Why do SETs sound so good?

[Guest thesloth]

Hello Erik2a3, I am familiar with those amps. Quality chokes and interstage get expensive. Speaking of which have you heard a Brooke 12A amplifier? The klipschorn brochure recommends them. Since 2A3's are so damn expensive I was thinkin of using 6GE5 instead. In triode mode it's properties look very close to the 2A3, mu=4.4, Rp=820, gm=5365. Did I mention they are like $5.

[Thaddeus Smith]

something like this?

 

http://spudkit.com/?page_id=13

[Guest thesloth]

something like this?

 

http://spudkit.com/?page_id=13

 

You can get almost 5 watts from 6LR8's in triode mode with this spud kit: http://www.neurochrome.com/novar-spud/

[joessportster]

I wouldn't mind taking a stab at building an SET kit designed by you... you know.. for comparison's sake

+1

 

all ways wanted to build an amp but have never taken the plunge, for fear of lack of support of my novice questions.   I definately prefer set amps and 45 is my top o the heap preference,  I would love to find a 45 amp that supports Headphones     

[Guest thesloth]

Hey Joe, if you want to use your headphones with your 45 amp just get some 10 ohm 10 watt resistors and run them in parallel. You can get the resistors at radioshack for a couple bucks.

 

Are your speakers 8 ohms?

 

Are the HiFiMan HE 500 the headphones you want to use? Are they 38 ohm impedance?

 

 

IF you answered yes to these questions then I have a way for you to get what you want. Paralleling the 10 ohm resistor will create a:

 

1 / ( (1/38) + (1/10) ) = 7.9 ohms which is exactly what load resistance your amp will want.

 

Audio power  output to headphones will be around .5 watts.

 

EDIT: I want to clarify that you use one 10 ohm resistor in parallel with the headphone driver per channel.

Edited August 4, 2015 by thesloth

[seanwalsh]

On my La Scala all three drivers have a sealed back chamber and a mass of air forward in the horn obviating a need for a dampening factor. These are the only speakers that my 2a3 amp excelled on.

[Guest thesloth]

Specs just help narrow down options.

Can we agree bandwidth is a spec that means something? I mean you do want to hear everything in the audible range.

Can we agree power is a spec that means something? Nobody wants to buy an under powered amp to pair with inneficient speakers.

S/N ratio? Who wants an amp that has hum or hiss?

I will say distortion is something that is tough to gauge quality on.

Specifications are not meaningless. But I do agree that specs on paper won't always say an amp will sound good or not.

[Fjd]

 

If "straight wire with gain" is the target.  This $5 chip amp comes close and sounds very good also.

 

I have not had the same success with chip amps that you have. I have tried several and find them all good but lacking.

 

The solid state amps I think deserve recognition are the offerings from Nelson Pass. The DIY First Watt amps I have heard,

built and tweaked are amazing.

 

 

Dave

 

 

 

While I haven't had any experience with those nice looking and expensive NAD amps that a couple on the forum are using, my experience with the simple chip amps has been similar to Dave's where they seem to be lacking that "life" that seems to be part of the listening experience with my tube amps.  I'm not sure if this is a power supply type of issue, feedback type of issue or something else since many seem to be built using the evaluation boards rather than well-engineered designs.

 

I think quality transformers play a big part in tube amps and also a big part in my most interesting chip amp.  This chip amp is made from a roached McIntosh MC250 that had a couple of LM3886 modules inserted into the circuit.  This amp does have a pleasing sound to it that I'm sure the transformers play a significant part (similar enough to be a cousin to the Mc250).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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Edited August 9, 2015 by Fjd

[oldtimer]

 

 

Most owners of Klipsch speakers do not realize what they are missing until they try SE class A

LOL.  Those that have and are musicians are not so easily impressed with coloration.

 

This is a quote from the F6 manual from the legend in amplifier design much as Paul Klipsch is in speaker design has to say.

 

"It is easy to make an amplifier that measures well, but more difficult to make one that sounds subjectively exceptional to discerning listeners and does so reliably"

 

And another quote,

 

"Besides measuring reasonably well, the best sounding amplifiers: tend to be simple, are intrinsically linear, run deep Class A'  use high quality components"

 

This is the case in a quality SE Class A amp whether tube or transistor and the reason they are so popular with Klipsch owners that can hear the difference. 

 

One can always use specs and graphs to decide what amplifier to buy instead of their ears but I bet if you are a decent musician you will want to hear what your guitar purchase sounds like before you buy it and not rely on what is said in sales brochures. There is no such thing as a perfect amplifier, just one that sounds best to your ears. When I was young I made the mistake of buying amps with the best specs because that is what supposed to sound the best. 

