It's sometimes defined as "Fast Slew-rate," as a function of transient 
response in op-amps.

"Soft" and "warm" to some ears might be labeled as "Slew-rate limited" to 

It all gets back to: "to hell with the specs; do I like the sound?"

Mark Durenberger
On the Road

-----Original Message----- 
From: Tom Fine
Sent: Wednesday, June 18, 2014 8:35 AM
To: [log in to unmask]
Subject: Re: [ARSCLIST] headroom

Nor do sharp drum hits. Between output transformers and power supply sag, 
plus speaker damping, many
tube systems sound "soft" and "cushy" to my ears. Not all of them (most 
McIntosh, for instance).
Some people prefer the "soft" and "warm" sound ("warm" to me translates to 
audible harmonic
distortion in harmonics that some find euphonic). I much prefer accurate, 
"fast" and "crisp," which
usually means solid-state throughout. I'm not saying that's impossible with 
tubes, but I am saying
that it's not typical, especially in vintage amps.

-- Tom Fine

----- Original Message ----- 
From: "Mark Durenberger Mobile" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, June 18, 2014 9:20 AM
Subject: Re: [ARSCLIST] headroom

> Hi Tom.  My guess is that those fast "spikes" probably wouldn't make it 
> intact through the output transformers...
> Mark Durenberger
> On the Road
> -----Original Message----- 
> From: Tom Fine
> Sent: Wednesday, June 18, 2014 7:35 AM
> To: [log in to unmask]
> Subject: Re: [ARSCLIST] headroom
> Hi Mark:
> I don't listen loud enough for this ever to have happened to me, but I 
> have no doubt that it's
> something that does happen in more raucous studio monitoring environments, 
> and perhaps some
> home-listening situations. Do you think a typical Williamson or 
> Ultralinear tube power amp would be
> less likely to blow the tweeter? I'm wondering if their rise and attack 
> times are too slow to bring
> the full impact of the pop or tick to fruition in the speaker-motor?
> One thing I wish John Atkinson would test and publish for all equipment he 
> puts on the Stereophile
> bench is pulse response. He does this for digital stuff, to look at jitter 
> and distortion. But he
> should be testing pulse power to clipping with power amps and pulse power 
> to cone breakup with
> speakers. Music, especially modern music, is full of percussives, if it's 
> not processed and
> toothpasted to the point of having no dynamics. A thing I've noticed with 
> the new high-resolution
> remasters of the first 3 Led Zep albums is how much headroom there is 
> between peak drum hits and
> other transients vs. average level. And they used plenty of dynamics 
> compression, more than typical
> for that era. Still, there is nearly 12dB difference between peak level 
> and average level in some
> songs, which is huge for rock music. Turn up the volume some and those 
> Bonzo drum hits really move
> the air.
> -- Tom Fine
> ----- Original Message ----- 
> From: "Mark Durenberger Mobile" <[log in to unmask]>
> To: <[log in to unmask]>
> Sent: Wednesday, June 18, 2014 7:49 AM
> Subject: Re: [ARSCLIST] headroom
>> As usual're spot on.  BUT don't forget that loudspeaker 
>> high-frequency drivers can be taken out by such steep-rise-time 
>> transients faithfully passed through a good amplifying system :-))
>> Mark Durenberger, CPBE
>> On the Road
>> -----Original Message----- 
>> From: Tom Fine
>> Sent: Wednesday, June 18, 2014 6:20 AM
>> To: [log in to unmask]
>> Subject: [ARSCLIST] headroom
>> Hi Paul:
>> This opens up a whole new area of discussion!
>> I have a phono playback system with a lot of headroom and am very 
>> surprised at just how loud tick
>> and pop transients can be (6-12dB above musical peaks in some bad cases). 
>> I definitely agree that
>> clipping distortion plus tick equals worse sound. I think many of the 
>> tube preamps don't clip
>> because tubes aren't as fast into clipping and then the tick goes by and 
>> all is swell again,
>> especially if there's enough power supply current so nothing sags. My 
>> father did tests on mic
>> preamps, and talked about it at one of his AES NYC Section sessions. He 
>> found out that almost all
>> solid-state designs could be driven into clipping with European condenser 
>> mics relatively close to
>> muted trumpets, drum strikes or hard-hit piano notes. In the midrange 
>> frequencies, this was very
>> audible and distracting. The tube preamps, with the same sensitivity 
>> specs, and usually
>> older-vintage input transformers, did not overload as easily and did not 
>> present annoying clip-pops.
>> Keep in mind, this was circa early 70s testing, but also keep in mind 
>> that those early 70s
