Amp for my 2 channel

[RGA]

What do the others here think of this option? I like the idea of a tube amp and I see that they have a 7 day return policy.. Excuse my ignorance Poultrygeist, but what is S.E.T.?

Here are some links about SET (no feedback) amplifiers. Single ended amplifiers are the only truly linear amplifier devices that do not create errors to then need to be corrected by the amplifier - the damage has been done before the error correction circuit begins (called Feedback).

SET based systems typically always sound better than competing designs (however you pay a big price in amplifier power) The way to correct that is to use High efficient speakers. in other words speakers that can play loud with little power. The problem is high efficient speakers tend to cost more because efficient speakers use better quality drivers.

Whether they are Solid State or tube. Single ended no feedback amps do the least damage to the signal from input to output. Here are some links about it from several sources.

http://www.stereophile.com/reference/70/

"Negative feedback, quite simply, is the application of an inverted portion of an amplifier's output signal to its input terminals. This "extra" signal is subtracted from the input and serves to reduce the effective amplifier gain (as the input signal is then smaller). In addition, steady state distortion is thought to be reduced as the out-of-phase distortion components contained in the feedback signal cancels out some of the errors created by the amplifier circuitry.

This scheme presents two very obvious problems. Firstly, all amplifiers introduce some delay to passing a signal from its input, to its output and then back to its input. During this delay period, a feedback amplifier is operating at its natural (referred to as "open-loop") gain. It is not until this initial delay period is over, that the circuit begins to exhibit its intended operating ("closed loop") gain characteristics. There must be, by the very definition of a feedback system, some change in the gain factor G, during the transition from open to closed loop operation. This gain modulation would probably not be audible by itself, as the propagation delays of most good amplifiers are quite small, except that the increased gain of the amplifier during the initialization period results in a decreased maximum input capability before overload. Simply put, an amplifier which utilizes 20 dB of feedback (a relatively modest amount by modern standards) and requires an input of two volts to clip during closed loop operation, would overload with only two tenths of a volt input during the forward delay period. Once the amplifier is overdriven, it may take many times its delay period to become fully restored to normal operation. The distortion created by this condition has been commonly referred to as Transient Intermodulation Distortion (TIM), Dynamic Intermodulation Distortion (DIM), and Slew Induced Distortion (SID).

In addition to this obvious form of feedback induced distortion, there exists another more subtle effect of signal regeneration. Because all amplifiers have some forward propagation delay, the fed back portion of the output signal will always lag behind the input. There is therefore a constant introduction of "out of date" information into the amplifier. Under transient conditions (which is what music is; transients), this results in the presentation of an error correction signal intended to reduce the distortion of an input signal which has already passed through the amplifier and is either already out of the circuit or well on the way out of the circuit. The signal present at the input by the time the feedback has arrived may bear no relation to the previous signal and thus will not be properly acted upon by the regenerated information. The current input signal is then distorted once, through the subtraction of an erroneous feedback waveform, and again by the amplifier. Additionally, the error signal present in feedback is passed through the amplifier and again fed back, with all of the newly created distortions, to make yet another trip through the circuit, until it is allowed to decay through successive attenuation. Thus, a distortion signal which originally may have lasted only a few microseconds, can pass through the amplifier enough times for its effective duration to have exceeded the threshold of human audibility. The mechanism originally designed to reduce audible distortion, actually, under transient conditions, serves to regenerate, emphasize and, in fact, create distortion.
Negative effects of negative feedback.../...

[in a SET amp] such distortion regeneration does not take place. The circuits have been designed for maximum linearity without corrective mechanisms, and thus responds as easily to transient signals as it does to steady state waveforms. The amplifiers make no attempt to reverse the path of time in order to correct their own errors. Those distortions created by these circuits (which are almost entirely harmonic in nature) are allowed to pass only onto the loudspeaker, and not back to the input.

Despite the absence of feedback, the forward propagation delay of all our amplifiers has received much attention. All our output transformers have been designed using this criterion, obviously with a keen eye on cost. It is obvious that if this delay is not absolutely invariant, for all conditions, the DeltaT component of the input signal will not be accurately preserved. Thus, those factors which determine delay have been carefully observed and stabilized. In addition, the operation of all amplification stages at nearly constant power, independent of signal conditions, i.e. Class A operation at every stage, greatly contributes to the symmetry and linearity of our circuits.

It is, however, not enough for an amplifier to operate linearly by itself. In order to minimize audible distortions, the device must be able to operate as well into a real loudspeaker as it does into a laboratory resistive load.

