Matching SET Amps to Speakers

[bonzo75]

Bonzo, how much space to the side and to the rear do you think is enough?

A dealer told me that it was important to have 5' to the rear and 1.5' to the side. But I'm not sure if he actually tried it or if he's just talking.

I think 1.5 feet is on the lower side. Needs to be 2.5 to 3 imo, though if one is buying from dealer with in house demo 1.5 can be experimented with.

 

[perart1]

Was that the O/96 or O/93?

I have also heard orangutans with silvercore 833c 20w, jadis 100w integrated, a German 300b amp running the 520 valves, in the same room as NAF. In another room with kondo overture and in another room with the airtight 300b and el34. It works best in that 10 to 12 watts range. Much better than the Cessaro Wagner in the same room (cessaro you have to go beta and above to get good sound).

Art Dudley had it for 18 months or so before purchasing it, he loved it that much.

I think that bonzo75 makes a good point; if you can not accommodate large horns, where do you go? Small horns....very often compromised. I have heard the Devores many times driven with low powered SETs; 2a3, 300b , 211 and have always been struck by their naturalness and the way they draw you into the music. Recently at a Hi Fi show in the UK the 93's were driven by Leben amps to great effect in a large room where they had room to breathe. The current Uk importer made a comment that he thought that the 93s were kinder to rock and pop than the 96s which he reckoned favoured classical/jazz etc. not sure how many people would agree with that.

There is an alternative; the Horning range of speakers. Perhaps not well known in the USA, but worthy of consideration. The Euphrodite in particular. It has 98 db efficiency, a TQWT design with no crossover, a single cap, between the mid range and tweeter, a set of eight 8" drivers in isobaric config that handles frequencies below 200hz and can be positioned close to the rear wall. Again, i have heard this speaker handle low power SET amps as well as the Horning SATI. Jeffrey Catalano at high Water Sound would be the guy to talk to in the US

Caveat; my listening tastes are classical and jazz, although i have blasted my ears with Thelma Houston, Pressure Cooker. The Hornings can handle Beethovan's Fantasia suite superbly, so what is not to like

 

[GerryM5]

I think that bonzo75 makes a good point; if you can not accommodate large horns, where do you go? Small horns....very often compromised. I have heard the Devores many times driven with low powered SETs; 2a3, 300b , 211 and have always been struck by their naturalness and the way they draw you into the music. Recently at a Hi Fi show in the UK the 93's were driven by Leben amps to great effect in a large room where they had room to breathe. The current Uk importer made a comment that he thought that the 93s were kinder to rock and pop than the 96s which he reckoned favoured classical/jazz etc. not sure how many people would agree with that.

There is an alternative; the Horning range of speakers. Perhaps not well known in the USA, but worthy of consideration. The Euphrodite in particular. It has 98 db efficiency, a TQWT design with no crossover, a single cap, between the mid range and tweeter, a set of eight 8" drivers in isobaric config that handles frequencies below 200hz and can be positioned close to the rear wall. Again, i have heard this speaker handle low power SET amps as well as the Horning SATI. Jeffrey Catalano at high Water Sound would be the guy to talk to in the US

Caveat; my listening tastes are classical and jazz, although i have blasted my ears with Thelma Houston, Pressure Cooker. The Hornings can handle Beethovan's Fantasia suite superbly, so what is not to like

I’ll second Devore O93’s or O96’s. Much more practical than large horn systems but if you have the space excellent large horn systems are something to behold. I had both Devores powered by Line Magnetic 845. The music was enthralling.

 

[Addicted to hifi]

I love the deep bass on my klipschorns which in my room go down to nearly 30hz.on many discs the bass is chest pounding.

 

[thomask]

Just thinking about setting up a second system in a 24 sq room using 9W 300B SET. Horns are out of the question.

Then Vaughn Cabernett II may work in your room. It has small footprint but 93db/W with nice sound out of Accuton ceramic driver.


I bought this Vaughn Cabernett II speaker used 5 years ago as backup for Lansche 4.1

I am willing to part with it at reasonable price since I have Altec A7 and Lansche 4.1.

If your are intereted in this , please PM me.

Thomas

 

[Kingrex]

Pure Audio Project has a new mid/high driver. Its a 10" coax. It has a heavy cast iron horn with a 1.4" diver thru the center. It's drop dead amazing. Best PAP setup I have owned. I have the 10 Voxative and 15 horn. Now 15 coax. My 845 SET uses about a quarter of a quarter watt to play at 70 db. Many amps will drive it. Its 96db efficient. And, it's biampable. I actually find it plays better with 2 sets of speaker cables from 1 amp to it.

