SET amp owners thread

[PeterA]

I know that David Karmeli teaches this audio maxim.

Say there is an imbalance, an emphasis, in the treble region. How can the bass being "right" make "all else" right, if something is not right?

I wrote that when the bass is right, all else falls into place. Perhaps I should’ve added “in my experience”. I have heard very few systems with correct or convincing bass. None of those systems had emphasized treble frequencies. I have heard a lot of systems that sound bright. They don’t have proper bass presentation.

 

[PeterA]

I know that David Karmeli teaches this audio maxim.

Say there is an imbalance, an emphasis, in the treble region. How can the bass being "right" make "all else" right, if something is not right?

I agree if the system components are well chosen. If they are poorly chosen, in my experience the treble and midrange are pretty hard to get right also. If the system components are well chosen, the base presentation can be a challenge because of the room then the set up becomes really important.

 

[Amir]

David told me the hardest part of the sound reproduction is proper bass reproduction so it does not mean other parts are not important.

 

[bonzo75]

David told me the hardest part of sound is proper bass reproduction and it does not mean other parts are not important.

When you look for a wife, find a woman with a nice heart, doesn’t mean other parts are not important

 

[tima]

I wrote that when the base is right, all else false into place. Perhaps I should’ve added “in my experience”. I have heard very few systems with correct or convincing bass. None of those systems had emphasized treble frequencies. I have heard a lot of systems that sound bright. They don’t have proper bass presentation.

Similar to my experience as well. Bass and lower midrange, at least in classical, is the backbone of the rhythm section. Broadly ~40Hz to ~260Hz. Lower brass, percussion and lower strings undergird and contrast with mid and higher frequency instruments. Bass with timbre, articulation and a balanced response to the dynamics from the recording -- bass with character and vivacity. It wasn't until I put in place the JBL M9500s that everything fell into place -- at least as well as it could in my room. Timpani, bass drum, trombones, baritones, tuba, double bass, even contrabassoons and bass saxophones and bass clarinets (which I've played.) Of course the M9500s also brought a horn driver and its virtues.

 

[Amir]

When you look for a wife, find a woman with a nice heart, doesn’t mean other parts are not important

Kedar I am single and I did not find a woman yet so I will keep your advice in my mind

LOL

 

[bonzo75]

Kedar I am single and I did not find a woman yet so I will keep your advice in my mind

LOL

Please ask Romy for dating tips and use his style of conversation it will work

 

[Amir]

Please ask Romy for dating tips and use his style of conversation it will work

Romy is not expert in this area, I just follow your advices

 

[djsina2]

Finally negative feedback is used, which makes the Lamm unusual in the pantheon of SETs. Feedback helps linearize bandwidth at both extremes.

Isn’t negative feedback unnatural?

 

[microstrip]

Similar to my experience as well. Bass and lower midrange, at least in classical, is the backbone of the rhythm section. Broadly ~40Hz to ~260Hz. (...)

Yes, it is all written in the Jim Smith book. It is why, in his opinion, finding the proper listening position is the key point for a good sound.

 

[Ron Resnick]

David told me the hardest part of the sound reproduction is proper bass reproduction so it does not mean other parts are not important.

Yes, as I wrote above this is one of David's maxims. It makes some sense to me. My quibble with Peter was that it does not mean everything else automatically falls into place, if something else is unbalanced or emphasized or unnatural.

When David's disciples repeat any of his maxims I think it's appropriate to give David credit for the point -- as you are doing here -- and not allow it to seem like it is original thinking.

 

[bonzo75]

Isn’t negative feedback unnatural?

Always avoid it. It is also a bit stop start. Gives better grip and push. It seems Lamm in US is used more by people requiring low watt amps to push hard to drive speakers, in which case this makes sense

 

[DasguteOhr]

Similar to my experience as well. Bass and lower midrange, at least in classical, is the backbone of the rhythm section. Broadly ~40Hz to ~260Hz. Lower brass, percussion and lower strings undergird and contrast with mid and higher frequency instruments. Bass with timbre, articulation and a balanced response to the dynamics from the recording -- bass with character and vivacity. It wasn't until I put in place the JBL M9500s that everything fell into place -- at least as well as it could in my room. Timpani, bass drum, trombones, baritones, tuba, double bass, even contrabassoons and bass saxophones and bass clarinets (which I've played.) Of course the M9500s also brought a horn driver and its virtues.

