The SET paradox per Robert Harley

[tube fanatic]

Since we've been having some nice discussions on here about using SETs with Klipsch speakers I thought that this short narrative by Harley would be an interesting read:

 

http://www.enjoythemusic.com/tas/223/editorial.htm

 

Maynard

[robert_kc]

I agree with the article. 

Hi-fi equipment is like every other human creation - it’s imperfect.   IME satisfactory electronic test results represent a necessary though not sufficient condition for good sound quality from an amplifier.  IMO the goal is not to satisfy an oscilloscope or distortion analyzer or some software tool, it’s to satisfy a music lover.    And that involves a music lover listening to the reproduced sound and either having a smile on their face – or not.   I use my ears to decide when I think that my hi-fi systems sound closest to natural music – vs. letting electronic hardware and software decide for me.  

My goal for my hi-fi systems is to recreate as close as possible the experience that I had in the symphony hall and opera house – or perhaps I should say an accurate facsimile.  Because the complex sound of a full-scale orchestra cannot be reproduced with 100% accuracy via recorded music, this introduces subjectivity regarding sound quality (i.e., which compromises a listener is willing to accept).  Moreover, different people have different sensitivities to various aspects of sound.  Each person must choose the trade-offs that suits him or her.   Where there are inevitable imperfections in the reproduced sound, I want those imperfections to be pleasant sounding vs. unpleasant – to my ears.  I’m seeking an accurate and enjoyable facsimile of classical music from my hi-fi systems.  

I attend live classical performances on a regular basis.  I listen to my hi-fi on a regular basis.  I understand that humans can’t remember exactly how something sounded - nonetheless my long-term listening impressions are the most relevant methodology for judging how natural one of my hi-fi systems sounds to me.     I want that “magical” moment when I’m listening (for example) to my SACD of Brahms German Requiem and I completely forget about the hi-fi equipment - because I’m moved by the music.  If in my listening notes I consistently rank – based on many listening sessions over a long period – system configuration “A” (including a specific complement of tubes) as “magical”, and I consistently rate other configurations as something less – that tells me that configuration “A” is the best configuration in that room – for me.    

IME a few technical specifications do not completely define an amplifier’s subjective sound quality.  This belief is based on currently owning more than 2 dozen hi-fi amps, and having owned hi-fi equipment since 1970.   What I think is important is for each of us to find a system configuration that consistently sounds “magical”.  That configuration will be different for different people because of the type of music that they listen to, their listening room, how loud they like to listen, how their ears and brain process sound, and which inevitable colorations and limitations they find pleasing (or at least acceptable), vs. displeasing.

I rely on professional technicians to use electronic tools to ensure that my amps are operating properly (e.g., critical voltages are within specifications).   And I use my tube testers to ensure that a tube hasn’t gone bad.   But I use my ears to decide what sounds like an accurate and enjoyable facsimile of live classical music.  I’m able to achieve excellent results with both my Klipsch Palladium and RF-7II speakers by pairing them with specific tube amps, equipped with specific tubes.  (I’m also able to achieve excellent results with my Snell Type CV speakers (which don’t have horn loaded drivers) via careful amp and tube selection – as determined by my ears.)  It’s all about synergy between the music, the various hi-fi components, the room, and the listener.    IMO Klipsch and tubes go together like peanut butter and jelly.   With the right tubes, and with the right music (i.e., smaller scale music), my 10wpc Inspire single-ended-pentode (SEP) amp sounds fabulous (assuming a good quality recording) driving my Klipsch RF-7II.   (The crossover in my Oppo universal player off-loads deep bass to my Klipsch R-115SW subwoofer.)    My more powerful push/pull tube amps excel at large scale orchestral music (e.g., Mahler Symphony 2).

Bottom line – the scientific community understands quite a bit about reproducing music – but the key issue about what a listener thinks is enjoyable is still partly subjective, and many people prefer tube amps in general, and some people specifically prefer single-ended tube amps. 

 

[TubeHiFiNut]

My LaScalas are driven by CazTech SE-845 amps. Having tried them with a variety of amps, SE and PP, this is the amp I prefer.

 

The only things I rely on when evaluating components are my ears. If a new component results in my listening to more music, it stays. If not, it goes. Connecting me emotionally with the music, the pace, rhythm and soul of the music is paramount. It doesn't make any difference how good something "measures" if it doesn't meet my requirements.