In order to adequately control the cone excursions of the loudspeaker and to optimize power transfer, the effective output impedance of the amplifier should be as far below the impedance of the load as possible. The ratio of these two impedances is referred to a damping factor, usually referenced to an eight ohm speaker. Thus, a damping factor of eighty reflects an amplifier output impedance of one tenth of one ohm. The design of the output transformer is extremely critical, and taps on the output are normally provided to match the load impedance best possible.

A problem in the normal expression of damping factor is that its measurement is performed using steady state signals. This results in a factor relying quite heavily on the action of an amplifier's feedback. The damping ability of an amplifier under transient conditions, before the feedback mechanism has been able to reach, is only accurately expressed as the steady state damping factor divided by the feedback factor. Thus, an amplifier with twenty decibels of feedback and specified damping factor of one hundred, has a damping value of only ten under transient conditions. This not only reduces the amplifier's ability to control the cone movement, but allows voltages created in the speaker voice coil to mix with the output signal and enter the amplifier's feedback system. In this condition, distortions created by the speaker's motion are not only unattenuated, but are emphasized through feedback regeneration.


http://www.audionote.co.uk/articles/...feedback.shtml

Interview with one of the biggest SET manufacturers (starts at about 2:40) http://www.youtube.com/watch?v=zEUW3...eature=related

http://www.enjoythemusic.com/Magazin...amplifiers.htm

http://www.stereophile.com/interviews/399/

[JoeE SP9]

An amplifier does not have to be an SET to be without feedback. There are SET's that have feedback. Also, there is global and local feedback. Global includes the entire amp in the feedback loop and local uses only a given stage of an amplifier. Most amplifiers including SET's have more than one stage. Amplifiers that aren't SET's and have no feedback (local or global) are made by Densen, Octave Electronics and others. Most SET's are two stage amps. They have an input/driver stage and an output/power stage.

Most moderrn amplifiers that have feedback don't have any global feedback. They have very small amounts of local feedback. With only local feedback the time and phase distortion caused by global feedback is pretty much eliminated.

[Feanor]

An amplifier does not have to be an SET to be without feedback. There are SET's that have feedback. Also, there is global and local feedback. Global includes the entire amp in the feedback loop and local uses only a given stage of an amplifier. Most amplifiers including SET's have more than one stage. Amplifiers that aren't SET's and have no feedback (local or global) are made by Densen, Octave Electronics and others. Most SET's are two stage amps. They have an input/driver stage and an output/power stage.

Most moderrn amplifiers that have feedback don't have any global feedback. They have very small amounts of local feedback. With only local feedback the time and phase distortion caused by global feedback is pretty much eliminated.

I think the evils of negative feedback have become a major bugaboo. Most amps use some feedback, mostly only local in case of half-decent amps. It is used because it works and produces better results than not using it, to put it simply.

Feedback delay is the source of the real problems, such as they are. Feedback used intra-stage is typically minute. Good grief -- I've heard of people concerned about feedback used internally in opamps: these delays here are measured in hundreds of a picosecond, (10^-14).
.

[Poultrygeist]

Speakers with an efficiency rating of 92 dbs only need an amp of 2.5 watts to reach a listening level of 96 dbs in a moderately sized room and I hope no one on this forum listens at prolonged levels of 96 dbs.

A single ended triode ( S.E.T.) is the simplest circuit design there is and uses the least number of parts. It is also one of oldest designs dating back to the 1920's. Typically there is just a driver stage coupled to a single output. Triodes do not require negative feedback, something found in most push-pull circuits, solid state or tube. Feedback creates time smear and a 2-D soundstage.

SET's are the easiest way to achieve a liquid sound that becomes holographic with stunning clarity and detail.

[Feanor]

Speakers with an efficiency rating of 92 dbs only need an amp of 2.5 watts to reach a listening level of 96 dbs in a moderately sized room and I hope no one on this forum listens at prolonged levels of 96 dbs.

....

By this logic my 86 dB sensitivity Magneplanars would need only about 20 watts to kickout 96 dB, however in practice this is not the case.

[Mr Peabody]

JoeE, have you heard either the WAVAC or Kron? A high power SET seems intriguing.

Not meaning to hijack but if some one wanted to pick up a SET to play with so didn't want to make a big investment but wanted to be sure he got the true SET experience from it, what amp would it be?

[RGA]

Speakers with an efficiency rating of 92 dbs only need an amp of 2.5 watts to reach a listening level of 96 dbs in a moderately sized room and I hope no one on this forum listens at prolonged levels of 96 dbs.

A single ended triode ( S.E.T.) is the simplest circuit design there is and uses the least number of parts. It is also one of oldest designs dating back to the 1920's. Typically there is just a driver stage coupled to a single output. Triodes do not require negative feedback, something found in most push-pull circuits, solid state or tube. Feedback creates time smear and a 2-D soundstage.

