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

[morricab]

The problem was the impedance curve which I think was fixed in later examples. The designer used a solid state amp, and so only had caps to keep lows out of the smaller drivers. So it started at a nice impedance in the lows but as you went higher in frequency the impedance dropped as each additional driver was rolled in and thus in parallel with the LF driver. This is bad for SETs. Later I suspect he was convinced to put in a real crossover, which included coils and fixed the problem- resulting in a much flatter impedance curve.

Well the current version is a SET dream...

OVERVIEW​

• 109 dB efficiency
• Up to 27 Ohm drivers, with Strontium ferrite magnets
• 180 mm spherical tweeter horn
• 570 mm spherical midrange horn
• 950 mm spherical low-midrange horn
• 100 V CPC crossover design
• Orbital designer frame
• Subwoofers available as separate units

 

[Atmasphere]

Well the current version is a SET dream...

OVERVIEW​

• 109 dB efficiency
• Up to 27 Ohm drivers, with Strontium ferrite magnets
• 180 mm spherical tweeter horn
• 570 mm spherical midrange horn
• 950 mm spherical low-midrange horn
• 100 V CPC crossover design
• Orbital designer frame
• Subwoofers available as separate units

Well it seems like that would be the case. What's really needed is the impedance curve.

 

[morricab]

Well it seems like that would be the case. What's really needed is the impedance curve.

Given that they make a point of declaring they use drivers with quite high impedance, I seriously doubt we are going to see any SET, or OTL for that matter, unfriendly impedance curves.

 

[marslo]

Well the current version is a SET dream...

OVERVIEW​

• 109 dB efficiency
• Up to 27 Ohm drivers, with Strontium ferrite magnets
• 180 mm spherical tweeter horn
• 570 mm spherical midrange horn
• 950 mm spherical low-midrange horn
• 100 V CPC crossover design
• Orbital designer frame
• Subwoofers available as separate units

A kind of such a setup ?

 

[morricab]

A kind of such a setup ?

Maybe you want to weigh in on SET + Duo and Trio?

 

[marslo]

Maybe you want to weigh in on SET + Duo and Trio?

I am not sure what do you mean? If you click on enclosed picture you will see SET plus Trios LE 26 with separate subs.

 

[morricab]

I am not sure what do you mean? If you click on enclosed picture you will see SET plus Trios LE 26 with separate subs.

Your experience with these speakers with a SET amp is what I meant.

 

[marslo]

Your experience with these speakers with a SET amp is what I meant.

Ok, thank you for the clarification.
I do not think Trios are more difficult to drive than Duos with modern SET like Crossfire.
I use also as a second amp Cirlcle Labs A100 integrated ( hybrid desing) and despite its 60 watts per channel I have the impression that Crossfire with 30 W pc is more powerful.
As far as sonics are concerned Trios do really need subs, without them the bass is limited to 100 Hz and the playback is limited to female voices ( outstanding btw).

After several month with REL Carbon Special and Trios I am more and more satisfied, but I wish they had a built in DSP like AG bass satelites.

Trios LE 26 are a significant leap forward compared to Duo Mezzo XD, the only thing is that Mezzos are easier to setup , especially the integration between mids and bass is easier.
Trios have better midrange, soundstage, micro and macro dynamics and in big classical create a more realistic reproduction of symphonic orchestra and the venue.

For smaller rooms Duos are probably the best value for money in AG line though.

But Trios with separate subs ( REL Carbon Special are very good , the only thing I am missing is DSP) are significantly better than Duos.
I had Duo Omega G2 , then Duo Mezzo XD ,now Trios and all of them are driven by Ayon Crossfire in its 3 iterations.

 

[bonzo75]

Ron and I heard trios driven by airtight 300b 9w integrated and it drove them fine. Though the audio note 9w 300b in that same room couldn't control them.

 

[gestalt]

Ron and I heard trios driven by airtight 300b 9w integrated and it drove them fine. Though the audio note 9w 300b in that same room couldn't control them.

Air Tight amps use negative feedback to lower their output impedance where Audio Note amps don't. Good example of one of the trade offs.

 

[G T Audio]

Unfortunately the Trio was never really SET friendly and Duo was only borderline. Further bass quality of their active boom boxes didn’t and don’t sound natural and never heard them adequately mesh with high end SETs or any good tube amplifier. I agree that Jim did a fabulous job marketing AVs.

david

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...

 

[G T Audio]

Air Tight amps use negative feedback to lower their output impedance where Audio Note amps don't. Good example of one of the trade offs.

The Air Tight and the Audio Note are simply not quiet enough to use with a high efficiency horn. They produce too much noise because they were never designed for use with a high efficiency loudspeaker. When measured on the bench the AT barely produces 4 watts, as their HT voltage is only around 370v and the cathode bias resistor is 880ohms. No way is this ever going to make 8 watts. Well not without massive distortion...

 

[mtemur]

Unfortunately the Trio was never really SET friendly and Duo was only borderline. Further bass quality of their active boom boxes didn’t and don’t sound natural and never heard them adequately mesh with high end SETs or any good tube amplifier.

I can not agree more. I heard Duo and Trio with top quality SET amps but nothing special happened in terms of sound quality. Duo was even sounding better with Mark Levinson 33H mono amps. I’m not a fan of Avantgarde speakers. They have thin plastic kind of horns, Cessaro speakers have better implemented horns in this regard.

