Class 'A' vs 'AB' amplifiers: The search for a perfect soundstage and an emotional connection

[@PearlAcoustics]

With a big thanks to '@qumq001', they discovered that on the Pass Labs INT-25 recording, the Left and Right inputs to the amplifier were reversed, hence you'll hear the muted trumpets from the left, rather than the right on all the other recordings! Sorry about this, totally my mistake, I think it's time I left for my holiday ;-) I will try and reply to all the comments when I can! Harley

[@padde1]

use headphones and turn them around for the INT-25 ;)

[@billspencer8540]

One of the finest amplifiers I had the pleasure to listen to is the Technics SE-A100. This one sports distortion specs that gives modern amplifiers a run for their money. A true marvel of human engineering.

[@texfish]

It's so good to watch someone talk calmly and intelligently about a subject without constant editing cuts and over the top gimmicks. This site and the British audiophile are the best sites on KZbin.

[@erics.4113]

The Brits are the best for dry information delivery. All those years of BBC injection and you hear the accent and immediately think it's true science lol

[@texfish]

😀

[@MrBonger88]

It is refreshing isn’t it? I’m so tired of all the click bait garbage. Anyone with a camera and access to audio gear on Amazon thinks that they’re credible reviewers these days

[@texfish]

They both seem to have a good knowledge of what they're talking about too,which helps.

[@erics.4113]

@@texfish they do. Taren(sp) British audiophile is one of my favorites to watch

[@ptbfrch]

The Sugden... Goodness me. Thank you for this comparison! I cannot afford the SP4, but will probably go for their integrated if I can put the budget together. Such a musical, open, clutter free sound.

[@PearlAcoustics]

👍

[@budgetaudiophilelife-long5461]

THANKS HARLEY 🤗 FOR SHARING YOUR JOURNEY 👍💚💚💚😊

[@PearlAcoustics]

My pleasure!!

[@peterlarkin762]

Very interesting points made. Especially timbre... probably the most important and least discussed element of sound reproduction. Here's my experience with amplifier soundstage: I have a couple of class AB solid state diy amps, one of which can run with up to 300mA idle current bias. As the bias is turned up, the soundstage grows (more separation, wider stage) and tonality is shifted. It sounds 'clearer'. However imaging and overall cohesion starts to go down at the same time. There's always a sweet spot! If an amp sounds good, it's not just the Class, it's how much effort the designer has gone into tweaking it, trying different parts etc. and what that designer considers important characteristics (measured spec vs. subjective enjoyment).

[@PearlAcoustics]

So true! Thanks for sharing your observations

[@guillermoq7884]

I prefered both Class A Amps, Pass Labs had a wider well defined airy soundstage, the Sugden had stronger and detailed bass with a wide soundstage. I found both Class AB had narrower soundstage and muddy/less detailed bass. It's interesting thet we can hear this differences even through the KZbin compresion codecs...thanks Harley !

[@PearlAcoustics]

You’re very welcome. Thanks for taking the time to give your feedback. It’s very welcome

[@rap-soldier2185]

SUMO 9 OR ANDROMETER

[@glen7589]

I appreciate you taking the time for this comparison. I preferred the PASS for the layered dimensionality and instrument separation. The vocals had a little sharpness or edge to them which the Sugden smoothed off a bit but it didn’t have the instrument layer or separation like the PASS. ❤

[@PearlAcoustics]

You’re very welcome. Thanks for sharing your conclusions

[@HiFi-Tom]

Fully agree to the importance of Timbre, Harley. Especially in voices, to me it makes the performance come alive. This is exactly what pushed me over the edge to buy my new power amplifier. One of the reasons mentioned in my video is - timbre 😉. Appreciate your videos very much and hope to get to hear your speakers one day!

[@PearlAcoustics]

Thank you Tom! You’re very kind. I hope you get to hear them too. Reach out to us via our website, maybe we can arrange something- who knows?

[@NickP333]

Wow, the Pass amp has excellent separation, realistic tonality, a more human element to the vocals and the timbre, of course. That said, the Sugden seemed to have those same attributes, just a bit more refined and pleasant to listen to. The Musical Fidelity was nice too, but the Sugden was my personal favorite. Thank you, Harley. Looking forward to hearing about the new amp.

[@PearlAcoustics]

Thanks for sharing your observations and indeed for your very kind words!

[@Gma7788]

This is an early judgement 😕 which you should not do in the first hours as Mr Pass has warned you. You've been warned ⚠️ by the maker himself that the first hour is a throw away hour. The amplifier hasn't stabilised yet. You guys are expecting instant results straight away. That's not what happens. You can't judge the sound in the first several hours...

[@NickP333]

@@Gma7788 🤦‍♂️ OMG…. Firstly, thank you for expressing Mr. Pass’ “warning”. I’m sure Nelson would be proud. 😂 I also appreciate you caring for my well being….lol These online sound samples / demos of gear is mostly just for fun. This is not critical listening by any means. Whether an “early judgement” or even if the amps had all been playing for a week or more straight, again, this is not critical listening. It cannot be taken too seriously or done online. It is merely a fun exercise. Anyone interested in this level of gear, I’d like to think knows better. Until he or she has a chance to live with and listen to a piece in their room, in their system, for a somewhat extended period of time, this is again….just a fun experiment.

[@NickP333]

@@Gma7788 Oh, and I’m glad to see you liked your own comment. You deserve it!

[@OldGuyHifi]

Very enjoyable and informative video. I am in agreement with you on a preference for Class A. I have both in my room and for more serious listening I choose the Class A. It is a vintage Ken Ishiwata designed Marantz integrated amp for the mid 80's. A delightful unit. Thank you.

[@PearlAcoustics]

Thank you for sharing your story and fir your very kind comments

[@Bob-sw2zj]

Thank you for explaining Class A and then the comparisons. I just purchased an Accuphase A75 because of this video. Pass Labs are too big and too hot for my situation. Accuphase sounds amazing and with a small footprint and less heat. It is the best amp I have ever owned and because of your explanation, I understand WHY is sounds so good! Thanks again.

