| Columns Retired Columns & Blogs |
Again, JA1 becomes a part of a company's QC department. Seems like it is happening too often, as at these prices once is too often. I do feel bad writing this as there are owners who are left unaware.
Infigo Method-3 monoblock power amplifier Measurements
Sidebar 4: Measurements
Logistical issues meant that I measured different samples of the Infigo Method 3, serial numbers 3022-0002 and 3022-0003, than those auditioned by JVS. I started the testing with sample '0003, using my Audio Precision SYS2722 system. Initially, I used a balanced connection between the Audio Precision's signal generator and the Method 3. I preconditioned the amplifier following the CEA's recommendation, operating it at one-eighth the maximum power into 8 ohms for 30 minutes prior to testing. At the end of that time, the right-hand heatsink was warm, at 101.8°F (38.8°C), but the left-hand heatsink was at room temperature (see later).
Then I encountered problems: I saw bursts of high-frequency noise coinciding with the waveform peaks; these bursts went away when the XLR ground (pin 1) was floated. But with the ground floated, the Method 3's frequency response resembled that of a high-pass filter, rolling off below 3kHz with a first-order, 6dB/octave slope, and the voltage gain into 8 ohms was 8dB lower than the specified 26dB. With pin 1 grounded, the gain rose by 2dB, but it was still 6dB lower than specified.
Informed of these issues, Infigo's Hans Looman responded that pin 1 of the cable's balanced XLR plugs must be connected to ground. If that wasn't the case, the high-pass response with the balanced connection was due to "the signal ground connection being via ground capacitors only." This would explain the high-pass behavior. As for the HF bursts, they "could have been the result [of] the way the shield in the cable may not have played nice in this particular connection when there are ground issues already." He added that although there are heatsinks on both sides of the chassis, the current version of the Method 3 is equipped with circuit boards on only one side. "If you look inside, you can see that the non-assembled side (the left one as seen from the front) has a milled-out section in the heatsink that can also hold a board, similar to the one in the right heatsink. The original concept was to have the amplifier work either in bridge or biamp mode to drive the two sets of binding posts. Because of this, the leftover half acts basically as a single-ended input mode on the XLR connector, with pin 2 as the hot connection for that side and pin 1 as signal ground."
The 6dB shortfall with the balanced connection was likely due to the XLR plug's pin 3 not being connected to anything. (With a balanced connection, the pins 2 and 3 levels referred to ground are in antiphase and are each 6dB lower than when referred to each other.) I continued the testing by running a single-ended signal into the amplifier's XLR jack with a Cardas RCA–XLR adapter, using the adapter's pin 1 as ground and pin 2 as signal. The voltage gain into 8 ohms was now the correct 26dB, and the frequency response was full range.
Fig.1 Infigo Method-3, frequency response at 2.83V into: simulated loudspeaker load (gray), 8 ohms (blue), 4 ohms (magenta), 2 ohms (red) (1dB/vertical div.).
Fig.2 Infigo Method-3, small-signal 10kHz squarewave into 8 ohms.
The Infigo preserved absolute polarity (ie, was noninverting). The input impedance was 9.89k ohms at 20Hz and 1kHz, 9.7k ohms at 20kHz. The Method 3's output impedance, including the series impedance of 6' of spaced-pair loudspeaker cable, was very low, at 0.09 ohm at 20Hz and 1kHz, increasing slightly to 0.12 ohm at 20kHz. The modulation of the amplifier's frequency response due to the Ohm's law interaction between this source impedance and the impedance of our standard simulated loudspeaker was small, at ±0.1dB (fig.1, gray trace). The response into an 8 ohm resistive load (fig.1, blue trace) was down by just 0.6dB at 100kHz, though the increasing output impedance at very high frequencies means that the ultrasonic rolloff into 4 ohms (magenta) and 2 ohms (red) was slightly greater. The Method 3's reproduction of a 10kHz squarewave into 8 ohms (fig.2) was superb, with no overshoot or ringing.
Fig.3 Infigo Method-3, spectrum of 1kHz sinewave, DC–1kHz, at 1W into 8 ohms (red) (linear frequency scale).
Measured with the single-ended input shorted to ground, the amplifier's unweighted, wideband signal/noise ratio was an excellent 85.3dB ref. 1W into 8 ohms. This ratio improved to 87dB when the measurement bandwidth was restricted to 22Hz–22kHz and to 98.5dB when A-weighted. While power-supply–related spuriae were present in the Method 3's noisefloor (fig.3), these are negligible at –87dB and below ref. 1W into 8 ohms.
Fig.4 Infigo Method-3, distortion (%) vs 1kHz continuous output power into 8 ohms.
Fig.5 Infigo Method-3, distortion (%) vs 1kHz continuous output power into 4 ohms.
