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SETs

99.185.54.154
Posted on November 18, 2020 at 07:22:53
JURB
Audiophile

Posts: 2056
Location: North Ohio
Joined: May 29, 2016
 There was a thread that went to hell on this, thank you for doing that and you now who you are. I'll return the favor as soon as I gather up enough battery acid. And actually it seems at least one offender is on my side. Doesn't matter, want a political forum they are all over the place.

Anyway, here are a coupe of things. SETs have mainly second harmonic distortion, so does the human voice. That is why they are careful about mic polarity on AM broadcasting, they want to up modulate not down modulate.

Single ended pentodes and tetrodes I think will run into higher orders of even order distortion which are not quite as tolerable. Maybe not as bad as odd order but still not as good.

It is also listening habits. Some people do not feel the need to shake the ground outside and register on a seismograph in other countries.

So take a scope or whatever, figure out where one watt is and play at that level no matter what power you have on tap - ONE WATT. Most will be surprised at just how loud it is.

There is so much more that people can bring up. for example the semi saturation of the output transformer core. It doesn't have not be so saturated to be able to be used as a modulator to affect the sound.

It just occurred to me, on SET output transformers, why not a magnet to cancel out the magnetic bias on the core ?

Hmm.

 

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one thing, posted on November 18, 2020 at 08:35:47
Story
Audiophile

Posts: 10426
Location: NJ
Joined: December 11, 2000
 or correction.

human voices don't have 'distortion', they are what they are, original and full of natural harmonics just like everything else



 

RE: one thing, posted on November 18, 2020 at 09:37:50
Hornlover
Manufacturer

Posts: 2529
Joined: March 8, 2002
 I was going to mention that. The origin of the sound from a non amplified source has zero distortion. It does have a harmonic structure, of course, but that is a different story.

 

You obviously haven't heard me sing! (nt), posted on November 18, 2020 at 14:26:23
1973shovel
Audiophile

Posts: 10117
Location: Greenville SC
Joined: February 25, 2007

 

OK!!, posted on November 18, 2020 at 14:57:23
Story
Audiophile

Posts: 10426
Location: NJ
Joined: December 11, 2000
 I won't



 

RE: one thing, posted on November 18, 2020 at 15:41:04
JURB
Audiophile

Posts: 2056
Location: North Ohio
Joined: May 29, 2016
 "or correction.

human voices don't have 'distortion'"

I mis"spoke". In retrospect I think the proper word would be "content".

 

RE: You obviously haven't heard me sing! (nt), posted on November 18, 2020 at 15:43:34
JURB
Audiophile

Posts: 2056
Location: North Ohio
Joined: May 29, 2016
 "You obviously haven't heard me sing!"

I have a disk of me doing Karaoke. Want to compare ?

 

RE: SETs, posted on November 19, 2020 at 07:56:56
CG
Audiophile

Posts: 432
Joined: October 11, 2000
 Your suggestions are very probably a big part of the appeal of SET based amplifiers.

A detail you didn't mention in this post is that there's no "crossover" area in single ended amplifiers of any kind where one complement of the devices starts providing all the current for the output while the other provides less or none. This area of operation is messy for a bunch of technical reasons.

Benchmark Media has performed a number of objective tests and published the results. Yeah, they want to promote their solution to the problem, but the attached article does make you think some. Douglas Self, Bob Cordell, Arto Kolinummi, and others have published books that specifically address the problems with crossover distortion and propose some solutions. Single ended devices avoid that problem altogether.

I can't offer an informed opinion about the differenced between triodes, tetrodes, and pentodes, so I won't offer any opinion at all!

 

If you've had the nerve to do Karaoke..., posted on November 19, 2020 at 10:32:48
1973shovel
Audiophile

Posts: 10117
Location: Greenville SC
Joined: February 25, 2007
 ...you're a step ahead of me. I won't even subject myself to my singing.

 

RE: SETs, posted on November 19, 2020 at 20:49:08
hahax@verizon.net
Audiophile

Posts: 4306
Location: New Jersey
Joined: March 22, 2006
 So does class A push/pull solve the problem with other compromises of course, mainly heat and lower output.

