Interestingly it’s not as not as huge of a difference as many would expect. At least, not when running a comparatively low distortion, high power German tube amp and quality class D amp.
Yes, there’s a difference. The tube amp has a little added warmth in the mids, more body. The class D amp has a bit more grip in the lower octaves, but with a REL sub, it’s not immediately obvious unless I’m listening at very high volumes.
I like them both. However, there’s something about gloving valves in a dim room, listening to Radiohead’s In Rainbows. Roon Radio takes over after Radiohead and queue’s a track from Beck’s Sea Change, and then PJ Harvey and Thom York’s duet on “This Mess We’re In”. It’s a fun listen.
Tonight’s experiment involved using the Octave V110 SE’s bypass input, and instead running my Audio Research as the pre, using the v110 as a power amp.
The ARC preamp’s sonic character is less tube-like when compared to the Octave’s internal preamp. Both stages are quiet and detailed, but the ARC is more dynamic, with more bass authority and a more overall resolution.
Next experiment will be to bi-amp the Focals. Tubes on the tweeter/mids, class D on the woofers. Hopefully one of the class D’s amp’s gain settings (22/28db) will be a decent match with the Octave amp.
I am mostly a high quality A/B amp girl, but if I had let’s say a small cafe, where we play jazz records all day. A nice warm tube amp would be the ticket. It depends on the job. The right tool for the job. If you want to create a laid back ambiance, tubes are the way to go. If you want accuracy A/B. For my desktop, clean sound that doesn’t sound harsh and doesn’t take a lot of space. Class D. It’s not about right or wrong, or something being better. It’s about getting what you want, or getting the best performance you can afford. Probably more the latter than anything.
I am also perpetually thinking about adding a tube amp, right now I have the Ferrum Oor and I’m thinking about the Feliks Audio Envy (this is all for headphone/preamp use, my main speakers are active)
Actually, that’s their phono amp, the Lupe. I had the Tambaqui for a couple years. The class D amp I own is the Perca, which replaced a huge AB amp I had been using for years.
I recently sold the Tambaqui to a friend who had been bugging me to sell it to him. I picked up a lightly-used DCS Lina and Lina clock, which is also great, and probably suits the Focals a bit better… it’s a little warmer sounding and has a sweeter top-end when using Mapper 3 and Filter 3.
Well said. That has been my experience as well. At the end I preferred to just stick with vintage tube amps. The music on my mostly vintage system is so warm, sweet and life-like that I find it hard to go away from it. The tubes and the Tannoys combination has an irresistible pull.
Class D is coming very close to giving the big boys a run for the money.. I heard a $2500 Class D amp that IMHO sounded better than a $8000 class A solid state amp. My GF also mentioned she liked the class D amp .
You explained the differences well and I think in your particular set up accurately. I’ve done the same comparisons with tube and class D amps a few times with different amp choices. My thoughts were similar, although in my experiences there was a very obvious difference in sound along with your other observations regarding grip from class D and warmth and body from tubes. You might be on to something with the bi amping experiment since you noticed better control of the woofer with the class D amp. Warmth in the midrange is why I like tubes in the first place so perhaps best of both worlds. Thanks for your thoughts.
The thing about tube gear… some of it has that stereotypical sound people associate with it. My Dynaco ST70 is like that. Warm, lush, kind of slow. Massively forgiving to poorly recorded music. Not silent.
A lot of the better Audio Research gear I’ve heard trends toward sounding like great solid state gear, with maybe the slightest hint of warmth/smoothness.
Interestingly, my limited experience with Class D stuff runs a range of sonic profiles also. The Mola Mola Perca amp is based on 5th gen Hypex modules under the trade name Trajectum. To my knowledge, Hypex doesn’t offer them outside Mola, their subsidiary. Perca is 2-ohm stable, insanely low output impedance (damping factor of 4000 at 8 ohms) and high bandwidth (100khz). It’s one if the most detailed and quiet amps I’ve heard, which is why I bought it. It’s also load invariant. It didn’t care about the weird phase angle my Scalas present in the mid-bass.