The Infigo Method 3 is specified as offering a maximum output power of 250W into 4 ohms (21dBW). Stereophile defines clipping as when the output's percentage of THD+noise reaches 1%; the Method 3 clipped with a 1kHz signal at 110W into 8 ohms (20.4dBW, fig.4) but at 100W into 4 ohms (17dBW, fig.5) rather than the specified 250W. The other Method 3 sample, '0002, clipped at the same powers into both impedances as sample '0003.
Fig.6 Infigo Method-3, THD+N (%) vs frequency at 12.67V into: 8 ohms (blue), 4 ohms (red).
Fig.7 Infigo Method-3, 1kHz waveform at 20W into 8 ohms, 0.013% THD+N (top); distortion and noise waveform with fundamental notched out (bottom, not to scale).
I examined how the percentage of THD+N in the Infigo's output changed with frequency at 12.67V, which is equivalent to 20W into 8 ohms and 40W into 4 ohms (fig.6). The distortion was very low at low and midrange frequencies into both impedances but rose precipitously in the treble. When I examined the THD+N waveform with a 1kHz signal at 20W into 8 ohms, I saw crossover distortion (fig.7). I was surprised by this, as the Method 3's output stage is specified as operating in class-A, which eliminates crossover distortion in a push-pull circuit. I confirmed this finding with the magazine's APx555 analyzer; the crossover distortion was also present with sample '0002.
Fig.8 Infigo Method-3, spectrum of 1kHz sinewave, DC–10kHz, at 20W into 8 ohms (linear frequency scale).
Fig.9 Infigo Method-3, spectrum of 5kHz sinewave, DC–40kHz, at 20W into 8 ohms (linear frequency scale).
Fig.10 Infigo Method-3, HF intermodulation spectrum, DC–30kHz, 19+20kHz at 20W peak into 8 ohms (linear frequency scale).
The levels of the distortion harmonics are very low with the 1kHz signal (fig.8) but, as predicted by fig.6, very much higher with a 5kHz signal at the same power into 8 ohms (fig.9). The third, fifth, and seventh harmonics are dominant in this graph, each close to –60dB (0.1%). Along with this increase in distortion at high frequencies came a plethora of high-order intermodulation products when the Method 3 drove an equal mix of 19 and 20kHz tones with a peak level of 20W into 8 ohms (fig.10). However, the second-order difference product at 1kHz was lower in level, at –80dB (0.01%).
As both my samples of the Infigo Method 3 behaved identically on the test bench, I had JVS's samples shipped to me. I performed a limited set of tests on one of his amplifiers, serial number 3022-0005, which performed identically to the first two samples: clipping at 100W into 4 ohms, with crossover distortion in its output, and with much higher distortion at 5kHz than at 1kHz. With this sample, in contrast to the first two samples, the level of supply-related spuriae fluctuated occasionally during testing. (Sample '0002 had a slightly higher level of random noise in its output than sample '0003, but neither noisefloor level changed with time.)
It appears that all four samples of Infigo's Method 3 amplifier had a manufacturing defect that disabled class-A operation. Hans Looman let me know in an email that he was able to reproduce my findings: "I am scrutinizing the bias circuit to find and fix what's causing it, most likely an optimization I have made that caused unforeseen side effects," he wrote, adding "I am still researching and measuring the possible cause, which is potentially linked to the difference in power measured as well." He will be sending Stereophile samples that have had the problems addressed in production. We will report on their performance in a subsequent issue.
JVS's report on the sound of the samples was positive, and the first two samples I measured had been used at shows, apparently without any issues, by a loudspeaker manufacturer. Is this surprising? Despite the observed crossover-distortion products, the distortion level is very low with a 1kHz signal, so it might have not set off alarm bells. While the THD at higher frequencies is much higher in level, the odd-order distortion harmonics will be at the top of or beyond the limit of human hearing sensitivity.
The shortfall in 4 ohm power might not be an issue with music, even with the demanding impedance of JVS's Wilson speakers, as I doubt he asked the amplifiers to deliver more than 50W or so. The clipping power into 4 ohms at high frequencies will be lower, but that would probably not be noticed with typical music spectra, which tend to be "pink" in nature. This would also be the case with intermodulation distortion.—John Atkinson
NEXT: Manufacturer's Comment »
 | |||||||||||
|
|
| |||||||||
- Log in or register to post comments
COMMENTS
Modern class D typically
Submitted by Joonas Viinanen on October 18, 2023 - 9:32am
Modern class D typically doesn't suffer from crossover distortion
Has JVS ever reviewed anything...
Submitted by MatthewT on August 31, 2023 - 9:54am
That was not the best ever? At some point a peak of perfection must be reached with no point in continuing. How do four defective examples escape QC?
Just goes to show...
Submitted by Archimago on August 31, 2023 - 11:23am
The limitations of human hearing and points at the importance of making sure reviewers have *very* good auditory acuity as we get older to pick up hi-fi anomalies.