SET's are the easiest way to achieve a liquid sound that becomes holographic with stunning clarity and detail.

The sad part is that your last sentence really does say it all. But it amazes me that people judge it without hearing it. Instead they look at the measurements and see 5% THD and then assume it has to be warm and fuzzy - or they connected some tube preamp to something and it sounded warm and fuzzy so that means all SET amps must be the same.

I don't really blame them since I was a Bryston/PMC/B&W/YBA/Classe/Martin Logan lover when I started out. I read all about SET and how bad it was. Fortunately for me my first audition was pseudo blind. Listening to a big silver box that looked like a giant Krell. The clearest cleanest transients by a country mile that I had ever heard. Nothing the least bit "warm and fuzzy" about it. But it had a transient attack that was startling and could play loud with deep very tight bass lines and pristine crystal clear highs. Turned out to be an 8 watt SET. That's why I was so pleased to read Wes Philips' take on the Ongaku experience way back. Wes is such a Krell/Dynaudio/Wilson/Solid state to the hilt guy and when he FINALLY after all his years reviewing gets around to a SET as he put it "everything else was just noise." I love that because it's basically what happened to me. And it continues to - it doesn't wear off. It's not a parlor trick that lasts for an hour it's years and years. Distortion can't make things clearer. Distortion should do everything but. And the consistent listening experience of great SET amps is ALWAYS "better transients and better decay" - distortion can't do that - a lack of feedback a lack of getting in the way of the initial signal - can.

[RGA]

By this logic my 86 dB sensitivity Magneplanars would need only about 20 watts to kickout 96 dB, however in practice this is not the case.

Interesting - maybe you should tell Magnepan they need a bigger amplifier in their very own showroom. They use an amp (a receiver in fact) under 40 watts.

The 1.7 played quite well with an 18 watt SET - never had to push the volume past the 11'o'clock position on the full gain volume control. It played quite loud with controlled non mushy bass. Granted the transformers are exceptionally good but 18 watts had zero problems playing to quite loud levels.

I don't know why you don't actually get out and listen to some of these systems. Every time I read some putz on an internet forum claiming you can't play loud with 10 watts just tells me they never audition anything. I can tell you right now that a Soro and AN E/SPE He with an 18 watt amp in 25 X 25 by 15h room will blow you into next week. You will be in physical PAIN that's how loud it can play.

This is a room a small speaker with a small powered amp can handle and play very loud in. If a speaker/amp combo needs a bazillion watts then something is wrong somewhere. Either the speaker is incompetent or the amplifier is so "unclear" that it needs to be cranked to be able to make things out. Which of course may in fact be true because when transients are not clear - the sound seems lacking so it needs to be cranked up in attempt to add back clarity.

"A nice big room for a rather average looking system. But this collection of gear really did fill the room with life-like music.../...The music I heard was big-band circa 1960 or so. Nobody said who it was that was playing. I didn't ask. I hung around for three numbers. Easily, this was the best sounding exhibit that I heard during my visits to the various exhibitor rooms. There was astoundingly good prat. This system has the 'timing thing' very close to being right. Foot-tappin, finger-snappin', and at times jaw-dropping, good music. The speakers and the vacuum tube electronics were Audio Note UK. They have my attention." http://www.theanalogdept.com/vsac08.htm

[RGA]

JoeE, have you heard either the WAVAC or Kron? A high power SET seems intriguing.

Not meaning to hijack but if some one wanted to pick up a SET to play with so didn't want to make a big investment but wanted to be sure he got the true SET experience from it, what amp would it be?

The downside is you have to spend to get quality SET in my experience. Smaller makers less economies of scale. Antique Sound Labs but they really are not quite as good here - their MG 15 can be run in Single ended triode - the amp is around $1500 but it's not truly the real meal deal.

Wavac and Kron are very expensive - we're in the $10k plus zone usually.

There is DIY options - The Kit One is probably the one to beat in the 300B and 2a3 camp because it is so upgradable. But even here it is system dependent. No question about it - SETs are a pain. You have to work to find the right matches.

Still with an easy to drive speaker the Kit One would be a reasonably inexpensive option - but you have to build it. One day I intend to.

These two reviewers liked it enough to buy it.

http://www.audionote.co.uk/articles/...w_Listener.pdf

http://www.enjoythemusic.com/magazin...ionotekit1.htm

Interestingly I went to their website - they are selling a 70 watt Kit power amp (AB1) so I am interested to see where they think it compares. The only thing is that the Kit One is just about the ugliest amplifier I have ever seen - it looks like something from Young Frankenstein. http://audionotekits.com/kit1mk2.html

Though the kit is getting up over $2k these days.

