SET the best?

It pointed out that “all” other current GaN based amps use existing modules with chips that are currently used in non Audio devises like power chargers.

@mglik If he's getting semiconductor devices made for him I can see that happening. Usually you have to buy quite a lot of such devices to get any semiconductor manufacturer to pay attention to your order! But he might have an in with one of his former employers. But FWIW the chips used in switch mode power supplies have a lot in common with the requirements you face in building a class D amplifier.

@mglik  @atmasphere  There are so few threads focused on SET amps....Is it too much to ask that the AGD and GAN and Class D discussions be moved to their own thread or one of many already in existence?

I realize this is a 'resurrected' thread, but I for one am glad @mozartfan  did so.

Thanks. - David.

For me looks very weird that someone who was SET fan suddenly became digital amplifier fan. I can't say that SET are better or worth than digital amplifiers. But they are so different. These amplifiers topologies work best for completely different music, completely different speakers and completely different people.

It is like after be sport car fan become big SUV cars fan. 

As ASIC chip designer I can add. For any chip production you need to produce millions of chips of this particular model. Otherwise you will lose a lot of money.
For example, companies like Chord who made FPGA based DACs use FPGA for their custom DSP algorithms. Thay do it not because FPGA is better than ASIC. It is opposite in ASIC is possible to get in many times higher performance.
But they do it because ASIC production need to produce millions ASIC chip.
Therefore nobody does produce a special chip for audio!

There are so few threads focused on SET amps....Is it too much to ask that the AGD and GAN and Class D discussions be moved to their own thread or one of many already in existence?

@david_ten There are also a good number of SET threads. The comments are relevant due directly to the question asked in the OP. It appears that if the answer were 'yes' at one time that SETs are rapidly being eclipsed, even by class D amps let alone other tube topologies.

@alexberger

AGD are not digital amps as well as the other 90% class D amps. They are analog with the small exception of Technics, Lyndgdorf and maybe a few others

@alexberger 

There is a big difference between an ASIC, and a FET. You should know this being you design ASIC's. You should also know most class D amps are not digital so what's your point of all your mis-information??

well I have not heave your amp, nor any other Class D. 

Only several PP amps. 

EL34, KT88,Kt120, all were excellent in dynamics and musicality.

But have you read anything suxch as **wow this xyz PP amp is magical..**Maybe Jadis' new KT170 has some magic,, but that tube along with the KT150, to me looks just like a  bigger KT88 style tube..and so??? More power? More  bass/highs..?? OK, Big deal.

But how often have we read, **WOW sets are magical, pure lineraity..*

My tech who built his UX250 amp, had 1 cap not soldered, well solder broke off after so many years,,, we reapired it,, brought it  back,, NOW I was hearing SET magic for the 1st time. Once you heard SET sound,, there is no possible way the  audiophile will turn his back ona  SET. Maybe as a 2nd system, which I am sure many of us here have bother PP and SETs.

But once struck with SET magic,  one could never forget the magic (in certain recordings/music styles). 

SRTs the best??

Lets  rephrase.

Which amp design offers the magic  **something SET -like**?

EL34 SET's yes, But not a  El34PP. 

Hi @ron1264 ,

I'm not an expertise in Class D amplifiers.

But all of them digital and PWM are very different from SET.

For example, most of SET fans use high sensitive speakers like: horns or full range drivers. And they like these speakers not just because they don't need huge power amplifier - but because dynamics, texture, transparency advantage over mainstream low sensitive speakers.

I can't imagine any benefits from class D for high sensitivity speaker. 

About analogue chips for audio. Any small production parts "for audio" will cost crazy expensive. Look, for example , at prices for AN Kaisei electrolytic capacitors precising vs regular electrolytic capacitors.