Having said this, I heard the Method 3 at Pacific Audio Fest in 2022 and thought they sounded excellent with the Alta Audio Adam speakers. Obviously a company needs to be true to their claims - proper XLR connection, Class A (no crossover distortion), and must achieve power specs. However, the "needs" for human hearing is simply not that high, and few speakers/rooms need more than 50W anyways as JA1 alludes to.
Yeah, a "good enough" kind of perfection presumably was reached for JVS based on his subjective opinion/review despite clear objective limits of this amp.
JA1 characterized the measured performance of ...
Submitted by Ortofan on September 4, 2023 - 9:47pm
... the Alta Audio Adam speakers as "a mixed bag."
https://www.stereophile.com/content/alta-audio-adam-loudspeaker-measurements
The 4 units in question are
Submitted by hlooman on September 2, 2023 - 8:07am
The 4 units in question are all first builds, they have been shown on various audio shows to first get our new company out there. They went from an audio show to Stereophile so they were reviewed as is.
Also please see comment 'Core issue'
What are we to make of this defective $55k amp?
Submitted by teched58 on August 31, 2023 - 10:22am
But don't take my word for it. Read the experts:
JVS:"I've heard few amplifiers I've been as eager to return to time and time again as the Infigo Method 3 monoblocks."
BUT WAIT. What's this?
JA1: "The 6dB [gain] shortfall with the balanced connection was likely due to the XLR plug's pin 3 not being connected to anything."
AND
"It appears that all four samples of Infigo's Method 3 amplifier had a manufacturing defect that disabled class-A operation."
And, finally, in the "Truer words were never spoken" dept.:
JA2:"Whenever a designer claims to be doing something fundamentally new—like "low-temperature class-A"—it makes one suspicious. "
Low-temperature class-A: the
Submitted by Rodan on August 31, 2023 - 1:57pm
Low-temperature class-A: the holy grail! Often claimed, never truly achieved. See room-temperature fusion.
Low-temperature class-A: the
Submitted by Rodan on August 31, 2023 - 1:57pm
Low-temperature class-A: the holy grail! Often claimed, never truly achieved. See room-temperature fusion.
The original design calls for
Submitted by hlooman on September 2, 2023 - 8:28am
The original design calls for boards installed in both sides of the amplifier, to run fully balanced, of course with all XLR pins connected in that case.
For several reasons these first amplifiers have only one board installed, which sadly creates the measurement discrepancies and power shortfall.
As mentioned in my manufacturers comment, we are implementing changes that remediate these.
Also as mentioned in the comment, we found and have fixed the issue that showed up in JA's measurements that "disabled class-A operation".
Does the Infigo launch inspire confidence or concern?
Submitted by teched58 on September 2, 2023 - 2:46pm
Given that four of your early production units had defects, what are we to expect from your production units?
I don't mean to be unkind, but the fact is that you botched your pre-launch manufacturing, although you are very fortunate to have had Jason Victor Serinus as your reviewer, and you have have many nice words about your amp from his review. So as long as you avoid the objective part written by Mr. Atkinson, you should be ok.
At your previous gig (Reasonesence Labs), a firmware update was apparently botched, too. Also, if the comment is correct, the balanced inputs on the Infigo amp may also have issues.
The track record does not looking promising for those customers who may be concerned with the technical aspects of the product.
But again, fortunately you had JVS reviewing your kit.
Maybe you should raise the price to pay for the upcoming engineering and manufacturing fixes that appear to be necessary?
For the record
Submitted by hlooman on September 4, 2023 - 11:06pm
As mentioned in other comments, all four units were the same so they all behaved the same. I understand people like to pile up on words like 'defect' and 'botched' or other remarks about balanced inputs but don't take it out of context please.
As JVS mentions in his comment they sound wonderful.
We're a young company and unfortunately made a mistake launching these the way they were. Mea culpa.
To set this straight: I have never been involved with any firmware for Resonessence, I have only consulted for them to do their audio shows to help promote their DACs.
Thanks, Hans.
Interesting
Submitted by Gregory68 on August 31, 2023 - 12:19pm
Hmm the invention of class A Amplifier that actually operates as class a/b. Genius. I’ve never herd this amp but the review reminds me of the story of the emperors new clothes.
Oh, is that it?
Submitted by Glotz on September 1, 2023 - 9:47am
"In class-AB, the transistors that are on the half of the amplifier that is not contributing to the output current switch off above a certain setting." True. "In Infigo's approach, each half is separately biased to always keep conducting regardless of the cycle of the output signal." I'm no scholar of amplifier topology, but to me it does sound like something new, though experts may disagree.—Jim Austin
Core Issue
Submitted by MhtLion on August 31, 2023 - 1:10pm
Personally I understand QC can go south and the last minute adjustments can havoc things. But, you knew they were going to Stereophile but didn't do the final test before putting into the shipping container? If so, what kind of QC can a regular customer expected? More importantly, are you going to call everyone who already purchased it and offer free service? I failed to read it on your response. I urge you to reach out to everyone who may already have it and offer a free service.