Another intriguing option is the Grant Fidelity A534 300B. I have heard very good reports and I have seen the absolutely stunning build quality in person but have not had a personal real listen with it. It's $1400 and Grant Fidelity makes some very high quality kit for absurd prices relative to a lot of bigger name companies. But you have to take more risk since they don't have dealers. Kind of the Zu of amplifiers I suppose. But it looks gorgeous too IMO http://shop.grantfidelity.com/Grant-...Amplifier.html

[Poultrygeist]

I own two SET amps but I've heard many over the years at Hornfest and never once have I heard one that didn't put a smile on my face.

[Poultrygeist]

Here's perhaps the finest $30K SET available today, the "Dowdy" Lama's GM-70. It's three piece chassis weights 250 lbs and it probably makes all of 10 watts. After hearing it I know why it's called "The Voice of God".

http://www.youtube.com/watch?v=IGFfCxo6nbg

[Feanor]

Interesting - maybe you should tell Magnepan they need a bigger amplifier in their very own showroom. They use an amp (a receiver in fact) under 40 watts.

The 1.7 played quite well with an 18 watt SET - never had to push the volume past the 11'o'clock position on the full gain volume control. It played quite loud with controlled non mushy bass. Granted the transformers are exceptionally good but 18 watts had zero problems playing to quite loud levels.
...

I've played the Maggies myself with a 40 watt receiver and they're listenable but it's not quite like having adequate power for the loud passages.

...
I don't know why you don't actually get out and listen to some of these systems. Every time I read some putz on an internet forum claiming you can't play loud with 10 watts just tells me they never audition anything. I can tell you right now that a Soro and AN E/SPE He with an 18 watt amp in 25 X 25 by 15h room will blow you into next week. You will be in physical PAIN that's how loud it can play.
...

I've said repeatedly that I would love to hear my Maggies powered by any decent tube amp. It's entirely a lack of opportunity that I haven't do so. (Poppychubby once said he'd bring his Golden Tube here so we could listen but he hasn't gotten around to it.)

I'd prefer for a start my tube listening with a 60+ wpc tube amp, like say a pair of Dynaco MkIII's, but I'd give a SET amp a try provided it could handle 4 ohms.

...
This is a room a small speaker with a small powered amp can handle and play very loud in. If a speaker/amp combo needs a bazillion watts then something is wrong somewhere. Either the speaker is incompetent or the amplifier is so "unclear" that it needs to be cranked to be able to make things out. Which of course may in fact be true because when transients are not clear - the sound seems lacking so it needs to be cranked up in attempt to add back clarity.
...

It's obvious to me too that power requirements are often assumed to be higher than they actually are. E.g. some people insist that 400 or 500 wpc is essential for Magneplanars; this is certainly an exaggeration at least in case of medium sized room, (say 15 x 25 x 8 feet), and at reasonable listening levels. (Unlike Tube Fan, I don't consider 100 dB a necessarily level at any time for any sort of music.)

[blackraven]

By this logic my 86 dB sensitivity Magneplanars would need only about 20 watts to kickout 96 dB, however in practice this is not the case.

I agree with you Feanor. There are some speakers that greatly benefit from high powered amps and Magnepans are one of them. I can tell you that I would be clipping a 20wpc tube amp all the time with the type of music that I listen to and at the moderate to loud volumes that I sometimes play it.

[RGA]

I agree with you Feanor. There are some speakers that greatly benefit from high powered amps and Magnepans are one of them. I can tell you that I would be clipping a 20wpc tube amp all the time with the type of music that I listen to and at the moderate to loud volumes that I sometimes play it.

Well someone needs to tell the Magnepan dealer here this. They carry top Bryston, Rotel, Classe, Meridian, Musical Fidelity, Sim Audio, McIntosh, Ayre. With the 18 watt Soro (not even a really expensive amplifier when you compare it to some of these others) it sounded far better. I get the sense that the superior transient attack and lack of a need to turn the volume up because it is so much clearer is the reason that the watt numbers are trumped. You don't feel the need to crank it up to make things out. I said this awhile ago. Magnepan may actually be better than even their owners give them credit for being. It can take advantage of a "quality" amplifier rather than just needing a brute force amp. And perhaps a SE tube amp can get rid of the notion it needs to be played loud to sound good reputation they are getting. To me 1 part of the mark of a good speaker is one that can take advantage of superior electronics.

All these amps have 4 ohm taps and the Maggies are not ridiculous impedance difficult loads.

