How far have ss amps really come in the last twenty years??

[Sir Sanders Zingmore]

Back on topic, if I can paraphrase Roger Sanders. His view is that amps that are sufficiently accurate and are operating in their linear range will be indistinguishable.

He goes on to say that in the real world, amps do not all sound the same. This is not as inconsistent as it seems.

His thesis is that most amps are underpowered for the speakers they drive. This leads to clipping, and amps behave differently when they clip and therefore sound different.

 

[Sal1950]

His thesis is that most amps are underpowered for the speakers they drive. This leads to clipping, and amps behave differently when they clip and therefore sound different.

There are other reasons too, most of which have already been covered here.
I think the point is that all of these inaccuracies can be measured, if you pair amp X with speaker Y and run the usual battery of measurements on them, audible problems can be pinpointed.
But since many amps are engineered to have a house sound or particular types of distortions, and many speakers present such non-standard loads, no flat claims on the sound of amps can be made.. Until they hit the bench as a pair that is.

 

[DonH56]

LOL, I am certain you are 100% correct! There is no real reason why i would be attracted to the philosophies that you and apparently others on this site abide by. To me, measurements are an interesting aside...and are always going to be of secondary interest to what I hear with my own ears....clearly YMMV.

What philosophy is it that you feel I and others have, that you disagree with, from my statements? That there are other musicians on this site who may have valid opinions, that science and music are not polar opposites, or that measurements have value? You seem to have judged all science-minded folk as ignorant, intolerant, and unworthy buffoons with no ability to hear let alone create and play music, but are willing to devote effort to tell us just how irrelevant we are... I don't understand, is this attack on the site and the majority of its members some sort of sentence imposed upon you for past sins?

Here is what I said:

The assumption that none of the rest of us have backgrounds in music is false. The implication that science (or engineering) and music are opposites is similarly false.

If you've no faith in measurements you are in the wrong place.

 

[Xulonn]

Back on topic, if I can paraphrase Roger Sanders. His view is that amps that are sufficiently accurate and are operating in their linear range will be indistinguishable.

He goes on to say that in the real world, amps do not all sound the same. This is not as inconsistent as it seems.

His thesis is that most amps are underpowered for the speakers they drive. This leads to clipping, and amps behave differently when they clip and therefore sound different.

Is it possible that amplifiers designed to have more "dynamic headroom" and/or "soft clipping" (are they related?) might sound better driving music with a high dynamic range and many peaks?

Are modern recordings with their extremely limited dynamic range easier for amplifiers to handle compared with wide-dynamic range recordings?

Do amplifiers with big power supply filter capacitors - like the 1990's Classe Model Seventy with its four 10,000µF PS caps that will arrive here in Panama this month - have more headroom and better bass that can make them sound "more powerful" than other amplifiers with similar RMS output ratings but less PS capacitors?

Do large banks of smaller caps function as well good as aone or two really big ones? (I assume that peak discharge rate would be a factor.)

Do any of our current crop of ASR favorite amplifiers address clipping and try to reduce its negative effect?

McIntosh has always been big on clipping mitigation, addressing it with their "Power Guard" technology - which I assume is a dynamic compression technique. (The below amplifier has nice big VU meters that would certainly please Amir.)

10/2018: McIntosh today announced a power amplifier to replace the MC302 but it’s no ordinary replacement.

The engineering team of the legendary brand doubled the filter capacity of the new MC312 ($7,000) to lower distortion, improve bass performance, and make the amp better suited to handle extreme dynamic swings in music. In technical terms, the net effect is a boost in dynamic headroom from 1.8 dB to 2.3 dB — 27% higher than its predecessor.

Standard McIntosh accoutrements include Power Guard circuitry that monitors and adjusts the input signal in real time to prevent clipping...

 

[DonH56]

Responses IME/IMO.

Is it possible that amplifiers designed to have more "dynamic headroom" and/or "soft clipping" (are they related?) might sound better driving music with a high dynamic range and many peaks?

Dynamic headroom is usually a combination of an unregulated power supply for the output stage and specsmanship. For the same amplifier you can specify lower distortion at a lower power level, and thus specify more dynamic headroom (peak short-term output power capability), or specify higher power with higher distortion. The supply voltages are higher until a large load hits and then they sag. That higher voltage sustains greater headroom than the long-term rating with a heavy load (and thus sagging supply voltages). Regulated supplies provide very "stiff" voltage rails so do not sag (as much) and generally provide very clean power right up to clipping and very little "dynamic headroom". If the amplifier provides the power needed without clipping then the regulated low dynamic headroom design will generally have lower distortion and better performance. It's a trade, debatable which is the better choice for you.