 

[Solypsa]

Pure Audio Project has a new mid/high driver. Its a 10" coax. It has a heavy cast iron horn with a 1.4" diver thru the center. It's drop dead amazing. Best PAP setup I have owned. I have the 10 Voxative and 15 horn. Now 15 coax. My 845 SET uses about a quarter of a quarter watt to play at 70 db. Many amps will drive it. Its 96db efficient. And, it's biampable. I actually find it plays better with 2 sets of speaker cables from 1 amp to it.

Do you know the oem? BMS?

 

[miniguy]

Then Vaughn Cabernett II may work in your room. It has small footprint but 93db/W with nice sound out of Accuton ceramic driver.


I bought this Vaughn Cabernett II speaker used 5 years ago as backup for Lansche 4.1

I am willing to part with it at reasonable price since I have Altec A7 and Lansche 4.1.

If your are intereted in this , please PM me.

Thomas

 

[miniguy]

What do the impedance/phase angle curves look like?

 

[thomask]

What do the impedance/phase angle curves look like?

I do not have exact curve but the manufacturer claims it to be tube amp friendly.

The above videos show the speaker driven by 48 watt SET Line Magnetic 508.

But please note that the listening room is very large (17 ft wide 30 ft long and 20 ft high).

Thus you may be able to play it loud enough with 8 watt SET in small room.

It has two 10 inch active woofers claiming 27 hz to 30khz with ribbon tweeter.

 

[miniguy]

I do not have exact curve but the manufacturer claims it to be tube amp friendly.

The above videos show the speaker driven by 48 watt SET Line Magnetic 508.

But please note that the listening room is very large (17 ft wide 30 ft long and 20 ft high).

Thus you may be able to play it loud enough with 8 watt SET in small room.

It has two 10 inch active woofers claiming 27 hz to 30khz with ribbon tweeter.

93 dB doesn’t matter much if the impedance curve looks bad

 

[Kingrex]

Do you know the oem? BMS?

I dont. But its a similar paper driver on the new 10 to the 15s. I'm pretty sure the compression driver is a Beyma. I really am shockes how good it sounds.

The crossover is also well made. A lot of Mundorf gold caps and air core chokes. And the ability to biamp is nice. I am almost ready to try it. I am building up another set of interconnect. Then I may put those Altec 1570B to the woofers.

I have also considered getting a Legacy iV2 to power the woofers. Only thing stopping me is Atmasphere has a few beta class A amps out made with gallium nitrite. Hmmmmm

I also had a pair of Thrax 100 watt class A only monoblocks here. The Thrax had more pronounced bass. More authority. I liked it. But the SET 845 had a little better mid/high realism. The 845 piano and violin are a little closer to that live un-amplified real. But I must say, the Thrax was shockingly close. Close enough I had to think for a moment, am I willing to spend $38k. If the thrax played with my current preamp it would be a stronger sell. They do something with their impedance where it does not play well unless tied to a Thrax preamp.

So there is another thought for the OP. What preamp, tied to what amp, tied to what speaker. That little chain really is the foundation of equipment making the sound. Then you need good source.

 

[Solypsa]

Will have to stop by- you are having a lot of fun! love to hear Thrax if its still around...

 

[Kingrex]

Will have to stop by- you are having a lot of fun! love to hear Thrax if its still around...

I returned the Thrax to Ed. They are nice amps. Before I decide on a SS amp, I need to hear the Dartzeel too. But these high end SS amps bother me in that you have to have their preamp to work correct. I assume the same for Boulder. I will also listen to the Boulder Integrated.

Ultimatly my goal is a SS integrated and bookshelf speaker to go in the 2nd home. Simple, small and elegant in tone. I need to just focus there, but I don't even have the speaker to start auditioning the amp with it. But it's nice to hear the brands sound in a system I am very familiar with.

 

[Atmasphere]

SETs do not employ feedback and so have a fairly high output impedance. So the usual rules of how to drive a speaker simply are not in play. With most speakers made today, the speaker is supposed to be 'voltage driven', which is to say that the amp driving it is capable of acting as a 'voltage source'. A Voltage Source is an amp that can make constant voltage regardless of the load impedance; this is an amp that doubles power as impedance is halved or cuts power in half as impedance is doubled. The former is a solid state amp, the latter is either a solid state amp or a tube amp with sufficient feedback to allow it to act as a voltage source.

A tube amp that does not use feedback tends to act more like a power source in that it will attempt to make constant power rather than constant voltage. No amp is a true power source; they all exhibit a power curve. To work with this kind of amp the speaker has to be designed about the Power Paradigm rules rather than Voltage Paradigm rules. You can't mix the two types of amps and speakers- if you do a tonal anomaly will arise. As a generaly rule of thumb the impedance of the speaker does not have to be flat, but the impedance does have to be high enough that the amp can make power on the flattest part of its power curve.

