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As usual Tom...you'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.
>
>