"XLR plug's pin 3 not being connected to anything". This may be a bigger issue in my regard. Because this is not a QC problem. This is a core engineering problem. Based on the review, yet it appears that you produced a beautiful sounding amp. I personally feel sad such tragic things happened on your first Stereohile review. But, I urge you to the right thing by fixing every amps which are already in shops and homes, not just what's in your factory. This way, I hope you can rebuild the reputation.
Core issue
Submitted by hlooman on September 2, 2023 - 7:44am
The 4 units in question are all first builds, they have been shown on various audio shows to first get our new company out there. They went from an audio show to Stereophile so they were reviewed as is.
The original design calls for boards installed in both sides of the amplifier, to run fully balanced, of course with all XLR pins connected in that case.
For several reasons these first amplifiers have only one board installed, which sadly creates the measurement discrepancies and power shortfall.
As mentioned in my manufacturers comment, we are implementing changes that remediate these.
Revise balanced configuration
Submitted by kai on September 2, 2023 - 2:24pm
When implementing changes you should revise the way the balanced input works.
Balanced is NOT about just feeding one leg/pin to one amp and the 2nd to another one.
You need a (forced balance) circuit to remove common mode signals (noise) from the signal path and make sure both amps are driven with the same signal level.
Only this way the amp can be made compatible with all kinds of balanced and unbalanced sources.
It’s good that no one has it
Submitted by MhtLion on September 3, 2023 - 9:08am
It’s good that no one has it yet. I hope you survive this crisis.
It looks so boring...
Submitted by PeterKKB on August 31, 2023 - 2:49pm
For such a premium product they could have had at least spent a bit of money on design: this thing looks horrible (like a heating radiator).
It is just kind of a sad commentary on the state of MFG.
Submitted by jimtavegia on August 31, 2023 - 3:06pm
1.) I could never be a reviewer and expect to hear the small differences people claim they can hear. 2.) Every reviewer has their own pet speakers that they are use to hearing, yet some claim reviewed amps are state of the art in comparison, but have a hard time hearing malfunctions at low volumes. 3.) It is hard to believe that these manufacturers do not have the same testing protocols that JA1 has and used all the time.
I feel for reviewers, but it may be time for testing to be done first and if the gear is found defective sent back and no review printed. This would be a radical change at Stereophile but might be due consideration. Broken products returned would lead to that the manufacturer not being allowed to resubmit any products for one full year.
The other dangerous issue is reviewers who rate products, but have no testing gear and cannot inform the audience of any sonic issues just by "listening" to said gear. Much money is often at stake here.
I wonder if this review would increase, or decrease sales.
Submitted by Anton on August 31, 2023 - 3:47pm
No such thing as bad publicity?
Not with this kind of exposure.
Submitted by georgehifi on September 1, 2023 - 1:30am
As much as I barrack for the good linear amps, this one with this kind of exposure has seen it's last hurrah.
Cheers George
Their Latin isn't much better than their engineering
Submitted by Auditor on September 1, 2023 - 6:05am
"Infigo" definitely does not mean "impressive". It's a verb and it means "to fix (in), to drive (in), to attach". I wonder how the confusion might have happened, but I can't think of an explanation.
This isn't Jason's mistake. It's on the company's website.
There are always many
Submitted by hlooman on September 2, 2023 - 8:14am
There are always many different interpretations to translate a word.
Impressive is one of them.
https://latin.english-dictionary.help/english-to-latin-meaning-impressive
It is confusing indeed.
No room for interpretation in this case
Submitted by Auditor on September 2, 2023 - 9:49am
I realize this is an odd place to have a discussion about Latin, but we have to.
Yes, words often have several meanings. But in a real language they don’t just have whatever meaning you feel like giving them.
In Latin, the ending of a word is of fundamental importance. It tells you what type of word it is (e.g. a noun, a verb, etc.) and what its function is (e.g. subject, adverbial phrase, etc.). A Latin word ending in -o is almost certainly not an adjective. This vowel doesn’t appear at the end of adjectives. So, if you find a Latin word in -o in the dictionary, there’s no way it can mean “impressive” because there’s no way it can be an adjective. (Actually, it could be a masculine/neuter dative singular or ablative singular, but let’s not get into that. I doubt you wanted to decline the word.)
There’s only one word “infigo” in Latin and it’s the verb I mentioned in my previous post.
At least, your link gives us the source of the error. I don’t know who compiled this dictionary and what he or she used, but it’s just bristling with errors.
Two lessons here...
1. Information found on the Internet should be used with caution. Anyone can just toss anything onto the Internet. “Is this a reliable source?” is a question that should always be on one’s mind when gathering information online.