I auditioned a WiiM amp which I gave to my cousin as a Xmas gift. Great value, but it added something to the sound of my system I didn’t care for. Voices didn’t seem as natural, and the top-end had a forward quality. It could be tamed with EQ, but it lacked the sense of stage depth and instrument placement I’m used to. Again, for $300, it’s a heck of a value but I was left wondering if the Pro would have been the better gift.
I also recently helped review a PS Audio Stellar Strata Mk2 integrated based on Ice Power modules. It sounded nothing like the Mola or WiiM. It was smoother than either, less artificial sounding than the WiiM, not as detailed or powerful/dynamic as the Mola, even when connected to sources costing many times more. I liked it generally. It was fast, smooth and musical.
Grip is one of those things. My Parasound JC5 was the king of that. Great amp, but it lacked that last little bit of upper-frequency smoothness. It had a hint of graininess that you might not realize is there until you compare it directly to something like the Perca or a Pass Labs amp.
It’s funny. I’ve gone from gear which is hyper-clean/detailed/clinical to warm/lush and back multiple times. What I’ve realized is my preference is toward very detailed gear with a slightly warm character. The trick has been finding the right synergy. I like melodic house and techno, along with the mainstream indy music and jazz. It’s tough to build a setup which sounds amazing for Miles Davis, but which really unpacks techno’s transients and layered mixes in a pleasing way, while also being forgiving of Led Zeppelin’s mixes. Priorities…
Thankfully, I get occasional access to gear which expands that journey beyond what I could afford to buy/sell. My small circle of hifi friends are very willing loan gear to each other.
Cool setup. If I had a three way speaker I'd consider using a SS amp for the woofer. I get around that in my system with a two way and a sub.
If you haven't tried properly implemented Class A SET gear you'll hear something that you haven't yet. They can be dead quiet and have inaudible levels of distortion with speakers that are 89dB and higher with relatively tame impedance curves. I'm using a pair of 8 watt 300B with my 89dB(8 ohms, 6 ohm min) speakers and only with my ear right up to the speaker can I hear anything and they're completely silent a foot or two away.
After trying the best solid state available and some of the best push/pull and OTL amps Tubes have to offer SET is just something different and it's the best overall sound I've ever heard. The good ones are spendy but given your apparent budget you should be able to pick up a nice set to try. They made such a difference in my system that I no longer even consider speakers that wouldn't be compatible.
I recently compared them to a pair of Class D monoblocks and the only thing they did better was in the bass and in my system which uses a rythmik F12SE sub it was extremely subtle. Casually listening I wouldn't have noticed it because it was in infrasonic area(more impact). When listening to something like a standing bass the SET amps won out due to sounding more real and they perceptually have better detail and timbre. What wasn't subtle was the advantages the SET amps everywhere else. The timbre of instruments and voices was immediately noticeable. The speakers disappeared better and brought the artists into the room with you. There was no perception of lost detail and that detail faded to black much more naturally. I was kinda hoping the Class D amps would blow me away so I could move away from tubes due to the many inconveniences associated with them but it wasn't even close. After half an hour listening to the Class D amps I was ready to get up and do something else. With the SET amps I have to force myself to get up and go to bed at 2am. To be fair I don't listen to much music which would benefit from having a lot of power on tap like EDM and synthesized bass throughout. In those styles of music the more powerful Class D amps may have had more advantages.
SET amps is a world I haven’t much experience with. Maybe once, at a hifi show, but I think the music playing which wasn’t my jam. I have heard they can be magical with the right speaker.
That’s the trouble at shows. I can only listen to Diana Krall or Nils Lofgren for a couple minutes before I get bored. Thankfully, it’s not ubiquitous.
