I have the Sugden A21SE and it’s the best amp I’ve had in my many years in audio. It is incredibly musical and has a totally fatigue-free purity. The sound is enveloping and immersive.
The absent Pass meter isn’t a voltage consumption one, it’s a bias meter (not needed on a pure Class A amp), which illustrates when the amp is switching from Class A to Class A/B amplification, when it leans to the right.
Great review, thanks! I think Sugden A21SE is more of a direct competitor to INT-25. A21SE is 2x30W pure classA , it uses linear power supply and more traditional ClassA design where tranzistors always working. It also weights more than ANV50 due to the need of bigger heatsinks. ANV50 only uses 20W at idle or so, has switching mode power supply ( classA should use hundreds of watts, new design approach, and sounds maybe more like AB).
I have Pearl Acoustics Sibelius speakers... They replaced both my Tannoy Stirlings and Altec 19's after just a few days of listening. Incredibly detailed speakers with spectacular soundstage. Highly recommended. I use mostly tube amps, but also listen to a Pass First Watt J2. As the speaker's voice coil is driven directly from the amp, different amps can make a slight difference, but they sound good with most tube amps with 15 to 30 watt ratings.
What a refreshing video. Subscribed! As a Pass Labs XA30.5 owner, I am always interested in comments on their lower-powered offerings. Loved your comments on each of the amps and your advice on choosing the right amp. The only thing I would have liked to know - granted, easily looked up after the fact, is the speaker sensitivity, impedance, room size and typical listening volume. As it turns out, 87 db is a shade on the low side for the Pass Labs, although the impedance looks pretty benign.
Some of that will be in the review video of the speakers because listening volume is more apt and important with them than other speakers and oh yeah thanks for subbing
This must be the fist Sugden vs Pass amplifiers review to my knowledge and that by itself makes it one review most solid state audiophiles would rush to watch - a great idea indeed and, for me at least, better late than never. Popping the lids is definitely elucidating. I had no idea of either of these devices circuitry and while the build and parts quality of the Pass looks impressive, and despite the huge fins, I'd still like dual mono construction at the money. Going to the Sugden, things are a tad clearer: I can see a number of innovations - dare I say surprises - there starting with dual mono construction but with switching power supplies! Now, that's a first for Sugden! Nice to see good quality output transistors and I would guess from looking at them that this is a push-pull and thus no A21 clone. These two design choices might explain the midrange? So, even though it's probably the first Pass vs Sugden, I'm still looking forward to another battle but this time involving their iconic products i.e. the A21 or its clones from Sugden. From the Pass camp there's a lot of circuit choice but one of their classic ranges/models, as close as possible to the A21 topology would allow for a like-with-like comparison.
We are so fortunate to have so many topologies to utilize in the systems that can be created. Such a diversity of sources as well. The limiting factor might be a lack of imagination.
Wonderful video, Terry. A really well thought out presentation 👌 For all your viewers, I'd be more than happy to answer any specific/further questions they have on the amplifiers or indeed our Sibelius loudspeakers. Thanks again for all your hard work.
Thanks Terry, you always put together such interesting pieces. Ive always associated class A with a lush liquidity in the mid range that gives huge insight to voccals, so its interesting to hear your findings on the Sugden. Some of my favourites over the years have been Musical Fidelities class A/B designs.... but its been a while since Ive heard current ranges. Thanks again for a great vid...
Thanks Terry very interesting insight into the Sibelius. I have a pair of Sibelius Speakers and my experience is also that they are very revealing of amplification. When I bought them I had a Hegel H90, the sounded so bad I nearly sent them back. Luckily I was able to try some other amplifiers and the difference was night and day. The first time I heard them with a Pass labs XA25 I knew I had made the right choice of speaker. I now have a Canor AI 2.10 and I absolutely love them. They make me smile every time.
What didn’t you like about these speakers with the Hegel H90? From memory I think I saw these speakers being used with a Hegel H90 by the Sibelius designer and he was saying that they were a great match together
@@hclandscapes There was a reduced bass and the speakers took on a boxy quality, hard to describe but like speaking through cupped hands (this might be something to do with my room). I heard a demo of the Norma IPA 140 and loved it, but couldn’t afford it, I thought it’s little brother IPA 70 would be an alternative, but when I heard that, that lacked bass too, that was a disappointment. Harley does mention the H90 in one of his videos, that’s why I originally chose it. Working together with Harley and Ajay of Art and Sound I found a great amp. Ajay has a pair of Sibelius and I took my Hegel to compare with his amps. Eventually Ajay was able to visit me, with the Norma IPA 70 and 140 along with the Canor that I eventually purchased. I purchased the Hegel as virtually new and sold it without losing too much, but I did have to spend more on an amp than I had originally intended (though I was always going to spend the money eventually). The Sibelius are are great, but I think you need to be really careful with amp matching, you really need to hear the combination before committing to an amp.