2. Languages are tricky. To stay out of trouble, it’s best not to use a language one is not familiar with.
Hans Looman Reasonessence Labs
Submitted by Turnerman1103 on September 1, 2023 - 12:30pm
Hans Looman proudly boasts about his connection to Resonessence Labs in his website
.I am one of probably hundreds of customers who were left high and dry by Resonssense Labs when they abruptly closed down .
I was the owner of the $5000.00 Reasonesence Invicta DAC . After noticing that Reasonesence Labs was offering upgrades to my DAC to “Invicta Pro “ status from the standard Invicta version at a cost of $1000.00 I happily sent my DAC in and $1000.00 for the upgrade .
10 days later I received my upgraded DAC back . Unfortunately, after just a couple of weeks after receiving my upgraded DAC back I started having problems with display .
I contacted Reasonesence Labs immediately only to discover that they had closed down ! There was no explanation given . Phones were disconnected - email address deactivated . Nor did not offer any information on their websites for the owners of their products who had spent thousands of their hard earned $$$ as to how they could at least have their expensive Resonessence products repaired in the future . Nothing ! They just disappeared.
I was stuck with a just upgraded $6000.00 DAC that stopped working properly after only a week.
I would never have sent Reasonesence Labs my $1000.00 upgrade if I had known that they would shut down just a few couple weeks later ! They were ethically obligated imo to have informed me before I invested a $1000.00 for their upgrade. An upgrade that turned out to be faulty
Resonessence took my $1000.00 for the upgrade knowing very well that they would be going out of business shortly afterwards . Very unethical business practices - a cash grab .
Last year I noticed Hans Looman had started a new audio company . He proudly advertises his previous connection with Resonessence Labs on his website !
Over the last year I’ve emailed and left voicemail messages for Hans Looman many times politely asking him if he could please just recommend someone who could help me get my Invicta DAC repaired. He has never once had the courtesy to return my emails or my phone calls .
I realize company’s go out of business - but the way Resonessence continued to take money for upgrades from their customers knowing full well they were going out of business is deplorable.
Wow! That is bad on so many
Submitted by bhkat on September 1, 2023 - 11:57am
Wow! That is bad on so many levels.
Rlabs
Submitted by hlooman on September 2, 2023 - 8:03am
I have been consulting to Resonessence Labs and helped them run the various audio shows they were presenting in the past nearly 10 years.
It is very sad indeed that they stopped business the way it happened.
I have not been part of any of the service of Resonessence products and have no tools or means to service them.
Unfortunately the person most qualified to do servicing passed away from a car accident...
I did not hear any voicemail messages but did see your message from our contact page today. The answer remains unfortunately that there is no official Resonessence service at this point...
LOL, seems that...
Submitted by MatthewT on September 1, 2023 - 4:04pm
"En fuego" would be a more appropriate name for this company.
Well... this comment section
Submitted by hlooman on September 2, 2023 - 8:39am
Well... this comment section certainly is on fire...
amp
Submitted by David Harper on September 2, 2023 - 10:40am
This is a good example of why "high end" audio is such a joke. 55K for a component that doesn't actually do anything other than impress silly audiophiles because it's so expensive. In addition to being profoundly ugly it doesn't even work properly. All together now.... PLACEBO!!!!!
I do have some schadenfreude...
Submitted by MatthewT on September 2, 2023 - 11:34am
When expensive gear fails. My vintage and "mid-fi" gear keeps plugging along.
This article and the comments
Submitted by cgh on September 3, 2023 - 9:03am
This article and the comments haven't really reduced my confusion. I am not in the market for a new amp, but always enjoys reading about what's new and out there. Assuming that a SP review is basically one and done (notwithstanding any follow-ups buried in the back of the magazine) I am mystified as to why the amp being reviewed isn't the final design lent out with a bow on top. Further, I am always confused when one is reviewed that has defects or flaws (that didn't happen in transit). I realize that nascent companies may not have the financial resources to produce numerous products and, in this case, there may only be a few amps in existence, but I would think it would spend time on the bench getting a once-over before the review.
So when I read the manufacturer's comments I scratch my head. Comments like "we thank John Atkinson for uncovering some things that will lead to demonstrable improvements." Is this still a work in progress or an evolving product?
"Scrutinizing the bias circuit to find and fix what caused those issues revealed a small undershoot..." again, is this a final product at $55k or a WIP?
"Thanks to John's input, we are incorporating a redesign of the topology of the bias circuit that is free of this anomaly..." again.. and a "redesign of the topology"???
Sounds like a WIP. It's galling that it should command a price tag like that. Presumably we are talking about a bunch of solid state analog and digital circuits and a box, so the NEW thing, the thing that commands the premium, is the design; something that is perfectly articulated by the designer, conceived, built and tested. Yet the design appears to be in flux. Yeah, I don't get it.