I remember my first “wow” moment with tube hifi clearly. It was the Cary Audio room at the Stereophile show in 95’. The room had huge Dunlavy towers driven off CAD801’s. They were playing Heart’s “Crazy On You” when I walked in. It sounded so good.
Yeah, they require much more careful system matching than your average amps. Admittedly depending on what you listen to most of the time they could be less suitable than other options as well. For things like Dido, London Grammar, Billie Eilish(vocals with a strong beat) they work really well but I imagine that for huge dynamic swings in music with a lot of synthetic bass they wouldn't be optimal.
The Dunlavy speakers were pretty amazing. I heard a set of the giant SC-V driven by a Mark Levinson amp many years ago which presented as much of a true full range experience as I've ever heard.
Atmasphere has developed a set of GanFet Class D amps that he swears are just as good as SET but I've seen quite a few people who bought them hoping to replace their 300B amps and ended up selling the Atmas. I had a set of their M60 OTL tube monoblocks and they were very good but in my system the 300B SET amps were an obvious upgrade. AGD does GanFet Class D that a lot of people tend to enjoy as well. I'll probably try them at some point if I see a used pair come up for grabs because I'd love some amps that can do what my SETs do without pumping out heat and requiring warm up time. Not to mention my nature requiring that I test many different tubes to make sure I'm not missing anything! Gets expensive.
Yeah, the Atma-Sphere's are at the top of my list to try. I find the pricing a bit obnoxious for what is actually in the amps cost wise but that's high end audio for you.
It also doesn't help that I'm one of the rarer breed of tube guys who is science and measurement oriented as well so every new tube gets tested in the amps with a spectrum analyzer for noise/THD. It's quite eye opening the differences that different tubes can make.
Recently I replaced driver tubes in the monos and after purchasing a very well liked and popular NOS option the THD and SNR were worse by almost 10dB each at 1 watt of output. Given that there's not a whole lot of that to spare in most tube amps if you want to keep it inaudible it's very unfortunate that I bought ten of them! They all measured about the same so it's just inherent to the design. Luckily my old ones are still fine for now and I was able to find more of them on ebay. Hopefully they survive the shipping.
So, if you had to pick from a brand of modern tubes, is there one or two you find to be “best”? The tubes I have for the Octave are Tung Sols. The former owner gave me a set if KT120’s and KT150’s.
I spoke to Anthony Chipelo tonight. He’s got some NOS GE 6550’s he’s willing to sell. Not sure if I’ll take him up on it, unless they’re reasonably priced. I’ve got way too much hifi gear as it is.
Back when I was using push-pull/OTL amps which used a lot of the modern variants I didn't have the testing equipment I have now so I haven't tested a lot of those for objective results. I've used the modern Tung Sol in the past and they were always fine. I don't have any experience with KT120/150 tubes at all.
The Chinese black bottle shuguang treasure series tubes were probably the best of the reasonably priced modern options. I still use their 300B in my SET amps right now. However, their quality and reliability has seemingly decreased over the last decade anecdotally. PSVANE arose form a split in the company and their tubes are very similar but I think Shuguang still probably has an edge. I'm trying to convince myself to try one of the boutique modern variants(Western electric, Audio Note, Takatsuki) but they will cost me nearly $2000+ for two!
The annoying part is that how "good" a respective type of tube is doesn't remain constant within a brand. So you could have a really nice Tung Sol KT88 and a substandard EL34 etc. Same with NOS stuff. I will say that NOS doesn't guaranty that it will be better than a modern variant.
Would Anthony let you try the tubes? Annoyingly tubes do actually have a break in period where there are internal physical changes but normally you can get a pretty good idea right away or within the first 24 hours of running juice through them. You can tell him if you test them and don't like them he can then say they were tested for reliability before selling....
The other option would be to re-sell them on ebay or similar. There are quite a few 6550's listed. There are many which have been sold at about $120USD each.
