Single-Ended Triode (SET) Amplifier Revolution of the 1990s. Did it really happen? Was it Successful?

PeterA

Well-Known Member
Dec 7, 2011
8,612
5,059
1,235
North Shore of Boston
Hi Peter,
I am sincerely thrilled that you are enjoying high-efficiency!

Yes indeed I am. I can enjoy low efficiency too. It is just a different sound, and I presume there are many levels of each. I really enjoyed ddk's 16 ohm MItsubishi Diatone cone speakers driven by the Lamm SET also.
 

caesar

Well-Known Member
May 31, 2010
3,697
374
578
Yes indeed I am. I can enjoy low efficiency too. It is just a different sound, and I presume there are many levels of each. I really enjoyed ddk's 16 ohm MItsubishi Diatone cone speakers driven by the Lamm SET also.

Hey Peter,
You are luckier than I am, what can I say? :)

High end audio is an experiential subjective hobby, but I was never lucky to enjoy the audiophile brands like Wilson, most Magico (unless with a really musical amp like Symphonic Line or Gryphon or CAT), D'Agostino, dCS, MSB (kinda semi-musical but boring), Pass and Audio Research (complete drek on most models), etc.

When I hear these systems other audiophiles rave about, all I perceive is the audiophile vocabulary: there is the soundstage, and there are pin-point images on the soundstage, and there is the bass and the highs.... to me it's all just sound, but not music....

And on top of that, this popular gear only sounds good with audiophile music like Holly Cole and Patricia Barber....That's not what I am looking for.

I will take the Zu Omen Dirty Weekend for $999 with a $3K SET integrated ANY DAY over the Wilson WAMM or ANY NIGHT.

Cheers
 

Solypsa

Well-Known Member
Jun 7, 2017
775
457
160
Seattle
www.solypsa.com
Diatone tells us how far a two way reflex speaker had come 55 years ago ;)
 
  • Like
Reactions: mtemur

ddk

Industry Expert
May 19, 2013
5,559
2,684
920
Utah
Sorry, but that is completely untrue.

Personally, I have owned 2 pairs of Trios (pre G2). We also had them as demonstrators and used them at UK Hi-Fi Shows when we distributed Avantgarde Acoustic in the UK (1998 - 2014). We used them in large rooms with TRON amplifiers, an 8-watt 300B SET and a 12-watt 211 SET with absolutely no problems at all. In some of those rooms there was anywhere between 20 to 100 people inside and no issues driving Trios, or for that matter any of Avantgarde's Horns. Back in the early days (1998 to 2002) we drove Trios at the Frankfurt Show in Avantgarde's own room when Avantgarde used Tron amplifiers, before they brought out their own electronics.

The problem is that to drive horns, you need a specific design to cater for the very high efficiency and still be able to retain superb signal to noise. Putting it bluntly, there is only one manufacturer that has done this...
8 watts with Trios in a large room and a hundred people! If you say so. You must have had very special Trios with the only 8 watt amplifier in the world to drive them competently in those conditions.

Care to share what this specific design is and why it’s the only one in the world catering to very high efficiency?

david
 
Last edited:

G T Audio

Well-Known Member
Interestingly, when I just googled this subject of SET amplifier revolution, this thread comes up! If you have any additional links I'd appreciate it.

Look no further than the excellent series of magazines from Joe Roberts called Sound Practices. Its all in there...

If you have trouble locating them you can get them from HERE.
 

G T Audio

Well-Known Member
8 watts with Trios in a large room and a hundred people! If you say so. You must have had very special Trios with the only 8 watt amplifier in the world to drive them competently in those conditions.

Care to share what this specific design is and why it’s the only one in the world catering to very high efficiency?

david

Here is an article (see attached) written by Roland Kraft in Germany for Image Hi-Fi magazine and translated by Holger Fromme (owner of Avantgarde Acoustic) for me following the 1998 Frankfurt HiFi show where Trios were used in a very large room. The article gives some insight to your question. Here are some links to more recent shows driving Cessaro's in large rooms where only 8-watt and 12-watt amplifiers were used:

Munich 2012
Munich 2013
RMAF 2013
Munich 2014
 

Attachments

  • TRON-ImageHifi-6-1999-review-EN.pdf
    1.5 MB · Views: 32

PeterA

Well-Known Member
Dec 7, 2011
8,612
5,059
1,235
North Shore of Boston
Hey Peter,
You are luckier than I am, what can I say? :)

High end audio is an experiential subjective hobby, but I was never lucky to enjoy the audiophile brands like Wilson, most Magico (unless with a really musical amp like Symphonic Line or Gryphon or CAT), D'Agostino, dCS, MSB (kinda semi-musical but boring), Pass and Audio Research (complete drek on most models), etc.