This article and the comments
Submitted by hlooman on September 3, 2023 - 9:16pm
I am glad the manufacturers comments actually get read.
All of the issues at hand have no discernible effect on the sound quality of these amplifiers, otherwise they would most definitely not have been handed over to Stereophile for a review.
The word 'defective' gets taken very literal, for anyone who has heard them will not deem them to be defective in the literal sense of the word.
Was this review too soon? Maybe.
I take full responsibility for this and stand by the line in the comment that any equipment that goes out of our factory will meet specifications.
As for work in progress: things can always be made better and innovation should never stop.
Why risk $55K on a product from ...
Submitted by Ortofan on September 3, 2023 - 8:55pm
... an outfit with no track record when there are excellent products available from other well-established companies? Indeed, you could buy one each of the following two-channel amplifiers and still not have spent $55K.
https://www.stereophile.com/content/nad-c-298-power-amplifier
https://www.stereophile.com/content/benchmark-media-systems-ahb2-power-amplifier
https://www.stereophile.com/content/parasound-halo-21-power-amplifier
https://www.stereophile.com/content/rotel-michi-s5-power-amplifier
https://www.stereophile.com/content/mcintosh-laboratory-mc462-power-amplifier
https://www.stereophile.com/content/luxman-m-10x-power-amplifier
Ok
Submitted by daveyf on September 3, 2023 - 2:51pm
I read the review by JVS and afterwards the findings by JA. All I can say is thank goodness for JA’s work.
These amps are clearly a ‘home made’ product from a fellow who is probably working out of his garage.
Nothing wrong in that, but let’s get real on the price!
For the ask, I think one can reasonably expect a level of QC that is far above what these ‘prototypes’ offer. As to the JVS review, well it is another one of those…if you don’t experience the product yourself in your system, you only have yourself to blame by going by what this chap reports.
Happy Labor Day!
Submitted by Jason Victor Serinus on September 4, 2023 - 7:55pm
I've been offline at a family wedding in the Bay Area. Having now read the comments, I'm glad I could enjoy the wedding in peace.
I never thought I'd find myself agreeing with Archimago. But as the one person (besides me and Hans) who heard the Infigos before posting a comment to this review, he wrote, "I heard the Method 3 at Pacific Audio Fest in 2022 and thought they sounded excellent with the Alta Audio Adam speakers."
The pair of Method 3s many audiophiles heard at shows was the same pair I reviewed. Except for their bass, which lacked the solidity and color I expect, they sounded as good in my system as they did at the two or three audio shows where I heard them. (I tried to get into the Infigo room at AXPONA 2023 to write a show report, but the positive buzz around them was so strong that the room was too packed to afford a decent listen.) In the lighting used in the rooms I did manage to visit on other occasions, the amps looked as good as they did in my listening room. But I listen in low light where the blue glow emanating from their transparent covers was quite enticing. I'm sorry that black and white photos do not present them in the best possible light, as it were.
I was in shock when, after I had submitted my review, I learned of the Method 3's faulty construction and inability to perform according to spec. I remain mystified as to how monoblocks that did not perform as they were intended managed to sound as fine as the Infigos did at shows and in my listening room. All I can do is repeat what most Stereophile reviewers say time and time again (and which a lot of posters clearly don't accept): specs ≠ sound.
I am beyond eager to hear a correctly assembled pair of Method 3s in my listening room. If the sound remains as good as before but the bass gains in solidity and focus because of higher output power and true class-A operation, I expect they will be a knockout. Until then, I am not going to engage in back and forths with people who have never heard these amps in person. Life is too short, and I'm short enough as it is.
jason
Jason? Or Archimago?
Submitted by teched58 on September 6, 2023 - 6:57am
JVS wrote: "I never thought I'd find myself agreeing with Archimago."
The fact that Jason thinks it's highly unusual that he's in agreement with Archimago says much, much more about Jason (and his perspective as a reviewer) than it does about Archimago.
Mea culpa
Submitted by hlooman on September 4, 2023 - 10:53pm
Thanks Jason...
I am very sorry that all of this happened the way it did, and once again, I take full responsibility for this and stand by the line in the comment that any equipment that goes out of our factory will meet specifications.
I am looking forward to getting you and John a new pair of Method 3s.
I fully agree: specs ≠ sound - but promised specs need to be met.
Hans.
What in the heck?
Submitted by JPD-WA on September 5, 2023 - 8:11am
"Rather quickly, Editor Jim Austin suggested I review the Method 3."
"It appears that all four samples of Infigo's Method 3 amplifier had a manufacturing defect that disabled class-A operation"
Maybe Stereophile needs to have a policy that they will only fully review equipment (especially like very expensive $55K mono amps, et al!) once it has come to market, rather than letting consumers assume it has and be beta testers for that gear, in this case seeming to be prototypes!. All four samples were defective! How can that possibly happen if a manufacturer has their act together? If I had bought these based on a review, only to learn of this problem, I would be absolutely furious. The mea culpas from the manufacturer are weak.