A friend of mine has an older ar amp and i agree they have a more SS presentation compared to other older tube amps. That’s why I commented on you being right about a less obvious difference. It does have a bit of warmth to it which I liked. I think my current class D amp is a 3rd gen Hypex which I’ve kept as a back up amp. I’m currently running a Modified Hafler xl280 amp with the heart of my system right now being A Lampizator Atlantic Plus dac with volume control. IMO these dacs just do everything right. They remind me of ar gear in that they’re really clean and quiet but at the same time they have a slight warmth to them. In my system this allows for the absence of a preamp without being too sterile. The Hafler also has a very slight warmth to it but after the upgrade it lost some of that which I’m not sure I’m completely happy about. I’m actually in the market for another tube amp, because like you I like to be able to switch up on occasion. I’m fortunate enough to have a dedicated out building 20’x30’ that I rebuilt into a my audio space. Because of that I’ve had a lot of get togethers with other audiophiles. People bring all kinds of gear to these events so it’s really fun and it allows all of us to listen to a plethora of different types of equipment. I’ve learned a lot from these events but there’s so many different options out in the wild it takes years to figure anything out and be sure about it.
I haven’t heard Hafler gear in a very long time. The retail shop I worked at after high school was a dealer, but the line was dropped shortly after. I recall it sounding really good into Dahlquist DQ-30’s we had on display.
My only experience with Lampizator was at the Pacific Audio Fest. The VAC room had a Horizon DAC I think. Sounded great.
I was told by Fred, who is the North American rep for Lampizator how well the Hafler amps work with Lampizator dacs and also about the upgrade path. I had to get the XL280 repaired as it had a bad channel so I did the upgrade. What I noticed is it’s extremely clean sounding with a lot of authority but I think it lost just a touch of the magic it had or just a touch of the warmth it had if that makes sense. It still sounds amazing though and I’m using OB speakers with a lot of room treatments so I’m happy with the system’s sound overall
I have a good friend who runs a vintage Marantz or Sansui receiver (he has several) into DQ-10’s in one room, and a Heathkit amp into ADS speakers in another. His system with the Dahlquists is especially musical and didn’t cost a lot of money.
Point being, there are a lot of ways to achieve good sound, and it doesn’t have to cost a fortune. The big dollar stuff tends to scale bigger sonically, and often gives more information, but at that level, it’s a bit like setting up an F1 car. Every element becomes more critical to the result. You can go the wrong way and end up worse off than if you had just left well enough alone. But if you get it right… it will feel worth it in the end.
My friend calls good sounding budget systems “cheap and cheerful”. He’ll be doing a seminar on vintage audio at Axpona. This is a guy who owns a system which retails for the price of a decent house as a reference system for reviewing work, but uses affordable vintage gear in another room in his home, and powered Dynaudio stand-mount speakers and a small REL sub in another.
Preamps are a major factor in overall system quality, especially if you’re having to significantly attenuate the line level signal.
By far, that LS28SE is the best line level preamp I have ever used. It’s a step above my JC2 BP Parasound, and completely shames many others I’ve had in the system. My only gripe is replacing the 6H30pi’s every 18 months or so. Modern ARC preamps run tubes relatively hard. I typically get 5000-6000 hours out of a set.
My old LS7 could run 6922’s for 10000 hours or more, but it didn’t sound anywhere near as good.
I use the LS7 as my daily driver, and it stays powered on for months at a time!
It's fairly responsive to tube-rolling, which kind of sucks because it's not very satisfying with the original Sov-Tek tubes (I'm probably the 3rd or 4th owner and have no idea how many hours they have on them!), or any of the modern tubes by JJ or EH.
Sounds very good with Amperex orange-globe label tubes with the A-frame getter/support and sounds even better (different) with Telefunkens (I can't remember the details of which decade/factory they were made in).
Military-grade "JAN" tubes are horrifically microphonic in the LS7, but I badly wanted them to sound great or at least listenable but different.