 

For me, SIngle Ended amps and Hi Efficiency speakers (like my La Scalas) combine to speak to me and keep me listening to music into the wee hours.

 

This is what works for me. Others may find a different audio path. 

[Ski Bum]

Maybe I'm a reductionist stick in the mud, but it seems to me that the peculiar SE sound, which I happen to really like, has been plausibly explained, without appeal to novel measurement metrics.

[tube fanatic]

It's nice to see a couple of new folks getting involved in these interesting discussions!  There's no question that one's ears have to make the final decision about the sound of equipment.  After all, how often do we read about some magical specs only to find that the sound of the unit makes our ears bleed?  For me, the typical case in point is a SS amp with infinitesimal distortion which sounds positively awful.  And Robert, you have more than 2 dozen amps?  Wow, that eclipses what William and I keep on hand!  By chance, are either of you interested in DIY amp projects?  I haven't posted new designs on here in a long time due to the minimal level of interest, but will consider doing so again if there are enough guys who are into that area of enjoyment.

 

Maynard

[robert_kc]

6 hours ago, tube fanatic said:

It's nice to see a couple of new folks getting involved in these interesting discussions!  There's no question that one's ears have to make the final decision about the sound of equipment.  After all, how often do we read about some magical specs only to find that the sound of the unit makes our ears bleed?  For me, the typical case in point is a SS amp with infinitesimal distortion which sounds positively awful.  And Robert, you have more than 2 dozen amps?  Wow, that eclipses what William and I keep on hand!  By chance, are either of you interested in DIY amp projects?  I haven't posted new designs on here in a long time due to the minimal level of interest, but will consider doing so again if there are enough guys who are into that area of enjoyment.

 

Maynard

 

Tube_fanatic:  I should probably stop collecting amps.  I think I own a good sampling of various types.    With that said, I’d be glad to hear about your DIY projects.   I’m not a technician, though more than 40 years ago I built a Dynaco pre-amp and power amp from kits.  (In the early 1970s I was young and naïve, and I thought that Dynaco’s “new technology” (i.e., solid state) was better than their tube gear.)

 

Following are my current systems that provide a basis for comparing the sound of various amps.   Each amp has been auditioned with each set of speakers to find the best match.

 

Living room:  The speakers are Snell Type CV.   Subwoofer:  Klipsch P-312W.  The source components are Oppo BDP-95 (with USB hard drive containing high-res FLAC recordings), and Dual 1249 with Stanton 681EE.  Amps include a pair of McIntosh MC30s, Scott 296, McIntosh MX110 / McIntosh MC275, a pair of Pilot HF-56 mono receivers, an NAD pre-amp and Acurus A250 power-amp for movies, and a McIntosh 2155 driving JBL L830s in the kitchen / dining room.   A patch panel (banana plugs) allows me to connect the speakers to whichever amp I want, and a Niles AXP-1 RCA selector switch connects the Oppo to the amp.  

 

TV room:  The speakers are Klipsch Palladium P-37F.   Subwoofer:  Klipsch P-312W.  The source is an Oppo BDP-105 (with USB hard drive containing high-res FLAC recordings).  The amps are Scott 399, Fisher 800B, Kenwood KR-9050, Pioneer SX-1980, Fisher X-1000, Scott 299C, McIntosh MC240, and an NAD C375BEE.   The tube amps are for music.   The solid-state amps are for movies.   A patch panel (banana plugs) allows me to connect the speakers to whichever amp I want, and Niles AXP-1 RCA selector switches connect the Oppo to the amp.  

 

Office: The speakers are JBL L880.  Source:   Oppo DV-980H SACD/CD/DVD.  Amps: Fisher 500C, Scott 299B, Altec 353A, and an NAD D 3020 for general internet use (and summertime).   Banana jacks allow me to connect the speakers to whichever amp I want, and a Niles AXP-1 RCA selector switch connects the Oppo to the amp.  

 

Basement:  The speakers are Klipsch RF-7II.   Subwoofer:  Klipsch R-115SW.  Source:  Oppo DV-980H.  Amps: Scott 272, Inspire “Fire Bottle” SE Stereo Tube Amplifier HO, Scott 222C, McIntosh MX110Z tuner/preamp, Fisher KX-200, Marantz 2325 solid state receiver, Pilot SA-260, Scott 210F (mono), Fisher TA 500 (mono), Scott LK150.   A patch panel allows me to connect the speakers to whichever amp I want, and F/F RCA cables enable me to connect an amp to the Oppo, and a power amp to the MX110Z preamp.  

