Re; Dynamics, Class D vs tubes…

Another OP question w/o specifics.. my answer is “depends” LO

there are many good and bad tube designs, as well as Ds..

The speakers are rated 89 db at 1 meter and are nominal 4 ohm.  The amps compared were my Conrad-Johnson 27A (class A) and Marantz PM10 (class D).  For the comparison of dynamics I used C-J ART 88 line stage, C-J ART Phono, HW-40 w/SoundSmith Hyperion, Luxman D-10X using a mix of Redbook and SACD.  Dynamics in all cases were determined by the source material.  In other words there was no difference due to which amplifier was in the circuit.  Both amps were played at both moderate (75-80 db peak) and loud (100-105 db peak) volumes.  

Bill Stevenson,  Thank for your experiment and conclusion.  

Many amplifiers, regardless of class, require some increased volume setting to properly drive certain speakers.  It is usually the interaction between an amplifier and the speakers themselves that determine if the “dynamics” at lower volume fulfill your specific desires.  Do not go down the tube vs ss, class AB vs class D thinking there is a simplistic formula that will work for your hypothetical speaker. I wish it was that simple as it would have saved a lot of time and money (but then what would have been the fun in that…)  

I have a bunch of tube amps, I'm a tube amp guy. With my Tekton Perfect Set 2-12s my best demo was with a Rogue Sphinx V3 (class D with tube front end}. It took the class D amp to get the loudspeakers thumping. Big sound, big impact. 

West Coast Audiophile,  Enjoy!  I have given the specs of my speakers, the class D Amps I plan to audition are the new X mono blocks from Peachtree.  
Rounding out the field…Shindo Aurieges pre, Quicksilver V4 monos, KEF Reference 1 meta, Basis 1400 TT w/ Vector V4 arm + Benz Ruby OA low output with step up. ICs are Shindo, Spk cabling The Chord Company.  Vinshine Tia Hang.  
Please go ahead impress me now with your answer since you have my equipment list.

d/s

. drrsutliff, & russ69, …thank you.

For those that wonder the input impedance is 100K, so should play nice with the Shindo.

@daytrader if you have dog in the house, class D will hurt your pet!  I used class D amps for big PA systems, to entertain 80000+ people! Looking at your setup, I would recommend to consider class A SS, or tube amps if max power limitation is not concern. 

IME tubes are more engaging (more punch, detail, fuller sounding) at low volumes. 

The Class D amps I've tried have been far more dynamic than my tube and Class A amps. But not more engaging, musical, sonorous, inviting, mellow, inviting, or lubricious.

   It depends however the Class D Audio GaN Class D amp I am using currently is clearly the most dynamic in all regards of any amp I have owned.  Also zero fatigue to boot.

I like class d ncore hypex mcintosh using it in mi1502.marantz,atmosphere, Roland and other major manufactures using it.crutchfield let's you try stuff for 90 days they have some class d.it takes a very expensive tube amp to equal d sonic 2200 watts pascal. He may have a trial period. Fosi sell 48 volt gan per supply 80$ amazon or fosi audio direct.then thier mono amp 120$ . 250 watts into 4 ohms.low distortion amps. You don't need to change tubes.my favorite vtl 7.5 tube pre with ss amps.alot agree with this hybrid combo.enjoy the search.

mark200mph, very nice preamp!  I’ve been a fan of VTL for a long time. Thank you for the advice.  As for me this is just an experiment to see if I can better match up my recently purchased speakers to a better option, more powerful amp and still have my “tube cake” and if it too?  These newest X series monos from Peachtree use NCore X 500.  With the impedance of 100k they should at least be able to mate well but as for a better tube alternative to my Qsilver v4 monos, we will have to see or actually hear it.  I know they will sound more dynamic but at what musical cost?  Thanks for the alternatives you suggest. 
 

d/s

OP's question ... 

Class D amplification vs tube amplification, which is likely to be more dynamic at lower volume playback? 

And here I am thinking that enjoyment relative to lower volume playback is speaker dependent.  What do I know? 