Are modern recordings with their extremely limited dynamic range easier for amplifiers to handle compared with wide-dynamic range recordings?

Probably but depends how loudly you play them. Average power may be up even though peak power is down. And note there are plenty of good recordings with wide dynamic range these days.

Do amplifiers with big power supply filter capacitors - like the 1990's Classe Model Seventy with its four 10,000µF PS caps that will arrive here in Panama this month - have more headroom and better bass that can make them sound "more powerful" than other amplifiers with similar RMS output ratings but less PS capacitors?

It depends and there are many variables. Output impedance depends upon feedback. In a full-wave linear power supply the capacitors are recharged at a 120 Hz rate so bigger capacitors, or just more capacitance, can keep the power supply voltage from sagging as much under sustained heavy loads. That also means reduced dynamic headroom. That only matters if you need more power than the amplifier can sustain steady-state (long-term). It also means an amplifier with more dynamic headroom may actually sound "weaker" than one with as tiffer power supply and less headroom.

Note switch-mode power supplies (SMPS) recharge their capacitors at 100 kHz or more (sometimes much more) instead of 120 Hz. That means fewer, smaller capacitors will perform as well or better than banks of giant capacitors in a linear supply. The trade is complexity and high-frequency noise (albeit well above the audio band -- no 60/120 Hz power supply noise), as well as potentially cost, and reliability.

Do large banks of smaller caps function as well good as one or two really big ones? (I assume that peak discharge rate would be a factor.)

Smaller capacitors typically self-resonate (stop looking like good capacitors) at higher frequencies and have lower parasitic series resistance (ESR) than larger ones. That means a bank of smaller capacitors often performs better than a single larger capacitor, but take more area, more wiring to connect, and usually cost more.

Do any of our current crop of ASR favorite amplifiers address clipping and try to reduce its negative effect?

McIntosh has always been big on clipping mitigation, addressing it with their "Power Guard" technology - which I assume is a dynamic compression technique. (The below amplifier has nice big VU meters that would certainly please Amir.)

Benchmark does. I am not sure about the Hypex etc. amplifiers.

HTH - Don

 

[Blumlein 88]

Is it possible that amplifiers designed to have more "dynamic headroom" and/or "soft clipping" (are they related?) might sound better driving music with a high dynamic range and many peaks?

Are modern recordings with their extremely limited dynamic range easier for amplifiers to handle compared with wide-dynamic range recordings?

Do amplifiers with big power supply filter capacitors - like the 1990's Classe Model Seventy with its four 10,000µF PS caps that will arrive here in Panama this month - have more headroom and better bass that can make them sound "more powerful" than other amplifiers with similar RMS output ratings but less PS capacitors?

Do large banks of smaller caps function as well good as aone or two really big ones? (I assume that peak discharge rate would be a factor.)

Do any of our current crop of ASR favorite amplifiers address clipping and try to reduce its negative effect?

McIntosh has always been big on clipping mitigation, addressing it with their "Power Guard" technology - which I assume is a dynamic compression technique. (The below amplifier has nice big VU meters that would certainly please Amir.)

The Power Guard circuit did do something like dynamic compression. It monitored input vs output and reduced signal whenever distortion approached 1 %. It was very fast. Lights in the circuit fired photo-transistors to work. I had one of the little 752 McIntosh amps while I owned Acoustats. These were those that were made to look like tube amp, but weren't. For most listening it did fine. If you wished to really push it till the lights on Powerguard came on, it didn't fall apart. If you pushed it enough, then the compression was very noticeable, but not terribly awful like clipping would have been. In time I replaced it with about 6 db W more power. That was just enough to be enough.

I've owned a few of the old Classe amps btw. Model DR15, model 25 and one of the DR3 VHC amps. The last one was called a 30 wpc class A amp. It was, but it really was a 200 wpc amp that ran 30 watts in class A before becoming class AB.

 

[March Audio]

Benchmark does. I am not sure about the Hypex etc. amplifiers.

HTH - Don

Re the Hypex clipping mitigation, no nothing is implemented by default. However they do have a clip indication output which could be used to drive protection circuitry if the OEM vendor wishes. The modules also have a single cycle current limiter indicator output and a "hiccup" mode where if it current limits for more than 200ms it shuts down. Also a FATAL hardware fault shutdown. PSU under/overvoltage protection and over temp protection.

 

[Sir Sanders Zingmore]

Presumably, different methods for clipping mitigation cause amps to behave and sound, different.

