@daveyf : Trouble ( if any ) with the whole subject that is confirmed through the thread posts is that each one of us have our each kind of target for home MUSIC reproduction and even several of us just do not have targets about.
In my opinion and before to look for efficiency/amps and the like is to be very specific the kind of MUSIC/sound each one of us want it I think that this is the main and critical factor to decide the: MUSIC reproduction sources, transducers, electronics, room treatment, cables and the like even our seat position and the kind of chair to listen sessions.
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Dear @daveyf : It seems to me that if you put together some vali with facts and knowledge levels on speakers it looks as some way or the other we need something that just does not exist and we are looking in a transducer that makes all to be posible: there is no single or" surrounded " perfect speakers/transducer and never will.
In the other side some of those gentlemans with good speaker knowledge levels have not the same good knowledge levels about amps/electronics and this fact makes everything more complicated to really have a good conclusion.
Example: even its inherent importance of speaker impedance phase no one name it and this is something to take care when we are choosing an amp we need to know the speaker impedance measures/curve and its phase down there.
Topic per sé is endless..
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@daveyf : Yes, maybe me.
@unsound " speakers designers have to choose what paramters and associated compromises combine to best meet ultimate design goals. Some if not most of the best measuring loudpseakers have lower impedances, and ergo lower sensitivity. There are a bountiful number of well designed amps that can handle such loads with minimal consequence. "
In total agreement with you.
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Dear @daveyf : First than all I'm a MUSIC lover and each single week at least I ttend to enjoy Live MUSIC and this " attitude " I have it for the last 25+ years.
I hate to listen the system Hardware and my room/system is builded through several years around nothing less than MUSIC but to enjoy MUSIC in my home we all need some kind of source/hardware.
I used tube electronics over 10+ years till I learned.
My ADS L2030 " old " speakers has 95db efficiency, no there is no single design problem with:
Vintage Holy Grail ADS L2030 High Fidelity Stereo Speakers and ADS C2000 Control Photo #1889387 - Aussie Audio Mart
The other gentleman ixs totally wrong, maybe he need to talk with J.Curl about that design or learn in other way about that specific design. I really don't care on his post that only shows high ignorance in tha specific regards amps.
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Dear @daveyf .: You are rigth and I was lucky enough to found out all the power supply, protection circuit, input electrical circuit electrolithics at its original values through the best of the best caps: Vishay.
When I did it ( less than 2 years ago ) and I listened again what I listened was and is nothing less than stunnig for say the least. I bougth my 20.6 second hand and I did it to been paired with a pair of 20.5s that I owned too in a bi-amp configuration and latter on that I learned I sold the 20.5s
" The amplifier performed beautifully, showing maximum distortion of 0.42% THD + N at 20 kHz. This distortion level would not be audible on music and is comparable to published ratings for high - quality tube amps driving standard loads; here, we were using one-fourth of the amplifier's minimum rated load! "
but in that 20's monoblocks review ( not the 20.6 that are even better ) that THD does noit changes even at 1 ohm where the 20's shoiwed 800 watts. Even those reviewers made this experiment with the monobloks:
"" An enthusiastic reviewer might call a beefy amplifier an "arc welder" as an exaggerated compliment to its ruggedness and current -handling capacity. However, no one would really expect an amplifier to actually melt steel. Almost no one, that is, except this reviewing team. We say this amplifier is an arc welder and back up this statement with a photograph (Fig. B1) of two 0.05 -inch steel plates welded together by a pair of Mark Levinson No. 20s. Arc welding is accomplished by creating an electric arc that melts metal. The molten sections of the items to be joined flow together and are then allowed to cool. In practice, the power source is connected to the two pieces to be joined and to a flux - coated welding rod. The arc is struck by momentarily shorting the rod to the work pieces. The flux is vaporized, forming an ionic conducting path for the arc and cleaning the metal. The arc stabilizes at about 100 amperes and 30 V (creating temperatures of 3,000° F), depending on the thickness of the metal and welding rod. If this sounds like the world's worst amplifier load, you're right! Coauthor