Which camp are you in ??? And why are you there ???

[tube fanatic]

I have the sense that some folks involved in this thread have the impression that push-pull amps are the panacea for a "sounds good with all music" scenario.

Yes, and all of the high fidelity amplifier manufacturers in the 1950s and early 1960s must have thought that too, because none, absolutely none of them were still manufacturing single-ended power amplifiers back then. You could find lots of single-ended power amps back then in cheap radios and in low end guitar amps, but none that I ever saw were SETs, they all used pentode output tubes. Back then the "hi-fi nuts" found that the added power and lower distortion of PP sounded better, so that topology became the standard.

Well, having been involved in the industry at that time, I can tell you that the switchover to push-pull was seen, in part, as an expedient for getting much more "bang for the buck" in terms of output power and lower claimed distortion specs. But, with that in mind, and not getting into tutorials about amplifier design, the ability of a push-pull amplifier to deliver on its "promise" is dependent, in part, on having a perfectly balanced output stage with a perfectly balanced phase inverter. Throw the balance between the tubes out, and then see what you get. Most manufacturers of push-pull amplifiers also used a feedback loop between the opt secondary and earlier stages to get improved bandwidth and lower distortion, except that doing so often caused phase distortion problems. And, not everyone from that era was totally satisfied with push-pull pentodes/beam power tubes either. Hence the work of Hafler and Keroes with ultralinear designs (http://oestex.com/tubes/ul.html). As a "hi-fi nut" from back then myself, my own experience is that push-pull is not necessarily better sounding than single ended. There are too many other factors which can either enhance or detract from sound quality with either design.

[sebrof]

I have the sense that some folks involved in this thread have the impression that push-pull amps are the panacea for a "sounds good with all music" scenario.

Yes, and all of the high fidelity amplifier manufacturers in the 1950s and early 1960s must have thought that too, because none, absolutely none of them were still manufacturing single-ended power amplifiers back then. You could find lots of single-ended power amps back then in cheap radios and in low end guitar amps, but none that I ever saw were SETs, they all used pentode output tubes. Back then the "hi-fi nuts" found that the added power and lower distortion of PP sounded better, so that topology became the standard.

With this logic:

Britney Spears makes the best music

Folgers is the best coffee

Ford F150 is the best vehicle

Mamma-san Electronics makes the best receivers

Sorry, not buying it. Just because it sells doesn't mean much to me.

If you want the very best, take your time, put it together carefully, and you will be rewarded.

[sebrof]

For those of us more technically minded, what are the reasons on paper for the advantages to SET? I understand what people are referring to about the smooth mids of SET, so I'm curious what the SET crowd would say is the reason for that sound. The natural progression would be to then implement that advantage into other topologies. Have any of you SET guys played with any Class D amps?

3 things come to mind:

1. No feedback (usually). This eliminates the type of distortion caused by the feedback loop lagging the output.

2. Simple circuitry. There are a total of 7 components between my CDP and my ear (selector, volume, driver, coupling cap, power tube, OPT, single speaker driver).

3. Class A. This eliminates switching distortion found in Push Pull designs.

None of these are possible (I don't believe) or at least not practicle, in a PP design. And I don't believe any of these are huge issues with topologies that have to deal with them.

I currently have SET with either single driver speakers or KHorns. That is not to say that SET is the only way, or even necessarily the best way, to make a good amplifier. SET is probaly not quite as good as you would think if you read what's on the internet, and is certainly no where nearly as bad as you would think if you read through this thread. It does simpler music and vocals exceptionally well, and it plays the classic rock I listen to well and as loud as I want (95 db+).

If you primarialy listen to loud music, or if your room is large, or if what SET offers does not turn you on, I would suggest another type of amp. But if you're like me and mostly use you rig to relax and chill at the end or beginning of the day, SET may just work for you.

[Don Richard]

Well, having been involved in the industry at that time, I can tell you that the switchover to push-pull was seen, in part, as an expedient for getting much more "bang for the buck" in terms of output power and lower claimed distortion specs. But, with that in mind, and not getting into tutorials about amplifier design, the ability of a push-pull amplifier to deliver on its "promise" is dependent, in part, on having a perfectly balanced output stage with a perfectly balanced phase inverter. Throw the balance between the tubes out, and then see what you get. Most manufacturers of push-pull amplifiers also used a feedback loop between the opt secondary and earlier stages to get improved bandwidth and lower distortion, except that doing so often caused phase distortion problems. And, not everyone from that era was totally satisfied with push-pull pentodes/beam power tubes either. Hence the work of Hafler and Keroes with ultralinear designs (http://oestex.com/tubes/ul.html). As a "hi-fi nut" from back then myself, my own experience is that push-pull is not necessarily better sounding than single ended. There are too many other factors which can either enhance or detract from sound quality with either design.