 

Bedroom:  The speaker is a Klipsch WF-35.  Source is an older CD player.  Fisher TA 500 (AM/FM mono receiver). 

 

My Windows 10 laptop with Music Streamer II DAC can be connected to any of these systems via “sneaker-ware”.

 

Regarding single-ended tube amps, I own only one example, the Inspire “Fire Bottle” SE Stereo Tube Amplifier HO.  I’m very glad to own it.  It’s finicky about speaker mating – it works best with my Klipsch RF-7II.   I drive it directly from the Oppo’s variable output (i.e., no pre-amp), in order to provide a “minimalist” configuration.   (The Oppo’s crossover off-loads deep bass to my Klipsch R-115SW.)  After much tube rolling, I’ve arrived at a combination that produces “magic” – for my ears.   With that said, in this same basement system, the McIntosh MX110Z (with treble controls attenuated) paired with the Scott LK150 also sounds fabulous, and delivers more dynamics for large scale orchestral music.

 

Back to the topic of subjectivity, and relying on imperfect and fallible memory of sound vs. electronic measurements – as I said earlier I agree that the listener’s visceral response to the reproduced music is most important.  Here’s my reference for sound quality:  my local symphony hall where no electronics are used during classical music performances:

[davesans]

I am fairly new to this forum I picked up a pair my first pair of Klipsch Forte's earlier this year just for the reason to get into a SET amp. So I have been doing a lot of reading on SET amps and checking out all the different ones on the web not sure yet if I am going to buy one already built or make one myself. 

[Bossman]

Nice posting Maynard. This article has some good info. I find it ironic that some people pay more attention to the specs and measurements of music equipment than they do to how the equipment actually sounds. That goes for amps and speakers. When I build a pair of custom speakers, I use testing equipment to measure the frequency response but I don't necessarily use the measuring tools to finalize the product. Once I get a frequency response close enough to flat or in the ballpark, I then turn off the testing tools, turn on the music, close my eyes and listen to music critically. From there I make judgements and adjustments and use the tools to see the adjustments made. People would be surprised how well a pair of 3 way horn loaded speakers can sound with with a frequency response that is not perfectly flat. Just my 2 cents..  

[Ski Bum]

Measurements do matter, regardless if you're looking for a linear, transparent amp or one with more of an audible impact on the reproduction.  The problem is that audiophiles refuse to acknowledge that these flea watt single ended amps are as much processors as amps, and Harley is just compounding the situation by romanticizing the amps with technical naivete and bad logic.  It seems more in service of consumerism than borne out of a love of music or genuine curiosity about the devices that reproduce it.  The DIY realm is refreshingly devoid of the flowery prose that Harley spews.  I wonder why?  

 

My issue is with blind consumerism, not amps that don't conform to prevailing engineering norms.  I love to ride that compression of low power, singled ended tube amps. 

[DaMuffinMan]

Maynard.. I would love to see you do a low budget SET amp that could be modified more in the future once finances opened up. I have learned a lot about tubes since joining here and looking around.  I also have a question regarding speaker efficiency. I can't seem to find that information on my 1983 Cornwall 1.5.  does anyone know what they are? And does the speaker lose efficiency over time? The speakers sound great I don't plan on messing with them.

 

Thanks

[Bossman]

On 11/14/2016 at 5:08 AM, tube fanatic said:

By chance, are either of you interested in DIY amp projects?  I haven't posted new designs on here in a long time due to the minimal level of interest, but will consider doing so again if there are enough guys who are into that area of enjoyment.

Maynard, Im interested.

[tube fanatic]

Here's the link to the "Little Sweetie" mono SETs (my most popular SET design) which I posted a year ago:

 

https://community.klipsch.com/index.php?/topic/159805-the-long-awaited-little-sweetie-mono-sets/&page=1

 

If anyone prefers a SEP, I can post links to a couple of those as well.

 

Over the winter I'll post a couple of newer designs.  I just have to find the time to draw schematics and put together the text.

 

Maynard

[DaMuffinMan]

By chance, are either of you interested in DIY amp projects?

 

 

HELL YEAH! 

[DaMuffinMan]

Been doing some reading and came across this on another forum. From what I am learning here, would anyone say this is a BOGUS statement, or is there any truth to it?