I don't have any experience with the KEFs Reference 1 Meta.  Do they sound to your liking when played low?  The one review I read (What HiFi) was addressing their sound when played loud(er).

Even so, none of that prepares us for the scale and authority of the KEFs’ presentation. On the end of our reference system, they sound much larger than they are, delivering the kind of chunky bass more often heard from floorstanding alternatives. Certainly, rivals such as the Bowers & Wilkins 805 D4sound nowhere near as large-scale, muscular or punchy.

I have had tube amps (Prima Luna), Class D (Class D Audio), Class D hybrid (Rogue, Heaven 11) and Class A/B SS (Rega, Adcom) amps in my systems for the last 20 plus years.  My systems are not in the same league as your equipment is,  that's for the certain.  While the Class D amps have performed well, I have been the most engaged by the tube amps.  I love my Prima Luna/ Musical Fidelity/ Zu Audio set-up and would be reluctant to replace it.  Dynamics are not an issue with tubes.  I find I have to up the volume to get the Class D hybrid set-up to sing (Heaven 11, Golden Ear BRX).

Be well, 

Rich 

I have the KEF Reference 1’s, non-meta, and my gut tells me that a solid state power amp is a better choice. Do they seem lacking with your current tube mono’s? Also, any reason you are not considering A, A/B amps? FWIW, I have had good low volume results with Coda and Audionet so far.

4 ohms, 85db speakers are probably not the best match for tubes.  With that said I hear little difference in low level listening dynamics using either my Atma-Sphere 30w tube amp or 100w Class D amps with my QLN 8 ohm, 87.5db easy to drive speakers. 

@zlone

I drive my KEF Reference 1 speakers with an old Krell KSA-80 class A amp, rated at 80-Watts into 8-Ohms, 160 into 4 and 320 into 2.  The results are stunning, but I have not really compared amplifiers.  The speakers were demonstrated with McIntosh but unfortunately I took little notice of the power source - the speakers were the best I have heard at any price.  The KEF specs say 50 to 200 Watts.  I would err on the high side!

I really don't understand why the amplifier should affect low level dynamics, unless the amplifier compresses the output which surely would be at high volume?  A "straight wire with gain" would leave dynamics unchanged?

To answer some of the questions above.  The speaker choice was of one of consideration of space as we moved into a new home and I lost my audio room.  I’ve had these V4s for a long time and the Shindo pre combo was a match made in heaven running my Eminent Technology LFT8b panel speakers.  God I miss those!  But moving I had to make do with a great room and a BDI TV audio console that housed all my gear but hides the beauty of the gear, all with speakers that as she put it were not an “eye sore”. LOL. So looking into monitors and coming off satisfaction from a secondary system, Peachtree Nova300 into KEF LS50s, I went for the Reference 1 Meta.  The only thing lacking is a tight base impact and maybe some high extension.  The speakers are capable but my tube gear is midrange magic focused with my KT-88s.  Lows and highs are good but not as good as can be had from the KEFs.  So, just thought if I could have my cake and eat it too?  Thanks everyone for the suggestions.  I know the answer is try out on loan new amplification but it needs to be at least 100k input impedance to have a chance. 

@daytrader , @billstevenson has this right. Whatever dynamic contrast that exists in the system should come from the signal and not the amps. Some amps can 'sound' more dynamic than others but if you measure them you'll see no difference. That is because distortion can cause the ear to be fooled into the perception of dynamics.

A good class D amp can sound right, like an excellent tube amp, at low volume no worries.

Thanks Ralph. 👍

So amp typology for the most part isn’t going to matter much?  Tubes vs solid state is closer than ever but still obviously not identical delivering music.  I guess I’m just looking for a better full range match for my current speaker choice.  While still keeping the equipment with the least amount of change.  I tried the KT150s for a little more bottom end , approved by Mike Sanders, but didn’t like the frequency response.   Might just have to stop here and let sleeping dogs lie.  

@daytrader , your last sentence is a worthwhile venture and costs nothing for now... ;)  You've indicated rather particular desires, worth the time to spend to satisfy.....