 

RE: SETs, posted on November 20, 2020 at 07:05:04
CG
Audiophile

Posts: 432
Joined: October 11, 2000
 Not necessarily, because the complementary devices usually are not really the same and there is also the challenge of "Gm doubling" when both the NPN and PNP (or equivalent MOSFETs) devices conduct in the crossover range. It's possible to work around these details, but the solutions come at a price of some kind.

There are very few amplifiers claiming to be class A that truly operate in class A across all their output range. As you say, the power dissipation means that most true push-pull class A amplifiers run hot and have low output powers.

There's no magical solution and all come with the compromises you cite.

"Well, (hahax), it just goes to show you, it's always something - if it's not one thing, it's another." - Roseanne Roseannadanna. 1977

 

RE: SETs, posted on November 23, 2020 at 08:04:29
morricab
Distributor or Rep

Posts: 9175
Location: switzerland
Joined: April 1, 2005
 Just to add one more thing, SETs especially (but tubes in general) seem to be able to generate far higher dynamic power without audibly distorting (the key there is audibly) than transistors that tend to hard clip with nasty consequences. This is probably the reason behind the ancedotal stories that "tube watts" sound more powerful than "transistor watts".

 

RE: SETs, posted on November 23, 2020 at 21:44:24
JURB
Audiophile

Posts: 2056
Location: North Ohio
Joined: May 29, 2016
 "Just to add one more thing, SETs especially (but tubes in general) seem to be able to generate far higher dynamic power without audibly distorting"

It was tubes in general that impelled me to design my amp, which may or may not ever fly. The economy is probably going to shit so I don't want to dump a ton of money into this and sell zero units and I don't want my mail market to be overseas.

I had to make a major change in the design and have a few things to deal with, so it is not dead, it is just that I might not do it at all.

I will reveal what I figured out though about tubes.

Tubes are al diodes. Sure they can have grids, but they are still a diode. That means they do not conduct in reverse.

I push pull, when one output clips, the transformer and speaker cone are free wheeling and can move more. This will round up some of the clipping and that is why it is not harsh like a solid state amp.

No solid state device has that characteristic, bipolar, ant MOSFET, even JFETs, VFETs, LFETs, you name it and it is not open during reverse voltage.

In a way it is soft clipping, but if a solid state amp has it it subtracts, in a tube amp it adds.

This characteristic is what gave old tube guitar amps their sound. Not that often but sometimes on stage they would have a little amp in a box with a mic. Someone like BB King would do shit like that with Lucille.

So absolutely, what the human voice puts out probably should not be considered distortion. In a way yess, but those harmonics are what makes us able to form words.

In most cases the vocal chords are full of harmonics, the mouth modulates the harmonics. However there are people I do not understand well and I know now why - their voice lacks enough harmonics for me to discern correctly. One is a pretty good friend so I have to deal with it. And he likes to debate, land sometimes it gets heated but after we crack open a brew, maybe light a hog leg. And we are not worried about any pipsqueak virus either so no masks unless we got out to a pubic place.

Actually two other friends have lower voices but they got the harmonics. Easy for me to understand. And that is in person or on the phone, doesn't seem to matter.

So it can be said that SETs have a "vocal" quality. Many people like voice, like singers, certain announcers etc.

The guy with the FM voice, deep and EQed to make sure it is deep. And close to the mic. The thing is their voice had enough harmonics.

Actually we had one guy, Bill Friedman with his overnight BLF Bash and he stayed back from the mic. He sounded like he maintained about a six pack in him, and played some of the best music, not the top forty at all. He was the exception, and was on the air for decades. And ours, I don't believe he was ever syndicated.

Anyway, another friend, now deceased, had about the deepest voice around, deeper than mine on a good day. No problem understanding him. he could sing some, and he actually took voice training. Not for singing but for announcing. He ws telling me that like the guy who on AOL said "Welcome" and "You got mail" made a fraction of cent very time that was used, or just installed on a computer. Got rich.

So, that "vocal" quality can mean something a bit different than many think.

 

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