It's much worse when the voice lacks body between 200 Hz and 600 Hz. For example, listening to Hans Theessink is very good. It sounds as if everything is there, but the voice doesn't stimulate the room or the air sufficiently. You don't get goosebumps because the speaker or pickup has a weak fundamental tone. Older Audiotechnica MC cartridges, for example, used to have this problem. They sound precise, but have a dip in this range. Changing the VTA or VTF doesn't help, because it impairs other ranges, such as the dynamic range.
P.S older audiotechnica mm cartridges (AT...ml )have no problems,on the contrary, they play captivatingly

 

[PeterA]

Yes, as I wrote above this is one of David's maxims. It makes some sense to me. My quibble with Peter was that it does not mean everything else automatically falls into place, if something else is unbalanced or emphasized or unnatural.

When David's disciples repeat any of his maxims I think it's appropriate to give David credit for the point -- as you are doing here -- and not allow it to seem like it is original thinking.

Ron, did you read my post #4101 above. I address your criticism directly. David gave me advice remotely, judging from various system videos I sent him as we discussed natural sound presentation and quality of bass. This was with my former system. Those discussions continued when he introduced me to the Lamm ML2 amplifier when I visited him for the first time. During this period, I learned by doing and listening. David encouraged certain experiments. In the process, I began to understand what he was describing. It is nice to see David Karmeli’ knowledge and experience being appreciated on this forum.

Referring to his customers and friends as “disciples” is, in my opinion, wholly inappropriate, even more so at this time of year. I see you chiming in and joining the others who refer to DDK as a guru, the leader of a cult, a puppet master, and his customers as disciples and puppets. I expect better from you as a forum owner, reviewer, dealer, and member of the industry. At least you don’t giggle uncontrollably.

 

[DasguteOhr]

Isn’t negative feedback unnatural?

No, it's like poison, the dose is decisive for death. A little bit, used well, can sound very good.
the impedance curve of the loudspeaker then plays less of a role of sound.

 

[Argonaut]

No, it's like poison, the dose is decisive for death. A little bit, used well, can sound very good.

Yup agree , the nature of its implementation into some circuit topologies can be used to benefit integrity of the signal , Interestingly PYE introduced an interesting design feature Into their PF91 back in the early 50’s by the provision of adjustable positive feedback (in addition to the main negative feedback) in order that the effective output impedance may be reduced to zero to improve loudspeaker damping.

That said however … for my part negative feedback has a questionable place within a Purist SET circuit application .

 

[Al M.]

Isn’t negative feedback unnatural?

Totally.

I love the wholly unnatural sound of my Octave tube amp, which employs modest feedback.

Trouble is, the Octave amp sounds significantly superior to my old parallel push-pull triode 2A3 monoblocks (15 W/ch), which had neither global nor local feedback, as confirmed by a technical expert who examined them. And dare I say, the Octave sounds more "natural". Wholly unnaturally natural, that is.

 

[Argonaut]

Al … At risk of speaking for him I suspect that @djsina2 might have been referring to within SET circuit topology .

 

[Al M.]

Al … At risk of speaking for him I suspect that @djsina2 might have been referring to within SET circuit topology .

I understand, but it could be viewed as a general purist principle. The designer of my zero feedback monoblocks was certainly proud of his design. In the 1980s it went against the trend.

I do see your point though about feedback in the context of SET purism. The whole point of SET is being purist, avoiding the alleged problem of crossover distortion (which, as Ralph would argue, isn't one).

 

[DasguteOhr]

Yup agree , the nature of its implementation into some circuit topologies can be used to benefit integrity of the signal , Interestingly PYE introduced an interesting design feature Into their PF91 back in the early 50’s by the provision of adjustable positive feedback (in addition to the main negative feedback) in order that the effective output impedance may be reduced to zero to improve loudspeaker damping.

That said however … for my part negative feedback has a questionable place within a Purist SET circuit application .

In a purist set circuit, the last capacitors and resistors/coils of the power supply before the tube play a major role, because the music signal is modulated the operating voltage. Of course, the OPT also plays a role; its quality determines the control of the speaker and the amplifier's bandwidth at the output winding (internal resistance).