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Most D-Sonic are stable down to at least 2 ohms.
Tim
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Hello georgehifi,
FYI, You’ve been using the abbreviation "ect" rather than the proper "etc.’ to refer to the words of Latin origin "et cetera". Translated literally from Latin, et means ’and’, while cetera means ’the rest’.
An easy method to remember the distinction is that etc. means et cetera, while ect is the typical involuntarily sound people make after reading one of your posts.
You’re welcome,
Tim
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I just read this article about Purifi Audio, and their class D amp that is said to be "completely indifferent to frequency, level and impedance variations, with measured intermodulation distortion way below any other technology." There's no mention of power doubling down all the way down to 2 ohms but an amp that is completely indifferent to actual speaker impedance variations seems promising, right? Here's a direct quote from the article: "The first product to be unveiled by Purifi is the 1ET400A, a 400W Class D single-channel, analog-input, amplifier module. Effectively, this is the module used in the prototype Lyngdorf 8 x 400 Watt Class-D amplifier shown at the ISE 2019 show. The technology is said to be completely indifferent to frequency, level and impedance variations, with measured intermodulation distortion way below any other technology." Here's a link to the full article: https://www.audioxpress.com/news/purifi-audio-promises-to-reduce-distortion-in-speakers-and-amplifie...
Tim |
Hello George, For class D amps that double their output as impedance is halved down to 2 ohms, it looks like all the new Merrill Element amps, also using the new GaN fast switching transistors, all are capable but they're expensive, starting at $15K/pair for the Element 114 mono-block amps: https://merrillaudio.net/products/
However, Merrill's previous Veritas monoblocks, came close to doubling power down to 2 ohms at low rated distortion levels: https://merrillaudio.net/veritas-mono-block-power-amplifier/#1519988773686-7ab00bcd-5607 I don't know dsper's budget, but I've been considering buying a used pair of these and most are listed at about $5K/pair. I consider a pair of these in good condition the likely best bargain solution. New, the Veritas were priced at $12K/pair. The OP, dsper, was inquiring about a class D amp that could handle his speaker's crazy low impedance loads of less than 2 ohms without freaking out. Since this new amp from Purifi Audio was born out of the research work of Class-D pioneers Bruno Putzeys (of Philips, Hypex and Kii Audio fame) and Lars Risbo (Toccata Technology and Texas Instruments) and can handle speaker impedance loads under 2 ohms, even if it does so at less than ideal wattage and distortion levels, I thought dsper still might want to give it a try, anyway. If Purifi offers the typical internet-direct free in-home trial period, there's literally no risk to dsper from giving it a whirl. Tim |
What I've learned lately on this thread is to avoid using speakers that present loads to the amp of less than 2 ohms. I believe if speaker designers and manufacturers decide to rule out the use of the majority of amps working well with their speakers, then we can certainly decide to rule out the purchase and use of their speakers.
Flipping the proverbial bird at reasonable and responsible amp designers and manufacturers, as well as reasonable and responsible potential customers, should rightly have consequences, not be rewarded and not be considered a recipe for success in a high sound quality speaker product.
Tim
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m-db:
"I’m a class D fan but I’m not fooling myself either. Their plate glass transparency along with switching amplifiers general lack of congestion make them a tool in my studio. In the living room they’re simply no match for the relaxed musicality of my tube amps. All the best with that Ralph, you’ve got the ears for it. "
Hello m-db,
’Plate glass transparency and a general lack of congestion’ is a very good description of good class D sound characteristics. I’m a big class D fan, too, using a pair of D-Sonic M3-600-M monos for my main speakers for music and two additional stereo class D amps for HT, one in bridged mono for the center and one in stereo for the rear surrounds. They all function and sound great and they draw so little juice at idle, I’ve just left them on virtually 24/7 for the past 5 years.
I usually describe their sound as very detailed, accurate, dynamic, smooth without ever sounding harsh or bright and so neutral they’re like ’the audio ideal of a straight wire with gain’. But ’plate glass transparency’ is very descriptive and really paints an accurate picture. I hope you don’t mind if I steal that phrase.
