Is a small SET amp too powerful (for anyone)?

[NOSValves]

Seriously, why invest in crazy or even stupid amplifier ideas when the room you're listening in is complete crap.

You're about the last guy on Earth I'd consider taking an audio advice from but in this particular case, I'd tend to agree with you.

Man Jeff I sure hope I'm a few steps higher on the list. LMAO !!!!!!!!!!

[Marvel]

Why

in the world would anyone brag about a battery for the power supply?

[+o(] Talk about one of the worst voltage sources out there - is there

even sufficient filtering in that small chip? Hey, at least it has the

option of a wooden volume knob!

Let's see... a battery has no ripple, so filtering is for... what? Depending on the load, the dc voltage source would be very stable. I suppose you can point to something the shows why they are "one of the worst voltage sources out there."

[Erik Mandaville]

"The flip side is the SET distortion is much more euphoric, easier to tolerate,"

You might be thinking of the word - euphonic - which is how distortion charactistics of these low-power amps are often described. Pleasing rather than abrasive to the ear.

edit: I'll leave the Stereophile quote out. It had to do with euphonic distortion.

[pauln]

Using the generic term distortion is highly misleading and may lead to misunderstanding. Here are some different types - I'll make names (some of which may be correct) until someone straightens it out. If I am mistaken in my definitions, PLEASE indicate what I left out and got wrong, we are here to learn, and occasionally feud, right?

CLIPPING - that is when the curvy extremes of the wave form begin to be limited so that they appear to flatten like little mesas (and upside down mesas). This happens when the available power of the amp is maxed out but the wave form keeps trying to be bigger. The extreme case is the approach to square waves. What is important here is that the composite frequencies that comprise a square wave have additional higher frequency components compared to the more sine like wave signals. The higher frequencies don't appear and cause the flattening - its the other way around. Clipping sounds bad.

HARMONIC DISTORTION - clipping is an advanced form of this, but it may be caused in other ways. Typically, the nature of the amp topology/circuitry determines how and what harmonics are progressively added to the signal as more power is demanded. Again, in these cases it is not the additional frequencies that cause the modification to the wave, but the other way around. For example, the emergence of the second harmonic in a triode a la SET is a rusult of the minor imbalance in size between the upper and lower parts of the wave. This shape of wave may be decomposed to represent the presence of an additional frequency component an octave above the original signal, but again - it is not the case that the tube sings an addiitional tone that shapes the wave - the wave shape just is, but can be deconstructed into frequencies as if there was another tone emerging.

AMPLITUDE DISTORTION - a non-linearity in the amp responce, usually a compression of the signal on peaks, but not clipping.

FREQUENCY DISTORTION - this is a deviation from 'flat response' as in an amp that can't play real low or real high frequencies as well as the middle. In some tube amps (and SETs) this can be caused by the operation of the output transformer.

FREQUENCY DISTORTION type II - this is the true generation of additional tones by the amp (but not feedback from instability). Called the Tones of Tartinni after the work of said fellow many years back, its like this - when two different frequencies are simultaneous, there are two additional tones that comprise the addition and the difference of these frequencies. For example. if you have 1000Hz and 1200Hz at the same time, you also have 2200Hz and 200Hz as well, although these are much lower in level. As the number of tones is increased the permutations and combinations increase rapidly. An amp which is prone to this will sound 'off' and lousey. These additional tones are somewhat like the upper and lower side bands of signal theory. Oh, and a single note that starts and stops repeatedly also has sidebands based on how fast the notes are played.

INTERMODULATION - I think this may be limited to mechanical systems (styli and speakers) in which two frequencies are superimposed in the same element so that the higher frequency is alternately raised and lowered (a la Doppler shift) by the lower frequency. This is minimised by low excursion (Klipsch) and emphasised by high excursion. This sounds pretty bad lending a strident ugly character to the sound. Imagine a bass playing low and an oboe playing high through the same speaker cone... the bass will wiggle the paper back and forth - the very same paper on which the oboe notes are playing... some don't beleive in this kind of distortion because they claim that the Doppler effect in the cone is opposite and equal to the Doppler effect within the microphone element that caught both the original sounds at the recording time. That could be true, but how much music these days is captured that way... most I think is superimposed in the studio as separate signals, so I guess it depends.