 

At least your response did not bring up extraneous crap with little relevance.  Who here has heard something they describe as "air" over their systems?  Now who here has heard that same supposed "air" at a live performance?  My mind is not closed, but my ears have a lot of experience.  You are right, quality is quality.  Coloration should begin and end at the point of attack on the instrument.  Any further coloration is just masturbation to certain listeners ears.

[Fjd]

 

 

 

Most owners of Klipsch speakers do not realize what they are missing until they try SE class A

LOL.  Those that have and are musicians are not so easily impressed with coloration.

 

This is a quote from the F6 manual from the legend in amplifier design much as Paul Klipsch is in speaker design has to say.

 

"It is easy to make an amplifier that measures well, but more difficult to make one that sounds subjectively exceptional to discerning listeners and does so reliably"

 

And another quote,

 

"Besides measuring reasonably well, the best sounding amplifiers: tend to be simple, are intrinsically linear, run deep Class A'  use high quality components"

 

This is the case in a quality SE Class A amp whether tube or transistor and the reason they are so popular with Klipsch owners that can hear the difference. 

 

One can always use specs and graphs to decide what amplifier to buy instead of their ears but I bet if you are a decent musician you will want to hear what your guitar purchase sounds like before you buy it and not rely on what is said in sales brochures. There is no such thing as a perfect amplifier, just one that sounds best to your ears. When I was young I made the mistake of buying amps with the best specs because that is what supposed to sound the best. 

 

At least your response did not bring up extraneous crap with little relevance.  Who here has heard something they describe as "air" over their systems?  Now who here has heard that same supposed "air" at a live performance?  My mind is not closed, but my ears have a lot of experience.  You are right, quality is quality.  Coloration should begin and end at the point of attack on the instrument.  Any further coloration is just masturbation to certain listeners ears.

 

 

 

 

To add to the Nelson Pass quotes, "IM distortion is the elephant on the dance floor.  Much of the time IM distortion simply forms a complex 'noise floor' which masks musical detail. At lower levels, it takes the life out of the music and makes it uninteresting, even irritating. It isn't as noticeable with very simple music, but it stands out with orchestral material as if the instruments were covered by a veil. At high distortion levels, the sound simply turns to mud, and we turn it down."

[Fjd]

I would really like to dip my toes in the SET or SEP but do not how deep I should go. What is a good tube amp (best bang for the buck) one can buy or build without spending a ton of money. I have looked into some of the http://tubelab.com/ offerings being a DIY'er but am not against buying a decent retail one. I have looked at Yaqin and Music Angel offerings as well as some of the others. It is a lot easier finding a good SET if you get into the 4 figure offerings but being  retired on a limited income I do not want to spend that much especially owning 3 Class A SS amps that are considered some of the best. That being said I still would like to hear the sound of a decent tube amplifier either SET or SEP. 

 

 

 

I have no affiliations with these companies but have bought from Parks Audio (PCBs), Tube Lab (PCBs), and Bottlehead (full kits).  Given you have built the DIY First Watt clones the Parks Audio PCBs and Tube Lab PCB will probably be the most economical choices (and sound good) and handle most of the layout issues and you only have to order parts and something for the case. 

 

While the single ended amplifiers seem relatively simple, layout is critical for good results.

 

Parks Audio

http://www.parksaudiollc.com/

Shannon Parks forum on DIY tube

http://www.diytube.com/phpBB2/

Tube Lab

http://tubelab.com/

Tube Lab forum on DIY audio

http://www.diyaudio.com/forums/tubelab/

Bottlehead

http://bottlehead.com/

Bottlehead forum

http://bottlehead.com/smf/

[Thaddeus Smith]

I would really like to dip my toes in the SET or SEP but do not how deep I should go. What is a good tube amp (best bang for the buck) one can buy or build without spending a ton of money. I have looked into some of the http://tubelab.com/ offerings being a DIY'er but am not against buying a decent retail one. I have looked at Yaqin and Music Angel offerings as well as some of the others. It is a lot easier finding a good SET if you get into the 4 figure offerings but being  retired on a limited income I do not want to spend that much especially owning 3 Class A SS amps that are considered some of the best. That being said I still would like to hear the sound of a decent tube amplifier either SET or SEP. 

 

send a message to Maynard (Tube Fanatic) and see what he has available for sale that might suit your needs.

[Ski Bum]

Why do SETs sound so good?  My wild guess: a mish-mash of various things.