amplifier - but because dynamics, texture, transparency advantage over mainstream low sensitive speakers. ~~~~~~~~~~~~~~~~~~~~~~~~~~~ Yep Box xover types had their day in the sunshine, Clouds are forming, Ck out the xover box used speaker listings,, likea grave yard,, where in 2 yrs you will see lots on unsold Zu and Tektons just sitting, day after day, week ,,month.... sad, thats suffering. My FMS aint going no where, A 2A3 dual tube amp is on the way. My Dual FMS is going to get a nice match. $550+$350 35 lb speaker.

~~~Wife Friendly~~ as a  huge bonus. 

@alexberger 

Fair enough

SET amplification is ~~Esoterica~~ Only for a  select few. 

A couple years ago considering class D for summer amp replacement for my 845 space heater. Did much research looking for any and all comparisons to SET. While some were positive about class D, the ones that caught my attention were those with high efficiency speakers. The one commonality I observed in those cases claimed there was some loss of texture with the class D. Now, I'm not sure if they're talking about timbre or micro dynamics, perhaps some combo of both, but either way, I find this is special quality of SET and my horns. I don't hear my tubes as tubes, rather I hear them as what the Brits call them, valves. These valves breathe as flesh and blood beings. no SS device can match this special ability.

Hello,

absolutely I need to confirm the GaN Fet AGD uses for the Audion, Vivace, and Tempo (either in the AGDGaNTubeKT88MKii or in the new GaN power module for the Tempo) were optimized specifically for Class-D application hence for Audio.

The article of Rick Backer is therefore perfectly correct.

I cannot disclose the name nor the products of the 2 very large customers these chips were originally intended for (customers of International Rectifier), but I can confirm these were 100% audio applications. The current GaN-Fets available today from many suppliers are indeed designed and specified for Adapters and Battery charger (pc/tablet/phone) applications, and they have therefore different characteristics (very different) than the one we are using. To use them in Class-D is possible of course, but several additional layers of circuit design optimization are necessary.

Hope this closes the case about the truthfulness of what Rick Becker reported. 

quality of SET and my horns. I don’t hear my tubes as tubes, rather I hear them as what the Brits call them, valves. These valves breathe as flesh and blood beings. no SS device can match this special ability. ~~~~~~~~~~~~~~~~~~~~~~~~~ What SET tube are you running?? Well yes your extentiatial experience of SET’s as *life giving energy to the musical notations** paraphrase mine,,, is just another way of saying what others have taged as **psycha-delic* (greek psyche = soul breath) PP amplification though sweet, is not the same as SET valves. You know SET;’s have had their share of critics over the past decades *the cold ice bucket splash** for the following reason. , some of these criticisms are the result of the evident fact of slim choises in speakers that would pair up successfully with a SET amp. Fostex has come some ways with new designs,

Tang Band also has given some good sound, then AER, Cube, Voxativ all in the past 10 years have made superior Full Midrange Speakesr avaliable. Meanwhile Stereophile and other online stereo reviews have focused primarily, if not exclusively on covering box xover.low senstivity type designs to the complete neglect of higher Sensitive Full Midrange Speaker designs, aka Full Midraange w assist. I for one have no idea how all this shoving SET designs ina corner and worse the clear fact that Full Midrange Speakers have not gotten shoved ina corner,, but **thrown under the bus**.

Full Wide Band Midrange speakers are the most grand **revelation** in my entire audio hobby history.

The WOW factor was off the chart when this discovery was established as *the truth*. I realize Audiogon has always beem always will be about xover.low(er) (makes you happy?) design styles as Front and Center (I get THAT = marketing sells, I wish to say propaganda works,, but this will only call up sour energy from the xover fan-atics and the mods may steop in to cancel my post),, Back in the 1970’s 1980’s the audio retail showrooms were packed full with all sorts of over /inefficient speaker designs. WE were sold in with no thoughts of a **Full MidRange Speaker** The new Full Midrange Speakers now have been around some 10 years, and still not much attention among audiophile discussion. With new SET’s now making their debut with very affordable prices,,, its posssible the new Full Midrange Speakers also may grab some of this new interest as they ride the tail of *The New SET Revolution**. PP amplification sun is lowering in the west, while the SET Star is arising in the east. Side note to all of this Jadis has a new KT170 design tube.. I took a close look at the tube,, Looks like nothing more than a huge KT88. = I’ll pass.