Sanders’ approach is simply to have enough power that you almost never need to listen to clipping (or its mitigation)

 

[March Audio]

Presumably, different methods for clipping mitigation cause amps to behave and sound, different.

Sanders’ approach is simply to have enough power that you almost never need to listen to clipping (or its mitigation)

Yes its possible for it to be intrusive. I have considered implementing a simple LED clipping indicator without any further intervention.

I like your approach. You definitely need a pair of my P701s

 

[wynpalmer]

According to Stereophile measurements, the HP100 isn't flat to 20 khz, and well down by 200 khz.

https://www.stereophile.com/content/hovland-hp-100-preamplifier-measurements

Noise performance is also marginal, and might be enough to make them audible. Its output impedance is 2400 ohms rising to more than 4000 ohms at 20 khz. Depending upon the amp you are feeding this could alter the frequency response and further alter the volume out the amp if you measured signal level on the two bits of gear prior to the amp. And .25 db is getting up enough to also make the results an unmasking due to volume alone. Probable/possible volume mismatch and FR differences could make this not transparent vs the RME.

I am aware of the Stereophile review and measurements. and I have indeed measured the buffer response into the AHB2 input, and the -3dB point is about 200kHz rather than the 80kHz that Fremer claimed, and into the 50k load that the Benchmark AHB2 represents. The interconnect has a measured 150pF equivalent shunt capacitance. If you assume that the 4k output resistance is correct, you get a -3dB point into 200pF of c. 215kHz.
Note that even the 80k number is higher than say, the -3dB point of the Ncore400s that I also have.
I do not use stock tubes, although I have not modified the output buffer. The output buffer consists of an unknown Nfet with a series combination of a c.1.8k/20k resistor to ground, giving an equivalent series R of about 1.7k with an unknown fet output impedance. The output cap is a 2.2 u tantalum bead.
The response looks, essentially, first order, so of course there is finite loss at 20kHz, but it's less than 0.1dB (simulations say 37mdB) and I consider that to be essentially flat.
The overall noise, including phono, is not particularly good, and I have boosted the phono gain 6dB above stock, using a custom SUT, for my Miyajima Madake cartridge, giving up overload in exchange for noise improvements, but the line stage on its own is adequate- certainly not audible at my normal listening position/loudness.
The preamp, apparently, generates a lot of second harmonic which I have not measured. I suspect that the difference may be due to that.
I have tested my sensitivity to level shifts using an on-line tool and 0.25dB is just audible to me if I effectively do an ABX test. I validated the 0..25dB accuracy by playing an LP test tone back and checking the output levels for match.

EDIT: I just checked and the FET used is a PN4393. I built up a quick circuit simulation for the buffer including the FET and the nominal output resistance is indeed a bit above 4k.

 

[anmpr1]

Back on topic, if I can paraphrase Roger Sanders. His view is that amps that are sufficiently accurate and are operating in their linear range will be indistinguishable.

He goes on to say that in the real world, amps do not all sound the same. This is not as inconsistent as it seems.

His thesis is that most amps are underpowered for the speakers they drive. This leads to clipping, and amps behave differently when they clip and therefore sound different.

When it comes to controlled amp testing, Stereophile (and those of similar take) typically argue that the problem with these tests is a) 'associated equipment' of low resolving power, and b) inexperienced panel listeners.

In 1987, David Clark took a group from the Southeastern Michigan audiophile club--members who routinely heard differences in amps, and had them level match some gear: Pioneer SX-1500 receiver ($219.95); NYAL Futterman OTL-1 mono amps ($12,000); Mark Levinson ML-11 stereo amp ($2,000); NAD 2200 ($548) and Hafler DH-120 ($320).

Associated gear was Sota turntable/Van den Hull MC-10/Eminent-Technology tonearm; Audio Research SP-11 preamplifier; Meridian MCD Pro CD player; Magneplanar MG-IIIA speakers.

I don't need to spell out the results of the test, but I will. Everyone heard 'differences' in casual listening. No was able to distinguish among them with levels matched. Don't get me wrong. Personally I'd much prefer to own a Mark Levinson amplifier over a Pioneer receiver. Unless it was one of their monsters from the late '70s, in which case I'd take the Pioneer.

 

[BDWoody]

[/QUOTE]

A knob that's both ' hefty ' AND ' silky ' , the stuff of dreams ..

When it comes to controlled amp testing, Stereophile (and those of similar take) typically argue that the problem with these tests is a) 'associated equipment' of low resolving power, and b) inexperienced panel listeners.