[@PearlAcoustics]

Glad it was helpful! Enjoy your Accuphase. Great products

[@chrissimmonds4383]

Thank you Harley, for your enthusiasm in identifying the amplifiers that can reveal the low level detail in recordings that differentiate the different classes of output stages, and which also make for long tem enjoyment of music. I have recently aquired a Class A amplifier that is 'probably' one of the rarest amps ever made and it dates from the 1990's. It's a JVC AX-SD1GD, made just before they went bust, were very expensive, brought about JVC's demise, which was subsequently bought out by Kenwood. It runs quite warm, is built beautifully and has made me sell my previous amp, my Quad Artera Stereo which is highly regarded. The JVC is low powered (35watts per channel to 8 Ohms), weighs about 14 kilos, (double mono construction) is an integrated amp and it sounds wonderful driving my PMC Twenty5/23 floorstanders. It sounds much more powerful than 35 watts and I'd like to try it with your Sibelius loudspeakers. It's also very revealing of low level Information, unexplained noises, even performer's breathing and off mike sounds which add to the effect, which were not noticed before. I am a fan of JVC amps and knew about their development of this 'luxury' compact hifi system, but could never find them for sale. One evening I saw an Ebay ad for the selling of a lot, held by a hifi collector who bought stuff when it came out, played it once then mothballed it. An item in the lot gave me a jolt, I recognised it at once and snapped it up, fearing it was a scam or a mistake, but no, I now have the amp. I did not expect the sound, it is superb and I've not stopped listening to it since, something I never could do with my Quad Artera A/B amp. I tired of listening very quickly with the Quad and couldn't really figure out why, it had tremendous power and slam, but it made me not want to listen for long. After seeing and listening to you debating about the best amps for your listening, I was gearing up to buying one of the Sugden class 'A' amps but the JVC has now satisfied my quest. i'd still like to hear it with your Sibelius loudspeaker though, so I'll have to find the nearest stockist. I live in Essex, UK. Thanks again, for your very interesting videos. Please carry on.

[@PearlAcoustics]

Hi Chris, thanks for sharing your wonderful story and observations. Sorry for the late reply but I have been away on holiday. If you reach out to me/us via our website, maybe we can find a way of getting you and your JVC hooked up to a pair of our loudspeakers? Enjoy your amplifier, I am sure it’s very fine. I would love to hear it!

[@gordonwong7158]

Great comparisons. Thank you I have to admit the int25 was so much better for me and emotionally engaging. This was the same experience when I had auditioned it before. Luckily I wasn’t listening closely when you declared which was which so it was blind for me. Only when I replayed your KZbin did I see the one liked was passlabs. Thank you for the experience

[@PearlAcoustics]

Thank you. 🙏 the comparisons are only for fun but it is strange how differences can be detected, even though the sound is way inferior than listening in the room. Enjoy the PassLabs, it’s a wonderful machine.

[@sginfdfw]

Thank you for taking the time to not only explain but also show the point you were trying to get across. For me, I have to say I preferred the Sugden SPA-4 rendition of Clare Teal. As you mentioned in your video, Timbre is very important in creating that "perceived" performance. Now, I'm on a mission to save for a new amplifier...

[@PearlAcoustics]

Glad it was helpful! Thanks for sharing your appreciation

[@RLC-ej8qc]

I just closed my eyes and I can say really the INT-25 beats the others.Thank you for this very informative video.

[@PearlAcoustics]

You’re very welcome. Glad you found a favourite 😀 of course, it sounds way, way better in the listening room

[@dirkbusche54]

The differences between Class A and AB are quite clear, with Class A you can hear the character of the recording room much more precisely, amazing. I listened with AB: Neumann Monitors KH 120 A (Class D), McIntosh MHA 150 (only Preamp-Function), via AppleTV 4k sending the signal via LAN to Lumin Streamer and this sends the signal via 2 Reclockers into the McIntosh-DAC.

[@PearlAcoustics]

Thanks for sharing!

[@pauldavies6037]

that's a lot of digital stuff

[@jakbenardete7707]

Harley, first of all thank you and great job, it's always a learning experience and a pleasure to watch your videos. For me, with headphones, the sound differences were small but distinct. Hard to choose number one between the Sugden and the Pass, could live with either but might slightly prefer the Sugden, #3 is easily Rega, and MF had the least pleasant sound of the four. Even thoough I love Class A amps, I think I am a tube uy through and through, but would love to try a combo of a tube pre and a Class A power, that should be fun.

[@PearlAcoustics]

Thank you! You’re very kind. Deep down, I am a tube guy too 🙏

[@HenrikScheel_]

I got the Sugden 75 w and I agree. Sugden are actually very competitive in their pricing compared to same quality products. I have tried a lot of brands but Sugden was the end station for me.

[@PearlAcoustics]

Thanks for sharing your experience

[@brianbillings6815]

This was a fantastic, informative video. Despite KZbin's compression algorithm one can hear the track pretty well. Perhaps it is my being so used to AB amplification but it sounded fuller to me. The most noticeable difference for me was the difference from a lower powered amp to a higher powered amp. My personal favorite of these being the Musical Fidelity. I'll have to explore the comments to see how my experience compares!

[@PearlAcoustics]

😉👍

[@danielgeiger7739]

Another great video! Re soundstage beyond the speakers, my Sibelius DEFINITELY deliver, and they do literally disappear. Same also for center channel and depth in the center. Re amp comparisons, I could not hear much soundstage difference; might be difficult with earbuds. However, very strong timbre differences. The two big boys sounded anemic (sort of ironic with all the famous "headroom" of big amps), while the two CAs sounded fuller, with the INT25 having most life in it. I can also confirm Sibelius being great at fine timbre separation. As you may recall, I am an amateur HIPP baroque string player (viola d'amore). Particularly with gut strings, bow speed, pressure, position opens up a lot of expressive possibilities. Sul ponticello and flagolette/harmonics are possibly the most obvious ones, but there are infinite gradations. Playing the same note on different strings results in different timbres. Extreme case on violin is open string (say a) vs. 4th finger one string lower (d string 4th finger = a, or even 5th position g-string). I can certainly hear and appreciate those nuances in good recordings with the Sibelius speakers. -- Enjoy your holiday in France; currently doing the same in Vienna.

[@PearlAcoustics]

Thanks for sharing your wonderful explanation and experience. And thanks too for your kind wishes. I am back from France now and listening to Brandenberg No. 5 while I write! Enjoy Vienna, I am off there in June.

[@capelight52]

I preferred the Rega over them all! Terrific auditioning. Appreciate! Francis

[@PearlAcoustics]

Thanks

[@colinbenfield326]

Even with ear buds in the class A sound was like a better microphone was being used. The Sugden was lovely.

[@PearlAcoustics]

😉

[@stuartboros7693]

The pass labs was definitely my preferred amp- it sounded the most natural, the most like live music. What’s interesting is that I listened to this thru my bedroom home theater system which uses the Magnepan LRS+ driven by my old Nelson Pass designed Adcom 545 II. (I have Galion solid state A75 amp on order to see how it compares to the Adcom.)

[@PearlAcoustics]

Thanks for sharing!

[@AstroSam66]

I'd prefer the Sudgen and then the PASS. I'ts really astounding, how much wider the sound stage is and how much more "musical" the Class A amps sounded against their Class A-B brothers. Thank you for this eye (ear 🙂) opening demonstration!

