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Why has single ended output become popular

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#241
"A good 5 W amplifier is a 50 W amplifier."

Here I'll have to agree with you completely. Or at least an amplifier that dissipates 50 Watts. It takes a wasteful design to get monotonicity.

But what's everybody's hardon for direct heating? If you can get the linearity with the advantages of a cathode, why are we fighting over a bridge we took almost a century ago?

YOS,
Chris
 
#246
The curves of directly heated valves show less "falling over" at high voltage/low current. I'm guessing this is due to less "edge effect" in the cathode-grid electrostatic field. Has anyone done simulations for the Laplace equation for the directly/indirectly heated cases?
 
#248
5W out of this amp! Direct heated with center tap secundairy (heater transformer). This one can drive 4Ohm speakers with ease and no seperate power supply (this box contains the entire stereo amp).
 

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#249
And there's not really any "asymmetry", certainly nothing interesting.
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That is a differential amplifier, the worst kind of balanced amplifier. Halving the current does not mean halving the symmetry. I`m surprised that he addressed the issue, the general assumption is that topological symmetry lowers distortion.
 
#251
50AE said:
I achieved 12W using an IT and EL802 driver tube. Didn't measure how much it entered in A2 though.
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There are some other tubes that are similar enough in therms of mu and are also high transconductance frame grid driver tubes.for people that want to replicate this: 6E5P E810F D3A E280F 6J9P/E180F E186F EF184 E55L and about a dozen more. The 6C19 or ED8000 12B4 makes a good low mu interstage driver

RFT made an oddball tube forseries regulator use EC230? Edit no ik conflating ECC230(6080) i think it was the EC360
 
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#254
I keep seeing these generalizations, execution is very important and it can easily swamp the technology.

My best 2 amps are a diy Class A triode EL84 PP built by my partner, and a SIT-3 SE amp built by Nelson. Very different topology, both very well executed, both put a smile on my face.

dave
 
#255
But I do agree that horns are not for everybody. The clarity afforded by narrow dispersion and the room largely removed from the playback can be quite illuminating on imprecise setup and other things not quite right in a system, but when it is right I've not heard any better for a dedicated listening room. Personally, I find 'stats and ribbons to be flat and relatively undynamic (is that a word?) compared to my horns. But ribbons eg. RAAL can be magnificent if not used too low, and by too low I mean any lower than the highest octave and a half, and when used high like that can match in well with a horn midrange in terms of both sound and high sensitivity.

In terms of layering, clarity and wonderful playback of complex and orchestral music I am of the strong opinion that once you get to a decent enough speaker/amp setup that the source does matter a lot. There are several 'normal' dacs here that cannot run with my high-end dac once the music gets complex and requires a lot of 'sorting out'. It is even noticeable on girl and guitar, but glaring on say Bruckners 8th in full swing. As for vinyl...well I think there are a lot of things to get right there, and they are rarely inexpensive.

To my ears, excellent orchestral playback requires more than one amplifier, plenty of authority from the speaker in the lower frequencies and subtlety in the mids and highs. The same amp doing all these things just does not make sense to me...it is always a compromise whether that be SS or hollow state, SE or differential.
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This is a down-to-earth description of reality.
 
#257
acg,

The relatively narrow dispersion of some horn systems reminds me of something similar.

Since I lost hearing in one of my ears, I perceive both live music and recorded music differently.
There are no directional cues like there are with 2 ears.

Now I do most of my listening near-field. That effectively removes many of the reflections of the sound (the larger ratio of near sound amplitude, versus reflections far sound amplitude does that).

Also, the power required from the amplifier is lower when the speakers are closer.
That makes the job easier for the amplifier.
In addition, the speakers are more linear at the lower power.

Near field listening is not the same as horn speakers in a big room, but there are some common effects, even though the causes are different.
 
#258
6A3sUMMER,

Sorry about your lost hearing in one ear.

I've always prefered nearfield listening, even with box speakers, and do it now with a large horn system in a relatively small room. Success here relies on the physical traits of the room and loudspeaker, and is certainly not a common solution, but it can be made to work with wonderful results.
 
#259
50AE said:
Through my 10 years of auditioning many SE and PP amplifiers (BOTH pure class A), I've always founds strengths and weaknesses in both. I like listening to every kind of music, from "a girl with a guitar" to "three overdriven guitars playing simultaneously with double kick drum". And these are my conclusions:

-I hate THD and resulting IMD, even if it's 2nd harmonic
-PP always sounds cleaner and controlled, handles complex music well, but lacks micro-resolution
-SE gives that micro resolution and overtone coherency. This is especially apparent on string instruments and vocals, where you need harmonic integrity. But SE tends to "give away" easily even at half power.
-Both can give excellent bass and highs.
-So far my current favourite topology is pentode SE with deep CFB and UL. It gives me SE intimacy of details with PP control with complex music.
-A great PP I've auditioned is the Thrax Enyo - A GU50 pentode, again using CFB + UL. It gave me the SE intimacy.

In a few words, SE gives excellent tonality and coherency, but its distortion is always a drawback. No, I don't believe distortion to be a benefit, at least for my ears.




This is true. Anyone who says the contrary, try plotting inductance of a DC magnetized SE transformer starting within micro AC flux densities.
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An old audio guru once said to me, you have to have at least 2 different amps to listen to different generes of music.
 
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