Great video as always. I would have gone for the Sugden A21SE class A at 30wpc which is nearer the Pass Labs or the Sugden IA4 at 33wpc class A. The ANV50 is more of a hybrid. But I am biased as I own a Sugden A48B class A/B amplifier. Will be interesting to see how the tests on both amplifiers turn out with different speakers though.
GREAT, thorough discussion, Terry. The Leema Amp is the closest amp in the group to my McIntosh MC152 Power Amp (pre-amp Freya +). Makes me wonder how the Sibelius Speakers would sound in my set-up. 🤔 I know they are a quirky, unusual speaker with very careful placement requirements, which I bet that you cover when you review them.
Really liked this one Terry, made me open my mind a bit regarding how I think about hifi. Especially about matching amp to the current (no pun intended) phase in life. You are growing as a hifi youtuber, keep it up! :)
The comments on the Sugden amplifier fail to mention that the unusually light weight of the amp is due to the controversial use of a Switch Mode Power Supply... which detracts from the configuration of all the other original Class A amplifiers in the range. As such other amps in the range would have been a fairer comparison to the Pass Labs Pure Class A amplifier.
I showed the internals so you could see all that, as I explained at the start of the video these are thr amps I am using to review the speakers not arranged to create a comparison. But the stark differences is what makes this video worthy
Your video reviews/presentations are Class A. I thoroughly enjoy watching your reviews. Many thanks for putting such effort, attention to detail and inspiration in all your videos ❤
My favorite words/input; "How it sounds with electronic music." Love it bud, you're one of the only reviewers who covers that genre and it's extra important to me and I'm sure many others! 🤙😁
Exactly. Far too many HI-FI reviewers testing world class audio with Chris de Burgh and Nora Jones. Some of us want to hear the low end 'thwack' a decent amp or speaker system has to offer.😂
Great Job of explaining the different flavors and sound of the different Amplifiers. Usually , the power have to match the sensitivity of the speaker. Three very good amplifiers. Class A vs class AB , power all come into play. I personally use the Big class A Pass amps (monos). Thats the flavor I like and it matches up pretty good. Class AB would also be good. Depends on the speaker and the sound you like. Again, excellent review. Everyone, enjoy the Music.
Pass Labs and Sugden are both great amplifiers. But to me the Gryphon Diablo 120 beat both of them in delivering a more musical convincing performance. I use Audiovector r1 arreté speakers.
Very cool sir! I appreciate how even when you provide your preference it’s done in a way that it respects other options and tastes. Have you tried different sources too with the amplifiers and sibelius? Reason I ask, when I auditioned the Sibelius and a couple different amps the source made the amplifier performance slightly vary and creating a different presentation. It also revealed which amplifiers were colouring the sound more as when I would climb the ladder in source quality, some amplifiers seem to fly and others stayed on the runway (amplifier scaling?) Curious to know if you had a similar experience.
Pass: clear detailed, unique sound (relative to AB operation) Sugden/Quad: power, fuller, closer to AB. Luv em all. i just have to add DAC, speakers, preamp that will contribute to the sound I prefer. Pass: toaster hot. Sugden/Quad not as hot and power hungry (sliding).
Although class A amplifiers don't produce any crossover distortion, they may produce inter modulation distortion due to non-linearity. This is normally corrected by negative feedback. However, negative feedback can cause problems under some circumstances. The power devices in the output stages have to be really fast and wide bandwidth to get the feedback back around the loop quickly to correct any non-linearity. Lateral power mosfets are fast enough to satisfy this requirement with ease.
he should throw some printed circuit boards in if you judge an amp by the volume of circuitry. I understand that the philosophy on which he has built his career is 'less is more'.
Thank you for the wonderful review Terry. About 6 months ago I had the opportunity to demo the pass lab setup I believe it was the XA30 paired with one of their budget preamps and I can't remember the speakers we were listening to but like you I found the sound overly saccharin and cloingly sweet. That sound though was quite enchanting however to me it seemed to be too much of a good thing. I'm an American and over the last decade I've come to really love British amps my current amp I use is the rega aethos. I don't know I like that sort of lighter acoustic Mass that I hear with a majority of British amplifiers that in my opinion allow a lighter more fleet of foot Sonic characteristic. Essentially none of the timbre of the music is Weighted down unnecessarily. Which I feel is what contributes to the classic British sound of Prat. I wonder if you're findings with the sugden have anything to do with the fact that even though it's a class a design it however uses a switch mode power supply?
