High end Vintage SS amp vs the best Class D amps

[Doodski]

An older Emotiva XPA-5 will be sold off. I already have one of these Nc502mp 6ch amps running on 15 amp circuit and not a problem yet. I run a 9.2.6 setup. So the plan is to run the base 9 channels on the 502 plus my front heights (slim towers) for a total of 11 channels used. 1 channels sits unused on the front L,R,C,LS,RS. The remaining 4 height channels will be driven by a Denon 8500h. Confused yet? I might be….

Geeeech... You must be running near ~7-8 peak horsepower there. I like it!

 

[AdamG]

Geeeech... You must be running near ~7-8 peak horsepower there. I like it!

Plus 5K on the Subs.

I have just issued myself a Warning for off topic thread drift..

 

[Doodski]

Plus 5K on the Subs.

I have just issued myself a Warning for off topic thread drift..

Ima sure if you ask nicely @amirm can issue you a thread ban for a couple of days while you sort this out.

 

[AudioSceptic]

I have multiple zone thermostats. The room with all the A/V gear has its own wireless thermostat.

Thanks. That must be some system (and the A/C too).

 

[MaxBuck]

Thanks. That must be some system (and the A/C too).

Maybe @amirm needs to start running tests on air conditioners. Maybe a "new subforum" idea.

 

[Angsty]

I love my restored NAD C272 power amp. Plenty of power, lots of headroom, low distortion, but heavy with some moderate heat output. I love it but if it was lost today, I would be buying a NAD C298 with Purifi modules. Time have changed and progress has been notched.

Then, I would immediately fret about what would happen if I needed service a decade from now. I hate throwing away stuff that should be able to be repaired, like my old C272.

 

[AudioSceptic]

Maybe @amirm needs to start running tests on air conditioners. Maybe a "new subforum" idea.

 

[MattHooper]

Plenty of anecdotal and subjective comparisons are out there, but they are full of fluff and thin on objective differences. The Benchmark is underpowered for a stereo power amplifier.

Your mention of the Benchmark being under-powered brought to my mind this question:

I've often seen it said that some tube amps can "sound" more powerful than their power ratings suggest. FWIW, although my CJ amps are pretty powerful for tube amps, 140W/side (into 4 ohms), when I was going back and forth between it and a Bryston 4B3 (300W into 8 ohms - and up to 500 into 4 ohms per channel), the CJ seemed to keep up even when cranked pretty loud. That is tons of dynamics, punch, no sense of a loudspeaker running out of steam (Thiel 2.7 speakers, 87 dB, nominal 4ohms). Whereas I did get a struggling-for-loudness/dynamics when I have used certain older low powered tube amps.

Other people have talked about even lower powered tube amps driving even some tough speakers surprisingly well. I believe it's been suggested that various aspects of a particular tube amp's design, e.g. the design/quality of it's transformers, can influence these attributes.

Is there anything technically justified to this proposition that a tube amp with lower power than a solid state amp can in practice "sound powerful" like the SS amp, due to transformer design or anything else?

Thanks.

 

[Blumlein 88]

Your mention of the Benchmark being under-powered brought to my mind this question:

I've often seen it said that some tube amps can "sound" more powerful than their power ratings suggest. FWIW, although my CJ amps are pretty powerful for tube amps, 140W/side (into 4 ohms), when I was going back and forth between it and a Bryston 4B3 (300W into 8 ohms - and up to 500 into 4 ohms per channel), the CJ seemed to keep up even when cranked pretty loud. That is tons of dynamics, punch, no sense of a loudspeaker running out of steam (Thiel 2.7 speakers, 87 dB, nominal 4ohms). Whereas I did get a struggling-for-loudness/dynamics when I have used certain older low powered tube amps.

Other people have talked about even lower powered tube amps driving even some tough speakers surprisingly well. I believe it's been suggested that various aspects of a particular tube amp's design, e.g. the design/quality of it's transformers, can influence these attributes.

Is there anything technically justified to this proposition that a tube amp with lower power than a solid state amp can in practice "sound powerful" like the SS amp, due to transformer design or anything else?

Thanks.

Well, the more common tube amps clip more gently. And sometimes it is hard to decide where to draw the line between high distortion and clipping. A SS amp that clips hard might become noticeably bad while a similar or slightly lower powered tube amp might be somewhat overdriven, but still sound not so bad. Whether this effect is enough to explain what you describe I'm not sure. It could in some cases.

 

[MattHooper]

Well, the more common tube amps clip more gently. And sometimes it is hard to decide where to draw the line between high distortion and clipping. A SS amp that clips hard might become noticeably bad while a similar or slightly lower powered tube amp might be somewhat overdriven, but still sound not so bad. Whether this effect is enough to explain what you describe I'm not sure. It could in some cases.