When I hear these systems other audiophiles rave about, all I perceive is the audiophile vocabulary: there is the soundstage, and there are pin-point images on the soundstage, and there is the bass and the highs.... to me it's all just sound, but not music....

And on top of that, this popular gear only sounds good with audiophile music like Holly Cole and Patricia Barber....That's not what I am looking for.

I will take the Zu Omen Dirty Weekend for $999 with a $3K SET integrated ANY DAY over the Wilson WAMM or ANY NIGHT.

Cheers

Caesar, I'm not describing what is best, only that I can enjoy both the typical low efficiency High End Audio brand systems in some cases, and also the high efficiency systems I've heard in some places. Sure, I have preferences, and they are swinging more in one direction, but I can not honestly say I did not enjoy my former Pass/Magico system. With ddk's help from afar, I did get that system sounding pretty good, IMO, and even diehard tube guys like Ron and Jeff who never heard a Magico system they liked, actually enjoyed that system too.

I love the SET/horn system I have now and certainly hear the differences. I agree with you about how some systems conjure up the audiophile vocabulary. I have moved away from that type of sound. People prefer what they prefer, but I get where you are coming from. You have long been a critic, and I am now beginning to understand why.
 

caesar

Well-Known Member
May 31, 2010
3,697
374
578
Look no further than the excellent series of magazines from Joe Roberts called Sound Practices. Its all in there...

If you have trouble locating them you can get them from HERE.
Thank you so much! I will check these out
 

caesar

Well-Known Member
May 31, 2010
3,697
374
578
Caesar, I'm not describing what is best, only that I can enjoy both the typical low efficiency High End Audio brand systems in some cases, and also the high efficiency systems I've heard in some places. Sure, I have preferences, and they are swinging more in one direction, but I can not honestly say I did not enjoy my former Pass/Magico system. With ddk's help from afar, I did get that system sounding pretty good, IMO, and even diehard tube guys like Ron and Jeff who never heard a Magico system they liked, actually enjoyed that system too.

I love the SET/horn system I have now and certainly hear the differences. I agree with you about how some systems conjure up the audiophile vocabulary. I have moved away from that type of sound. People prefer what they prefer, but I get where you are coming from. You have long been a critic, and I am now beginning to understand why.
Hi Peter,
Yes, no one can really rationally explain people's preferences. Some of my friends, like yourself, like many different sounds. Me, not so much.

So I ended up wasting a lot of precious time (and money) checking out the hyped up drek. I wish the Neil Grobbers / "audio journalists" had more integrity, like Fremer and "Yoda" Valin, to compare experiences of different gear instead of hyping up every piece of drek as the best. But such is life. Yet I am dearly thankful that there is high efficiency gear that really moves my soul.

Gratitude is riches.
 

Atmasphere

[Industry Expert]
May 4, 2010
1,343
630
595
St. Paul, MN
www.atma-sphere.com
I wish the Neil Grobbers / "audio journalists" had more integrity,
Integrity is a thing you have or don't have. There is no 'more' or 'less'. You have it or you don't.

FWIW you did not experience what they did with that equipment in their listening environment. There is no integrity in claiming that the equipment they experienced is 'drek' on that basis, regardless of your experience with that same equipment. Your experience is not theirs.

We examined the SET phenomena when it began in the early 1990s- was it a threat to our business model? We concluded that it was not (this conclusion has proven correct over the intervening 25 years or so). Many people prefer SETs over other types of equipment, including our own which we know for a fact outperforms all SETs made (measurable and audible). But that does not stop people from preferring SETs anyway, even when confronted by obviously superior (in every way) technology, some of whom might call that equipment 'drek'. Do you get my point?
 
  • Like
Reactions: tima

morricab

Well-Known Member
Apr 25, 2014
5,780
2,078
553
Switzerland
Integrity is a thing you have or don't have. There is no 'more' or 'less'. You have it or you don't.