NEGATIVE FEEDBACK - well, for we SET folks this is considered something to avoid, but generally in the amp world it is used to varying good effect in some designs. The way it works is that a sample of the output signal is compared to the input signal using a circuit device called a comparator. The comparitor subtracts the output from the input so that any difference between the two (distortion) is provided as an 'error signal'. A small amount of this error signal is inserted back into the input signal as a reverse signal in order to provide a degree of correction. This correction for an unvarying constant signal can be extremely effective in correcting any variances that occur to the input signal on its way to becoming the output signal. The sort of philisophical issue with SET folks and some others is that the feedback loop is not instantaneous but slightly delayed in its effect, which diminishes its operation with changing dynamic music signals, and might even mis-correct because of this delay. Also, the NFB can respond to the back signal from the speakers, and this signal having been through the networks may evoke NFB correction attempts to supposed error signals that have no real correspondence with the actual sound.

CROSSOVER DISTORTION - this is the mis-alighnment of the wave form as it passes from positive to negative in amps that use separate elements to drive the upper and lower parts of the wave. In these amps, the signal is sort of passed back and forth between the elements and both parts get combined to drive the speakers, or in push pull tube, combined in the output transformer windings. Since the slight mis-alignment is fairly constant it makes up a lesser and lesser portion of the signal as the wave gets bigger and bigger - this is why some amps don't sound so good at real low levels but seem to clean up as you turn up the volume. Since the musical wave form being passed back and forth crosses the zero level somewhat arbitrarily with complex music signals, the crossover distortion has no harmonic relation to the sound and tends to sound like low level noise. (White noise/static)

TUBE / SS DISTORTION - lots has been done on the different distortions of these elements. The triodes tend to have second harmonic distortion which is difficult to hear because it is highly frequency compatible with the original signal. Tetrodes and pentodes have higher harmonic distortions, but these tend to be even harmonics which are somewhat frequency conpatible. The SS elements tend to have the odd distortion harmonics which tend to not be frequency compatible with the original signal. This makes them much easier to detect, especially the higher odd orders which lend an edgey sound because they are not harmonically related to the origianl frequencies. This is why a SET can play at a measured couple of percent distortion (predominately the second) and it sounds clean and clear, while a fraction of a percent in some SS is hard on the ears. The other thing is how quickly the harmonic distortions come into play... Triodes do this very gracefully by first producing the second, then addition higher evens in ascending order. SS tend to bring up the higher harmonics (odd ones) more suddenly, and Op Amps engage them almost all at the same time when pressed to their limit. This is why headroom requirements for SS for good sound tend to need to be pretty robust, whereas tubes, and SETs in particular can get away with much less calculated headroom but still sound loud with lots of appearent reseve capacity. This is part of the effect that makes some claim that tube watts are louder than SS watts - the tubes can be driven past their spec without losing their good sound. The SS can produce the higher odd harmonics which serve as loudness detectors at comparable levels (that is the detection or perception of a signal as loud occurs faster/earlier for the SS compared to the tubes).

[Painful Reality]

That was some cool distortion.

[coda]

What I have learned -

1. The most important thing in life is priorities.

2. No wait a minute. The second most important thing is priorities..

3. The grass is always greener where there aren't any elephants.

4. The accomplished wisdom of a lifetime can be found in a bucket of chicken made from a secret recipe of 11 herbs and spices.

[Painful Reality]

"The flip side is the SET distortion is much more euphoric, easier to tolerate,"

You might be thinking of the word - euphonic - which is how distortion charactistics of these low-power amps are often described. Pleasing rather than abrasive to the ear.

edit: I'll leave the Stereophile quote out. It had to do with euphonic distortion.

Euphoric is finger licking good if you ask me.

[Erik Mandaville]

"Euphoric is cooler if you ask me."

Okay, is euphoric cooler?

You have obviously found a worthwhile replacement for your formerly stupid audio hobby. Enjoy!

[DrWho]

Why
in the world would anyone brag about a battery for the power supply?
[+o(] Talk about one of the worst voltage sources out there - is there
even sufficient filtering in that small chip? Hey, at least it has the
option of a wooden volume knob!

Let's see... a battery has no ripple, so filtering is for... what? Depending on the load, the dc voltage source would be very stable. I suppose you can point to something the shows why they are "one of the worst voltage sources out there."

Point to a source that shows batteries putting out a constant / clean voltage without filtering.

Throw a battery on a scope and you'll see it waivering all over the place. I've been told it's due to variations in the speed of the chemical reactions taking place that are creating the voltage. I believe batteries also exhibit some levels of capictance in addition to their wildly varying internal resistance. Heck, not even car amplifiers use the battery without filtering - and that's far from an ideal acoustical situation.