[@PearlAcoustics]

You’re very welcome

[@rap-soldier2185]

SUMO 9 OR ANDROMETER AMP

[@christianevans4449]

The difference is clear in favor of the Class A team, for the type of music I`m favoring the Sugden. This is the same experience I had when I bought my Accuphase 30W A36-amplifier vs their own 90W E-380 amp. Actually I bought the amp without worrying about the power based on one of your videos, where you questioned hi wattage amps, thanks for that! I believe with this video and the quality of your recording we have a proof of superiority of Class A. Heat and power are the only valid concerns as far as Im concerned.

[@PearlAcoustics]

Thanks Christian! Welcome to the Class A fraternity ;-). Indeed, in the summer they can be a challenge ;-)

[@christianevans4449]

@@PearlAcoustics Thanks to you again. My system sounds lovely thanks to you.

[@stig-a.svarthumle4181]

I'm surprised I could pick a favourite here, but I prefer both class A amps and Sugden as my favorite. Listening to a mobile phone S21, it was still clear to me! I found the class-A so much more pleasing and AB almost fatiguing (causing stress). AB sounded like it had more contrast/dynamics when singing but lost details at the end of the voice as it faids out. I'm a class-A fan today! Thank you for your inspirational videos on sound and hardware. Greetings from Norway.

[@PearlAcoustics]

Thank you very much for sharing your findings and for your kind appreciation

[@andretim75]

first of all thank you so much for sharing these exquisit and very insightful information, the details of your lecture and quality of analysis is second to non - at least for what i found over the years in the internet, specifically youtube. As a professional musician, classical music, cello, orchestra, chamber-music and solo player myself, I am and always was fascinated of the secrets of sound, of timbre, finest audible details concerning music and the way we play it and the way we hear it ! My experience over decades is totally in line with what you explain here and I could describe so many situations , be it as a listener in different room acoustics while visiting classical concerts or be it whenever I do play myself in different locations, different halls or big rooms. The instrument plays a mayor role, as can easily be imagined, the ability to project well, the basic character of it being more on the brighter or darker side- especially concerning the cello ! - to pierce through a thick layer of sound created by other instruments, the set-up of ones own instrument with different strings, bridges etc. -- actually all that is subject to physical laws -- that is what I have a lifelong experience with and still am fascinated by the quest for the "best" ( quite subjective of course ) and most true to life sound being offered by a hifi-system. Actually it all becomes of course a matter of the time and the money one can effort to invest in this quest for it. But I very much appreciate your amazing expertise, the ability to explain all these subtle differences and details to a wider spectrum of people here in the internet ! Of course it was extremely nice to listen to the amplifiers you show and introduce in this video -- with a good headphone one can quite nicely differentiate basic characteristics of those, the potential strengths and possible flaws . I am about to look for a new amplifier myself and I think it will be a process rather than a short trial and purchase . I am looking for all your videos coming -- thanks a lot once more from Germany !

[@PearlAcoustics]

Thank you very much for your lovely comment. I totally understand the challenges musicians have in setting up their instruments in such a way that they can cut through an orchestra, when required, yet blend in when needed. In fact singers have the same challenges. When you are ready, you are always welcome to visit us in Belgium, to listen to a range of different amplifiers… of course by appointment.

[@andretim75]

@@PearlAcoustics Thanks so much for the very kind offer ! I will absolutely enjoy visiting whenever I have the chance to be there. Perhaps next year could be an opportunity, since our orchestra will play concerts in Belgium ( Antwerp , maybe one more place, possibly Brugge ) . Anyway -- very nice to have a conversation about all these challenges and the fascinating technical solutions and developments from a company like yours !!

[@PearlAcoustics]

@@andretim75 thanks for your reply. When you have more details on your your, please let me know. I am very curious about your orchestra snd programme! Feel free to reach out via email, via our website.

[@Jdvc-yd5tx]

AB has more 'bite' - better for live bar setting. A is better for private/studio use, easy listening. My favorite is the INT-25, so clean. I notice Pass Labs are now using single industrial FETs rated at 700w / 40 amp EACH (not parallel banks) which will help! 🎤

[@Grrrr3FKAGrrrrGrrrrGrrrr]

I think one pair Vs paralleled pairs, and push-pull Vs single-ended output stage types, is more significant to sound quality than class A Vs class AB. I have a Pass Labs XA25, I value it for the lively and dynamic sound I've only heard from push-pull amps with a single pair of output devices. I could see myself going back to class AB one day (because I've heard plenty of AB amps which sound smooth to my ears) but not back to an amp with paralleled output stages (they all seem to suck the spontaneity out of the music, expect for a few high-end amps I could never afford). After reading Nelson Pass' comments on the design of the XA25/INT25, I don't expect the single pair circuit to become a feature of the whole range of Pass Labs amplifiers, the motivation seems to be to produce a smaller/lighter alternative to their standard offerings, although he does say that the non-paralleled output stage has a more "organic" sound.

[@PearlAcoustics]

Thanks for sharing!

[@brentshock3787]

What an amazing video sir, thank you!

[@PearlAcoustics]

My pleasure!

[@FrouzakisGeorge]

Well, that was fun!! I was very surprised how much I liked the Rega. I think it has to be that there was quite a lot of bass compered to the other ones which seemed to be leaner. Now, I now class A is not by any means lean or anything. It probably has to do with the ability of the amps to really control bass. My wow moment, was with the Pass. When all the horns played together. That was something!

[@FrouzakisGeorge]

And then I read this "hence you'll hear the muted trumpets from the left, rather than the right on all the other recordings" : )

[@PearlAcoustics]

😂 sorry about that!

[@PearlAcoustics]

Thanks for sharing your experience

[@jacquesvilleneuve754]

Very interesting comparison. But I must admit that if someone is listening to his system occasionally the difference is not as important. The more you listen the more you appreciate...at a cost of course. You just need to choose the best for your budget. Definitely its worth to spend time listening before buying. Ears before eyes may I add. Great video, much appreciated. Have a great time in France.

[@PearlAcoustics]

Thanks for sharing your very kind appreciation. And Thsnks to for your comment. Just back from France. Had a great time and brought back some nice wine 😉

[@peterlundin7953]

Rega vs Pass: Aethos is warmer with a more distinct bass - The INIT is slightly more HiFi with a slightly clearer mid and treble but the bass is weaker and less inviting. Sugden vs MF: Sugden sound much like a cross between the Rega and Pass, quite inviting over all, the MF is grittier, the bass lack in decay, it falls of to fast seemingly cutting of the "timbre". I have a slight preferens for the Rega Aethos. This said I'm generally a tube-amp-preferer so I look forward to the next instalment! Listening trough an iFi iDSD Pro Signature (DAC/Amp) with Sennheiser HD-800S headphones

[@PearlAcoustics]

Thanks for sharing your observations! See you in the next one

[@DavidWallace-r1l]

I feel that the Sugden SPA-4 Class A added a richness or extra quality to the music which the others didn't quite capture, an interesting demonstration and food for thought. Thanks.

