"Things that cannot be measured"

[egellings]

Tube amplifiers do not need to be distortion generators; many are but some are not.

 

[magicscreen]

Tube amplifiers do not need to be distortion generators; many are but some are not.

Yes, they are always confused with overdriven guitar amps.

 

[egellings]

I built 2 pair, one large, one smaller, of home brew circlotron-style power amp mono-blocks (130wpc, 70wpc) that have low distortion. Loop and inter-stage feedback is used to clean things up a bit.

 

[magicscreen]

I built 2 pair, one large, one smaller, of home brew circlotron-style power amp mono-blocks (130wpc, 70wpc) that have low distortion. Loop and inter-stage feedback is used to clean things up a bit.

Yes, tubes have great sound. I have the Fx-Audio Tube-03 pre-amplifier. Using with a well-measuring solid-state amp. Great sound and low distortion at the same time.

 

[Tom Danley]

Depending on what he means by "returns the music", unless he's heard the master on the equipment it was completed with he doesn't have a frame of reference to judge. What we know is that the signal coming out of a tube Amp is not an accurate representation of what went in so at best it means he likes the distortion tubes provide.

Exactly!
Any alteration, even desirable ones like adding some even harmonics with music, at least on the first pass all reduce the number of generations that the device will pass without degradation.
Both even and odd harmonics harm / alter many natural sounds which unlike music are not harmonically structured.
On the other hand, the distortion spectrum of linearly run triodes can be remarkably good in light of how perceptual masking works on harmonic number.

 

[krabapple]

One must not contradict the genius friend. Semper Ubi Sub Ubi.

Alas, this is really, really old ground at ASR.

Yes. And so tiresome.

 

[krabapple]

I have a friend that I consider a genius in building/modifying Hi-fi electronics.

He has made solid state amps that measure flat AND tube amps that do not…

His comment is that no matter the measurements, the tubes return the music.

I attribute this to the second harmonics… “de gustibus non disputandum est!”

I'm gonna guess genius friend is also a vinylphile. Also gonna guess genius friend has never done a blind comparison.

 

[Tom Danley]

I built 2 pair, one large, one smaller, of home brew circlotron-style power amp mono-blocks (130wpc, 70wpc) that have low distortion. Loop and inter-stage feedback is used to clean things up a bit.

Very Cool, that is a very interesting output stage topology especially the simplified output transformer requirements.

 

[Sal1950]

He has made solid state amps that measure flat AND tube amps that do not…

His comment is that no matter the measurements, the tubes return the music.

I attribute this to the second harmonics…

Sorry but adding distortions to the source would not be a genius path to a High Fidelity result.

 

[solderdude]

How many times could a signal pass through a tube amp before it sounds noticeably poor ?
source -> tube amp -> ADC -> DAC -> tube amp -> ADC -> DAC -> tube amp -> ADC -> DAC -> etc.
Similar to having 10x the same tube amp in series.

We know when a good ADC and DAC are used many generations do not make it sound bad.

Can tube goodness only be added once ?
Will the sound keep getting 'better' each time it passes through another time ?
When will tube goodness go down again ?

 

[magicscreen]

I'm gonna guess genius friend is also a vinylphile. Also gonna guess genius friend has never done a blind comparison.

This is tiresome.
His genius friend likes tube and vinyl sound. So what? Stop whining about that.
Anyway Amir said you need to be trained for a successful blind test. Not everybody has the time and energy for that.

 

[beren777]

This is tiresome.
His genius friend likes tube and vinyl sound. So what? Stop whining about that.
Anyway Amir said you need to be trained for a successful blind test. Not everybody has the time and energy for that.

Training for blind testing:

"Ok, now close your eyes."

"No, no. That's okay. Let's try again. Close your eyes."

 

[BDWoody]

Anyway Amir said you need to be trained for a successful blind test.

Where did he say that?

A successful blind test is one with proper controls. Training may help in discerning a difference, but not sure what you mean when you say you need to be trained...

 

[audio2design]

This is tiresome.
His genius friend likes tube and vinyl sound. So what? Stop whining about that.
Anyway Amir said you need to be trained for a successful blind test. Not everybody has the time and energy for that.

You need to be trained to be a successful critical listener. You require no training in order to blind test a claim that YOU make about audibility.

 

[audio2design]

We should probably have a queue of people that will jump down other people's throats for saying something silly. It will save time and repetition

 

[Phos]

I have a pet theory that certain types of amplifier induced distortion mimics the sort of distortion you get at a live venue. Basically, I think it's a psychoacoustic effect. I would need to quantify the sorts of distortion that live venues cause to know if there's anything to it, but I don't really care enough.

 

[solderdude]

I have a pet theory that certain types of amplifier induced distortion mimics the sort of distortion you get at a live venue

Distortion doesn't mimic venue acoustics, echo, reverb, time delays
DSP can mimic that.

 

[KSTR]

@Phos,
While the situation got better over the last two decades, when I recall my early concert live sound experiences in the 70ies, often from basically broken PA setups in small/medium venues (bad amps being fed with misaligned crossover signals from a so-so mix into mediocre horn systems, all setup often by less experienced people)... well, I sure don't want any amp to recreate this sound, haha!
Only really big shows sometimes had phenomenal live sound, on of my personal highlights was a Peter Gabriel show in the 80ies.

 

[audio2design]

I have a pet theory that certain types of amplifier induced distortion mimics the sort of distortion you get at a live venue. Basically, I think it's a psychoacoustic effect. I would need to quantify the sorts of distortion that live venues cause to know if there's anything to it, but I don't really care enough.

And what mechanism would be causing said distortion? Would it be indoor or outdoor?

If you had large humidity differentials maybe you could get some distortion at bass frequencies. Ditto with temperature due to again density changes.

Hard surfaces don't deform much, and soft surfaces absorb, so touch to get distortion there.

 

[audio2design]

@Phos,
While the situation got better over the last two decades, when I recall my early concert live sound experiences in the 70ies, often from basically broken PA setups in small/medium venues (bad amps being fed with misaligned crossover signals from a so-so mix into mediocre horn systems, all setup often by less experienced people)... well, I sure don't want any amp to recreate this sound, haha!
Only really big shows sometimes had phenomenal live sound, on of my personal highlights was a Peter Gabriel show in the 80ies.

I remember Gabriel in the 80's. Saw him about 5 years ago .. he could still sing great. Much better than Sting (on the same tour).