I would at least try it out first. It's not like anyone buys these speakers to play slipknot at 100db so honestly - the average 70-85db listener even at the listening chair with a soft clipping amp should do quite well. Hence why corporate Maggie headquarters is using a small powered amp. Interestingly the exact same results were had with the Quad 2905. I have never heard this speaker sound better - the articulation in the midrange was truly stunning and not mangled by the inherent grain of some of those SS amps. And the beauty is the amps are less costly to boot.

But even if power is an issue - the Grant Fidelity Rita is rated at 45 watts - 450 watt peak. The Rita will drive pretty much everything. I was the first to review Grant Fidelity kit and it's nice to see that other outfits have given them some respect.

The Rita is the real deal. At under $3k it's ridonkulous. The thing is a battle ship of an amp at over 100lbs - I have the memories of the backache to prove it. 45 watts class A no feedback

http://shop.grantfidelity.com/Grant-...Amplifier.html

And apparently they use better tubes now than back when I reviewed it. So it's likely better and considerably less money. It's quite tempting indeed.

Edit: Just looked back and when I reviewed it the Rita was $5299. It was a great deal then. At $2,950 it is fair to use the words Giant Killer. It would be "THE" amplifier I would buy if I owned any speaker that need high power. The Shengya Mono-blocks I liked better because for the money with a preamp you could get better sound - but either way.

http://www.dagogo.com/View-Article.asp?hArticle=181

[tube fan]

My two favorite systems at the 2010 CAS were the Audio Note and the Teresonic. Audio Note was using the super Jinro, about 18 watts, and Teresonic was using a 2 1/2 watt set! Through the Audio Note, I heard the best reproduction of big band jazz ever! They played all sorts of music, even trance, bass and drums, DJ, etc., and at realistic levels. No Lady Gaga at background levels for the Audio Note guys. WAY over 100 dbs!

[Mr Peabody]

Poultrygeist, have you heard the MP301 or was it just a SET in the OP's price range? I noticed it has a headphone jack and at it's price cheaper than most tube head amps.

The Class D they have on sale has some interesting features.

[E-Stat]

Single ended amplifiers are the only truly linear amplifier devices that do not create errors to then need to be corrected by the amplifier - the damage has been done before the error correction circuit begins (called Feedback).

You are mistaken. Other feedback-free designs exist that are not such as the Ayre MX-R.

rw

[Poultrygeist]

Below is a review of the new MP-301 Mk2. I don't see how anything could come close to it at this price point. My MiniWatt shut down last night and for a moment my sadistic side said let her die and buy the MP. Well after cooling off the MW resurrected itself and I felt a little guilty. But with the 2a3 barely broken in, I can't justify the MP but I still want one. I know the Omens would love it.

http://www.head-fi.org/products/mp-301-mk2/reviews

[RGA]

You are mistaken. Other feedback-free designs exist that are not such as the Ayre MX-R.

rw

Can you clear this up - John Atkinson claims that it [MX-R's] circuit uses a low level of overall loop negative feedback. Which is more than zero.

There is more to the game than this anyway since class D amps have yet to impress me and some or maybe all have no feedback and run class A. So there is more to the game than either or element. No feedback is one, although even there I have liked amps with a little feedback more than others with zero. For instance I love the Sugden A21a which is both a SET and no feedback - but I like the AN OTO more which is a SEP and uses a little bit of feedback.

I have not auditioned Ayre extensively - Soundhounds did pick up the line and I did like their conversion from streamed sources quite a lot.

Wes Phillips was the big reviewer of this amp and ran his Dynaudio's on it. But since then he's heard what a big time SET amp can do. So I am not convinced that the sonic aesthetic offered up by Ayre is going to do it for me. As the Ayre dealer notes - "it sounds great...for solid state." I'd like to try a complete Ayre system at some point - Charles seems like an interesting fellow and has a passionate viewpoint on audio. And his prices are not insane for the most part.

[JoeE SP9]

Having owned and used Magneplanars and ESL's I can state with a lot of certainty that 20 Watts is not enough. 60 Watts was barely enough for a pair of MG-1's. I know this because I owned and used them at the same time. The only way I can get away with using 60 Watts to drive my current esl's is because they only run from 85Hz up. I don't care what Magnepan uses. I know how much power their speakers need in the real world because I've owned MG-1's, 2's and 3's. Two of my buddies have MG3.6R's and MG-20.1's. I get to hear them frequently.

No matter what is mentioned you always return to Audio Note. Puleeeeze!

As for the Rita's; I have a lot of familiarity with using a pair of 6550's, 45Watts from a pair, easy. However,450 PPW (or whatever) I think not! Also, according to Grant Fidelity they have no negative feedback. FYI they are not SET's.