I would be shocked if something like this ever happened with much less expensive Schiit Audio, for example (and I don't own their gear). I've seen videos and read interviews about their manufacturing and excellent quality control. I have a modest but well-reviewed Odyssey Audio amp (a Jon Valin top budget pick), and I know builder Klaus Bunge would never let this happen, and would be embarrassed to his core if it had.
Justifying
Submitted by daveyf on September 5, 2023 - 6:51pm
Is justifying an issue like these amps had really the way to go? As the poster above stated, if he, or for that matter, anyone else, had bought these amps for the price asked and found these issues, they would be furious. IMO, rightly so.
The question that could, and maybe should, be asked is…would it not be prudent for a few protocols to be enacted? Firstly, it would seem to be appropriate for any manufacturer to bench test their gear to make sure it is performing as advertised before sending anywhere for reviews.Secondly, it would seem to make sense that JA might consider measuring the gear before a reviewer lays his hands on it…that way the kind of surprise that JVS received would be less likely. A faulty product could then be sent back before review.
Sound does not equate to measurements, but what the manufacturer correctly states…for a lot of folks, a product needs to meet its advertised specs. The higher the price asked, the more imperative this is.
" it would seem to make sense
Submitted by georgehifi on September 6, 2023 - 1:15pm
daveyf :" it would seem to make sense that JA might consider measuring the gear before a reviewer lays his hands on it…"
Now that's a great way to do things JA, what about it???
Cheers George
I like the current set up...
Submitted by Anton on September 7, 2023 - 11:48am
Listen and report, then measure seems great.
Otherwise, JA would just be sending the crap back and we'd never hear about an issue and its sonic correlation.
There is not even any need for the follow up review at this point, we have seen it with past reviews: "Everything I said remains true, only even more so now."
'Just sniff it and move on,' as my dog tells me when I go to pick up its poop on a walk.
I like this way because it shows us that we are mere humans; and it is a bit amusing because audiophiles who say they can hear beyond what can be measured get a chance to stand there with their pants down while JA shows us that either 1) we are sometimes fooling ourselves, or 2) those stupid objective tests don't catch the essence of a product even when it is broken.
This way is more fun.
Otherwise, JA would just be sending the crap back
Submitted by georgehifi on September 7, 2023 - 1:04pm
It should be sent back if it's playing up on the bench and never reviewed or exposed to the public, and it makes the reviewer look like a fool if he waffles on about how good it sounds. (reminds me of that other mag).
Cheers George
Nah!! it really needs to be thrashed out.
Submitted by georgehifi on September 8, 2023 - 4:44pm
Nah!! it really needs to be thrashed out.
As it happens now nearly every second or third review!!!.
And what happens if it's a "good subjective review" because of "whatever", and then the impressed reader doesn't read the measurements because he/she has no idea how to interpret JA's measurements, he/she can end up buying a lemon of a product, that has no re-sale value because of the bad measurements caused by design faults or whatever before being sent for detailed subjective/objective review.
Cheers George
First Hand Experience...
Submitted by funambulistic on September 9, 2023 - 5:35am
After reading all the wildly negative comments here, I thought I would offer my experiential $.02 based on actually listening to actual and real Infigo product. Last June, I attended the Lone Star Audio Fest and Infigo had a room featuring their Method 6 stereo amplifier and Method 4 dac, driving a lovely pair of Rosso Fiorentino Volterra speakers (and associated cabling, of course). This was, by far, the best sound of the show but that is not what really struck me, as fantastic sounding as it was. What really stood out to me was the noise floor (or really lack thereof). I've never experienced such a void behind, below and between the music - the mental image that came immediately to mind was a vast black, noiseless chasm that almost gave me vertigo! It is a phenomenon that is really hard to explain but is readily apparent once one hears it (or, more accurately, does not hear it).
I cannot say how that specific equipment measured but I know how it sounded and I was very, very impressed (the Volterras were no slouch either). Impressed enough that I am seriously weighing the need for two kidneys. Based on that presentation, I believe Mr. Looman is onto something special (it did not hurt that his lovely assistant played just about anything I asked her!).
If a power amp with a low noise floor is ...
Submitted by Ortofan on September 9, 2023 - 11:42am
... what impresses you, then you should try the Benchmark AHB2.
As a bonus, it might save you a kidney, or two.
https://www.stereophile.com/content/benchmark-media-systems-ahb2-power-amplifier
A low noise floor...
Submitted by funambulistic on September 13, 2023 - 11:17am
... is not the only thing that impressed me, impressive as it was. Thank you for the suggestion, but I have not heard the Benchmark, so...