[@PearlAcoustics]

Thanks for your feedback and words of kind appreciation

[@zachjarrett8730]

My perception was a bit of a “plastic” upper midrange in the AB amps in general. The Class A seemed to treat this range differently, in a way that was more pleasing to me. It was noticeable in the muted horns and vocal. The trade off was the definition of the transients in the A was not as detailed, as in the brushed snare drum.

[@PearlAcoustics]

Thanks for sharing

[@JohannesNel-n8c]

Another fantastic video. Such a great you-tube channel.

[@PearlAcoustics]

Wow, thank you!

[@user-od9iz9cv1w]

Excellent discussion. I was drawn to the Pass amp in this demo followed by the Sugden. Both a little more 3D than the others. I believe that imaging and timbre depends on the accurate reproduction of low level information. This information is at barely detectable amplitude but out ears catch it just as you microphone does, and our brains are well evolved at using this information. Dogs even better. I find almost anything can destroy this information. Class A, simple or no crossover, lowest possible feedback, resistors in the signal path and transformers can really impact it. Triodes do better than solid state. A single high sensitive driver with little or no crossover is good. Output transformers are critical and OTL even better. Coupling caps are critical. An autoformer will work better than a resistive potentiometer. I like silver better than copper for transmitting signals. Over specified power supplies help. Generally the simplest circuit with best component quality will win out. So everything matters. When you get most of it right the sound illusion exponentially improves.

[@PearlAcoustics]

Thanks for your kind appreciation and addition to the discussion. Much appreciated

[@holmschanze5613]

Thank you for this very nice comparison of the systems. I noticed in your examples that class A sounds more natural and physical. the voice and the cast are connected and sound more alive. Unfortunately I can only follow the test via headphones. I would be happy if you started further comparisons.

[@PearlAcoustics]

Glad it was helpful! Thanks

[@MG-iv8oo]

harley, for you to include the aethos, you must hold this in relative high regard. the reason i ask is, i am looking to upgrade my amplifier and the aethos is a top contender. mostly because i have a rega amp (elicit mk5) and it has been great. i just want more power. always appreciate your thoughtful insights and just wanted to get your take on the rega aethos. much appreciated.

[@PearlAcoustics]

Thanks for your kind appreciation. The Rega Aethos is a very well made, solid amplifier. It does everything well, but I cannot say how much of an upgrade it will be as I have never heard the two side by side. Sorry I cannot help more in this point. Hopefully you can borrow one to find out in your home? If you do, please let us know how you get on!

[@obscurazone]

The sugden was immediately the most musical and engaging to me, out of all of them! Properly seasoned and tasty. Really well balanced and "live" sounding. The Musical Fidelity sounded rather lifeless by comparison, and certainly more vocal forward. Given that the M.F is an A/B amp, it makes sense that on this track the vocal stood out above the other instruments. Ultimately its about the kind of sound you prefer, there is no right or wrong. But - as you say in your intro Harley, with class A we are given a treat as hifi enthusiasts in that we can clearly hear the distinct separation of sounds. That's why I love class A...I just wish they didn't heat up like an oven.

[@PearlAcoustics]

Hi, thanks for your comment and contribution to the discussion. Coming soon is my video comparing tube amplifiers!

[@jonathandavis9507]

I would like to there to be more emphasis on timbre in reviews also, and I suspect (in some cases it’s been admitted) we don’t because not enough reviewers are listening to enough live music. And you’re absolutely correct that sound staging often does not often happen in live performance, unless you’re maybe lucky to be sitting in the middle of a band or orchestra 😅, and that is what a good speaker soundstage can give you!

[@PearlAcoustics]

Thanks for your reply

[@seanoreilly8603]

Nice one again Harley. Just a note. I own the Rega Aethos and it runs hot and is in Class A for the first 5 or 6 watts. I noticed you were playing it with the volume at five to twelve. I have never done that. Rarely even at quarter to twelve. That would be very loud. Around 80db. I have Arendal Tower S floor standing speakers at 89db. 4 ohms. My question is Harley. Did you really listen at five to twelve.

[@PearlAcoustics]

Hi Sean, thanks for your kind words. I don’t think I ran it at ‘five to twelve’ that was just a photo dropped in. However, I did contact Rega directly about the Aethos and their designer confirmed to me that the Aethos is only in class A at less than one watt. And what I find interesting that I didn’t find it ran particularly hot. Mind you, it’s been a while since I have run it for a very long session. Strange.

[@seanoreilly8603]

Thanks for the reply. Your kinda right about the heat. It does depend on how long you are listening to it. Like a few hours. Now that it's the summer it gets a lot hotter than the winter. But you have me kinda worried now if mine is overheating for no reason. It's a lovely amplifier. Thank you.

[@PearlAcoustics]

@@seanoreilly8603 no need to worry, I’ve heard many people say that they run hot - but I am comparing with powerful Class A amps that you can cook eggs on, just enjoy it. It’s a fabulous amplifier

[@seanoreilly8603]

​@@PearlAcoustics Cheers Harley.

[@PearlAcoustics]

@@seanoreilly8603 👍

[@thebingaling1105]

Great video again. Thanks. PASS Labs for me, felt like it had more energy and was more dynamic and enjoyable to my ears. I've recently been doing Class A/B vs Class D as part of my own system. Very impressed with the newer Hypex Class D stuff but in the end went with the Exposure 3510 integrated Class A/B. Just sounded more natural and enjoyable to me. Not in the same budget as these amps though. Maybe one day ill have the budget and to upgrade to some of your speakers.

[@PearlAcoustics]

Thank you very much for your kind words. And thanks too for your contribution to the topic.

[@proper90s43]

Thanks for the video. The Sugden for me, followed by the Rega (but i've always had a soft spot for Rega, so could be unconscious bias!). Any thoughts on sibilance in speakers and anything that can improve this without buying new speakers?

[@PearlAcoustics]

You’re very welcome. sibilance is complicated. It’s try some loudspeakers can exaggerate it. Mostly, it starts in the recording process. Sometimes introducing a ‘step filter’ can help, or invest in a piece of equipment like the Lyngdorf TDAI 1120 - where you can create custom filters all in the digital domain. I hope this helps?

[@avro66]

Very interesting video, I've always liked class A amplifiers, solid state or valve, just something about them I really enjoy.

[@PearlAcoustics]

Thanks! 🙏

[@rapier5]

Two channel stereo does an amazing job of creating the illusion of space. Note I say illusion. Unless you get it into your head your seeking the most pleasing illusion and not something 'real' I doubt one can ever be satisfied.