I'm also really looking forward to auditioning the class D amp or amps Ralph is creating. He definitely does have the ears for what good amps should sound like. Hopefully, he's able to make them reasonably priced since I get the feeling I'm going to be a future customer.
We all know George will be first in line.
Thanks,
Tim
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erik_squires:"My original point George was that you never accept anyone's experience with Class D as valid, or just as important as yours, and that is a type of disrespect I really really wish you would stop demonstrating."
I just wanted to weigh in and state, based on my personal experience reading and participating on threads concerning class D amplification on numerous threads here on Audiogon over the past several years, that Erik's quoted statement concerning georgehifi/George above is completely accurate.
On almost any thread concerning class D, George can be relied upon to post and express his unreasonable disdain for class D due to some sort of shortcoming, typically a shortcoming he has theorized but lacks empirical or convincing evidence for. I can't yet explain why George is so obviously and consistently anti-class D, but the real issue is that apparently, neither can he. At least, not convincingly.
I also don't believe there's any validity to golfnutz claim that Erik has
criticized Pass Labs or Spectral amps. In my opinion, Erik has been very respectful in all of the many posts of his that I've read. I think we should all refrain from making general critical claims about other members, especially without citing specific support for the claim.
Tim |
Hello dsper, I haven’t been able to follow this thread as closely as I wanted, but has anybody suggested the Merrill Audio Veritas class D monos that use the Hypex NCore1200 power modules and 1200 SMPS? Here’s a review that states they don’t quite double power in power for each halving of impedance down to 2 ohms (400w @ 8 ohms, 700w @ 4 ohms, 1,200w @ 2 ohms) but they sound great and are stable down to 1 ohm): http://www.stereomojo.com/Merrill%20Vertitas%20Monoblock%20Amplifier%20Review/MerrillVertitasMonoblo...
The Veritas sold new for $12,000/pair. With Merrill recently introducing a new line of Element series amps using the new and very fast switching GaN transistors, I’ve noticed numerous used pairs of Veritas monos for sale with an average asking price of about $5,000. I’m assuming many of these owners may be selling in order to purchase a pair of the new Element 116, Element 118 mono block amps or an Element 114 stereo amp. I believe a pair of the Veritas would be an excellent choice to drive your Thiel CS5s. My thinking is that any seller of a pair of amps they formerly invested $12,000/pair for would have cared for them very well and it shouldn’t be hard to find a pair in excellent condition. The best new options are probably the new Merrill Audio Element series amps using the new and very fast switching GaN transistors; the stereo Element 114 amp for $15,000 or one of their monoblock amps, the Element 116 amps for $22,000 or Element 118 amps for $36,000. Here's a review of the Eklement 116 monoblocks with comparisons to the prior model Veritas: www.enjoythemusic.com/superioraudio/equipment/0619/Merrill_Audio_Element_116_Veritas_Review.htmBest wishes, Tim |
clearthink,
Go lay down.
Tim |
Just got done talking with Merrill of Merrill Audio. He says a lot of his customers are trading in their $12K Veritas mono-blocks on his new line of Element amps with GaN FETs. He said the older GaNs sound better than the newest ones, interesting.
I've decided to buy a pair of pre-owned class D Veritas from him at less than half price, I'm going to pair them with a Levinson 326S preamp, Lumin D2 dac/streamer, Oppo 205, all balanced cables and Magnepan 2.7QR speakers.
Merrill said all of his class D former Veritas and new Element amps are stable down to 1 ohm, George.
Dsper, a $5K pre-owned pair of Veritas would be an ideal amp solution for any Thiels, Kappas or Apogees you care to use.
Thread question answered,
Tim
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It's apparent that georgehifi has appointed himself the official judge on this thread who administers the amp typology scales of justice with a big, heavy thumb on a particular scale and applies amp typology justice and fairness in the manner of a 15th century sadistic Russian czar. georgehifi: "Yes, they may be stable that’s only half of the equation, so is a $199 30w NAD 3020 integrated from the 80’s, it’s also "stable" at 2ohm loading, and also on the OP’s Thiel CS5’s, won’t make much music though." C'mon George, are you actually implying that a pair of the 1 ohm stable, 800 watt and highly praised Merrill Veritas mono-blocks won't make much music on the OP's Thiel CS5s? Here's a link to just one of a plethora of highly positive reviews on the Veritas and their music making abilities: ttps:// www.tonepublications.com/review/merrill-audio-veritas-power-amp-mono-blocks/
Tim |
George:
"Every amp I know of also has Class-A input stages, and "why suddenly is the Class-A linear the preferred way for the input", why not for the output as well???"