Feanor: Several years ago I heard some Wavac SET's driving some Legacy speakers. I wasn't too impressed with the speakers (never have been) and the amps were way too expensive for me to investigate further. They did make the Legacy's sound much better than usual. The amps seemed to have more than adequate power.

Cyto originally asked about an Emotiva amplifier. IMO you won't go wrong buying one.

RGA has managed to turn this into a soapbox for SET's and HE speakers, more specifically, into a sales speech for Audio Note.

[Feanor]

...
There is more to the game than this anyway since class D amps have yet to impress me and some or maybe all have no feedback and run class A. So there is more to the game than either or element. No feedback is one, although even there I have liked amps with a little feedback more than others with zero. For instance I love the Sugden A21a which is both a SET and no feedback - but I like the AN OTO more which is a SEP and uses a little bit of feedback.
...

More research is called for, however I believe most or all class D amps use feedback.

However the issue of class A is irrelevant in case of class D amps. Class A means that the operation of the transistor (or tube) is "biased" so, simply put, it runs in the middle of its power range thus avoiding distortion that occurs at very low operation levels. I.e. "crossover distortion" in case of push-pull amps. However class D amps always work the transistors at maximum output (or maximum for lowest distortion).

Local feedback is typically innocuous because the delay times, which cause the problems, are extremely short.

[RGA]

Having owned and used Magneplanars and ESL's I can state with a lot of certainty that 20 Watts is not enough. 60 Watts was barely enough for a pair of MG-1's. I know this because I owned and used them at the same time. The only way I can get away with using 60 Watts to drive my current esl's is because they only run from 85Hz up. I don't care what Magnepan uses. I know how much power their speakers need in the real world because I've owned MG-1's, 2's and 3's. Two of my buddies have MG3.6R's and MG-20.1's. I get to hear them frequently.

No matter what is mentioned you always return to Audio Note. Puleeeeze!

As for the Rita's; I have a lot of familiarity with using a pair of 6550's, 45Watts from a pair, easy. However,450 PPW (or whatever) I think not! Also, according to Grant Fidelity they have no negative feedback. FYI they are not SET's.

Feanor: Several years ago I heard some Wavac SET's driving some Legacy speakers. I wasn't too impressed with the speakers (never have been) and the amps were way too expensive for me to investigate further. They did make the Legacy's sound much better than usual. The amps seemed to have more than adequate power.

Cyto originally asked about an Emotiva amplifier. IMO you won't go wrong buying one.

RGA has managed to turn this into a soapbox for SET's and HE speakers, more specifically, into a sales speech for Audio Note.

Unfortunately Joe when a question comes up regarding SET which it did, then I go to the amps I have the most experience with - which happens to be Audio Note. I don't feel as comfortable talking about Cary when I have only heard a few amps and one set at a show. I could talk about some others but the prices are so out there that the relevance isn't there with the average likely budgets of the people asking the questions. Cyto asked about SET which pretty much goes hand in hand with Single Ended.

The Rita is not a SET - I was offering alternatives for the more power is better people. Discussions go in different directions - someone starts talking about something else I reply to them. There are lots of other designs trying to emulate pure class A, Zero feedback, Single Ended, - in other words lots of designers trying to make various SS designs sound more like a SET. Like the often our amp sounds valve-like to which I always think why not just buy a valve amp then. As those SS designers who chose the no feedback Radford at 1/30 the price of their own designs.

My dealer carries the complete Magnepan speaker line-up has sold them for decades and incidentally they also are a full Magnepan repair facility. They carry top of the line Classe, Musical Fidelity, Bryston, YBA, Ayre, Meridian, Rotel, Sim Audio, McIntosh. I am sure one or all of these would be viewed as having acceptable power to drive a 1.7 no? Answer is yes - they all have more than enough power to drive the Magnepan 1.7.

The fact that the AN Soro sounds better for a fraction of the price and I would bet some of the other tube amps in the store (Jolida, ASL, Octave, Wyatech, Mcintosh would as well would not surprise me in the least. They sell the stuff, tried all the combinations and that's what they like as well. They'd probably hook up the Wyatech labs as well if it were not for the expense of the Tubes. The Wyatech made the B&W N801 sound glorious - just could not play very loud. But there are bigger SE tube amps out there. And Magnepan - you know the people who actually design the speakers run small watt amps too. I in fact do care what the company is using. I would hope to give money to competent people who build speakers and actually try out some combinations.

[Ajani]

Unfortunately Joe when a question comes up regarding SET which it did, then I go to the amps I have the most experience with - which happens to be Audio Note.