Clark summoned Paul Grzebik to carry out the task. Paul has the reputation, in Detroit's technical community, for a willingness to try anything once, from building a parade float to scaling a TV transmitting tower. He readily agreed to our assignment. Clark drove both No. 20 amps with a 1 -kHz square wave to full output into a series resistor mixing network that combined both amplifier Fig. B1-Results of the arc -welding experiment. outputs in parallel to obtain the high current needed. After experimentation (and several blown line fuses), approximately 1 ohm was found to deliver the maximum current for starting and sustaining the arc. Wearing a mask and gloves (the intense blue light from the arc can burn the unprotected retina, while molten metal can splatter on the hands), Grzebik began welding. The arc turned out to be a fairly effective plasma tweeter, creating strong 1 - kHz square -wave sound radiation that required wearing ear protectors as well. Grzebik completed a small weld and, impressed, pronounced it satisfactory. After the welding, the No. 20s, still only lukewarm, were again put on the test bench. Distortion tests verified that no change in their performance had resulted from this extraordinary exercise. What's the point? With this test, Clark verified his confidence in the exceptional output capability and comprehensive protection built into these amplifiers. A few other amps might be able to weld steel without destroying themselves, but the No. 20s were certain to survive the experiment. One note: Don't attempt this feat yourself unless you are an accomplished welder, have the proper equipment, and are using amplifiers with extraordinary protection circuitry and output stages that can handle current extremes. Injury to yourself and destruction of lesser amplifiers may result. Don't expect manufacturers to repair your damaged amp under warranty, either! "
So, we don't have to care on what that tube manufacturer posted because it does not happens exactly as that. The very old 20's proved that and that design comes from 1986.
As always, there are designers and designers and J.Curl is really good . Remember the Vendetta Research phono stage? came from J.Curl and several other electronics designs as the Parasound and the like.
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Dear @daveyf : I know and listened sevral times in different home top room/systems the original JC 1 and the JC 1+ too.
But, I don't need to buy it because my Levinson 20.6 monoblocks was and till today it's the J.Curl Statement Design. Yes better than the JC 1+ and better that many today $$$$ SS monobloks and guess what: the 20,6 are pure Class A and doubles its power down to 0.5 ohms. It's a true beauty of design and it's a learning electronics for any SS amps designers.
That's what I'm talking about.
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@daveyf : As many others including what posted that gentleman ceratinly did not read yet te JC 1+ review that between other things states:
"
The JC 1+'s shielded input- and driver-stage circuit boards use an FR408 substrate, a substance that was developed for ultra-high-speed applications in supercomputers and aerospace.
• As in the JC 1, the JC 1+ input stage uses hand-matched pairs (footnote 2) of Toshiba 2SJ74 P-channel and 2SK170 N-channel J-FETs. Parasound and, I believe, Ayre Acoustics have invested heavily to secure an ample stock of these no-longer-manufactured, low-noise J-FETs. While the JC 1 driver was a single-stage circuit, for the JC 1+, John Curl designed a two-stage, cascode driver that would have some of the favorable attributes of vacuum tubes.
• As the number of high-performance loudspeakers with impedances that drop below 2 ohms is on the increase, Curl increased the number of Sanken NPN and PNP bipolar output transistors from 18 to 24. The output-stage circuit boards are now mounted vertically rather than horizontally, which should result in more effective heat dissipation. To deal with the increased current, the copper traces on the amplifier's main circuit board and the output-stage circuit boards are twice as thick as on the JC 1.
• The peak output current is specified as 180A, supplied by Nichicon Gold Tune capacitors, two more than the JC 1. Richard Schram says that although the Gold Tune capacitors were discontinued years ago, Nichicon continues to manufacture them exclusively for Parasound. "
Peak current : 180A. So what are you talking about? J.Curl does not makes that kind of mistakes.
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Dear @daveyf : About the JC 1+ I was refering to the speakers in demo by the seller in your OP and not about the owner of those Parasound amps that btw can handled with out problem to high SPL that 1 ohm impedance.
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Dear @daveyf : The issue thatan amplifier working harder develops higher distortions could not be exactly as was posted.