[@PearlAcoustics]

Thanks for your comment

[@PanAmStyle]

Harley, I tried a little experiment. First I listened to the comparisons through the speakers of my TV, with the video streaming over HDMI from an AppleTV 4K. It sounds silly, *but* I COULD hear the difference - not full range or high fidelity of course, but I was surprised. I could immediately detect the Class A difference - Clare’s voice had more harmonic texture (timbre) and weight. The second pair were hard to differentiate. Then I listened with good (though not “high end”) Beyer Dynamic headphones and I could discern the same differences in (and preference) in the first pair. For the big Sugden and Musical Fidelity power amps, a distinction was there, but I had a hard time decided which I preferred. At first I thought I preferred the Sugden as it had more weight and body. But on a second listen I found myself increasingly interested in the sound of the Musical Fidelity - it had a delicacy in the upper mids and higher frequencies that was almost beguiling. Next I will run it through my primary system to reveal more.

[@PearlAcoustics]

That’s interesting. Thanks for sharing

[@alexandreserainshuvaloff6640]

I am impressed by Pass Labs. I suggest it is a JFET circuit ? The second amplifier I prefer is the Musical fidelity. OK, this not about music at all but a neurotic geek stuff, but if I try to focus only on the piano line hidden in the background, I made the difference as I imagined myself in a jazz bar. I have some difficulties to listen to this record because of some harsh up middle frequencies coming to express themselves quite brutally on some amplifiers.

[@PearlAcoustics]

Thanks for sharing your observations with the community

[@YuengsNwings]

Most Class AB amplifiers run in Class A for the first watt or so. You've already done a video about how loud 1 watt really sounds, and considering that most of us habitually listen needing only 1/1000 watt to 1/10 watt I don't understand the need for a pure Class A amp. Preference for Class A amplifiers over Class AB is indeed personal bias.

[@PanAmStyle]

There’s Class A and then there’s “CLASS A” in my opinion. No, I can’t explain it.

[@1999zrx1100]

I agree, one way of tell if it’s done right is the power requirement, some 30 watt output amps require 100 watts where others require 300 watts. My Luxman L590AXII requires over 300 watts and is Sublime. 🤓

[@PanAmStyle]

@@1999zrx1100 My DECware SE84UFO 2.3 wpc, fed by the Lab12 Pre 1, pushing 90 dB sensitivity speakers sounds divine 😍

[@PearlAcoustics]

Thanks for sharing. Although that’s sometimes true, my experience is that many AB’s are only in class A in their preamp sections. Or maybe for the first eighth of a watt. In the end itsvthe music that matters and whether we can enjoy it with what we have. Best wishes

[@gdwlaw5549]

My girlfriend said to me this morning ‘ did you watch pearl acoustics last night’? ….’ How did you know ‘? ‘ you’re wearing faded blue jeans and a white shirt today ‘….😅

[@PearlAcoustics]

😂

[@danijel-c]

Perfect. ❤

[@VFR1990RC46]

Have you got some favourite Recordings with great or spechial Soundstage? Over the Years i found, that Loudspeaker Positioning and the Room itselve makes (with the Speakers themselves) the biggest difference in Soundstage and Resolution. Greetings from Germany

[@PearlAcoustics]

Hi, thanks for your comment and question. I have so many, it’s very hard to select! But on the pop front, I often turn to Willie Nelson’s ‘Little House on the Hill’ from the album God’s problem child. It’s not that it’s very special, is just my go to track to try and pick out all the different guitars on it. Try and count them 😉. Also try and workout where the backing singers are standing on the choruses. On some setups, they are on top of each other, right behind Willie, on others they are behind and slightly left and right of him.

[@VFR1990RC46]

@@PearlAcoustics its 3 Guitars and a Bass right :-)? I realy love the Direstraits recodings... Especially the Album Telegraph Road, Private investigations is like a Crime happening right in front of me when i close my Eyes 😂

[@PearlAcoustics]

@@VFR1990RC46 indeed 3 guitars, but I think there’s an extra acoustic rhythm hiding in there, if I remember correctly (it’s been a while). Dire Straits recordings have always been good.

[@arvindgoudar1586]

Thanks to your discussion on timbre. I am new to the audiophile world and after reading a thousand reviews of equipment, I have yet to come across a review which discusses the relationship to room physics. Its such a major contributor to anything that we hear. Everyone ends up rating the equipment. My question is, what were the room parameters ?

[@PearlAcoustics]

You’re very welcome. As you’ll discover in my other videos. Room is so, so important

[@geoffreybritain8878]

All the different preferences below point out why we have so many manufacturers of stereo gear. Run a double blind test and you'll still get a variety of choices in which is preferred. Plus, we may slightly prefer one amp for rock and another for symphonic.

[@PearlAcoustics]

Indeed!

[@dadowns100]

What do you think of the Sarah Willis French horn mash up with Cuban mambo music? Give it a spin!

[@PearlAcoustics]

Thanks for the tip, I certainly will!

[@MG-iv8oo]

many thanks. so helpful.

[@PearlAcoustics]

You’re very welcome

[@Derffee]

On the integrated amps, the first one on vocals sanded more natural sounding . the second one was a little bit warmer and the sound staging wasn’t as good but I preferred the sound to the second one on the integrated amps not too sure about the power amp if I could tell them apart. when I was moving into my music room, I would walk round it clapping to listen for echoes to help with the acoustics of the room

[@PearlAcoustics]

Interesting, thanks

[@gavinhall4112]

Soundstage is an interesting one because a lot of what we perceive as the "position of the trumpet" is more about how the engineer panned the trumpet than where it was physically located. I have experienced systems with almost supernatural levels of soundstage separation, but it felt as though they were offering a forensic examination of the music, rather than a cohesive musical whole.

[@PearlAcoustics]

That’s very true, sometimes a detailed soundstage can be a distraction and that’s where mono can play a useful role

[@davidgriffin79]

13:40 I think your not really taking into account the effect an amplifier's output impedance will have when it interacts with the speaker. All speakers and headphones have an impedance which is a function of frequency; depending on the loudspeaker's impedance characteristics, the amplifier could well subtly alter the frequency response of the system; there's an excellent article on this by John Siu over at Benchmark entitled: 'Audio Myth - "Damping Factor Isn't Much of a Factor"' which rather nicely explains the phenomena. What you're hearing could well be the different characteristics between amplifiers with 'high' and 'low' output impedance making the sound more 'recessed' which would move you back a row or two giving the impression of a narrower soundstage; of course it could also be expectation bias. 21:45 Interesting, listening through: restored Arcam rDAC -> Icon Audio (yes class 'A' tubed) HP8 MKII headphone amp -> Beyerdynamic DT 770 250Ω I prefer the Rega the most and the Sugden the least. Even through the KZbin algorithm, the Rega seems to have the most "flesh on the bone", with the other amps sounding a little too "lean" for my tastes; horses for courses.

[@PearlAcoustics]

Thanks for your addition to the topic and for sharing your findings too

[@davidgriffin79]

@@PearlAcoustics No problem and my pleasure.