The Power Paradigm is what was around before MacIntosh and ElectroVoice pushed for the voltage rules back in the 1950s. You can recognize a Power Paradigm speaker because it will often have some sort of controls or switches for its various drivers because the voltage response of the amp is an unknown. These controls are meant to allow the speaker to be adjusted to get flat response- they are not there to adjust to the room! If the designer ommitted these controls it will be harder to get flat response.

For more on this topic see
http://www.atma-sphere.com/en/resources-paradigms-in-amplifier-design.html

In the case of SETs, to get the most out of the amp, the speaker must be efficient enough so that the amp never makes more than about 20-25% of full power. Otherwise distortion will cause the amp to sound 'dynamic', which is happening because the distortion is showing up on transients and the ear is interpreting the distortion as loudness. So when looking at speaker options you need to divide the amp power by 5 and then see what speaker will work with that sort of power. This usually means horns for all but the most powerful SETs. The more powerful SETs tend to have limited bandwidth (usually bass is compromised to get high frequency response) since output transformers get very difficult to build that will do more than 7-10 watts. This is due to saturation issues in the core of the transformer. You can do a parafeed design to get around this problem but now you have a coupling capacitor in series with the primary of the transformer and that introduces colorations of its own. For this reason, the lower powered SETs are the best sounding. The type 45 and their brethren that make less than a watt at full power are the best simply because they have more bandwidth.

A powered subwoofer system is really helpful for getting around this problem!

 

[miniguy]

SETs do not employ feedback and so have a fairly high output impedance. So the usual rules of how to drive a speaker simply are not in play. With most speakers made today, the speaker is supposed to be 'voltage driven', which is to say that the amp driving it is capable of acting as a 'voltage source'. A Voltage Source is an amp that can make constant voltage regardless of the load impedance; this is an amp that doubles power as impedance is halved or cuts power in half as impedance is doubled. The former is a solid state amp, the latter is either a solid state amp or a tube amp with sufficient feedback to allow it to act as a voltage source.

A tube amp that does not use feedback tends to act more like a power source in that it will attempt to make constant power rather than constant voltage. No amp is a true power source; they all exhibit a power curve. To work with this kind of amp the speaker has to be designed about the Power Paradigm rules rather than Voltage Paradigm rules. You can't mix the two types of amps and speakers- if you do a tonal anomaly will arise. As a generaly rule of thumb the impedance of the speaker does not have to be flat, but the impedance does have to be high enough that the amp can make power on the flattest part of its power curve.

The Power Paradigm is what was around before MacIntosh and ElectroVoice pushed for the voltage rules back in the 1950s. You can recognize a Power Paradigm speaker because it will often have some sort of controls or switches for its various drivers because the voltage response of the amp is an unknown. These controls are meant to allow the speaker to be adjusted to get flat response- they are not there to adjust to the room! If the designer ommitted these controls it will be harder to get flat response.

For more on this topic see
http://www.atma-sphere.com/en/resources-paradigms-in-amplifier-design.html

In the case of SETs, to get the most out of the amp, the speaker must be efficient enough so that the amp never makes more than about 20-25% of full power. Otherwise distortion will cause the amp to sound 'dynamic', which is happening because the distortion is showing up on transients and the ear is interpreting the distortion as loudness. So when looking at speaker options you need to divide the amp power by 5 and then see what speaker will work with that sort of power. This usually means horns for all but the most powerful SETs. The more powerful SETs tend to have limited bandwidth (usually bass is compromised to get high frequency response) since output transformers get very difficult to build that will do more than 7-10 watts. This is due to saturation issues in the core of the transformer. You can do a parafeed design to get around this problem but now you have a coupling capacitor in series with the primary of the transformer and that introduces colorations of its own. For this reason, the lower powered SETs are the best sounding. The type 45 and their brethren that make less than a watt at full power are the best simply because they have more bandwidth.

A powered subwoofer system is really helpful for getting around this problem!

“SETs do not employ feedback and so have a fairly high output impedance.”

Generally true though there are exceptions - the Air Tight ATM-300R takes an unspecified amount of NFB from the primary of the output transformer, resulting in an average output impedance of about 1 ohm.

 

[Atmasphere]

“SETs do not employ feedback and so have a fairly high output impedance.”

Generally true though there are exceptions - the Air Tight ATM-300R takes an unspecified amount of NFB from the primary of the output transformer, resulting in an average output impedance of about 1 ohm.

Yes- there are a few exceptions. Then you run into an interesting problem- how do you find a speaker for such an animal? Its low power, so you have to use a speaker that's efficient. But that speaker was probably designed for an amp that has a high output impedance. It may not sound right with one with a low output impedance (the crossovers might not work properly for one thing...).