 

There are significant limitations to SET's. Glorious midrange, the best, really, but many people miss the deep bass, high frequency extension and dynamic range that other amps do better, or do not wish to be limited to highly sensitive speakers. SET is not the way to go if your primary listening is rock or classical orchestra.

[mkane]

On 11/16/2016 at 7:41 AM, DaMuffinMan said:

By chance, are either of you interested in DIY amp projects?

 

 

HELL YEAH! 

I'm in

[mike stehr]

2 hours ago, DaMuffinMan said:

Been doing some reading and came across this on another forum. From what I am learning here, would anyone say this is a BOGUS statement, or is there any truth to it?

 

There are significant limitations to SET's. Glorious midrange, the best, really, but many people miss the deep bass, high frequency extension and dynamic range that other amps do better, or do not wish to be limited to highly sensitive speakers. SET is not the way to go if your primary listening is rock or classical orchestra.

 

My 2A3 amplifier has deep bass...around 30-35Hz. I may be bold enough to say the SET amplifier has a more natural sounding deep bass than the solid state stuff I have.

 

That being mentioned, the thing about single-ended triode amplifiers with no feedback, (there is a internal degenerative fdbk) is that there will be an accentuation in the midrange.

If you like heavy metal, death metal, grindcore or whatever with distorted guitars recorded to be in your face...the attenuated midrange nature of a SET amplifier will make the guitars even more in your face. To the point of making it seem that the lower bass is drowned out. Classic rock is fine...

The problem with classical music and a SET amplifier is when there is a crescendo and all the instruments are full tilt. A SET amp will compress and sound squished when pushed into clipping when trying to play at realistic levels.

 

The SET will be fine when playing metal or classical at lower listening levels like late at night.

 

They just don't have enough power to play these genres of music at levels that classical and metal are usually played at. A guy with a large living room may want to pass on a SET amplifier if classical/metal are favored genres.

A single ended amplifier using a higher power pentode with some feedback might be up to the task for those types of genres of music. The feedback beats down the midrange, resulting in a more even bandwidth. But it still boils down to a lack of power.

 

 

[richieb]

Mike - I agree.  My Wright 2a3 monos provide an amazing amount of bass, not only for their low power but diminutive size. I'm also not sure I agree with the notion of roll off top end with SE DHT amps as I find the Wrights to have quite a nice sparkle. They also fill quite a large finished basement with power to spare. These observations are with Fastlane/ALK KHorns, I don't they do as well with the KP450/EAW/B&C (Frankensteins). 

My Dennis Had KT88 integrated at 8 watts or so probably provides more bottom end than the Wrights but not the high end sparkle or 2a3 clarity. 

Opening yet another can of worms I've had the push pull EL34 Quicksilver Horn Monos for a couple months now and have spent no time with the Wrights since they arrived. I've had more amps than I care to mention but the Quickies are right there as the most natural, neutral sounding amps I've owned. I find them more "live" sounding, not as "hifi" as the Wrights. And with the Frankensteins even at the very moderate volumes I listen, you are there. The Franks are more live sounding than even the KHorns. As great as they are, and they are, they sound hifi, albeit some of the best hifi you might find. 

[tube fanatic]

12 hours ago, mike stehr said:

 

My 2A3 amplifier has deep bass...around 30-35Hz. I may be bold enough to say the SET amplifier has a more natural sounding deep bass than the solid state stuff I have.

 

The problem with classical music and a SET amplifier is when there is a crescendo and all the instruments are full tilt. A SET amp will compress and sound squished when pushed into clipping when trying to play at realistic levels.

 

The SET will be fine when playing metal or classical at lower listening levels like late at night.

 

They just don't have enough power to play these genres of music at levels that classical and metal are usually played at. A guy with a large living room may want to pass on a SET amplifier if classical/metal are favored genres.

A single ended amplifier using a higher power pentode with some feedback might be up to the task for those types of genres of music. The feedback beats down the midrange, resulting in a more even bandwidth. But it still boils down to a lack of power.

 

 

The big issue here is how far from the speakers you sit when listening.  With near-field arrangements (which work great with LSs and CWs), even a low power SET can provide more than enough power for high level listening.  I gave up on large room systems a long time ago after experimenting with more of a near-field arrangement (typically 5-6 feet for me).  Being that close not only provides me with amazing musical involvement, but also makes it easy to keep even 20 db of headroom available for large crescendos while using very low power.

 

Maynard

[mkane]

   near field here also

[TubeHiFiNut]

I also prefer nearfield listening.