In 1987, David Clark took a group from the Southeastern Michigan audiophile club--members who routinely heard differences in amps, and had them level match some gear: Pioneer SX-1500 receiver ($219.95); NYAL Futterman OTL-1 mono amps ($12,000); Mark Levinson ML-11 stereo amp ($2,000); NAD 2200 ($548) and Hafler DH-120 ($320).

Associated gear was Sota turntable/Van den Hull MC-10/Eminent-Technology tonearm; Audio Research SP-11 preamplifier; Meridian MCD Pro CD player; Magneplanar MG-IIIA speakers.

I don't need to spell out the results of the test, but I will. Everyone heard 'differences' in casual listening. No was able to distinguish among them with levels matched. Don't get me wrong. Personally I'd much prefer to own a Mark Levinson amplifier over a Pioneer receiver. Unless it was one of their monsters from the late '70s, in which case I'd take the Pioneer.

Pioneer SX-1980 please.

Some of those old receivers are absolutely gorgeous...

 

[anmpr1]

Some of those old receivers are absolutely gorgeous...

Yes, indeed. I once owned an SX-1980. 'Lost it' in a divorce. I think she took it to spite me. Maybe I deserved spiting. I won't even deny that. But the Pioneer? No one deserves to have their monster receiver taken away. Because of my experience I advise everyone to keep their audio gear, but don't get married. Or if you must get married, at the very least, have your attorney draw up a hi-fi prenup. Easier to replace a girlfriend than it is to replace a monster Pioneer receiver. I hate to say that, but it's true.

 

[Vapor9]

When it comes to controlled amp testing, Stereophile (and those of similar take) typically argue that the problem with these tests is a) 'associated equipment' of low resolving power, and b) inexperienced panel listeners.

In 1987, David Clark took a group from the Southeastern Michigan audiophile club--members who routinely heard differences in amps, and had them level match some gear: Pioneer SX-1500 receiver ($219.95); NYAL Futterman OTL-1 mono amps ($12,000); Mark Levinson ML-11 stereo amp ($2,000); NAD 2200 ($548) and Hafler DH-120 ($320).

Associated gear was Sota turntable/Van den Hull MC-10/Eminent-Technology tonearm; Audio Research SP-11 preamplifier; Meridian MCD Pro CD player; Magneplanar MG-IIIA speakers.

I don't need to spell out the results of the test, but I will. Everyone heard 'differences' in casual listening. No was able to distinguish among them with levels matched. Don't get me wrong. Personally I'd much prefer to own a Mark Levinson amplifier over a Pioneer receiver. Unless it was one of their monsters from the late '70s, in which case I'd take the Pioneer.

I feel Stereophile nailed it in their assessment of the problems of controlled testing.

There is no way I could NOT notice the differences between my Cambridge Audio integrated, Peachtree 220 and my new March Audio P252. But, that is in my own listening room, with familiar music and with my familiar speakers, etc. Put me in a room where any of these variables are changed and I concede that I may have a problems telling them apart. And, of course, the resolving power is hugely important. I may not be able to notice the depth of bass available on the March compared to my Cambridge if they're being played through some mini-monitors or lean electrostatics.

 

[SIY]

There is no way I could NOT notice the differences between my Cambridge Audio integrated, Peachtree 220 and my new March Audio P252. But, that is in my own listening room, with familiar music and with my familiar speakers, etc. Put me in a room where any of these variables are changed and I concede that I may have a problems telling them apart. And, of course, the resolving power is hugely important. I may not be able to notice the depth of bass available on the March compared to my Cambridge if they're being played through some mini-monitors or lean electrostatics.

There's nothing stopping you from using your own setup and doing a controlled ears-only test. Many people have done so in order to show up that crazy notion that there's no magic in electronics- I was one of them. I was surprised by the results, but didn't try to rationalize my way out of them.

In Stereophile's case, of course, the mendaciousness is not accidental, ears-only evaluation is a challenge to their revenue stream so must be discounted at all opportunities. No-one with even passing familiarity with sensory analysis buys it, but that's not their intended audience.

 

[Sgt. Ear Ache]

I feel Stereophile nailed it in their assessment of the problems of controlled testing.

There is no way I could NOT notice the differences between my Cambridge Audio integrated, Peachtree 220 and my new March Audio P252...

oh really? You're positive of that?

 

[Vapor9]

oh really? You're positive of that?

Yes, absolutely. They each have their own distinct personalities. Subtle, yes, but there.

 

[anmpr1]

I feel Stereophile nailed it in their assessment of the problems of controlled testing.