Might I suggest that, since you are a reviewer and a very vocal advocate of SET/HE then, you should make it your goal to be familiar with a wide range of SET/HE models; for the following reasons:

1) Since most of the time you talk about one brand, you will NEVER be taken seriously by most persons (yes you mention other gear - but often ridiculously expensive stuff and hence not real alternatives to AN).

2) You might actually find SET equipment you like more than your favorite brand.

3) If you have direct experience with a wide range of SET from the ultra-affordable like the Musical Paradise MP301 and Miniwatt N3 all the way up to the ultra luxury ones, then you will have numerous SET recommendations that you can make at all levels...

While many audiophiles will at some point spend substantial amounts on gear, often they choose to test the waters with something more affordable (like what Mr. Peabody asked about earlier in this thread)... If you suggest a good say $1K SET amp and someone tries it and likes it, then chances are that when they are ready for the $3K to $5K amp, they will look in the SET direction again... If all you have to recommend in SET are in the $3K and up category, then only the richest audiophiles are likely to be willing to test the waters with such a piece...

[JoeE SP9]

The quote below is from Wikipedia:

• Class A designs are simpler than other classes; for example class AB and B designs require two devices (push-pull output) to handle both halves of the waveform; class A can use a single device single-ended.
• The amplifying element is biased so the device is always conducting to some extent, normally implying the quiescent (small-signal) collector current (for transistors; drain current for FETs or anode/plate current for vacuum tubes) is close to the most linear portion of its transconductance curve.
• Because the device is never shut off completely there is no "turn on" time, little problem with charge storage, and generally better high frequency performance and feedback loop stability (and usually fewer high-order harmonics).
• The point at which the device comes closest to being cut off is not close to zero signal, so the problem of crossover distortion associated with class AB and B designs is avoided.

So is this quote:

Single-ended output stages (be they tube or transistor) have an asymmetrical transfer function, meaning that even order harmonics in the created distortion tend not to be canceled (as they are in push-pull output stages); by using tubes OR FETs most of the distortion is from the square law transfer characteristic and so second-order, which some consider to be "warmer" and more pleasant.^[9][10]
For those who prefer low distortion figures, the use of tubes with class A (generating little odd-harmonic distortion, as mentioned above) together with symmetrical circuits (such as push-pull output stages, or balanced low-level stages) results in the cancellation of most of the even distortion harmonics, hence the removal of most of the distortion.
Though good amplifier design can reduce harmonic distortion patterns to almost nothing, distortion is essential to the sound of electric guitar amplifiers, for example, and is held by recording engineers to offer more flattering microphones and to enhance "clinical-sounding" digital technology.
Historically, valve amplifiers often used a class A power amplifier simply because valves are large and expensive; many class A designs use only a single device.

There seems to be some confusion about how amplifiers actually operate. The quotes from Wikipedia are better explanations than mine.

[RGA]

Might I suggest that, since you are a reviewer and a very vocal advocate of SET/HE then, you should make it your goal to be familiar with a wide range of SET/HE models; for the following reasons:

1) Since most of the time you talk about one brand, you will NEVER be taken seriously by most persons (yes you mention other gear - but often ridiculously expensive stuff and hence not real alternatives to AN).

Well I think this is the underlying point as to why after more than 20 year auditioning equipment why I happen to like Audio Note as much as I do. The ridiculously expensive alternatives ARE so far what I consider to be the alternatives, especially for digital replay. For amps and speakers there are alternatives that I quite like - but not all of them are SET friendly speakers - although someone pointed out success with a SET on a speaker I didn't think would be SET friendly. If true then I will have something new possibly to rant and rave about - although I already chose the speakers as one of my 5 favorites at CES. If it truly does sound good with a SET then I would buy it myself.

2) You might actually find SET equipment you like more than your favorite brand.

Something you may not be aware of - I like AN as a system. Not as much as individual components in a mix and match system. In the latter there is plenty of stuff I would buy over Audio Note. If I owned McIntosh OTL SS or Bryston amps I would not buy an AN speaker for example which will just sound poor IME. So I have a wealth of other speakers I would look to instead - incidentally - less expensive speakers! This applies to their amplifiers. Hearing the M6 in an appropriate AN system over lower models the improvement is striking. Listening to the M6 with a top Rotel Power amp into Magnepan speakers it didn't do a thing for me. Not much better than listening to far less expensive preamps. It is not a fix all. The Digital seems to do better regardless of systems but not the 1.1 - it takes the 2.1 or better. The 1.1 sounded rather shouty and thin in a Sim Audio set-up with Dynaudio speakers. I liked that it really showed up the discs and told me about the way those discs were recorded but it wasn't relaxing. Sounded less tube-like than the SS CD players in the room. Ie; in that set-up I would have purchased a less expensive CD player.