Lots of verbiage, but folks back then voted with their pocketbooks in favor of PP. All of the supposed PP problems can be dealt with through proper design. Global feedback can be applied to any topology, also. Of course there are compromises involved with any design, but modern amplifiers are very good indeed. SET power amplifiers are not examples of good, modern design.

If an 3 watt amplifier with 5% distortion will transport you to sonic nirvana, then go for it. I can't help but to notice that those who use or have used this type of amplifier say that they work best with certain types of music, such as soft jazz, chamber quartets, acoustic folk music and the like. Last night I played some E. Power Biggs on my system. As the clean low bass rolled out of the Khorns, I was transported back in time to the original performance, 1959 I believe. I strongly feel that 3 watt amplifiers would not have done that. This was followed by The Glory Of Baroque. The delicate sounds of the strings filled the room and sounded amazingly realistic. I did not seem to need a euphonic component in the signal chain to make this happen.

For good sound, first and foremost you need good speakers. They need to be properly located in a room with no glaring acoustical problems. The recording needs to be as clean and high quality as possible. The electronics are last in importance. If you are going through gear left and right and are still not happy with the results, maybe it's not the gear?

[SSnyder]

For good sound, first and foremost you need good speakers. They need to be properly located in a room with no glaring acoustical problems. The recording needs to be as clean and high quality as possible. The electronics are last in importance. If you are going through gear left and right and are still not happy with the results, maybe it's not the gear?

amen buddy som are never happy matterhow much they spend in $$$ [Y]

[SSnyder]

Think this way>>>>>>>>>>>>>>>>>>>>> what if someone say his minibike is a sweeter ride then your motorcycle? OKay going 20 mile per BUT>>>>>>>>>>>>>>>>>motorcyle will do 20 mile per ____________AND DO 100 PER!!!!!!!

[Don Richard]

With this logic:

Britney Spears makes the best music

Folgers is the best coffee

Ford F150 is the best vehicle

Mamma-san Electronics makes the best receivers

Sorry, not buying it. Just because it sells doesn't mean much to me.

If you want the very best, take your time, put it together carefully, and you will be rewarded.

The single ended amplifiers didn't sell for two reasons - low performance which engendered low demand. That's why Marantz and Macintosh didn't make them any longer (if they ever did).

BTW, I believe that is Pink Floyd with the top selling album, not Britney.

[Cut-Throat]

Well this begs for the question....wouldn't one not want to hit clipping at all... let alone frequently? I've heard tons of SET amps and what they do well they do very well. What they don't do well is very much the deal breaker for me. I like to listen to just about every genre of music imaginable and just can not stand to have an amp that just does horrible at one musical type and is spectacular at another. It's just to limiting. I'd just as soon have an amp that does all things respectable.

To take this subject further...I really do not completely fault the mushy sound of SET with complex music to just be a power thing. SET amps have an inherent problem tracking busy complex passage within music (impedance tracking). Higher power SET amps have the same character when presented with complex passages as there lower powered little brothers but to a slightly lesser degree. To me when presented with complex passage these amps just turn to mush loosing the inner detail of the music, every thing just kind of runs together. So what they excel at with Jazz and Acoustic music quickly is gone when the demand for extreme impedance complexity is presented. I know I for one get real bored listening to the same music type all the time. I run a lossless music server with 8000 tracks of every genre of music imaginable.... I let it randomly play so I just never know what will play next!

Craig

Here we go....[]

[sebrof]

BTW, I believe that is Pink Floyd with the top selling album, not Britney.

I stand corrected - Michael Jackson's Thriller sold over twice as many as the 2nd place seller. I believe I made my point []

(And I made up Mama-san Electronics)

[sebrof]

If an 3 watt amplifier with 5% distortion will transport you to sonic nirvana, then go for it. I can't help but to notice that those who use or have used this type of amplifier say that they work best with certain types of music, such as soft jazz, chamber quartets, acoustic folk music and the like. Last night I played some E. Power Biggs on my system. As the clean low bass rolled out of the Khorns, I was transported back in time to the original performance, 1959 I believe. I strongly feel that 3 watt amplifiers would not have done that. This was followed by The Glory Of Baroque. The delicate sounds of the strings filled the room and sounded amazingly realistic. I did not seem to need a euphonic component in the signal chain to make this happen.