You can read in the link that the JC 1+ gives you at full power output same distortion levels at 8ohm, 4ohm and 2ohms: 0.15%.
The other issue about is that the levl of distortions each one of us can detect it as an added colorations depends on what the brain amygdala whole audio/MUSIC information is hang on to for the life experiences of different kind of sound and different kind of SPLs.
J.Curl knows exactly how design " a huge ss amp upstream ".
Speaker efficiency always is important depending how you paired with the rigth amp in the rigth room and of course inside your MUSIC reproduction priorities or restrictions.
Now and is something that you don't touched yet other than " good sounding " and you did not tell us with wich electronics ( overall ) you were listened, with which MUSIC sources and MUSIC gender and at which SPLs.
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Dear @daveyf : IN any case and not so expensive you can find out the Parasound JC 1+ monoblocks that when you listen it in any speaker at any SPL you did not ask if you are listening tube or SS amp but only enjoying MUSIC.
John Curl is a very low profile Master Designer Electronics Engineer.
Parasound Halo JC 1+ monoblock power amplifier | Stereophile.com
Regards and enjoy the MUSIC NOT DISTORTIONS,
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Dear @phusis : " Indeed sufficient headroom is a prime takeaway here (regarding both speakers and amps) - that is, it’s that it actually matters, and far more than people seem to realize. "
Normally audiophiles do not cares enough about " headroom " eve3n some of them not even know what it means in electronics and especially when we are talking of speaker/amp combinations.
As a fact I learned through my first hand audio experiences when I owned thr Classé DR3-VHC This amp is a pure Class A design with a power of " only " 25 watts but in its times was only one of the few amps that handled with aplomb the Apogee Scintilla that gone even lower than 1 ohm impedance and with not high efficiency but around 79db at 3m. but ( if I remember the Classé came with 7db on headroom and from here its VHC denomination: very high current. ).
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Well, D.Wilson ( paw, unfortunatelly. ) was not so stupid and " deaf " as his national manager and he used only Krell/Spectral amplifiers with the Watt/WAMM speakers to monitoring all his great Wilson Audio recordings.
"
The manual suggests that direct-coupled Futterman and similar tubed amplifiers are inappropriate, but gives the OK for other tube models when used on their 4 ohm tap. I have to disagree. A 1 ohm load severely limits the output power from a tube amplifier. For example, a 100W output (17dBW, 8 ohm) into a 4 ohm load will typically fall to 7dBW, or 10W in level terms, when faced with 1 ohm. Simply, this means that the amplifier will clip 10dB earlier if a strong musical signal appears at 2kHz, which is not unlikely, since this frequency is well in the main music power band.
Let us also assume a typical case where the tube output impedance and cable loop are limited to 0.4 ohms. Overall there is a loss of 0.8dB over the whole range, but at the 2kHz minimum impedance the loss increases to nearly 3dB, this inducing a dip in acoustic frequency response of 2.2dB which may well alter the sound of the speaker.........................................................Last and by no means least, there is the matter of that awkward load impedance, and the corresponding, almost unforgivable dip to 0.33 ohms noted on the review pair.......................................................Depending on the amplifier used, there was also a touch of hardness on, or edge in, the upper midrange which was ameliorated by using the Goldmund Mimesis 3 power amplifier and one or two of the other high-current amplifier types such as the Krell. This mid-treble problem was rather amplifier-dependent (due to the impedance characteristic...."
Btw, we have to remember that that 1 0hm and 0.32 ohm at those frequencies is not a discrete impedance value but part of the speaker impedance curve and the adjacent frequencies and developed harmonics are " touched " too.
Stupid people are all over the world and just fine with me.
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Dear @daveyf : I think that in many ways the speaker impedance curve and phase is way more important than efficiency.
Almost no speaker manufacturer ( if not all of them. ) gives to the owners that speaker measured characterisatics and normally only gives the speaker " nominal " impedance.
With out those 2 characteristics how any speaker owner could mate in a " decent " way the amp for his speakers audio system?