FWIW you did not experience what they did with that equipment in their listening environment. There is no integrity in claiming that the equipment they experienced is 'drek' on that basis, regardless of your experience with that same equipment. Your experience is not theirs.

We examined the SET phenomena when it began in the early 1990s- was it a threat to our business model? We concluded that it was not (this conclusion has proven correct over the intervening 25 years or so). Many people prefer SETs over other types of equipment, including our own which we know for a fact outperforms all SETs made (measurable and audible). But that does not stop people from preferring SETs anyway, even when confronted by obviously superior (in every way) technology, some of whom might call that equipment 'drek'. Do you get my point?
Can you provide an obviously Superior measurement for us? I remember some measurements from Soundstage that indicated an odd order dominant spectrum that would not be ideal, IME. Sonically I find OTLs arguably the most transparent of all amps but often lacking a realistic tonal balance. Probably overall though my second favorite amp type...I still need to get my hands one a SET OTL...make one of those and maybe you have a new customer ;)
 
  • Like
Reactions: Carlos269

Atmasphere

[Industry Expert]
May 4, 2010
1,343
630
595
St. Paul, MN
www.atma-sphere.com
Can you provide an obviously Superior measurement for us? I remember some measurements from Soundstage that indicated an odd order dominant spectrum that would not be ideal, IME. Sonically I find OTLs arguably the most transparent of all amps but often lacking a realistic tonal balance.
Yes. There are two main types of non-linearities that relate to harmonic distortion: quadratic and cubic. The former is the kind that SETs express, the latter is the kind a fully differential amplifier will express. They are often combined in audio circuits where single-ended and push-pull are combined.

A Quadratic non-linearity will express the 2nd harmonic as the dominant component. This is what makes SETs sound so sweet. The 3rd follows at a lower amplitude; with each succeeding harmonic the amplitude is a bit less.

A Cubic non-linearity will express the 3rd harmonic as the dominant harmonic distortion component, but at a lower level than seen with single-ended circuits. The even orders are cancelled by the differential (balanced) nature of the circuit leaving mostly the odd orders, but since distortion is compounded less from stage to stage within the circuit the harmonics fall off at a faster rate as the order of the harmonic is increased. Its an inherently lower distortion approach- IMD is lower too.

In both cases the presence of the 2nd and/or 3rd masks the higher orders regardless of even or odd from the human ear. IOW the ear treats the 2nd and 3rd the same way- they contribute to lushness, richness, that sort of thing. The Soundstage article wasn't quite correct- much depends on the presence of the lower orders to mask the higher orders. This is why most solid state amps sound bright and harsh, since the lower orders are more effectively suppressed by the feedback in the amp. This leaves the higher orders unmasked. To really understand this its also important to know that any tube amp has quite a lot more higher ordered distortion than almost any solid state amp; that's how important the masking brought on by the lower ordered harmonics are!

I'm not going into how feedback works with distortion here; its an interesting topic of its own.

The ear apparently has a tipping point regarding distortion. It assigns a tonality to all types (hence the brightness of solid state). That tonality gets a lot of attention from the ear, often overshadowing actual frequency response. For this reason an amp that might have a higher output impedance (such as an SET or zero feedback OTL) and thus a less than flat frequency response due to sensitivity to the speaker load impedance, might actually sound more neutral than an amplifier that has a flatter frequency response if that response is accompanied by a lack of lower ordered harmonics to mask the higher orders.

If you can reduce distortion while maintaining the masking of the lower ordered harmonics, the amp will sound more neutral. This is why our OTLs sound more neutral than any SET. However, OTLs are well-known for being sensitive to speaker loads, perhaps more so than SETs. Our OTLs are particularly sensitive in this regard since they employ no feedback. But because they are fully differential they make considerably less distortion than SETs and you hear that in terms of transparency.

I suspect that the 'lacking a realistic tonal balance' you heard has everything to do with the speaker being less than ideal for the amp. You know how important this is to get the most out of an SET; it should be no surprise that its important for an OTL as well.
 

TheMooN

Well-Known Member
Jul 30, 2013
919
156
390
N/A
Look no further than the excellent series of magazines from Joe Roberts called Sound Practices. Its all in there...