I would agree that SET amps do best with certain types of music. But hey - If you want to go fast around corners get a sports car. That sports car will not take the kids and all their gear to soccer practice. You can get a vehicle that "does" everything, but at the same time does nothing exceptionally well.

While you were listening to E. Power Biggs (I need to look that up, sounds interesting) I was listening to Ben Harper. His voice, guitar, bass and drums sounded so incredibly real, so totally natural that I strongly believe a PP or SS amp would not have done that (I have tried both PP and SS). Ben was followed by Norah Jones - Her voice sounded as if it hung in the air in front of me. I did not need more than 4 watts in the signal chain to make this happen.

Enjoy your SUV. I'll enjoy my SET.

Like I said in an earlier post, there are many ways to make a good amp. It's interesting to me that people who don't prefer SET amps seem to attempt to make them seem wrong for some reason. There are people on this forum that drive KHorns with hundreds of SS watts. While I don't see why, and I certainly don't believe it's the best way to drive 104 db speakers, I respect the fact that they like what they have and I do realize that we all have different likes and dislikes.

[winchester21]

Long as it says VRD - it is AOK

Does it get any better- NO

[Mike Dubay]

Joe,

I have ended up with my feet in both camps. Bi amping Cornscalas with at KT88 SE on my mid horns and tweeters and solid state driving the bass bins.

I came to same conclusion, when I had my SE amp driving a full range single driver speaker it could do some things so well. The depth of the stage was staggering, i could clearly point to a location in my listening room where the sax was coming from when listening to classical jazz. But when playing my 70 to 90's rock they were lacking in the bass. I could not get a subwoofer to mate well with the system after many attempts.

But I believe you are right where you should be. I find the tinkering and trying of various equiptment and combinations the most statifying part of the audiophile journey. I am constantly researching, designing, building equiptment and enjoying the music from it. So you are just in the middle of a journey, you sound fustrated that you can't find an end all, which I don't there is and "end".

Maybe it is time for a "hardware hiatis", settle on a system that is enjoyable to listen to, then go to work on picking up source material for a period of time.

[DrWho]

3 things come to mind:

1. No feedback (usually). This eliminates the type of distortion caused by the feedback loop lagging the output.

2. Simple circuitry. There are a total of 7 components between my CDP and my ear (selector, volume, driver, coupling cap, power tube, OPT, single speaker driver).

3. Class A. This eliminates switching distortion found in Push Pull designs.

Just to play devil's advocate....

1. Why is no feedback a good thing? Also, emitter degeneration is still a form of feedback (or whatever the equivalent for tubes is)

2. Is simpler circuitry really better? If so, why? Why not just drive your speaker directly from the CDP? That would be more simple, no?

3. Is Class A the only topology with no crossover distortion? And is SET the only way to do class A? What about other class A approaches?

[DrWho]

3 things come to mind:

1. No feedback (usually). This eliminates the type of distortion caused by the feedback loop lagging the output.

2. Simple circuitry. There are a total of 7 components between my CDP and my ear (selector, volume, driver, coupling cap, power tube, OPT, single speaker driver).

3. Class A. This eliminates switching distortion found in Push Pull designs.

Just to play devil's advocate....

1. Why is no feedback a good thing? Also, emitter degeneration is still a form of feedback (or whatever the equivalent for tubes is)

2. Is simpler circuitry really better? If so, why? Why not just drive your speaker directly from the CDP? That would be more simple, no?

3. Is Class A the only topology with no crossover distortion? And is SET the only way to do class A? What about other class A approaches?

[NOSValves]

Long as it says VRD - it is AOK

Does it get any better- NO

Thanks for the comment on VRD's but honestly are you trying to start a war? LOL!! Really there are many real nice amps built today. Most of them cost a few more grand then the VRD's though.....

[NOSValves]

Well this begs for the question....wouldn't one not want to hit clipping at all... let alone frequently? I've heard tons of SET amps and what they do well they do very well. What they don't do well is very much the deal breaker for me. I like to listen to just about every genre of music imaginable and just can not stand to have an amp that just does horrible at one musical type and is spectacular at another. It's just to limiting. I'd just as soon have an amp that does all things respectable.