The Watt had pretty decent efficiency at 91 db but those very low impedances happens in a very usual frequency range where MUSIC comes.
That's why several audio system owners are not satisfied with the speaker or amp or boths.
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Dear @lonemountain " most bad decisions in audio are made based on bad info or lack of info. There is a lot of misleading info posted on forums "
yes, but in the forums are many very good information ( not bad information ) where we can learn. I learned in this thread with several of the posts of gentlemans that have higher knowledge level in the specific regards that me and one of them is @phusis and other like them.
Btw, I remember listened 4-5 times in the past the original Wilson Watt and this is a fantastic true monitor not high efficiency as a horn but measured 91db and this Watt has a problem for any amplifier ( tubes forbidden with ) at 1khz its impedance surve measures 1ohm and near 2khz 0.32 ohm . IN those times the preffered amps for it were Krell and Spectral.
As a fact David Wilson made it all his Wilson Audio LP Recordings using in the studio the Watts and at Wilson place the WAMMs. I own all those fantastic recordings that are impressive: microphones by Sennheiser ( recordings in the late 80's ), Recorder by John Curl, cables by Bruce Brisson. We have to remember that DW before started in the speaker design was a recording engineer for several years.
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Dear @ghasley : You say that prefers no negative feedback and maybe because you have a deep misunderstood on feedback amp issue but some of us can learn about in this link coming for a truly expert engineering:
whitepaper (sotaturntables.com)
He was designer in Analog Devices Inc: "
Several years? I was with ADI- designing a wide variety of ICs for almost forty years and was most fortunate to become an ADI Fellow and Senior Fellow.
I am not a free-lance engineer. I retired from ADI a few years ago and I design audio (and other gear) for fun and for free, "
Sometimes post in Agon and is a gentlemans that we have to listen and read him. But as always are other people that just never learned due to their own or audio sale agenda, especially in electronics items.
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@lonemountain : Now I understand why for you is important but not so important the speaker efficiency issue. I visit your virtual system and seems to me that you are an audio distributor od low efficiency ATC speakers.
@phusis " the claim that high efficiency is necessarily and always bound to be attained "with a price," sonically speaking, is a fallacy. Typically it comes down to (the need for) large size and a different speaker principle.."
Well , that large size is not exactly typically " because depends on the kind of drivers other than horns and an example are my ADS speakers that yes are " large size " but the size is due that the speakers can goes down to 16hz through two 14" acoustic suspension woofers but today I have the ADS from around 100 hz and up and the soft domes ( silk ) acoustic suspension 2" for the mid-range and 1" for the tweeter ( one a top the other:nearest as it can be. ) needs a very small " box space " due to its very high gauss magnets ( are not vented and non-ferrofluid. ) around 24k in the tweeters and 18K in the mid range, both drivers made it in Germany for ADS and its efficiency is 95db ( almost a horn . ). Unfortunatelly the drivers manufacturer just does not exist any more.
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Dear @lonemountain : Yes, today TAD speakers are not exactly high efficiency at 90db and are expensive but its sound quality level performance is excellent.
In the past Exclusive in Japan ( Pioneer ) had the 98db big 2401 Twin model obviously all TAD drivers and in Japan in those early 80's its retail japan price was 1,200,000 Yens and a direct competence to JBL and other USA speakers or from England as the Vitavox.
TAD today monitors for home audio are in the 85db efficiency and excellent performers too.
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Dear @alexberger : Yes you are rigth and I can see your Altec Lansing drivers, that EMT, the Tamura and the like. Congratulations.
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Dear @phusis and friends: we have to remember that atmasphere is a tube electronics and from several " vintage " years his flag ship argument to hit class A and AB solid state amps always is that: harsness/brigthness " but with out real facts. His article is only bla bla bla as always in that regards.
If he can proves what is his solid state agenda then that comes here and shows at least 10 SS top/high power amps tha showed what he said in the last 10 years with measures of those amps and what the reviewers said it about. Here one example and the other is my very old 20.6 monoblocks where just does not happens his bla, bla, bla,:
Halcro dm58 monoblock power amplifier | Stereophile.com
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