Hello George,
I don't think anyone's claiming a class A input stage isn't an excellent typology for an input stage since the class A typology is well known for it's very high sound quality performance. At low preamp stage input voltages, the excess heat generated by the highly inefficient class A typology circuitry constantly being in operation is not a major cause for concern.
While the extremely inefficient class A typology for an output stage is also excellent for sound quality, the excess heat generated by the highly inefficient class A typology circuitry constantly being in operation is definitely a major cause for concern since it's easily able to significantly raise the temperature in a typical domestic room.
But you already knew all this, George, before you made your comment. My question is why, knowing all the above, you even bothered to make it?
Obviously, one of the major advantages of utilizing class D output stages rather than class A output stages is its electrical efficiency and resultant dramatic decrease in the amount of electricity that is wasted by simply being converted to excess heat. Class A is about 10% efficient and class D is in excess of 90%.
Class A amps are typically expensive, operate at very high temperatures,are very large and heavy due to the numerous, large and heavy heat sinks required in an attempt to dissipate the large quantities of excess heat produced as a result of their extreme electrical inefficiency.
Class D amps are typically less expensive, operate at much lower temperatures, are much smaller and lighter due to the their lack of need for heat sinks required to dissipate the very small quantities of heat produced as a result of their extreme electrical efficiency.
The difference can be demonstrated clearly by a raw egg. Drop one on a class A amp at peak operating temp and you'll shortly produce a fried egg. Drop one on a class D amp at peak operating temp and you'll just have a raw egg mess that will remain until you decide you may want to clean it up.
Besides the advantage of your amp not acting as an HVAC component, there's also the class D advantage of cooler operating temps likely resulting in improved reliability and longevity due to the well known principle that sustained excess heat is a major factor in electrical component part failures.
However, I believe an individual's amp choice is likely made primarily on the basis of perceived sound quality and price to performance ratios, with amp typology traits being less important to most. I think Class D amps need to be leaders on these two factors to achieve continued success.
Tim
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Hello George,
Agreed.
While there's currently no such thing as a class D input stage there is a company, Mola Mola, that offers a class D preamp and pair of class D mono-blocks that have output and input stages specifically designed to perform optimally when used together; the preamp is called the Makua and the matching mono-block amps, based on Hypex NCore 1200 power modules and and smps (switch mode power supply),are called the Kalugas.
The part owner and chief designer of Mola Mola, Bruno Putzeys, is also the inventor of ucD (universal class D) as well as class D Hypex NCore technology. He designed the Makua and Kalugas, as well as a unique and optional class D internal dac board for the Makua, that are designed to specifically perform optimally with each other.
I'm planning on buying pre-owned examples of all 3 of these Mola Mola products, which have all received numerous excellent professional reviews, within the next monthor so for about $12-14K.
I'll post my impressions on all 3 of these once I have adequately had the listening time to form them. I'm sure you'll be awaiting my thoughts with bated breath.
Tim
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joysjane:
"Stay tuned for my first-hand experience as to how these amps drove my original un-modded Infinity Kappa 9's.
One of the amp killing speakers..."
Hello joysjane,
Wow, a teaser on the W4S SX-1000 class D amps and how they worked driving your very low impedance load and notoriously difficult to drive Infinity Kappa 9 speakers.
Full details next on News at Eleven?
Off the record, on the Q.T. and very hush-hush?
Very tantalizing, great job! You got me hooked, I'm certainly not touching that dial.
Drum roll, please?
Tim
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Buy a pair of pre-owned Merrill Veritas for $5K, they're stable down to 1 ohm. If you're unsure, just call Merrill and ask him if they'll drive the Kappa 9s.
Tim
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