There are not a lot of affordable SET amps of high quality out there. Audio Note isn't really affordable either. The entry level from them is the Meishu in terms of a 300B and it's in the $10k range. My experience with SET has been that it takes a lot of coin for it to really do justice to the sound. The Kit One is the least expensive good sounding SET that I have auditioned. And it's $2k and you have to build it. I was not thrilled with the Cary 300B or the ASL SETs I heard. The Wyatech Labs is good but expensive. I have hopes fort the $1400 Grant Fidelity. I heard a Bottlehead model that I didn't care for - can't remember the name of it though. A lot of them don't sound transparent - often rather mushy in the bass. I suspect it comes down to the transformers - they need to be excellent. The sound is heavily dictated on the quality of parts. This is less so with SS. Which is why you always read that some company has a $600 amplifier that is beating up expensive solid state and no one passes blind tests. I am never surprised by this in the world of SS.

3) If you have direct experience with a wide range of SET from the ultra-affordable like the Musical Paradise MP301 and Miniwatt N3 all the way up to the ultra luxury ones, then you will have numerous SET recommendations that you can make at all levels...

That''s a fair point. But like anyone else on these forums I do not have limitless resources or time to hear it all. I try to audition as much as I can - dealers are helpful but they tend to carry bigger name established brands. I'd like to listen to Zu for example but with no dealers I can't. I can order it in - but if another reviewer gets to it on our staff then I am out of luck on the specific brand. I tried to get a really interesting speaker in but the shipping to Canada for this small speaker maker was so high that it would have been difficult for him. Especially since I have never heard them in person and if I didn't like them then it would have been really costly for him.

As a relatively new teacher in Canada - we get laid off virtually every year at this time. So spending the money to go to an audio show is also difficult.

Ideally, what I would like to do is compare 6-7 SET amps at prices from $300 to $10,000. A Musical Paradise, a mini-watt, The GF, maybe a Glow Audio, AN Kit one, Tri Amp, Meishu and maybe an ASL and Shindo. And compare each of those price points to various SS amplifiers that I also happen to like. Say, Rotel, Sim Audio, Heed Audio, Sugden, Pass Labs, Classe, and maybe an Ayre (based on the fact that I liked their digital).

While many audiophiles will at some point spend substantial amounts on gear, often they choose to test the waters with something more affordable (like what Mr. Peabody asked about earlier in this thread)... If you suggest a good say $1K SET amp and someone tries it and likes it, then chances are that when they are ready for the $3K to $5K amp, they will look in the SET direction again... If all you have to recommend in SET are in the $3K and up category, then only the richest audiophiles are likely to be willing to test the waters with such a piece...

I do get your point. I tested the waters with the ASL MG Head DT headphone amp for under $500. It even sounded pretty decent as a preamp despite using the headphone output to RCA connector. But my fear of this is that there are more compromises to cheap tube amps than there are to cheap SS amps. With SS you are spending more for more power and not necessarily "better" sound - at least within the house brand sound. As the Bryston rep noted and they even said it on their website when questioned - a 3B sounds exactly the same as a 4b or 7b for sound quality - only when the 3b is driving something it can't drive properly (a too hard to drive speaker) will the 4b sound better. On efficient speakers they sound exactly the same - they themselves said this. YBA also said the same thing with their separates versus their Integra DT integrated. Sound quality is exactly the same - only the power demand is the issue.

With SETs the quality of parts is critical and there is only so much "quality of parts" in a $500 SET. Something has to give. A lesser off the shelf transformer is going to have greater difficulty sounding clean. Of course if the buyer is accepting of the fact that a $400 amp whether it is SET or not will have limitations and not be dumb enough to judge SET technology on a $400 amp then great. But a lot of people judge the entire horn segment based on 80s Klipsch or Altec.

For a cheap SET amp I really liked the Glow Audio. The Sonist speakers sounded very good with the amp - though I think the Sonist is a little too hard to drive. I auditioned at normal listening levels and never really had them push it. Others did and found the amp was more strained. But the Sonist may be a little more complex and no all that efficient. Even AN doesn't recommend amps less than the 10 watt OTO and the OTO isn't even recommended for the AN E - more for the easier to drive J and K. So on the cheap end of the spectrum I do have an amp I can recommend - the Glow Audio. But for better bass you have to spend on an amp with superior transformers - and that simply costs more money. Still you could use the Glow Audio with a single driver speaker of some kind and I suspect it would be outstanding and not too expensive. Maybe a ZU or Teresonic's smaller standmount.

Here are a couple of reviews of the Glow Audio

http://www.6moons.com/audioreviews/glow/one_2.html

http://www.enjoythemusic.com/magazin...io_amp_one.htm