There is no way I could NOT notice the differences between my Cambridge Audio integrated, Peachtree 220 and my new March Audio P252. But, that is in my own listening room, with familiar music and with my familiar speakers, etc. Put me in a room where any of these variables are changed and I concede that I may have a problems telling them apart. And, of course, the resolving power is hugely important. I may not be able to notice the depth of bass available on the March compared to my Cambridge if they're being played through some mini-monitors or lean electrostatics.

Back in the days of rec audio newsgroup there was a South Florida stereo dealer, Steven Zipser (real name). Anyhow, his organization, Sunshine Stereo, was his house. Tom Nousaine and Steve Maki challanged the Zipser to a little ABX. Here's Tom's write up, in Audio Critic.
_____________
On Sunday afternoon, August 25th, Maki and I arrived at Zipser's house, which is also Sunshine Stereo. Maki brought his own control unit, a Yamaha AX-700 100-watt integrated amplifier for the challenge. In a straight 10-trial hard-wired comparison, Zipser was only able to identify correctly 3 times out of 10 whether the Yamaha unit or his pair of Pass Laboratories Aleph 1.2 monoblock 200-watt amplifiers was powering his Duntech Marquis speakers. A Pass Labs preamplifier, Zip's personal wiring, and a full Audio Alchemy CD playback system completed the playback chain. No device except the Yamaha integrated amplifier was ever placed in the system. Maki inserted one or the other amplifier into the system and covered them with a thin black cloth to hide identities. Zipser used his own playback material and had as long as he wanted to decide which unit was driving the speakers.

I had matched the playback levels of the amplifiers to within 0.1 dB at 1 kHz, using the Yamaha balance and volume controls. Playback levels were adjusted with the system preamplifier by Zipser. I also determined that the two devices had frequency response differences of 0.4 dB at 16 kHz, but both were perfectly flat from 20 Hz to 8 kHz. In addition to me, Zipser, and Maki, one of Zip's friends, his wife, and another person unknown to me were sometimes in the room during the test, but no one was disruptive and conditions were perfectly quiet.

As far as I was concerned, the test was over. However, Zipser complained that he had stayed out late the night before and this reduced his sensitivity. At dinner, purchased by Zipser, we offered to give him another chance on Monday morning before our flight back North. On Monday at 9 a.m., I installed an ABX comparator in the system, complete with baling-wire lead to the Yamaha. Zipser improved his score to 5 out of 10. However, my switchpad did develop a hang-up problem, meaning that occasionally one had to verify the amplifier in the circuit with a visual confirmation of an LED. Zipser has claimed he scored better prior to the problem, but in fact he only scored 4 out of 6 before any difficulties occurred.

His wife also conducted a 16-trial ABX comparison, using a 30-second phrase of a particular CD for all the trials. In this sequence I sat next to her at the main listening position and performed all the amplifier switching functions according to her verbal commands. She scored 9 out of 16 correct. Later another of Zip's friends scored 4 out of 10 correct. All listening was done with single listeners.

In sum, no matter what you may have heard elsewhere, audio store owner Steve Zipser was unable to tell reliably, based on sound alone, when his $14,000 pair of class A monoblock amplifiers was replaced by a ten-year old Japanese integrated amplifier in his personal reference system, in his own listening room, using program material selected personally by him as being especially revealing of differences. He failed the test under hardwired no-switching conditions, as well as with a high-resolution fast-comparison switching mode. As I have said before, when the answers aren't shared in advance, "Amps Is Amps" even for the Goldenest of Ears.

 

[SIY]

Yes, absolutely. They each have their own distinct personalities. Subtle, yes, but there.

So you claim you'd able to distinguish them ears-only and level-matched? That seems to be a remarkable claim. A common one, but remarkable- and never backed up with actual data.

 

[Vapor9]

So you claim you'd able to distinguish them ears-only and level-matched? That seems to be a remarkable claim. A common one, but remarkable- and never backed up with actual data.

Actually, I find it more remarkable that people doubt the veracity of my claim or others who make the same. I also heard a difference in moving from my Parasound P3 to my current Wyred4Sound STP-SE preamp. Subtle, but still there. Is my hearing somewhat more attuned to certain things? I don't know, but I do trust it. I would like to run some A-B matched testing in the near future.

I do wonder why the skeptics visit sites like this. It seems to me they could just buy some $100 tripath integrated amp and be done with it as everything sounds the same. Reminds me of Julian Hirsch from Audio magazine who kept testing equipment, but never heard a difference between them.