[@pascaldeshayes5459]

Interesting, thanks! The class As sounded more relaxed and effortless to me. I was sort of forgetting the amp while listening.

[@PearlAcoustics]

Glad you enjoyed it! And glad you forgot the amp and could enjoy the sound clips 😉👍

[@markhusbands6132]

That Rega Aethos sounds really nice.

[@PearlAcoustics]

Glad you enjoyed it.

[@chelillingworth9466]

I built the Pass ACA and di a bunch of mods, class A, single ended, just a single Mosfet doing 8watts of work, woderfully transparent!

[@dlacy61]

I have them too!

[@PearlAcoustics]

I have heard they are very good. Thanks for sharing

[@20CycleMonger]

Charming presentation Harley. Ive noticed that imaging doesnt really happen live, but its a cool effect in stereo. You're a recording technician, so can you explain how some recordings achieve image height? Can't say much about the amp comparison.... (Bluetooth to my Node thru dac and AB amp to Magnepan LRS/RELs)I was left with an impression of your room acoustic with the Sibelius playing . Fun as you say, but Odd "Stereo system once removed" sensation. I'll see if that record is streaming , Thanks!

[@PearlAcoustics]

Thanks for your kind comment. You know, I have never been able to explain exactly how height works, especially in our single driver loudspeakers! It’s obviously a form of phasing time delay. The weird thing is that amplifier designers can’t seem to explain it either. Hopefully someone in this community can help?

[@linkwitzaudio689]

Interesting amplifier comparison. Siegfried Linkwitz can add more details on why our brain develops this sound stage illusion: It seems to be a survival mechanism, that developed human evolution, being able to quickly and accurately locate threats in reflective environments (caves, canyons). For exact sound source location, we predominantly use the -first arriving- direct sound. Reflections arriving >6msec later will be discarded by the brain in this process, if they come with similar sound "color". If the brain would not discard these reflections, it would have a hard time in spotting the position of sound sources in caves / canyons. There are some more factors at play. The performance of our brain in sound source location is just admirable. For this amplifier comparison, it would be interesting to find out, what exactly causes these different sound stage perceptions?

[@PearlAcoustics]

Thanks for your kind words and comment. I have spoken with many amplifier designers and I have never met one who honestly knows. It seems to be a mystery! As soon as a theory is put on the table, another contradictory hypothesis comes along

[@DaleCrommie]

I liked the Sugden most, but I also liked the Pass Labs. The Musical Fidelity seemed a little too crisp. My first go through the clips said the Sugden allowed my ‘ears’ to settle into the sound more easily. I use tubes, so perhaps Class A SS is a good thing. I left SS years ago, but I have wondered about Class A SS amplifiers over the years. Nice video.😄

[@PearlAcoustics]

Thanks! 🙏 and thanks for your comment

[@chuanyewlee9502]

Interesting discussion. It is likely at moderate listening levels say the first 15-20 watts, a well designed class AB amp is probably operating in class A mode verty similar to a solid state class A amp. As such ithe sound differences between one solid state class A amp and a solid state class AB amp largely comes down to which type of sound you as the listener like better as opposed to whether class A design is better than class AB. However differences start to appear more stark when one cranks up the volume and plays at say 80-100 watts, perhaps driving some large tower speakers to create a sense of a live concert when say listening to Tchaikovsky - 1812 Overture. I would think at some point most valve and solid state class A amps will have run out of juice due to the dynamic swings in the music, start to clip and perhapss the soundstage breaks down. Class A amps are great sounding for example the legendary Kondo Ongaku 15 watt integrated tube amplifier but we do need to realise it comes with some limitations as well.

[@PearlAcoustics]

Thanks for sharing your views with the channel. The strange thing is that, Most of the time we are only listening at around 1 watt, in a moderately sized room.

[@tonyhodgkinson4586]

Soundstage on the Pass Labs sounds more real and relaxed over the Rega. Sugden sounds more real and relaxing than the MF, overall I could take either the Pass Labs or the Sugden.

[@PearlAcoustics]

👍 thanks for sharing

[@jeremiahchamberlin4499]

I found the discussion of timbre fascinating, but I’m stumped as to why folks insist on pronouncing the word as though it is spelled ‘tamber’ or even ‘tambray’. No matter, as for listening comparisons, my ear was attracted to the bass playing, and I felt I could fingering hand on the strings on the Pass Labs vs. the Rega; Sugden vs. the Musical Fidelity it was harder to tell. I thought the Musical Fidelity acquitted itself fairly well against the Suden. I feel like I would really need to be ‘in the room’ to tell the difference. The difference between a deep and wide soundstage and one which is narrow and shallow is instantly recognizable in a room; not so much over earphones on an iPhone from a KZbin video.

[@PearlAcoustics]

Thanks for your comment and contribution to the topic. French originating words are often tricky, 😉

[@stimpy1226]

Pass is the first name that comes to mind when I think about solid state class A and integrated amps

[@PearlAcoustics]

Absolutely. He’s a living legend. In the UK the big name is Sugden.

[@markwroblewski6500]

​@@PearlAcoustics The proper class A amps are the KSA/KMA Krells.Sadly Dan D'Agostino makes now class AB greatly overpriced and kitschy-looking equipment.

[@EdBenji]

& the biggest price tag...$$$$$$

[@greglongphee2034]

I readily understand how one can get caught up in an endless quest for perfection. But there comes a time when one should just stop and smell the roses. Perhaps my favourite listening experience came listening to a lovely recording played on a Linn Sondek LP12 equipped with a Decca tone-arm and Decca Mark V cartridge. The result was fed into a little Naim NAIT integrated amplifier driving a pair of GALE 401 loudspeakers. Was it perfect? By no means. But it was sublime.

[@PearlAcoustics]

Absolutely!

[@sudd3660]

in the amp sound comparison only the pass labs stood out, the background trumpet is more to the left. and all the others war to the center. so large of a difference i have to ask if something gone wrong with the upload to KZbin or something else. i have little experience with live music so i can not decide with i like the most, only differences.

[@PearlAcoustics]

Hi indeed, as you have probably now discovered I made an elementary mistake when connecting the PassLabs and accidentally switched left and right! That’s why. Sorry

[@trevorharrison29]

I wonder if there is any "peril" by having a mix of amplifier types when bi-amping a pair of 2-way speakers: Tube/Valve class A driving each tweeter and solid-state class A-B / class D driving the bass drivers ??

[@PearlAcoustics]

Personally, I wouldn’t do it but it might be fun trying !

[@johntucker5994]

I can't comment on soundstage through YT. But tonal balance is important to me. On this recording, I felt the Rega Atheos overemphasized the vocals, which could lead to listening fatigue. The Pass INT25 had better balance, but I could see getting bored with the sound. The Pass I thought was similar in balance to the Musical Fidelity. In terms of natural balanced sound, while retaining some excitement, I thought the Sugden was best.