[mike stehr]

Key word clean.......

[consistent]

...truth is I use a 6SN7 pre over my SS amp. I find this has a fantastic balance. I have tried with tube SET and PP but nothing (to me) seems as satisfying as a good clean SS amp with tubes to control it.

[coda]

http://www.jalopnik.com/cars/novelties/youll-put-her-eye-out-kid-stereo-hoonage-causes-poppage-219811.php

[DizRotus]

Parrots original question was, Is a small SET amp too powerful (for anyone)?<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

His question was not any of the following:

Do you like SET;

Do you prefer SET to (insert alternative topology here);

Will SET play loud enough for your tastes; or

Will SET play louder (with or without distortion) than you like or need?

Any of the four questions above could reasonably be answered YES or NO.

IMO, all of the YES answers, so far, have actually addressed a variation of one of the alternatives posed above. Ive yet to read a YES reply that, IMO, satisfactorily explains how a low powered amp could ever be too powerful. Powerful enough and too powerful are not synonymous.

[NOSValves]

Parrots original question was, Is a small SET amp too powerful (for anyone)?<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

His question was not any of the following:

Do you like SET;

Do you prefer SET to (insert alternative topology here);

Will SET play loud enough for your tastes; or

Will SET play louder (with or without distortion) than you like or need?

Any of the four questions above could reasonably be answered YES or NO.

IMO, all of the YES answers, so far, have actually addressed a variation of one of the alternatives posed above. Ive yet to read a YES reply that, IMO, satisfactorily explains how a low powered amp could ever be too powerful. Powerful enough and too powerful are not synonymous.

I'm laughing............great post

[NOSValves]

"The flip side is the SET distortion is much more euphoric, easier to tolerate,"

You might be thinking of the word - euphonic - which is how distortion charactistics of these low-power amps are often described. Pleasing rather than abrasive to the ear.

edit: I'll leave the Stereophile quote out. It had to do with euphonic distortion.

Come on Erik you know just because I can type it word it doesn't mean I know what it means to all people[] I believe my piont was pretty darn clear and not in the least bit one sided. At least that was my intention.

Craig

[Colin]

YES. Mine are. Beyond the 10:00 posistion on the volume dial, my 3.5 watt 2A3 tube Paramours (6-watt max) driving the mid and upper horns on my Khorns in a small, but open, room are TOO POWERFUL. The C rated, slow, SPLs in the mid-90s are too LOUD.

Doesnt Stereophile magazine use 10% THD at any point in the bandwidth as the clipping level?

[coda]

Parrots original question was, Is a small SET amp too powerful (for anyone)?

His question was not any of the following:

Do you like SET;

Do you prefer SET to (insert alternative topology here);

Will SET play loud enough for your tastes; or

Will SET play louder (with or without distortion) than you like or need?

Any of the four questions above could reasonably be answered YES or NO.

IMO, all of the YES answers, so far, have actually addressed a variation of one of the alternatives posed above. Ive yet to read a YES reply that, IMO, satisfactorily explains how a low powered amp could ever be too powerful. Powerful enough and too powerful are not synonymous.

I'm laughing............great post

it's called a false choice.

the thread could have been easily titled "Is a low-powered SET too powerful (for anyone)?"

anyone just realizing this now should shoot themself.

[mike stehr]

This little amp has some powerful line noise on Cornwalls....icky...

I like this little SEP 50C5 amp, however. I'd like to try some sort of tube rectification with a power supply transformer, and then use DC heating for the 50 volts for each tube. I dunno, getting a RCA record console amp with no PS transformer quiet with Cornwalls is more of a challenge than I want to take at the moment....

I don't really want to cock with it until I put together a enclosure for a recepticle and my isolation transformer.

I think a 50C5 can sound good with Cornwalls, may take some noodling around....of course 6BQ5 sounds good with Cornwalls and has more power to boot....

[Erik Mandaville]

"Come on Erik you know just because I can type it word it doesn't mean I know what it means to all people"

Craig: I've read the above sentence a couple of times, and I guess I'm not really clear on its meaning (I'm probably just tired, or something). At any rate, it's not a big deal. I was simply suggesting that the word you probably meant to use was euphonic, not euphoric.

Erik

[DizRotus]

<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

If your amp's too powerful is your significant other too good looking also?