Give me the magic of a SET.

Last note, glad you brought up the issue with the 845 SET, the heat factor. I passed over the 845 for other reasons, went with the 2A3 which my tech wrote back,, **has high distortion at a whopping 5 %, and flea watt power..** I told him, neither spec concens me, I have a speaker design that can deal very effectively with both *flaws**. **are SETs the best amplifiaction??* If we are considering musical magic /midrange, then yes SET’s are the finest musical amplifier.

Note the topic My Long list of amps,, posted years ago, has 1M views, runs on to hundreds of pages,., Its all about BIG POWER amps, massive PP amps, massive SS amps, 

I have no interest whatsoever in either. as I have shown with convincing proff in my posts on this topic, that SET is **set apart** from the rest.

SET's are esoteric, = XXP amplifiers. 

Hardly a  mention of SET  in tghat entire topic.

In 20 years , it will be all about SET, SS and PP will  be a  rare mention. 

AS the poet wrote

absolutely I need to confirm the GaN Fet AGD uses for the Audion, Vivace, and Tempo (either in the AGDGaNTubeKT88MKii or in the new GaN power module for the Tempo) were optimized specifically for Class-D application hence for Audio.

The article of Rick Backer is therefore perfectly correct.

I cannot disclose the name nor the products of the 2 very large customers these chips were originally intended for (customers of International Rectifier), but I can confirm these were 100% audio applications. The current GaN-Fets available today from many suppliers are indeed designed and specified for Adapters and Battery charger (pc/tablet/phone) applications, and they have therefore different characteristics (very different) than the one we are using. To use them in Class-D is possible of course, but several additional layers of circuit design optimization are necessary.

@agdproduction 

I wonder if his nose grew while making that statement?

Currently Audio is a minuscule portion of the GaN market, even at the voltages/currents of GaNFETs that would be used in audio.

Most of the ones in this range are used for high volume high performance POL DC-DC and sync-FETs in DC-DC and AC-DC. Total volume in audio for GaN is puny right now. It is primarily a marketing tool at this point.

Then again, there is the simple fact that a Class-D amp is effectively really quite the same as a DC-DC. What makes a GaN good for a DC-DC would make it good for audio and vice versa with rare exception, more so on the silicon side actually than GaN.

The quote above w.r.t. complexity just sounds like talking points from the GaN systems white paper on their ref design and using their parts in a Class-D amp versus their competitor. Their parts due have advantages against some other parts in Class-D, dependent on how used, but the claims made would be relevant to any half-bridge DC-DC as well, not just Class-D. I expect GaN is chasing this market as the GaN market is still immature and they need to drive sales to ensure continued investment. By far the most important market for them will be electric Vehicles and those devices are much higher voltage.

Odd no one here is bringing up speakers for SETs???

Sure this is  the amp page,, however with SET's speaker selection is super critcal  

THe magic of a SET only opens to the degree a  speaker allows that magic to be registered.

Basically we have 2 speaker designs that work with SET's, 

,,although my tech just wrote back,,,,He and others who have heard his SET with Gryfx SP 10 ,,double stacked!!! system,, sounds **wonderful*** I said,, **huh??**, well I guess this is a testimony to the oft misunderstood power to a  low powered SET amp,. SETs are able to drive even a  heavy load.

My tech wrote,,**you realize a  2A3 has 5 % 2nd harmonic distortion,,and is only 3.5 wtts..**

I knows he loves the KT120's in his beautifuol Webster Organ 90 mono blocks. ...so I looked up 2nd HD on the 120's,, ~~~15%~~ Lets see how he wiggles out that one,,

OK 5%,, that leaves me ~~95%~~~ gorgeous pure linear high fidelity magic.... 

The 3.5 watts, no problem for my music requirements. 

More is not better.

My Defy's 100 watts, is not going to deliver the magic of a  3 watt SET. 

Big PP power is losing to the new SET amps popularity. 

I can't imagine any benefits from class D for high sensitivity speaker.

I can!! Low noise so low its hard to hear even with your head in the mouth of the horn- and greater detail/better 'focus' so images in the rear of the sound stage are easier to hear- and overall every bit as smooth- in fact smoother.

When you combine smoothness and greater detail at the same time that's when you're getting somewhere.

Good point!

so  how would you describe the sound of a  845 tube?  I guess this would depend on front  tubes, driver/pre tubes.

Compared to other SET and PP tubes, 845 always exciting, fast, immediate, impactful. Can also be refined or relentless, synergy important for last two. I prefer 845 driven by 300B, allows max refinement.