If u like british amps, try an LFD. Probably the best british amp out there. Combines tonal purity of class A with the exuberance & PRAT of Naims in one package.
I’ve read that the ANV is quite different to other Sugden Amps, so the ideal comparison might have been a more classic Sugden design (without knocking the comparison made!). The Rega Aethos completely rocked my world and it will be the centerpiece to upgrade my system around ❤️
I have read that the power output of the pass labs amp is seriously underestimated by the manufacturer. You might want to look around to see Reviews, such a Stereophile, because from what I’ve been told the power output is much higher and that might explain some of what you were hearing.
It didn't sound like its lacking power but at the same time it didnt sound like a powerful amplifier - its trading off outright control and authority for smoothness and gracefullness
Interesting account. I run my Sibelius with a Pass XA25 power with a PrimaLuna EVO 300 pre. I went that route as there is tube rolling options with the PrimaLuna, though have not done that yet. I hear you re different amp characteristics, so an other option is going full separates with at least some tubes, as opposed to integrated black box solutions. Incidentally I learned after putting my system together, the Pass XA25 PL combo was one recommended by some London outfit and Sibelius distributor. Living in California, Pass Labs had to be considered ;-)
My home designed and built mosfet power amplifiers can be switched from class AB to class A operation. They don't sound any better in class A compared to class AB operation. However, in class A the heat sinks run much hotter as you would expect. An interesting feature of class A operation is that the heat sink temperature is maximum when there is no signal applied to the amplifier. When you apply a signal and increase the output power the heat sink temperature goes down. I remember from my college days that the maximum theoretical efficiency of a class A amplifier output stage is 25% and 66% for a class AB output stage. However in practice the efficiencies are less due to circuit losses.
The Sugden must be an extremely limited class A design, probably moving from pure A to AB at only a few watts as it's heatsinks are WAY too small. On the Pass amp, fitting a 'current consumption' meter would provide no useful information at all, as a true class A amp draws the same power all the time, the meter would be sitting at 100% all the time.
Hi , by far the best hifi channel on youtube , or anywhere I should say. You should try to get your hands on the Shunyata Hydra Delta D6 or denali 6000 power supply/conditioner , would really like to hear your thougts on that one ! Thanks
Very good Video with a very important message for a lot of Audiophiles: Forget about dogmas and listen for yourself! Not a specific technology is the only truth but rather the very implementation of it is what matters the most Well done 👍🏻
Thanks for an excellent video - with a real message. Would love to see you do the same comparison of amps with a pair of Spatial open baffle speakers. Highly recommended. Driving mine (M3 Sapphires) with a Leema Hydra II Amp... The M3s similarly have minimal electronic crossovers. Front end here is Auralic and Chord (Dave) . Greetings, Terry, to you and yours.
Great review, nice info and comments, good background music, and good over-all presentation, but I do not like the long and slow blurred transitions. Unusual choice?
The big problem with class A: the terribly high temperature which forced me to sell my Sugden which nevertheless sounded wonderful. I live in a region where summer temperatures easily exceed 30 degrees. Sugden recommends a maximum room temperature of 35 degrees. The A21SE is a marvel at low-mid and bass levels, it is pure class A on ALL its watts unlike certain brands which have a slippery class A on the first watts. However, you should consider this issue before purchasing a class A amplifier, if you have children it can be dangerous as the cover becomes extremely hot. I also have doubts about the longevity of a device that operates at such high temperatures. Your video is interesting because I don't know Pass-Labs hardware very well (except by reputation). That said, for those who want a taste of Class A with serious hardware and an affordable price, consider Sugden. Be careful, once you get used to it, it quickly becomes addictive.
I've had really mixed experiences with Class A amplifiers. Some were way too laser-like and bright for me but others were just sublime. I guess it's how it's implemented.
Terry, this is one confusing video... The title have us expect an integrated shoot out, then you say it's about the speakers... and then you have the wrong Sugden for pure class A... The Sugden Masterclass IA-4 (or even the A21SE for that matter) would have been the de facto cousin to the Pass... The Sugden AV50 is like Coke Zero... Genuine Coca-Cola without sugar and without...the taste!!! If it doesn't heat, it's not pure class A and anyone telling you otherwise is trying to sell you something... The Sugden magic is HOT!!! I am whining here because I like you very much as a reviewer and comparison between pure class A integrated are hard to find and I got excited for a second with your title... Pass vs Sugden! The OG vs Nelson Pass the genius from a real reviewer I like! Alas...