If you have trouble locating them you can get them from HERE.

The problem is that to drive horns, you need a specific design to cater for the very high efficiency and still be able to retain superb signal to noise. Putting it bluntly, there is only one manufacturer that has done this...

So.....You are claiming that this miracle of amplification just happens to be the very ones that you produce....Really...How fascinating
Since by implication you are saying that all other SET designs, the designers themselves and the companies manufacturing them are sub optimal in comparison, might you educate us further as to why your products are so far ahead of your competition please ?
 

G T Audio

Well-Known Member
So.....You are claiming that this miracle of amplification just happens to be the very ones that you produce....Really...How fascinating
Since by implication you are saying that all other SET designs, the designers themselves and the companies manufacturing them are sub optimal in comparison, might you educate us further as to why your products are so far ahead of your competition please ?
I am not here to promote any products. I suggest you do some homework and investigation yourself. Reading the Hi-Fi Image articule might help. There are plenty of articles and forum posts (other forums) on the subject. It is not so much what I have done. It is more to do with what others have not done...
 
Last edited:

TheMooN

Well-Known Member
Jul 30, 2013
919
156
390
N/A
Graham....I have previously read that article and have just done so again.
Salient points pertaining to your most excellent SET amplifiers being:

1.Point to Point soldered components.
2.Partridge output Transformers.
3.Transformer coupled, eschewing capacitors in the the direct signal path.

1. I agree with that circuit construction methodology... however not unique to Tron

2. I love Partridge output transformers , particularly Double C Core, I own many amplifiers utilising them and have built my own also utilising them , however they can be matched and even exceeded in measured and audible performance by other vintage Transformers (Hashimoto, Tango etc ) and some later production transformers ( Tribute, Audio Note etc )

3. Admirable from *one* technical viewpoint, however again not entirely unique ( Kondo, Shindo, Aries Cerat etc)

Whilst I admire your ethos and the construction quality of your SET amplification, to claim that you are the only designer/manufacturer doing it in the *Right* way is imo somewhat disingenuous.
 

G T Audio

Well-Known Member
Whilst I admire your ethos and the construction quality of your SET amplification, to claim that you are the only designer/manufacturer doing it in the *Right* way is imo somewhat disingenuous.

I think it is disengenuos to buyers of SET amplifiers that when they connect them to their high efficiency horns, they hear copious amounts of hum or hiss, when really they should hear total silence.
 
  • Like
Reactions: dwhistance

TheMooN

Well-Known Member
Jul 30, 2013
919
156
390
N/A
I think it is disengenuos to buyers of SET amplifiers that when they connect them to their high efficiency horns, they hear copious amounts of hum or hiss, when really they should hear total silence.

I cannot image anyone here would be in anything other than agreement with that sentiment ...However my point stands.
 
Last edited:

morricab

Well-Known Member
Apr 25, 2014
5,780
2,078
553
Switzerland
I think it is disengenuos to buyers of SET amplifiers that when they connect them to their high efficiency horns, they hear copious amounts of hum or hiss, when really they should hear total silence.
Aries Cerat amps are totally silent...so are KR Audio for that matter...
 

G T Audio

Well-Known Member
Aries Cerat amps are totally silent...so are KR Audio for that matter...
I would hope AC would be quiet seeing as they make their own horn speakers. KR Audio only use a SET in their output stage. Their driver stage is solid-state so not a true SET amp as most would acknowledge.
 

About us

  • What’s Best Forum is THE forum for high end audio, product reviews, advice and sharing experiences on the best of everything else. This is THE place where audiophiles and audio companies discuss vintage, contemporary and new audio products, music servers, music streamers, computer audio, digital-to-analog converters, turntables, phono stages, cartridges, reel-to-reel tape machines, speakers, headphones and tube and solid-state amplification. Founded in 2010 What’s Best Forum invites intelligent and courteous people of all interests and backgrounds to describe and discuss the best of everything. From beginners to life-long hobbyists to industry professionals, we enjoy learning about new things and meeting new people, and participating in spirited debates.

Quick Navigation

User Menu

Steve Williams
Site Founder | Site Owner | Administrator
Ron Resnick
Site Co-Owner | Administrator
Julian (The Fixer)
Website Build | Marketing Managersing