Speakers for SET, usual suspects, Klipsch Heritage, Devore, Omega, I've used Alon (now Nola), also used Merlin VSM-MM, Spatial Audio, Zu, always been curious about Pure Audio Project, Coincident, Audio Note, some claim Tekton, Charney, Coherent, Reference 3a, Avantgarde, of course I'm missing some.

I want to add vintage speakers to the list, like:

Altecs - VOT A5 A7, 19, Valencia, 604.

Old Tannoy - Silver, Red.

Old JBL L200.

Used full range: Lowther, Klangfilm, Telefunken.

New full range drivers like:

Audio Nirvana, Lowther, Fostex, AER, Voxativ.

I use myself Altec 604E. They can be driven easily even by 45 tube.

how would you describe the sound of a 845 tube?

You can’t- any more than you could a 300b or type 45, because the output transformer and the individual tube’s match to it plays such a critical role.

People often say the tube has a certain sound. But with all the differences in transformers there's no way they could possibly tell.

People often say the tube has a certain sound. But with all the differences in transformers there’s no way they could possibly tell. ~~~~~~~~~~~~~~~~~~~~~~~ The local tech here also pronounces trans quality especially in SET desogns,, **only the best will do..***, His pure Colbalt in the UX250 vs say Z6 or Z11 steel,

are we talking nuances of dif.

I was refering to general charachertistics f the 845,

. I’ve read good things about the 2A3,, then here we read the 845 is simply gorgeous. Another comment likes the 300 as driver stage tube,whereas my tech says avoid 300B in any part of the design. He has no sympathy for the 300B, and yet some big manufactuers employ the 300 as driver tube. I guess as with all amp designs everyone will have his particular preferences. The 2A3 arrives next month, its a intergrated with my fav pre tubes AX and AU. Last note, what keeps me away from considering the 845 amp, is the weight, All offerings are over 70 lbs,, Even though it will not be moved around much,,I just don’t want a amp over 60 lbs, as my ultimate limit as I age. The 2A3 is right at max, 60 lbs. Lower weight = cheaper trans. I get that. But it is what it is. The Defy is 70 , one is enough. 60 lbs I can lift w/o injury.

Klangfilm, Telefunken. ~~~~~~~~~~~~~~~~~~ I’ve must have posted this YT vid at least 10 x’s here on Audiogon,, why not 1 more. Yes I understand the music is not at all demanding, and recorded with fantastic early 1960’s technology,,however have you ever heard such purity in vocals. The speaker circuit is going full circle,, it will come back to Full Midrange Speaker ye once again, starting in the 1920’s, In china, the FR is ever more popular vs xover/low sens types. 1st up, Coral Beta 10, have you ever heard,,,**FR lack bass**, hahaha well here ya go, have you ever heard such PERFECT bass repsonse in your life?? I have NOT

Post above is refering to this Coral Beta 10, NOTE the amp, ,, 2A3,, haha, can't wait, 

Looked 15 minutes for the YT vid showing the 1929 Colatura (sp??) FC in action,  can't loacte it, 

Here is another early production FC in action. 

WOWWWW

Beats any xover design/low sens configure, such as Wilson, Sonus Faber, Dali,  ZU, Tekton etc

Coral Beta, made in japan, one of the very finest Full Range speakers ever designed,,,looks awefully close to the DavidLouis VX8, which I hold as the wolds finest speaker,, at least in my exp.

No doubt the DLVX8  chinese tech paid very close attention to this  Coral Beta 8. 

One of the first versions of Altec 604 from 40x.

What I doubt you will see is a DavidLouis VX8 Mark2.

Not gonna happen.

When I see a  manufacturer with Mark 2, Mark3 new upgrade versions... begins doubts.

Fostex is famous for multiple offerings.

Many of Voxativ's models just don't make any sense at all.

AER has Model A, B , C. each with 2 versions..

To me thats all confusing.

The only Full Midrange that seems to make sense is the DavidLouis, 

1 model, 2 sizes.. 

Choose W6 or W8.

Even Tang Band can't seem to get it together. Dozens of  models. 

Why???

I was refering to general charachertistics f the 845,

. I’ve read good things about the 2A3,, then here we read the 845 is simply gorgeous. Another comment likes the 300 as driver stage tube,whereas my tech says avoid 300B in any part of the design. He has no sympathy for the 300B, and yet some big manufactuers employ the 300 as driver tube. I guess as with all amp designs everyone will have his particular preferences.

@mozartfan You’re making my point. Its not the tubes, its the transformers. IMO the tubes are all sounding the same- they have similar linearity. But the output transformers vary dramatically!

I have a set of Coral Betas you can have for the cost of shipping. One of the drivers has a damaged voice coil. These are the drivers in Coral cabinets with the passive radiators.

tubes are all sounding the same- they have similar linearity. But the output transformers vary dramatically!