[@PearlAcoustics]

Thanks for sharing your findings. Indeed YT is limited.

[@stimpy1226]

Lewis Layton, the recording engineer in the 50s and 60s for RCA did some spectacular recordings of the Chicago Symphony Orchestra. You could pinpoint almost every instrument and the timbral accuracy was quite realistic.

[@PearlAcoustics]

Thanks for this. They certainly had a fantastic reputation in those days. I know nothing about him. Do you have a favourite recording?

[@2011FM]

Rimsky-Korsakov' Scheherazade conducted by Fritz Reiner has been highly regarded as one the masterpiece works done by Lewis Layton on the legendary RCA shaded dog label. It belongs to The Absolute Sound' baker dozen LP vinyls endorsed by the late Harry Pearson who evangelized the beginning era of High End Audio in the mid of 70's along with J. Gordon Holt of Stereophile. Bravo!

[@stimpy1226]

Sherazade

[@tonydeniro284]

Side 2 is the better side, the 1st side is average. Also the rca white dog is known to be better than the shaded dog.

[@stimpy1226]

@@tonydeniro284 the reason that the second side sounds better is because there’s so much energy in the music on the second side with regard to the first.

[@jdm-uk-yank]

The INT-25 is a hybrid. Are you sure? I can't find that anywhere online

[@PearlAcoustics]

Hi, thanks for your question. To be strictly fair, I did not say the INT-25 is a ‘hybrid’ that’s a very different kind of amplifier. But I am guessing you are referring to the fact that I said that at very high power demands the Int-25 will deliver way more than 25 watts as it slides into AB. This is common with many class A designs, and when I said it, I believed it to be true, having been told so by a PassLabs dealer. Here is a quote from a HiFi Choice review, confirming the same thing “the conservative spec merely denotes the amp’s Class A reach, determined by its standing bias current. In reality, and ably assisted by a substantial power supply, it’ll deliver plenty more grunt as the INT-25 stretches its legs into Class AB territory.” I hope this helps?

[@peronnikbeijer213]

Yes, there is a subtle difference in timbre. I am listening in near field, so the sound stage was not different for me. To my ears, the Passlabs sounded best, which was a surprise to me.

[@PearlAcoustics]

Thanks for sharing

[@mikeuk4130]

How interesting, Harley. For me, in ascending order of listening ease and pleasure, it’s Rega, MF, Pass then Sugden. The last shines because of its deep (not just wide) and spacious soundstage, musical insight and feeling of all-round capability and sheer effortlessness. I remember your saying elsewhere that the Sugden A21 SE was noisier than the Pass over which you chose it (XA25?) but that its stagewidth was much greater. With efficient horns, for example, I think the former would be the most important factor in choosing. Finally, did you use the whole of the Int25 or just the power amp section, and how did you drive the other three? I feel the XA25, on extended and direct listening, should be the winner but, in this test, t’Sugden and Class A were easy winners. Great test.

[@PearlAcoustics]

Thanks for your kind appreciation. The two integrated amplifiers were used with their preamplifiers to create a fair comparison. Thanks for sharing your findings. Very informative and interesting

[@rayhunter7371]

My two cents worth - I have a pair of Plinius SA50 stereo amps bridged as monoblocks. They are Class AB/ true Class A switchable. I can make a direct comparison between the two modes on the same amps. Class AB has more bass - but is it distortion? Class A is more holographic with more delicate detail. One can "see" further into the performance. Late at night, if I am really wanting to pull out the best in a recording it has to be Class A.

[@PearlAcoustics]

That’s very interesting and absolutely in line with my expectations. Thanks for sharing

[@derekevans1932]

I am going to be controversial but this is my opinion for what it is worth. Listening on headphones, I preferred the forward/louder sounding Aethos, especially as it seem to show how she was using her voice, the slight inflections seemed heightened which I liked. It felt as though I was in a "club" listening. There did not seem to be much difference between the Music Fidelity and the Sugden to me, both quite clean and separated.

[@PearlAcoustics]

Nothing controversial about that. The Aethos is a great amplifier. I think the best Rega ever made. And this is such a personal thing. Glad you enjoyed it.

[@stevesjagcetera]

Interesting that I could hear the difference but generally not a lot of sound stage on any of the recordings. I listened through my class A amp, where I expect a much wider sound stage. My personal favorite was the Sugden where I heard a wider sound stage it almost pushed beyond my speakers, which nothing else did. Be interesting to hear through my system from the source recording.

[@PearlAcoustics]

Hi Steve, thanks for your comment. Of course the in room microphones cannot really begin to capture the subtlety of soundstage as it actually is, in the room. I do these only for fun, but at least your system captured some of it! Best wishes, H.

[@andersulrich2501]

Thank you for the video. Can’t say that I hear much of a difference trough my AirPods…What do you think of the Lyngdorf cd-2?

[@PearlAcoustics]

You’re very welcome. You know what? I really like the CD-2. I like its simplicity, its functionality and its inbuilt Dac is good. I tend to run it through the Sugden Dac. I think it’s very good value for money.

[@andersulrich2501]

​@@PearlAcoustics Great, thank you for taking the time to respond, I appreciate it!

[@richardcasey4439]

I would like to pair tube amps with Funktion One speakers. That would be fascinating.

[@PearlAcoustics]

Who knows, maybe you will one day!

[@barrymiller3385]

Hmmm... very interesting. Firstly, I could clearly hear a difference between both pairs. But... from the short clips that you played I couldn't make a clear decision as to which I preferred. I guess I would need more time to learn the sound of each.

[@PearlAcoustics]

Indeed

[@carlitomelon4610]

This was insightful and fun. All the amps sounded like the tiny speaker on my phone however...😅 Musical fidelity amps have been traditionally biased into class A for the first few important watts. I agree on your timbre comments. Would love to hear the Sibelius out here in Montana someday. Something so appealing about a single unfiltered transducer for monitoring acoustic instruments. Now be orf with you. Have a splendid holiday, sir! (Do you need a house sitter, btw??) 🎵🎶😉🎶🎵

[@PearlAcoustics]

😂🙏 thanks for your lovely comment. That’s very kind.

[@hwrk777]

On the 1st comparison I couldn't tell much of a difference, but on the 2nd pair, in my oppinon, I think the Sugden was the clear winner. It just seemed to have more weight to every note.