>> solid-state consoles are coveted by some to this day. I think that later 
>> transformerless designs,
>> with good input sensitivity control (real low-noise attenuator networks, 
>> not just a feedback
>> adjustment on an input differential amp), mitigated a lot of these 
>> problems.
>> I'm not saying you need tubes for good fidelity, in fact I use almost no 
>> tube gear in my studio and
>> none in my living room listening system. I am saying that, if you go with 
>> a solid-state design, for
>> anything involving wild and woolly peaks -- like a phono preamp or a mic 
>> preamp -- you better design
>> in a lot of headroom, more than you ever expect to need. You also better 
>> design a rock-solid
>> over-spec'd power supply, in either tube or solid-state equipment. In 
>> tape electronics design, there
>> is a known limit to headroom (the saturation point of whatever tape 
>> you're using). This, for
>> instance, is why Beyer Peanut transformers work fine for Ampex AG-440 
>> playback electronics (when
>> operated within spec -- +9 operating level is not appropriate for any 
>> older machine) but not so good
>> for mic preamps (except for low-output ribbon mics in front of moderately 
>> loud sources). And with
>> digital you have a brick wall limit to dynamics -- the distance from 
>> wherever you start to digital
>> zero. But even there, new debates rage about headroom. See the design 
>> notes for the latest Benchmark
>> DAC2 units. They were purposely designed with 2dB above digital zero 
>> headroom, explained better than
>> I can attempt in their white papers and technical notes.
>> -- Tom Fine
>> ----- Original Message ----- 
>> From: "Paul Stamler" <[log in to unmask]>
>> To: <[log in to unmask]>
>> Sent: Wednesday, June 18, 2014 12:21 AM
>> Subject: Re: [ARSCLIST] Upgrading Audio Systems
>>> On 6/17/2014 12:53 PM, Miller, Larry S wrote:
>>>> Regarding your reluctance to upgrade your system to the point where
>>>> you can't stand to listen to your favorite recordings, I completely
>>>> sympathize.
>>> Funny, I'm just getting ready to address that question in an article I'm 
>>> working on (about a phono preamp design that's been percolating for 
>>> several years). My suspicion is that the electronic gear that "makes 
>>> pristine records sound better but makes imperfect records sound worse" 
>>> is not, as is often asserted, "revealing more accurately just how bad 
>>> these records really are". I suspect, instead, that imperfect records 
>>> sometimes, through their imperfections (scratches, wear, etc.) stimulate 
>>> misbehavior in the electronics which then causes us to hear the records 
>>> as sounding worse.
>>> Back in the 1970s, when tube equipment was beginning to reappear in the 
>>> home-audio world, a lot of people reported that certain tube preamps 
>>> seemed to emphasize scratches less than their solid-state brethren -- I 
>>> heard this a few times myself. A well-done article in, I think, JAES, 
>>> pointed out that the tubed preamps in question all had significantly 
>>> more headroom than solid-state preamps of the time, and suggested that 
>>> this might explain the lesser audibility of scratches. That sounded 
>>> reasonable to me, and my own experiments (written up in audioXpress) 
>>> suggest that the worst scratches on LPs and 78s may be as much as 26dB 
>>> higher than the 5cm/sec considered "nominal level" in disc cutting. I 
>>> designed the preamp with that kind of headroom in mind, and its various 
>>> incarnations so far have sounded very good.
>>> I hope to submit the article for publication within the next six months. 
>>> The design actually comes in two flavors -- one intended exclusively for 
>>> RIAA discs, and one with adjustable compensation (mostly for 78s).
>>> Peace,
>>> Paul
>>>   One reason I'm so fond of the Stanton 881-S cartridge is
>>>> that it seems to make recordings sound good without getting to the
>>>> point, as do some moving coils, that mediocre recordings sound
>>>> unpleasant.  I often wonder why this cartridge isn't used in
>>>> transcribing 78s since it was available with an off the shelf 2.7 mil
>>>> stylus and, to my ear, sounds much better than the commonly used
>>>> Stanton 500. But getting back to upgrading, I'll offer an alternate
>>>> view.  I'm not one who frequently upgrades my system, but when I do,
>>>> that is, when I hear some piece of equipment that makes some of my
>>>> favorite recordings sound better, then acquire it, I'm essentially
>>>> rewarded with a new record collection, sometimes hearing things I
>>>> never heard before.  That's why I upgrade.