~~~~~~~~~~~~~~~~~~~~~~~

I’m  SO

glad you posted this Which confirms my exp in PP amplifaction with various tubes. EL34 KT88 KT120. I mean they might be dif in sound, but not by any significant margin,, l

ets just say a miniscule nuance..and this applies also to KT150 KT170 Nuance,, but with the wrong speake, all squashed to zero nunaces. I figured all SET tubes are only going to be variations on a SET theme. = nuance dif. Nada mas.

My frends pure cobalt trans, adds something special. But again, out of production and very expensive,, = not doable/practical.

Back to reality.

Z6/Z11. Not bad. So where does this lead us, if we can’t get the real deal Cobalt Dream Trans??? Speakers. Here’s where we can pick up ,,or lets say,, here is where we can elevate the SET amplifiaction to its magical pure linear Powers. Which is why I hammer non stop about the super high value of a FR (= Full MidRange Speaker) assist system. Why assist? WEll as we all know well, SETs tend to roll off both ends the spectrum,, No big deal.. **whaaaaaa???* you demand to know. WEll yes, No big deal. I am not going to explain why its no big deal as I have already explined no less than a dozen X’s around here,,and I want to get back to my music in the other room. btw I may pass on the Beta.s had you said, a pair of Beta 8 in good condition,,yeah I’d take you up, Those go for $2k a pair in excellent condition.. But I kknow the DLVX8 match if not pass up the Coral Beta 8.

To say 845 sounds similar to 300b or any other SET is nonsense. 845 plate voltage nearly 1000V vs 350v with 300B means everything. Power supply 845 massive, 300b baby in comparison. Certainly, transformers extremely important, but these two tubes and amps very different animals. Both 845 amps I've been running for many years sound similar and unlike my 300B or 2a3 I ran some years ago. 845 tube has unique requirements, results is unique sound qualities.

ahh yes, the magisterial  845 tube, has held me facinated for decades, 

Now afforadble, with the newer chinese designs,  still its the weight factor, as you mention. Getting up in age limits mobility.

+ one must consider heat factor, which if I did remain here in New Orleans, in a  small room, get the idea....heater in 100++ degree heat???

= Your *special requirements*

Hi @mozartfan ,

845 tube needs ~10KOhm output transformer that has more narrow bandwidth compared to 3.5K transformer for 300B, 5K transformer for 45 or 2.5K transformer for 2A3 tube. 

So, if you have high sensitive speakers in a small room I don't see any reason for 845 amplifier. Not just because price.

845 not for you, heat, weight, and reliability factors in as well. Heat is enemy of reliability, these things run hot, hot, hot, they have no soft start circuit so wear out tubes more quickly. I wouldn't trust just anyone with nearly 1000v running through these things, not sure I'd trust these rather unknown Chinese 845. Line Magnetic is one of better ones, although I've seen propensity to burn out certain boutique power tubes, which tells me they run them hard.

This is issue I see today with SET in general, some of these guys run higher plate voltage then output tubes can handle, too many instances of premature tube failure. People too often blaming tube manufacturers. Prior to purchasing any SET, I'd research this aspect of that particular amp, know what your in for.

This is issue I see today with SET in general, some of these guys run higher plate voltage then output tubes can handle, too many instances of premature tube failure. People too often blaming tube manufacturers. Prior to purchasing any SET, I'd research this aspect of that particular amp, know what your in for.

Its probably also a good idea to get some idea of what the tube is rated for. For example a 300b in class A1 (A2 an even A3 are possible modes of operation as well) will be good for 7 Watts. A type 45 is 0.75 Watts. When you get stories of greater power, how are they doing that? Is it by using a variant (there's a graphite plate version of the 300b called the 6300b for example) or are they running plate current (class A2 or A3)?

How anyone can say they know what the tube sounds like when the design of the output transformer easily trumps the tube is beyond me. All you can really say is how that tube sounds with that output transformer.

these things run hot, hot, hot

~~~~~~~~~~~~~~~~

I was joking with my tech, why he does not get the Wavac 833 amp, he said something to the effect,,,*I don’t need a heater in my home...** especially with our New Orleans 100+ degree heat 6 months of the year. well looks like I’ll never own a 845. As I say I already have a power amp with the Defy’s 12 tube set up. And surprisingly does not put out much heat. The center trans has been running cool. But thats about to change with dual FR + woofer + tweeter, ohm load about to test Defy’s power. Also need to ck with tech to make sure that ohm load is ok with the 2A3 amp.