 

[G T Audio]

I can not agree more. I heard Duo and Trio with top quality SET amps but nothing special happened in terms of sound quality. Duo was even sounding better with Mark Levinson 33H mono amps. I’m not a fan of Avantgarde speakers. They have thin plastic kind of horns, Cessaro speakers have better implemented horns in this regard.

You will never hear what an Avantgarde horn, or any other high quality horn loudspeaker for that matter, is capable of delivering using an amplifier like a ML33H. All the subtlety, beauty and magic of the performance will be missing...

 

[marslo]

@mtemur
Of course one may prefer Cessaros over Avantgardes, some of our fellow audiophiles have top systems based on the components of Cessaro line.

But the material of the horn itself is only one of elements of the horn speaker design, imho not of key importance. The drivers, the efficiency of the speaker as a result of the size and the shape of the horn, the number of horns and crossover points, internal wiring, the structure and material of the frame are also important.

Universum and Avantgarde use a kind of ABS, Cessaro horn is made of poliglass afaik, Animas and Totaldac have wooden horns.

Btw I did not have the chance to listen to good presentation of Cessaro horns during audio shows ( Munich and Warsaw), they can probably play much better ( for example Tang’s system sounds wonderful even on YT) . From the other hand I always liked Avantgardes and Acapellas more.

 

[mtemur]

You will never hear what an Avantgarde horn, or any other high quality horn loudspeaker for that matter, is capable of delivering using an amplifier like a ML33H. All the subtlety, beauty and magic of the performance will be missing...

makes perfect sense, using Mark Levinson 33H amplifiers with avantgarde Duo should not produce a good result but it was the best sound that I ever heard from avantgarde speakers including friends systems, dealers and Munich shows. ML33H amplifiers were running close to full power which confirms @ddk comment. actually all of these were 10 years ago and I remembered it when I read comments. preamplifiers were nagra PLL and audio consulting silver rock. silver rock was a better companion to ML33H. by the way I don't like anantgarde's own solid state amplifiers.

 

[caesar]

I never have understood the interest some have in very early 20th century technology. Sure it works, but it certainly isn’t better than current solid state technology. Other than being nostalgic I just don’t see any benefit to tube technology.

Hi,
To help you understand why people prefer "older technologies", let me quote the late Art Dudley from his Klipsch AK6 speaker review:

"In the years since the Klipschorn's debut, loudspeaker technology has progressed in many ways. Speakers that sound timbrally neutral and uncolored are much more common today, as are speakers with consistent and effective dispersion across their operating range. Thanks to the pioneering work of people like Jon Dahlquist, Jim Thiel, Richard Vandersteen, and John Fuselier (footnote 2), physical time alignment of drivers in a dynamic loudspeaker system is virtually a given these days, and the problem of baffle edge diffraction has been identified and smacked upside the head. The result is a great selection of loudspeakers that offer apparently flat frequency response, superb stereo imaging, and great airiness and transparency.

And what did we give up to gain such easy access to all those things? Natural-sounding dynamics. Impact. Pluck. Snap. Body—especially body. And soul."

Now with that said, high end audio is a subjective experience. There is no right or wrong taste or preference, so enjoy your Pass Magico system. If you have thoroughly explored and settled on your system as the best you can do for your budget, then great. But if you are curious about why so many folks on this site prefer different technologies, do try some high efficiency gear.
Cheers

 

[caesar]

This is where Google is your friend.

Actually, Google sucks for deep research. Google is great for superficial stuff or starting one's research. But when one wants to go deeper, people for pay a lot of money for much better databases.

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. For specialized subjects, there is nothing like getting cognitively, deeply diverse replies from experienced people like yourself . So thanks for all the information.

 

[PeterA]

Hi,
To help you understand why people prefer "older technologies", let me quote the late Art Dudley from his Klipsch AK6 speaker review:

"In the years since the Klipschorn's debut, loudspeaker technology has progressed in many ways. Speakers that sound timbrally neutral and uncolored are much more common today, as are speakers with consistent and effective dispersion across their operating range. Thanks to the pioneering work of people like Jon Dahlquist, Jim Thiel, Richard Vandersteen, and John Fuselier (footnote 2), physical time alignment of drivers in a dynamic loudspeaker system is virtually a given these days, and the problem of baffle edge diffraction has been identified and smacked upside the head. The result is a great selection of loudspeakers that offer apparently flat frequency response, superb stereo imaging, and great airiness and transparency.

And what did we give up to gain such easy access to all those things? Natural-sounding dynamics. Impact. Pluck. Snap. Body—especially body. And soul."

Now with that said, high end audio is a subjective experience. There is no right or wrong taste or preference, so enjoy your Pass Magico system. If you have thoroughly explored and settled on your system as the best you can do for your budget, then great. But if you are curious about why so many folks on this site prefer different technologies, do try some high efficiency gear.
Cheers

We can always rely on you Caesar to get to the heart of the matter. I had one of those Pass/Magico systems and enjoyed it for many years. Had I been exposed to really good SET/horn based systems earlier, I may have made the switch sooner, it is hard to say. Regardless, things have since changed for me and I can relate to what Art Dudley is saying here.

 

[caesar]

We can always rely on you Caesar to get to the heart of the matter. I had one of those Pass/Magico systems and enjoyed it for many years, mostly because I had not been exposed to really good SET/horn based systems. Things have since changed for me and I can relate to what Art Dudley is saying here.

Hi Peter,
I am sincerely thrilled that you are enjoying high-efficiency!