 

-harmonic coloration, being discussed in the distortion thread; given the relative power levels that Maynard pointed out, I'm not sure how much of a factor this is, but it seems reasonable, and is based on the real behavior of stuff, not tube pixie dust conjecture

-output impedance mediated distortion which includes linear deviations dictated by the load, as well as the back-emf "Carver effect" which we've discussed and some of us have actually measured

-the whole feedback thing (yes, directly related to the first two, and also related to the whole circuit complexity aspect).  Play with global feedback on these little tube jobs and tell me it doesn't have ramifications for imaging.  Too much may help the amp be linear, but the coinciding presentation also becomes, well, two dimentional/flat/boring/artificial sounding. 

 

Those are my stabs at the answer.  Of course I could just be mesmerized by the shiny mercury.

Edited August 13, 2015 by Ski Bum

[jacksonbart]

You're distorted and you like dust.

[oldtimer]

I make a conscious effort not to drive things into overload, so none of that part should matter to those who do the same?

[tube fanatic]

I am resurrecting this thread in view of a brief chat with William (wdecho) in regard to his recently constructed low power SET.  As he has stated, this is his first tube building experience and it has been exceedingly positive.  Such amps can be constructed by anyone who knows how to work with high voltages in a safe manner.  Given the fairly minimal cost of low power SETs, and the high efficiency of Klipsch speakers, the combination offers an avenue to phenomenal audio reproduction.  Just think- a pair of new Klipsch towers (like the KF-28s which Newegg recently sold for $360/pair), a self-constructed SET for around $300, and a decent CD player or other source and you will be transported to a new audio experience.  All for maybe $800!!!  Quoted with permission:

"This is truly an amazing little amp for such little money to build. It is hard for me to turn it off."

"This little amp has the best soundstage I have heard in my system."

"To me my horns just sound better with SE amps whether SS or Tube. As of right now, and my opinion is subject to change, I like the sound of the 6EM7 amp over the SS Firstwatts which are the best sounding SS amps I have ever heard. The tube preamp with the F4 type amp is a close second and is a great combination."

So, who's going to be the next forum member to give a build a try?  There has been some discussion in 2 channel about a low cost Chinese amp.  While it certainly is nice to look at, its cost is almost triple what it would cost to build a low power SET like William's.  In addition, it isn't a dual-mono unit, it has a single volume control and no balance control (in building your own, either of these can be easily included), and its output transformers are probably (speculation on my part) not as good as the units which William used in his.  Anyone who believes that most Klipsch speakers require high power is making a bad judgment.  My experience has been that even 1 watt/channel is often far more than is needed for a majority of listening situations.

Maynard

[joessportster]

Hey Joe, if you want to use your headphones with your 45 amp just get some 10 ohm 10 watt resistors and run them in parallel. You can get the resistors at radioshack for a couple bucks.

 

Are your speakers 8 ohms?

 

Are the HiFiMan HE 500 the headphones you want to use? Are they 38 ohm impedance?

 

 

IF you answered yes to these questions then I have a way for you to get what you want. Paralleling the 10 ohm resistor will create a:

 

1 / ( (1/38) + (1/10) ) = 7.9 ohms which is exactly what load resistance your amp will want.

 

Audio power  output to headphones will be around .5 watts.

 

EDIT: I want to clarify that you use one 10 ohm resistor in parallel with the headphone driver per channel.

Thanks for the information, It will be handy when I get another 45 amp...................Yes The headphones are HE500 at 38 ohms

[Mallette]

Single ended class A amplifiers are the most linear of all designs and usually the most simple circuits and few stages of amplification. Less parts between you and your music.

 

Not scientific necessarily, but that is the ticket IMHO.  As the best recordings are made with the most direct path possible to storage, and the best preamp is a straight wire with gain, and the best speakers are those that rely on nature as much as possible (K'horns), so too with amplifiers.

 

Dave

Edited September 23, 2015 by Mallette

[mike stehr]

My understanding is that the 45 tubes are some of the best sounding DHT tubes. George at tubelab.com recommends them highly for their sound quality. The only drawback is they are old stock (I have found one place still making them for $500 apiece) and the 2 watts or less they produce which is not a problem with most listeners and Klipsch speakers.  

 

When I had LaScalas, I lashed up a breadboard circuit using the 71A. That breadboard circuit seemed to sound best with LaScala...I tried 6BQ5/EL84 SEP, DHT 2A3, and 45 (I think). The 71A had dare I say best tone.

I didn't want to deal with 5 volt AC heating, so I used a pair of adjustable regulated DC supplies for the 71A filaments. It used 6SL7 driver tube in a SRPP configuration, with James 6123HS output transformers.

 

Old stock 45s are getting rare and spendy. I know Maynard is no fan of 6BQ5/EL84, but they can sound rather nice in a single ended amp...pentode connected with a touch of feedback.