Unless there exists a specific event in mind you've the desire to indulge...

@hilde45 's use of 'lubricious' in regard to class choice imho has never struck me as important under the typical use of the term. 🤷‍♂️

Personal experience the musical source tends to be silenced while a more primitive and generally more satisfying duet occurs....hopefully...😏

YRWV....sorry. *G*

The Chicago show is coming up....perhaps time for an audio exposition expedition?

Put together a dongle within it the sort of detail you'd want to have.

If a vendor won't play it between demos, then you'd rather not have their stuff. ;P *L*

So amp typology for the most part isn’t going to matter much?

@daytrader It better not. The dynamic contrast in any system should arise from the signal and nothing else. Its the system's job to convey this and do so without compression. Lower efficiency speakers do have a phenomena known as 'thermal compression' which is not an amplifier thing. This is one reason higher efficiency speakers are often cited for superior dynamic punch. 

Hilde:

You didn't have me until lubricious.

DeKay

@dekay I learned that word from a master of pleasure:

“Beauty belongs to the sphere of the simple, the ordinary, whilst ugliness is something extraordinary, and there is no question but that every ardent imagination prefers in lubricity, the extraordinary to the commonplace”
― Marquis de Sade

I had to look lubricity up  

oily smoothness

As opposed to the extra meaning in lubricious

offensively displaying or intended to arouse sexual desire. "he probed the ladies for every lubricious detail of their interactions"

Really depends on the design, but generally speaking, I’d say tube amps. 

That is because tube amps tend to boost the “bass-slam” frequency range when mated to highly reactive loads. It’s the same reason for why listeners often say tube watts sound more powerful than SS watts. Tube amps also clip softly, but that’s not the reason they often sound more powerful than a SS counterpart. 

Another reason is that IME, most Class D amplifiers sound flat and lifeless in terms of bass dynamics (well most of their bandwidth actually). The notable exception I’ve encountered is the Axxess Forté 1 integrated—the only Class D amp I have ever felt was worth owning. Its distortion is second harmonic dominant, similar to a good SET amp in that regard.  

 

I think the real answer is that you can probably find samples of each class of amplifier design that could be compared directly and hear no difference at all, especially at low volumes. On my desktop system I am often at less than 1 watt drive level especially if I am working on something that requires concentration. At low levels like that distortion should be vanishingly small and since these speakers are 78.5 db efficient and I am driving them with a 65 ish watt Emotiva amplifier there should be plenty of headroom for low level listening (and there is) 85-90 db listening levels are possible even with that relatively low powered amp coupled with very inefficient speakers.

My thinking is that with sensitive measuring equipment it would be possible to measure differences in dynamics but the differences would not audible unless the ampllifier in question was being overtaxed by the load. But in that case it wouldn't be a fair comparison.

My first adventure into this crazy hobby was a mono Heathkit receiver with a 5 watt rms amplifier driving an 8" Jensen Dual cone speaker and for a kid who liked his music louder than was smart, I found it acceptable much of the time. So I guess that sets the bar pretty low for a low powered system. I doubt anyone on this forum would find anything of such modest capabilities to be acceptable. That said, I think there are synergies that are quite possible to exploit, though I would say it often happens by accident and those magic equipment combinations that are greater than the sum of their parts are pretty uncommon, though I have experienced a few surprising marriages that were clear improvements over what came before.

For example, I have a very modest system in the living room of our apartment using a pair of ADC 303 ax main LR speakers, a JBL center speaker and a pair of Dayton Audio surround speakers. The surrounds have had upgraded drivers installed with a very nice fabric dome tweeter and nicer 6 1/2" woofer and sound pretty respectable especially at low levels. The ADCs have new fabric dome tweeters and crossovers and punch above their  original weight by a lot. Amazing what a really good tweeter will do for sound quality. Been driving this combo with an Emotiva MR1L that I thought sounded pretty darn good. Sadly the MR1 is not a great piece reliability wise. Its boxed up and awaiting an RMA from Emo. So what replaced it, at least for the short term is a Schiitt Audio Syn (analog surround processor) and 3 Stereo Hypex amps built with the NC502 modules rated at 500 wpc into 4 ohms. I have honestly never heard these speakers perform like they do with this amp combination. There is some secret sauce going on here that I cannot explain. I have run the ADCs with many different amps over the time I have had them and the choice of amp never seemed to make much of a difference until I arrived at this current pairing. I'll happily take the improvement but it was completely unexpected.