Yes, thanks. I am aware of that variable. And it's tough to winnow through the variables. Like in any particular example is either amp even getting close to clipping or not. I understand that, very loud musical peaks played really loudly aside, most people may be listening at levels where their amp is only "using/putting out" far fewer watts than they suspect, like even in the 5 - 10 w range. But I'm trying to ask a general question cutting through some of that, to whether some design aspects allow a tube amp to react to speakers in a way that sounds more powerful than the power rating may imply. Messy issue, I understand.

 

[tmtomh]

https://www.stereophile.com/content/boulder-amplifiers-2150-monoblock-power-amplifier-measurements

I would say one of the best high power amplifiers ever built.

 

[Jim Matthews]

A couple of years ago I compared a TPA3116 against a Mk 2 Krell KSA100. Here's a pic of that happening although it's not very good one



The Krell won but it does have about 15 times the power.

That's hilarious. Excellent illustration of accelerating change in electronics.

So much performance, so little cost.

 

[Jim Matthews]

Plus 5K on the Subs.

I have just issued myself a Warning for off topic thread drift..

You're gonna fire up this rig and all your windows will fall out.

I forsee a CSI episode based on your demise.
"Homebrew lithotripsy"

 

[Blumlein 88]

Well remember the Richard Clark $10,000 amplifier challenge? Hundreds of attempts and no one claimed the prize. Some class D amps have been used in this challenge. Makes you think any amp used within it linear operating range would be inaudible.

Then there were those Swedish series amplifier tests done blind. They found only one amp was truly transparent under blind testing. It was a large Bryston. I'm not sure if they made certain the amps weren't being overdriven, though I would expect they did.

 

[Slayer]

https://www.stereophile.com/content/boulder-amplifiers-2150-monoblock-power-amplifier-measurements

I would say one of the best high power amplifiers ever built.

One of the best (boulders past best ) yes, but not Boulders current best. Check out the new 3050. Price if i recall is 35k for a single or 60k for a pair.

Boulder 3050 Mono Amplifier - 3000 Series - Boulder Amplifiers

 

[AdamG]

You're gonna fire up this rig and all your windows will fall out.

I forsee a CSI episode based on your demise.
"Homebrew lithotripsy"

I have cracked floor tile and crated sheet rock cracks in the past. Not counting dishes, glassware and multiple wall hanging art tragedies.

 

[Angsty]

But I'm trying to ask a general question cutting through some of that, to whether some design aspects allow a tube amp to react to speakers in a way that sounds more powerful than the power rating may imply. Messy issue, I understand.

I believe the issue may be psychoacoustics versus just physics. People tend to have a higher tolerance for distortion when it is even order versus odd order. Tube amps tend to have more even order distortion; solid state amps tend to have more odd order. So it’s conceivable that a lower powered tube amp driven closer to the top of its output range with relatively high distortion could sound as “powerful” as a SS amp with relatively lower distortion, before it clips.

I’d welcome a more expert opinion to weigh in.

 

[restorer-john]

Like in any particular example is either amp even getting close to clipping or not. I understand that, very loud musical peaks played really loudly aside, most people may be listening at levels where their amp is only "using/putting out" far fewer watts than they suspect, like even in the 5 - 10 w range. But I'm trying to ask a general question cutting through some of that, to whether some design aspects allow a tube amp to react to speakers in a way that sounds more powerful than the power rating may imply. Messy issue, I understand.

People don't realize how often their amplifiers hit the rails on transients, particularly if they were playing dynamic content at an already elevated level to start with. The thing is, solid state amps, and tube amps all behave differently to one another in overload conditions. Some are dreadfully audible and others benign.

It's one of the major missing pieces in audio reviews these days, unfortunately.

 

[MattHooper]

View attachment 142527

Cripes! I let my Boulder amp go for only 25 grand in our yard sale. What was I thinking? Nice ol' lady sweet talked me down.

 

[MattHooper]

People don't realize how often their amplifiers hit the rails on transients, particularly if they were playing dynamic content at an already elevated level to start with. The thing is, solid state amps, and tube amps all behave differently to one another in overload conditions. Some are dreadfully audible and others benign.

It's one of the major missing pieces in audio reviews these days, unfortunately.

That's interesting and seemingly part of the conundrum. On one hand I hear in many cases with average speakers that our amps are usually barely taxed, e.g. if playing below 80 or 75 db. Others will emphasize that "you actually need more power than you assume" (e.g. for big peaks/transients). What's a poor audiophile to do?