To be fair it is integrated shootout but just using one pair of speakers, and the speakers review is the reason i have them. I have compared a sugden amp vs a pass labs amp but they are at widly different prices so its apples to oranges but still its all as the title suggests. The title is a little click bait for sure but there is no embellishment with it really
Audio Research power amplifiers do a great job of sounding like tubes, which they are but being basically neutral in character. My Pass XP-22 pre into my Audio Research VT-100 Mk III driving my Maggie 3.6 R's have a beautiful synergy. I will add that I have very high-quality, musical sources feeding my preamp. After all, isn't our passion all about relaxing and letting the music flow rather than being a critical listener driving yourself crazy every time you sit down to play music.
May have been mentioned in other comments but this particular Sugden is not a Class A amp - the pre-amp section is but the power amp section is far from Class A. You need to try the IA4 for a fairer comparison.
Yes but not buying anything My system is set Still largely in boxes Awaiting furniture and energy to assemble Great vid Terry practical informative and entertaining. 👍
I think a Luxman L590 might just be the sweet spot you're looking for, being a bit more sharp than the Pass. Sugden Masterclass isn't really class A by my standards : the A21 would be a more fitting comparison, but might present the same limitations as the Pass. 13:21
Nice review. Im interested in the smaller sugden a21se, and will demo soon. Id be really interested to hear your thoights on the Primare i35 integrated amp, being class D. I heard one recently and thought it amazing in many respects, but couldnt tell if it would be lean sounding in my room (i will be doing another demo soon). I am coming from a roksan k3. Cheers!
I have the Sugden A21SE. You’d have to spend at least $5K, or more, to get a Class D amp that would be its equal. The Sugden is totally grain-free and pure. It’s not lean in any way - it’s perfect. Imaging is holographic. The only amp I’ve had in my system that sounded similar was one of the very expensive John Curl designed Parasounds.
Only problem with this is the only class a amp in the test was one that isn't really powerful enough to do justice to 90% of speakers on the market which automatically screwed the test towards the class ab or hybrid amps. I love class a you can't beat the naturalness of midrange treble which is, apparent on even a 25 watt version and if you can aquire one with enough power then you get the best of all worlds (other then power consumption lol)
The sugden is 50watts and that is enough for the speakers for sure. The idea of big power class a is very desirable but as I discussed this comes a price tag to match
@@PursuitPerfectSystem Yes that's why I go second hand for everything a nice big krell can be picked up for a grand or two and that's 200w+ class A in your face :D (might be a good idea for a review - new class a vs 20 years old class a? Hilariously my reference amp is now an old Nad 208THX I picked up for 300 quid - so far it's easily seen off everything I've tried up to £2k odd.
The speakers still have to have an inductor in the signal path. Unfortunately these speakers have a poor frequency response with poor treble, unlike having a dedicated tweeter. Also they do not have a tight bass, unlike a sealed cabinet. Class AB is generally superior as regards sound quality if done right. Class A is just an expensive audiophile gimmick nowadays, while having higher ultimate distortions with lower available power abilities, while consuming huge amounts of wasted electricity with no real acoustic benefits on a sound quality basis. Modern transistors omly need the minimum current to conduct a constant current, and sound better sound quality wise than if they where running full on cooking temperatures. I have experimented with my amp's running class A and AB with the minimal current. Class AB wins hands down.
I forgot to add that using class A amplifiers on single driver speakers allows their best innate qualities to shine through and thus the reviewer has the chance to compare them at what they do best. Single drivers give them the best chance of producing sound in the range of most critical frequencies (i.e. that range that matters the most) without it being adulterated . On another topic: isn't it strange how many manufacturers have picked up producing full range metal cone drivers after E J Jordan? Which begs the question: when are we ever going to see a comparison of quality class A amplifiers on Jordan speakers? That would be quite something. I would even venture saying that Jordan drivers are for solid state amplifiers what Lowther drivers are for valve amplifiers. Hmmm.... that could be interesting too.
It's always amazed me how much we spend on speaker cable , but in the amp the binding posts are connected to the transistors with bell wire lmao. Go figure !