Edited September 24, 2015 by mike stehr

[Fjd]

I figured it might be time to bump this thread since I was reading this article by Steve Deckert titled "Why the SET and Efficient Loudspeaker Approach Works" and thought it may be of some interest.

 

Why The SET And Efficient Loudspeaker Approach Works 

Article By Steve Deckert

 

http://www.enjoythemusic.com/magazine/manufacture/0703/

 

"[What are the advantages are to using SET amplifiers with high efficiency loudspeakers?

 

To answer this, lets start with the advantages of a SET amplifier over any other type. A Single Ended Triode is the simplest circuit design there is, using the least number of parts. Typically this is a driver stage coupled to a single output device. Triodes do not require negative feedback, something found in most all push-pull circuits, solid state or tube. Negative feedback is used to lower distortion specs and in the case of solid state devices it is often the only thing keeping the transistors from exploding all over the inside of your amplifier. Feedback a problem? If you don’t mind the time smear it creates and the resulting 2 dimensional sound stage, then no I guess it’s probably not. 

Aside from the amplifier’s superiority by simplicity, there is a more profound reason for using SET amplifiers. The magic predominately lies in the first watt. By magic I mean inner detail and most of the dynamics. For example, a pair of 96dB loudspeakers playing with one watt of power against the average noise floor in your listening room (55dB) is 40dB of dynamic range. (96 – 55 = 41dB) Adding a second watt increases the dynamic range by only 3 dB. For every additional 3dB you need to double your power. This should clearly illustrate that there is over 10 times the dynamic range in the first watt as there is in the second.

This brings us directly to loudspeakers. A typical loudspeaker today is 86 dB efficient with 1 watt. It also usually has a complex crossover that attempts to keep the frequency response and impedance flat. The crossover alone will usually dissipate a significant portion of the first watt as heat before it even reaches the drivers. To reach the same loudness level as the 96dB loudspeaker will with 1 watt requires over 8 watts on the 86dB loudspeaker. If we used 2 watts on the 96dB loudspeaker the other would require 16 watts to keep up. If we used 4 watts on the 96dB loudspeaker the other would require 32 watts to keep up.

The problem here is resolution. If you can not hit a listening level with the 1st watt, you’re not likely to hear what’s happening in that 1st watt. For a driver to achieve a high efficiency it’s moving parts must be low in mass. That makes it dramatically faster or more accurate than a loudspeaker with heavier moving parts. If you like inner detail and want to hear all of the textures and layers of a good recording you need fast, efficient and coherent loudspeakers. 

A good SET amplifier combined with a single full range driver with no crossover or a simple two-way using minimal crossover parts on the tweeter only, has a purity and depth that you simply don’t find in more conventional systems. It is a benchmark for coherency, and noted for its ability to create hauntingly real holographic sound stage. Bass and dynamics with this combination sound more realistic in part from the tremendous speed and in part from the coherency.

I’ve consulted many people about their audio systems, and the most common complaints include dry somewhat fatiguing sound with a fairly boring soundstage followed by the realization that it simply doesn’t connect you to the music emotionally like it could. Experience has taught me that by far the easiest way to get a liquid sound that becomes holographic with stunning clarity and detail, something that excites the listener, is to set him up with an SET and simple pair of efficient loudspeakers. It also usually ends up being the least expensive solution.

The biggest conformation of this is reports from audiophiles who used to have several hundred watts and many thousands of dollars invested in show winning audio gear, but now report that even a good two watt SET on efficient loudspeakers has better dynamics and weight which they find simply amazing. If you’ve ever observed how audiophiles rotate through audio gear during their lifetime you might also find it interesting that the ones who finally land on SET amplifiers and good loudspeakers seldom find anything they like better.

The bigger is better mentality that is directly connected to more expensive the better is certainly the handicap that stunts most audiophiles from discovering truly high fidelity sound. Will the guys at the audio salon laugh... yes the will. Will your fellow audiophiles laugh when they hear you sold everything and got a two-watt amplifier... yes the will. Is this important to you? Only you can decide, but I would suggest it has little to do with high fidelity.

In closing, remember this – It is dangerous to place amplifiers, loudspeakers, cables etc., into neat little categories in an effort to make some sense of it all. Not all tube amplifiers sound good. Not all solid- state amplifiers sound bad. With the Internet audiophiles have been set free to research things in a far more unbiased way then ever before. Before the Internet there were only trade magazines, and manufacture’s literature to educate us all and it goes without saying – fairly biased sources. Of course the Internet is full of misinformation, some intentional, some out of ignorance, but at least you can find all sides and make your own determinations.]"