So, just thought if I could have my cake and eat it too?  

No magic bullet, no free lunch.

Typically Tubes gives midrange engagement but the frequency extremes less defined especially in the bass.  SS typically gives better bass and treble control but a more neutral midrange.  An economical compromise might be a tube pre + SS amp.  But to get the “cake” usually means much more costly components - I noted that a couple of audiophiles stopped caring tube or SS after they upgraded enough (~50k+ components) - I’m hoping to be able to afford to achieve this level of satisfaction.

Both GanFET and sliding bias Class A amps (Krell, Westminster) seem to have the both midrange warmth and top to bottom SS definition.

Maybe get bi-amp speaker - tube for top, SS for bass

Not to forget, with a tube pre amp one would need a solid state amp with 100k input impedance to give that dull range .  Any suggestions, lower than a $33,000 Rei? 

@daytrader you don't need an amplifier with a 100k input impedance with many tube preamps, there are many made today that have a low output impedance.

It’s a Shindo Aurieges, this is how Stereophile measured it…

The output impedance at 20kHz was very low, at 23 ohms. It rose to 139 ohms at 1kHz, which is still low, but at 100Hz it measured a very high 3700 ohms. It rose even further as the frequency dropped, to 11k ohms at 50Hz and 16.5k ohms at 20Hz. I assume that this drastic rise in impedance is due to the Aurieges Equalizer Amplifier’s output being taken from the tubes’ plates via a coupling capacitor. With line preamplifiers having an input impedance of less than 100k ohms, this increasing output impedance at low frequencies will roll off the bass.

On the test bench, Shindo Laboratory's Aurieges Equalizer Amplifier produced mixed results. The very low levels of distortion and extraordinarily high overload margins must be set against its nonflat RIAA response, its high level of flicker noise, and its high output impedance at low frequencies, which will make system optimization tricky.—John Atkinson

Not to forget, with a tube pre amp one would need a solid state amp with 100k input impedance to give that dull range .

@daytrader We make tube preamps that can drive 1000 Ohms no worries, with the output impedance being a straight line across the audio band, so no loss of bass impact. IOW not all tube preamps are the same.

 That is because tube amps tend to boost the “bass-slam” frequency range when mated to highly reactive loads.

@helomech This statement is false. Usually its the other way ’round. What tends to cause tube amps to seem to have more power than solid state amps of the same rating is the way they make distortion, particularly, as you alluded, near clipping.

Usually its the other way ’round. What tends to cause tube amps to seem to have more power than solid state amps of the same rating is the way they make distortion, particularly, as you alluded, near clipping.
 

My experience is otherwise. Maybe because I am more accustomed to push-pull tube amps. IME it is quite obvious when a tube amp begins to run out of steam because the dynamics suddenly go flat. 

Maybe because I am more accustomed to push-pull tube amps. IME it is quite obvious when a tube amp begins to run out of steam because the dynamics suddenly go flat. 

@helomech Its really hard to generalize how tube amps clip. Some are quite graceful; typically having little or no feedback. But if the amp has a lot of feedback the clipping point will be a lot more obvious. Some in the middle WRT to feedback will seem to just compress a bit (if the power supply is adequate) before the onset of obvious clipping.

Most tube amps with feedback have a higher output impedance than a solid state amp, but if treated properly can behave as a Voltage source on most speakers. Because of the higher output impedance they generally don't like obtuse phase angles (highly reactive loads) and tend to make less power driving them on that account Since obtuse phase angles are usually a bass issue the amp might seem a bit bass shy.... But again we are talking generalizations since not all speakers are the same in that regard!