 

[Tirebiter]

SETs do not employ feedback and so have a fairly high output impedance. So the usual rules of how to drive a speaker simply are not in play. With most speakers made today, the speaker is supposed to be 'voltage driven', which is to say that the amp driving it is capable of acting as a 'voltage source'. A Voltage Source is an amp that can make constant voltage regardless of the load impedance; this is an amp that doubles power as impedance is halved or cuts power in half as impedance is doubled. The former is a solid state amp, the latter is either a solid state amp or a tube amp with sufficient feedback to allow it to act as a voltage source.

A tube amp that does not use feedback tends to act more like a power source in that it will attempt to make constant power rather than constant voltage. No amp is a true power source; they all exhibit a power curve. To work with this kind of amp the speaker has to be designed about the Power Paradigm rules rather than Voltage Paradigm rules. You can't mix the two types of amps and speakers- if you do a tonal anomaly will arise. As a generaly rule of thumb the impedance of the speaker does not have to be flat, but the impedance does have to be high enough that the amp can make power on the flattest part of its power curve.

The Power Paradigm is what was around before MacIntosh and ElectroVoice pushed for the voltage rules back in the 1950s. You can recognize a Power Paradigm speaker because it will often have some sort of controls or switches for its various drivers because the voltage response of the amp is an unknown. These controls are meant to allow the speaker to be adjusted to get flat response- they are not there to adjust to the room! If the designer ommitted these controls it will be harder to get flat response.

For more on this topic see
http://www.atma-sphere.com/en/resources-paradigms-in-amplifier-design.html

In the case of SETs, to get the most out of the amp, the speaker must be efficient enough so that the amp never makes more than about 20-25% of full power. Otherwise distortion will cause the amp to sound 'dynamic', which is happening because the distortion is showing up on transients and the ear is interpreting the distortion as loudness. So when looking at speaker options you need to divide the amp power by 5 and then see what speaker will work with that sort of power. This usually means horns for all but the most powerful SETs. The more powerful SETs tend to have limited bandwidth (usually bass is compromised to get high frequency response) since output transformers get very difficult to build that will do more than 7-10 watts. This is due to saturation issues in the core of the transformer. You can do a parafeed design to get around this problem but now you have a coupling capacitor in series with the primary of the transformer and that introduces colorations of its own. For this reason, the lower powered SETs are the best sounding. The type 45 and their brethren that make less than a watt at full power are the best simply because they have more bandwidth.

A powered subwoofer system is really helpful for getting around this problem!

I have a pair of Avantgarde Duo Grossos that I purchased over 10yrs ago as the cornerstone of a long overdue system upgrade. Next came a pair of Lamm ML2.1 mono blocks which at the time made sense to me because of the low output tube amps and powered subs in the AG's. It has been a long process but learned over the years that the Grossos are not the easiest speakers to set up and still find myself with the urge to tweak placement, toe in etc. Basically I have found that they require both precise equipment matching and positioning, otherwise they just sound off...which is to say that even though I have found pleasing combinations, I am still not completely satisfied.

Reading this and other threads concerning SET amps and horn speakers I am finally starting to understand the love/hate opinions that many express when talking about AG speakers. So perhaps it is time to come full circle and look at replacing the Grossos. My inclination is to go old school and look at a pair of Classic Loudspeakers w/field coils. I have spoken with John Wolfe, who is a really informative guy and he recommended the T-3.4 models due to the fact that the ML2.1 output is only 18 watts and that the sensitivity of the T-3.4 is in the range of 97dB/w/m compared to 107 in the AG. Additionally, as I dig into the technical aspects of amp/speaker matching I find that the Lamm elevates output frequency performance by using a monstrous output transformer.

According to the rules of thumb you mention above, I should expect to be able to use a bit less than 4 watts to avoid getting into distortion issues. And therein lies my concern, for John himself stated that he would rather see his speakers driven with amps more in the range of 30watts to fully experience his designs. Regardless, he felt that I would be fine unless I wanted to push rock or classical music at full tilt boogie levels. Reading between the lines I think he is saying that the ML2.1 are not quite up to the task even with the performance of the large output transformers.

The question becomes, do I take a chance with the T-3.4's and if the ML2.1s are not up to snuff am I going to be chasing my tail again?

Brock

 

[Cellcbern]

FYI - Bache Audio 002ab - 96 db with built in powered subwoofer - comparison with Bastanis Mandala in 6Moons reivew:

6moons audioreviews: Bache Audio 002AB

 

[Tirebiter]

The Bache look interesting but am exploring options that don't involve built in powered subs...the list is limited for sure.