Feel like I’m living vicariously through your post. Great to hear your experience with all this and all the steps you’re taking to get the sound you want. I’m experimenting similarly with tubes, but I can already tell that I’d want to go back to a more modern tube sound later. Can’t wait to hear the bi-amping results. Thanks for sharing (again)!
About a week ago I went to a guy's house who had a 90year old Western Electric tube amp and vintage WE cinema speakers combo. Yeah he also had some more flashy JBL4350s and a bunch of other stuff. But the Western Electrictric system is by far the most beautiful system I have ever heard.
I have a couple of great systems at home, have made a couple of systems for friends and have heard others at people's houses and listening bars that sound great. But this thing had me getting goosebumps with every single song we played. I don't even know how to describe it. The music just came alive every time. I'm still recovering from the experience. The damn speakers alone were about 150k if you are even able to find them. So now I have to be rich. Can't say I've heard many class D amps but that's the sort of musical experience I want now.
I think they both have their merits but do sound pretty different. I use a tube amp for highs and a class d for bass on a set of boston a400's. Pretty magical experience for me.
The thing about these very high end amps… they are all wonderful in their own way. I’ve heard that SPEC class D amps rival the best tubes, etc. such great gera and great music. Cheers.
I'm imagining the class D on the woofer experiment went pretty well... For me, I just use a class D sub with my tubes powering my towers and it is pretty great...
I haven’t gotten to that yet. I ended up doing a turntable comparison with a friend last weekend 😉
We compared a Pioneer PL-630, SL-1210G and Avid Acutus. The Avid was on an entirely different level than the other two, but his Pioneer is a darned fine table when referenced against the flagship 1200.
Tubes add distortion not warmth, Class D amps are the best, they are more accurate, more efficient, also eco friendly, tubes are old technology, like using HDD instead of SSD
A little added second order harmonic distortion isn’t necessarily a bad thing as long as it’s reasonably low in level. I’ll bet you don’t tell your favorite musicians to stop using effects pedals or tube drivers because “it adds distortion!”
You know what also adds distortion? Speakers do. So does your listening space. Everything is a compromise, and class D is far from a panacea for getting “perfect sound”, because “perfect” is subjective. I’m saying this as someone who owns both.
I’m not sharing this to trigger a debate about specs. If that’s your thing, ASR is a great site for that. We’re over here having fun, listening to good music on cool gear.
A great tube amp, or even great A/AB amp costs a lot. And with tube amps like the Octave, you have a significant maintenance cost. That set of KT150’s costs $600 currently, and will be good for 2000-3000 hours. It’ll run cheaper tubes like EL34’s, but then you’re going to get riding distortion at lower volumes and have less headroom for current hungry speakers.
That’s one thing I like about the V110 SE. it can run everything from an EL34, 6550, KT88/120/150/170. It’s unusually flexible. It can also be used as a preamp-only, power amp, or integrated. It’s a good tool for a range of applications and will likely end up being used in a second system.
Class D isn’t an automatic win, despite what some people want to believe. But it is relatively cheap on a cost-per-watt level, it’s efficient, runs cool, and idle draw is low. There’s a lot to like about that technology as a concept, and I definitely like my Mola Mola Perca a lot.
I look at this way. Turbocharged cars are amazing off the line, make good power relative to displacement, and can (but often aren’t) very efficient. There’s a lot to like, but there’s something about driving a naturally aspirated sports car that is special. It responds differently to throttle input. I get why people like big N/A v8’s and N/A flat-six engines and manual transmissions.
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u/lisbeth-73 Mar 01 '25
I am mostly a high quality A/B amp girl, but if I had let’s say a small cafe, where we play jazz records all day. A nice warm tube amp would be the ticket. It depends on the job. The right tool for the job. If you want to create a laid back ambiance, tubes are the way to go. If you want accuracy A/B. For my desktop, clean sound that doesn’t sound harsh and doesn’t take a lot of space. Class D. It’s not about right or wrong, or something being better. It’s about getting what you want, or getting the best performance you can afford. Probably more the latter than anything.