To take this subject further...I really do not completely fault the mushy sound of SET with complex music to just be a power thing. SET amps have an inherent problem tracking busy complex passage within music (impedance tracking). Higher power SET amps have the same character when presented with complex passages as there lower powered little brothers but to a slightly lesser degree. To me when presented with complex passage these amps just turn to mush loosing the inner detail of the music, every thing just kind of runs together. So what they excel at with Jazz and Acoustic music quickly is gone when the demand for extreme impedance complexity is presented. I know I for one get real bored listening to the same music type all the time. I run a lossless music server with 8000 tracks of every genre of music imaginable.... I let it randomly play so I just never know what will play next!

Craig

Here we go....

Well aren't you going to ask me how many SET amps I've owned?

[NOSValves]

3 things come to mind:

1. No feedback (usually). This eliminates the type of distortion caused by the feedback loop lagging the output.

2. Simple circuitry. There are a total of 7 components between my CDP and my ear (selector, volume, driver, coupling cap, power tube, OPT, single speaker driver).

3. Class A. This eliminates switching distortion found in Push Pull designs.

Just to play devil's advocate....

1. Why is no feedback a good thing? Also, emitter degeneration is still a form of feedback (or whatever the equivalent for tubes is)

2. Is simpler circuitry really better? If so, why? Why not just drive your speaker directly from the CDP? That would be more simple, no?

3. Is Class A the only topology with no crossover distortion? And is SET the only way to do class A? What about other class A approaches?

Boy are you are really trying to be devils advocate X5

[NOSValves]

Like I said in an earlier post, there are many ways to make a good amp. It's interesting to me that people who don't prefer SET amps seem to attempt to make them seem wrong for some reason. There are people on this forum that drive KHorns with hundreds of SS watts. While I don't see why, and I certainly don't believe it's the best way to drive 104 db speakers, I respect the fact that they like what they have and I do realize that we all have different likes and dislikes.

That's kind of a funny take on things if you ask me. I really do not see but a few folks in here talking bad about SET amps. I do see a number of folks stating why they do not prefer to use them but also stating that they do certain things extremely well. I myself think SET guys have some kind of inferiority complex and get their panties in a twist every time some one does not bow to the all mighty SET gods. Touchy bunch if you ask me and many of the more vocal types can be pretty darn nasty in my experience.

Craig

[NOSValves]

For those of us more technically minded, what are the reasons on paper for the advantages to SET? I understand what people are referring to about the smooth mids of SET, so I'm curious what the SET crowd would say is the reason for that sound. The natural progression would be to then implement that advantage into other topologies. Have any of you SET guys played with any Class D amps?

3 things come to mind:

1. No feedback (usually). This eliminates the type of distortion caused by the feedback loop lagging the output.

Wrong properly implemented feedback lowers distortion.... look at the distortion specs of your SET amps usually on the 5%+ range is the norm... then look at the distortion spec of any well thought of PP amp... they handily trouce any SET amp in that regard! The bad rep on feedback was from engineeers applying way to much to get the distortion, bandwidth and dampening factor as high as possible during the Spec/power wars. Careful small amounts of properly tuned feedback is not an huge issue. Like everything trade off are made. But your blanket assessments are just not true.

Oh and many zero feedback PP designs exists and have for many years. I personally like just a bit of feedback.

2. Simple circuitry. There are a total of 7 components between my CDP and my ear (selector, volume, driver, coupling cap, power tube, OPT, single speaker driver).

Simple is fine until its too simple to do the job.....

3. Class A. This eliminates switching distortion found in Push Pull designs.

CLASS A is not a SET only thing Class A can be achieved with PP designs no problem at all. VRD's for instant have around 15 solid class A watts before they start to reach into the A/B mode. Just about every PP amplifier has some amount of Class A operation.

None of these are possible (I don't believe) or at least not practicle, in a PP design. And I don't believe any of these are huge issues with topologies that have to deal with them.

See above wrong.... oh and many very simple PP designs exist. Problem is PP is hard to do right in an overly simple manor

I currently have SET with either single driver speakers or KHorns. That is not to say that SET is the only way, or even necessarily the best way, to make a good amplifier. SET is probaly not quite as good as you would think if you read what's on the internet, and is certainly no where nearly as bad as you would think if you read through this thread. It does simpler music and vocals exceptionally well, and it plays the classic rock I listen to well and as loud as I want (95 db+).

If you primarialy listen to loud music, or if your room is large, or if what SET offers does not turn you on, I would suggest another type of amp. But if you're like me and mostly use you rig to relax and chill at the end or beginning of the day, SET may just work for you.

See my comments above in bold

[edwinr]

Craig... How many SET amplifiers have you owned? [A]