I looked at the smallest one a few years ago and I think they start at about £15k but yeah could be a nice choice with the sibelius but again it would be a very warm lush sound
Enjoyable review as ever, but (and sorry to be pedantic) as a lover of the Finnish composer's music, FYI Sibelius is pronounced "Sib-AY-lee-es" rather than :Sib-E-lee-es"
You can't build a Class-A amp that is not pulling max power at idle because that is precisely the definition of Class-A. I understand that this concept drives people nuts in 2022 because you can also identify as a little black lesbian girl, but sorry, it does not make any sense. If the Sudgen can deliver say 50 Watts max but only pulls 10 Watts at idle then it is by definition a Class-A/B, whatever the advertising claims. Additionally, Class-A was never the gold standard. There are some good reasons for Class-A, but there are also good reasons for Class-A/B. If there is any gold standard, then it is Class-A single-ended, (isn't Pass SE?) but SE designs require a very special speaker design. A speaker design that doesn't exist these days anymore, like the legendary Altec A-5/A-7.
looks to me like the Pass Labs is the only genuine class A only one of the three. The higher powers the other two offer and increasing into lower impedances suggest transition into class AB. Also just look at the heatsink size, the Pass Labs are the largest, yet it's power the lowest. There's no way the Leema can be that powerful all in class A with heatsinks that small. It looks like the Sugden is using switch mode PSUs, which may account for it's sound signature.
I actually think that Class D is now the gold standard in terms of performance. We are literally approaching total amplifier transparency with near zero distortion. However I also accept that majority of audiophiles don’t like total transparency and enjoy some degree of euphonic distortion in the signal chain. Enter class A.
I dont think class a means any type of distortion quite the opposite, its what the designer does to make the amplifier sound a certain way that matters most here, kind of the point of the video :)
@@PursuitPerfectSystem I enjoyed the video and totally agree with the conclusions. I was simply responding to the question posed in the thumbnail re gold standard. I get it, I’m a Gryphon Class A owner. I do think that the euphonic sound signature you refer to in the video though comes from strategic use of distortion (fully intended by designers) similar to that which tube amplifiers have. Would be fascinating if you got similar price segment Class A, Class A/B, and Class D and compare. I would tune in for that!!
Yeah that would be cool to do, but it would still be product A vs B vs C I dont think we can ever do a proper class A vs AB vs D I think that is something maybe only a designer can do as they can keep all things equal in the middle if that makes sense :)
Over 7000 quid for 25 watts? Is Pass Labs having a laugh? And why were it 7200 quid when it's $7500 dollar in U.S. and Pass Labs based in U.S. $7500 dollar in U.S. is around 6200 quid.
Single small driver Sibelius is all intermodulation distortion, with excuses for base, and pathetical efficiency, last thig to be mated with low power amps. The PASS INT-25 would have been nice for a $500 gizmo from AliXpress but at $7500 is pure class-snake oil amplification, The ANV50 is CLASS-A...for the first 4 watts, I think my P-P tube amps, and my Crown commercial PS series kind of do the same class-A trickery, without the snake oil, real amps for 2020 are Hypex/Purify/ICEPower without snake oil and BS.
i tend to disagree on only using oone pair of speakers to your try out testing Not all amps fit with all speakers You needed at least 3 different pairs i find to be complete and objectif
If the higher power amplifier gives you tighter bass and the amplifier costs the same or less then whats not fair about it? Should I have only compared low power amplifiers to give the Pass Labs an advantage surely that would be more unfair ? I dont think power in watts has anything to do with an effortless sound, in. fact I know it doesnt
I find it amusing when people potentially spend more money on a system to listen to music than a studio spend on the gear making it. Do you seriously hear things we can't hear mistakes we make or is it all in the head and imagination? My studio monitors were not cheap, quality costs money, but seriously £7k just for an amp over £4k for speakers? Sure clarity definition and the rest are perfect, bleeding heck they should be, maybe I have a screw loose or missing one, but my own personal Hi-Fi system cost a fraction of that and ticks all the boxes.
Work tool vs pleasure tool and yes maybe you are not hearing everything when hearing enough is enough is the goal. Only one way to find out go listen to some systems. Also remember regardless of how you make it doesnt mean thats how I want to listen to it too thats a whole videos worth of debate 😀
you don't have to spend a lot of money for class A + plus watts and current this way I love OEM products CODA CSIB first 20 watts are class a 150w 8ohm 300w 4ohm 20 transistor per channel bipolar. FET differential input stage, MOSFET voltage gain DC coupled to an ultra wideband bipolar output stage. it's going to be a different presentation from pass and gryphon but on paper pretty much same stuff just more money
The real comparison was class a vs a/b and that a doesn't automatically mean better, the prices of the products were exactly right to show what the video intended