[@PearlAcoustics]

👍

[@buckaroobonsi555]

I closed my eye's so I could not tell what I was listeing to. I liked the Pass Labs INT-25. It was dramaticly cleaner, more vibrant, and had better seperation! In the first A-B test. The Sugden SPA-4 did not sound as good to me as the Pass Labs did. It had more warmth and the vocals where a bit more forward but the seperation and sound staging was not as good and it did not seem as vibrant as the Pass Labs. Very little difference between the sound of the Sugden and the Musical Fiedelity M8 as it comes to me via KZbin. I would have a hard time picking between the two. They both had some things I liked and disliked. In fact they sounded so close that I would need to spend a few hours listening to one and then the other to truly decide which one I would want to take home and live with forever. I think I am leaning towards the M8-500 though at this point! The Pass Labs INT-25 was exceptional and even through KZbin it was a clear standout. I am a classicaly trained musician and know what I like and that Pass Labs INT-25 is something! I can only imagine how much better it would be in real life! The fact that your mic caught the differences between amps well enough to make it past the KZbin compression scheme is also amazing!

[@PearlAcoustics]

Thanks for sharing your observations and views.

[@crtgamer2355]

Passlabs is the winner for me, warm and musical, analogue sound. The Rega is good but lacks that warmth and smoothness of the Passlabs, still amazing. Sugden is great but a little harsh, while the Musical Fidelity is very clinical with nothing really stand out, but still good. Great video as usual, please consider doing a review of the Van Morrison - Avalon Sunset album in a future video, I think you will really enjoy it.

[@PearlAcoustics]

Hey, thanks for the kind words and the tip for an album to review. I will certainly give it a listen. Van M. Has always had my deepest respect

[@crtgamer2355]

@@PearlAcoustics Enjoy! :)

[@channel-ls4uv]

To my ears the Rega sounds the smallest, no debt in the soundstage. The PassLabs has the widest image (but I think the image is turned around). The Sugden has most dept and precision in the image, The Musical Fidelity sounds wider than the Rega, but doesn't have the clear placement in the image the Sugden or Passlabs can project

[@PearlAcoustics]

Indeed, you’re absolutely correct, I screwed up up by accidentally switching the inputs on the Pass. And didn’t even notice during the editing. Sorry. Unfortunately it was too late to correct it. Best wishes from Belgium

[@mcvlot]

Nice! Rega last (metalic), Pass nice soundstage (2), Sugden very stable (#3), Music Fidelity #1. Same result on a IEM and on a quite decent HiFi set. Main differntiators I could distinguish: voice naturallity, and sound stage. Except for the Rega it was fairly subtle.

[@PearlAcoustics]

Thanks for sharing!

[@kindface]

I preferred the Aethos' AB to the Pass' A. The Aethos had more colour, the highs less harsh, better soundstage and I like its more expansive bass notes. I hear more sibilance from the Pass which I didn't enjoy while it's bass were more "blobby", had less gradations and were less subtle. Between the Sugden and the MF, their highs had less difference and in absolute terms, I didn't enjoy both of them in this respect. For the bass (I'm bass-centric as I've lost some 60% of my mid-tone hearing on both ears), the MF's AB again bested the Sugden's A. For me, as far as the ABs go, the Aethos was better than the Musical Fidelity's. I guess I just like softness overall and in the bass notes, the softness somehow brings out the different gradations of the bass notes better than a more powerful bass. And, oh, by the way, Clare Teal is one of my fav female jazz vocalists. Her "Hey Ho" is my fav. Maybe next time you could try Tutu Puoane's "You Are My Sunshine" as an audition track. I enjoyed this episode very much, thanks so much !

[@PearlAcoustics]

Thank you very much for your kind words, suggestions and contribution to the topic.

[@crazyprayingmantis5596]

Interesting how to me the Pass sounds more pleasing , is it because the L and R are reversed

[@PearlAcoustics]

😉👍 could be! Sorry about that!

[@razzman2987]

10.000 $ amp it better sounds good ..class A is special indeed . Love youre videos 👍

[@PearlAcoustics]

Thanks!

[@tsangchinkeung7322]

Thank for the context of “soundstage” and “timbre”, it is really educating and reminds me my music halll experience. I write to you just to notice you that your endeavor to present such a video is remarkable, and I am looking forward to watch your further heartfelt production!

[@PearlAcoustics]

Thanks!🙏

[@nathanevans6277]

Unfortunately I haven't been able to listen to the sound clips yet. Like Harvey, I am a big fan of single driver speakers. They have a coherence to the sound that most multi-driver cannot compete with. I think this is down to timing. Although multi-driver can produce a flatter amplitude response they are much inferior in the time domain. Human hearing is more sensitive to timing errors than it is to amplitude errors. For me the best amplifiers currently available, based souly on listening, are class A valves. Having said that the latest class D amplifiers from the likes of Purifi and Hypex are closing the gap. I don't think it will be very long before class D overtakes the class A valve amplifier.

[@PearlAcoustics]

Thanks for your comment. I hope you enjoyed the video

[@CoolJay77]

I'm finding thew Sudgen SPA-4 to be the most airy of the four amplifiers.

[@PearlAcoustics]

Thanks for sharing your observations

[@benjaminsturgeon2147]

Well done. Thanks Tom

[@PearlAcoustics]

🙏

[@hayno7066]

The drums on the Sugden stood out to me. Overall, that was my favourite.

[@PearlAcoustics]

👍

[@papabear1417]

Does this episode go against 'what are you listening to?' I prefer Yamaha. All manufacturers have a sound. For me like the way Yamaha reproduce the sound of vinyl and cd.

[@PearlAcoustics]

Hi, thanks for your question. I don’t think it does. One should be able to switch one’s attention from the quality of the sound and the content of what one is listening to. It’s a question of making sure that we don’t forget why we buy all this gear… to listen to, and enjoy, music.

[@Rabazoline397]

Class A more crisp and tube sound and AB more clear sound, more detailed in vocal areas both quite good for me better separation than A class, but A class is more natural like in the pub's and more on warm side. Probably depends what kind of music type is listening that day but both are very satisfied and similar.

[@PearlAcoustics]

Thanks for sharing your observations

[@jensrasmussenjr]

The difference between A and AB is probably due to A being more rigid in its output impedance compared to AB and thus in better control of the complex load of a loudspeaker.

[@PearlAcoustics]

Interesting comment. Never thought of it like that. I guess that’s down to the amplifiers intrinsic architecture… ?

[@buckaroobonsi555]

I have to agree that class A does sound slightly better than all other class of amplification. I have to agree that sound staging and how natural the sound sounds is likewise the best. That said class AB does not rule out the same it is just more difacult to aquire! You pay dearly for it though in terms of effeciency, heat, power consumption, output power, durability if used often and for long. Then you have the cost to purchase and the availability of said units!

[@PearlAcoustics]

Thanks for sharing. With regards durability, if an amplifier is well designed, it should last for decades, even those that run hot. But I get your point!

[@philpembroke5373]

3D sound in a concert hall. Mussorgsky 'Pictures at an Exhibition', the bells appeared in space behind and to the side, 30 feet into the air. (LSO, Gergiev, Barbican Centre).

[@PearlAcoustics]

Indeed that happens. Especially in the Barbican! Many musicians hate playing there because of the acoustics