"I believe Mr. Looman is onto something special"
Submitted by georgehifi on September 9, 2023 - 1:45pm
And buyers should buy a pair based on that and don't read or believe any measurements and spec on anything they purchase???.
The ideal mag for that type of subjective/suggestive only reviewing/purchasing, is Absolute Sounds.
Maybe this way of buying should go for purchasing ones car/fridge/tv/anything the same way also??? Just believe the one selling it to you and don't do any due diligence.
Cheers George
Curmudgeonly Commenter Will Curmudgeon...
Submitted by funambulistic on September 13, 2023 - 11:26am
I do not believe I wrote anywhere that buyers should by this. I was just reporting on what I heard and what I heard was excellent. I do not know how the specific components I auditioned measure (nor do I really care) and guess what? Neither do you!
Of course, you are free to interpret what I wrote as you see fit (which you obviously did)
Nice price point though
Submitted by daveyf on September 9, 2023 - 5:00pm
While the question of value differs for each of us, the price point that these amps has been offered at lets one look at a number of competitors. Personally, I would not touch an amp that is constructed so that it is unable to drive a variety of speakers at the price asked. These amps, even if they sound good to one listener at a show, are not a product that would give a consumer confidence. I think one of the interesting arbiters of gear, and many will disagree here, is how well the product holds up on the secondary market, price wise. Should be interesting to see how these amps do?
"I think one of the
Submitted by georgehifi on September 9, 2023 - 10:10pm
"I think one of the interesting arbiters of gear, and many will disagree here, is how well the product holds up on the secondary market, price wise. Should be interesting to see how these amps do?"
Looking at what's happened to it here, I think that may be a very rare one to see on the used market, and rightfully so.
Unless potential new buyers don't do their due diligence to see what rep it's got or going to have.
Cheers George
Infigo Method-3 monoblock power amplifier
Submitted by vlavalle on September 13, 2023 - 5:08pm
This product is a Canadian made product, but to sell it in the USA, you need to list the specs of the amp at 8 ohms (NOT 4) RMS and across the entire audio frequency range (20-20K) and at what distortion level. Thus, your 250 watts may actually turn out to 125 RMS w/ch with both channels driven at .08% distortion (just a guess at the distortion level) across the full audio range! If my guess is correct, and the amp only produces half of what you are advertising, who would pay such a high cost for a medioric amp?
Beautiful Junk
Submitted by a.wayne on September 17, 2023 - 9:00am
Amp needs a total redesign ..... !
The End ..
Get it together first!
Submitted by hiendmmoe on September 19, 2023 - 6:40am
Reading measurements is always somewhat a YA or NA specifically when the objectives vs subjectives poor their options into the subject matter. Usually I dismiss those ones as members of the YA vs NA when measurements produce some sort higher or lower numbers that some will call out on.
But, a manufacturer that sells a &50,000. Amplifier who sends it out for the world to hear and doesn’t have his shit together first; that’s is totally unacceptable. Just think if you’re the purchaser off of this amp and run into these issues after your investment. That’s not what this hobby should be about: it should make you happy not sad!
I am incredulous
Submitted by 13DoW on October 4, 2023 - 3:25pm
A manufacturer knows that JA measures most review equipment so I am incredulous that you would not measure what is being sent to ensure it is working! A well established manufacturer should be able to pull a piece from inventory and check the production test report. A new company can't do that but why-oh-why not hand measure the sample as a pre-review check? The words 'roost', 'home', 'to', 'coming' and 'chickens' spring to mind. And, JA-classic was told it was a manufacturing issue but the designer comments suggest it a design flaw that was not worked out.
Qudos to JA-classic for not giving the design a hard time but the reviewers, whose reviews would have been pre-biased (pun intended) to think the product was class-A, must be pissed.
constructive
Submitted by adifferentpaul on October 5, 2023 - 9:06am
This is one of those times where measurements do help in finding something to be resolved, and looks like an issue is now fully known about and already corrected. But the real reason for all the drama is the simple fact that Infigo amps sound fantastic, truly fantastic. I heard the Method-3 monoblocks and Method-6 stereo amps at multiple hi-fi shows, and the Infigo/Alta rooms really stood out as some of the best sounding rooms. The amps sounded ultra-clean and ultra-smooth, and are definitely worth auditioning. I do wish pricing was more user-friendly, as I would easily purchase the stereo amp if more affordable.
Engineering Genius
Submitted by Joonas Viinanen on October 18, 2023 - 9:46am
Someone finally achieved what was impossible... he made a low temperature class A amplifier. How? by making it class A/B of course. lol
| Loudspeakers Amplification Digital Sources | |
Analog Sources Accessories Featured | |
Music Columns Retired Columns | |
Show Reports | |
Features Latest News Community | |
Resources Subscriptions |
© 2024 StereophileAVTech Media Americas Inc., USA
All rights reserved
