ralph, could you please confirm. |
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. |
@swampwalker, +1 big time! I have been talking to Ralph at Atma recently as I do want a second amp and want for it to be tubes. SET amps will not work with my current speakers. 6 ohm, 89db sensitivity in a very large room. In order for a SET amp to work for me, it would need to put out 100 watts. Some amazing SET amp! An OTL or PP tube amp could do the job at 60 watts. Especially OTL with the Zero autoformers by Paul Speltz. @swampwalker I remember the amp! I purchased a set of 300b monos from you also! I think we have sold each other gear several times over the years. |
Well great question. Since the OTL amp does not carry the 20% of rated power caution that Ralph has been talking about, and I have experienced, then the Crescendos can use all the watts available in the M60. Better said, most of the power available. Also, adding the Zero autoformers actually increases the power output of the M60s by some 50%. So the speakers would be utalizing, in effect, 90 watts. Yes indeed this would work great. Just have to decide if I want that many output tubes. I suppose it would be better to get a 12-16 ohm, 95db or better sensitive set of speakers😬 However, I did love the sound of Ralph’s amps. Uncanny resolution and sense of being right there in the midst of the performance. |
Good points @stfoth, We have to remember 50 watts with an 805 tube etc, is still a SET amp and the 20% rule comes into play. Speaker matching is still critical. Will it work with a 4-8 ohm, 90db effecient speaker? It depends. Big room, like to listen at 85-90db levels at times, sit 10-12 feet back, then it won’t. Small to moderate sized room, 70-80db listening, 8-10 feet back from the speakers, then it may work wonderfully indeed. Once the room gets bigger and you want to turn it up more often, then you enter a real risky area. Sometimes your happy, sometimes not with that system. Can be a frustrating place to be. |
I had his Firebottle amp with the KT150 tubes. Tried to drive 92db sentitive speakers in a large space and the combo did not work. I like the build quality and Dennis very much. I was actually selling the amp for a friend and put it into my rig. Wish I could of heard it on speakers better suited for it. |
@charles1dad Here is a picture of the one box solution I referred to especially conceived for you. In fact it was inspired by your system and posts. I see you as the DHT evangelist. Yes, this is a compliment of the highest order Charles. Introducing the 1DaDDHT music making tour de force! Ok, I am not talented enough to make this hybrid digital, Class D, DHT, DSD dac, room correction one box unit that I dream of for you and others. Here is what it could look like if Lyngdorf made it. http://s1097.photobucket.com/user/grannyring1/media/1DadDHT%20mod/DHT%20Mod_zpspmsxhs4w.jpg.html?sor... |
@blindjim Did you buy that set of Thor TPA30s on Audio Mart? If so, killer deal and good for you. I owned this amp twice. I have done numerous upgrades to them and they represent some of the best PP tube sound one could ever purchase. Wonderful el34 design getting the best out of this tube. I wanted so badly to buy them again and upgrade the film caps, but not enough power for me. Replace those Hovland caps with good copper foil PIO caps from the likes of Jupiter, Duelund, and Audio Note. Very nice improvement for sure. |
Thor TPA 30s. Great, great amps. First Watt M2 smooth and warm. Neither had enough omph when at times. Then an I got some TRL Samson monoblock amps and things just opened up with no more sense of tentative or nervous sound. These were 200 watt SS monoblock amps that are spectacular. Little known gems. Think I recall this rightly, but it has been some time now. |