Contents - The Colorado Audio Society

Contents

A Visit to Weinhart Design

Dean Peer—Live in Concert

Tube Be …. Or Not …. Tube Be?

Extending the Life of You and Your Electronics

Class D: The MP-3 of Amplifiers?

CDs Not to Take to An Audio Show
Copyright © 2010, Colorado Audio Society—All Rights Reserved
A Visit to Weinhart Design
Brian Boehler
In the middle of July, my wife and I spent a
week in California on vacation. We traveled from San Diego to Santa Barbara with
a stop in Los Angeles to visit Dave
Weinhart. I had met Dave at the Rocky
Mountain Audio Fest a few years ago and
always thought it would be interesting to
visit his showroom. I talked my wife into
taking a few hours on our way to Santa
Barbara to pay him a visit.
Dave and I conversed while he rushed to
move a large shipment of PS Audio equipment around so they didn’t interfere with
the listening experience. We sat down and
listened to a system consisting of Magico
M-5 speakers, Clearaudio Statement turntable, Bryston 28B amplifiers, EAR 912 preamplifier, and Running Springs power conditioning. Digital audio was provided by
computer with either the PS Audio PWD or
Stahl Tek DAC. The system was very dyWho is Dave Weinhart you ask? Dave
namic, controlled, and relaxed in a very
founded Ambrosia AV and had three stores positive way. On another wall there was
and about 28 people working for him. Due an assortment of Dali speakers, Meridian
to the changes in our industry and uncer- electronics/speakers, and varied other
tain financial times, his singular store now components. The room dimensions are
is Weinhart Design with a new emphasis. about 27 feet by 32 feet, give or take a few
He has been around long enough to see
feet. The ceiling height is about 12 to 14
the shift in our industry from two channel feet high and provided a large space to fill.
audio to home theatre and now to home Trust me, filling the space with sound was
automation. Dave loves high-end twovery easy with large speakers and 1,000
channel audio but offers a full range of ser- watts of power.
vices including automation, surveillance,
distributed audio/video, lighting control,
What I enjoyed the most was the fact that
media room design and build, home thea- we concentrated on the music and not the
tre, and high-end audio systems. On my
sound of the equipment. Dave engaged us
visit, Dave had just recently returned from by having us try to guess each artist and
a short vacation only to encounter some
song. He had picked various tunes that
plumbing problems and still he was grashowcased the system and different ascious in letting me visit in spite of the short pects of the sound but our focus was on
notice and bad circumstances.
enjoying the music and identifying the art2
ist, album, and song. This approach emphasized an enjoyment of the music without emphasizing the “sound” of the equipment. The truth of the matter was that
the “sound” of the equipment enhanced
the music which is exactly what you want
to achieve in an audition. How often do
you go to a showroom and they tell you
what you should hear? Do you feel like
they are treating you like an imbecile?
Dave emphasized the love of the music
and the equipment only as a means to
achieve the music. What a great concept
for a salesman in an audio store.
The sound was truly outstanding. It was
loud and dynamic with great PRAT as well
as totally relaxed and real sounding. The
musical selections drew you in and made
you want to hear more. I came away with
a sense that he demos this way due to his
love of music and his desire for visitors to
have an enjoyable experience. He isn’t
about the equipment of the month club
but about good solid value from respected
companies. His 30 years of experience
makes him somebody who can be trusted
to offer “real world” advice backed by
hands on experience.
Dean Peer—Live in Concert
Brian Boehler
Have you ever heard of or listened to music by Dean Peer? Did you know that he is
an amazing bass player with special talents
and techniques? Did you know he lived in
Boulder in the late 1980’s? No… well, then
let me give you a little background on the
man and his unique playing style.
album in worldwide distribution. This album showcases his ability to move all over
the map with technique, style, and genre.
Bass Player magazine called UCROSS an
“extravaganza of ringing notes, chords, and
clusters”, rating the bass performance an
“A”. Dean named the album after a visit to
the Ucross Dude Ranch in Clearmont,
You might ask, what style of music does
Wyoming. Many of the tunes on this alDean play? Fusion jazz, bluesy folk, funk, bum were auditory pictures, musical imstraight jazz, rock, new age, or progrespressions, and sonic vistas of the people
sive? Well, yes, all of that and more!
and experiences he shared during his time
Dean’s music defies easy classification. He at the ranch.
plays in all of these genres and others as
well. One person stated, “If Jimi Hendrix
His 1994 album, Travelogue, was called
had played bass, he might have sounded
“one of the best records of the year” by
like Dean Peer”. Dean Peer is an interna- Jazz Times, and features contributions on
tionally acclaimed solo bass artist and is
saxophones by Paul McCandless. This alwidely recognized as “the” authority in the bum has the feel of more normal jazz with
use of bass harmonics. He uses slapping
a few unique twists to keep it fun and
and chord voicings by means of his relively. Stereophile magazine wrote of
markable techniques for false and dual
Peer’s third release, Think… It’s All Good,
node (stopped and open note) harmonics. “On first listen you want more, and the
His signature motivation is to not be com- more you turn up the volume, the more
pared with other bassists like Stanley
there is to hear.”
Clarke, Jimmy Haslip, or Jaco. He utilizes
these numerous techniques in many differ- Take a tabla player, a violinist, a wind inent genres of music.
strumentalist and a talented bass player.
Bring them together at night in a church in
His first album UCROSS, released in 1991, Holland. Schlep in some Neumann and
was the first completely solo electric bass Sonodore mikes, a hand-built mixing con-
3
sole and dCS converters, a Mark Levinson
334, and a pair of Avalon Eidolon speakers
and just let it all happen. That's what
forms the base of bassist Dean Peer's
Think... It's All Good CD - some friends
jamming in a church recorded straight to
disc. Only a selection of the actual material
was transferred to CD. No dubs, editing or
any other type of manipulation. This way
of working captures the moment as it was.
Mistakes, background noises? It's all
there, but not in any annoying way. Dean
Peer is an innovative bass player who produces unusual and unknown sounds from
his bass guitar. The addition of tabla and
other percussion instruments plus such
rarities as ocarina and water bottle make
the palette of sounds very rich. The purist
recording techniques without any mixing
and the minimalist miking techniques produce a highly dynamic sound that sounds
great on a good stereo system.
You may wonder why I wrote this article
and what it has to do with CAS. Dean has
hooked up with some of the high-end fathers due to his unique approach to music
and his focus on good sound. George Cardas has supplied Dean with his cables and
sponsored some of his concerts. Some of
Peers’ albums have been remastered by
Dean Peer—Live in Concert
Brian Boehler
XLO and even our local Avalon Acoustics
has helped sponsor some of Peers’ recordings including his latest, AIRBORNE.
Check out Dean Peer’s press conference at
the 2010 CES, http://vimeo.com/8678155.
AIRBORNE, is a bass and drum duet featuring Bret Mann on percussion. It was released in 2010 on ILS Records, in association with Cardas Audio. Avguide.com reviewed AIRBORNE, calling Dean “a remarkable solo artist on his
chosen instrument, with
a dazzling array of playing techniques at his disposal. . . seemingly limitless chops, and—most
importantly—a wealth of
inventive musical ideas
to express.”
and devices, Peer turned his bass into an
entire sonic environment that worked
hand in hand with Bret Mann.
I believe that our primary love of this
hobby is the music and secondarily the
equipment we buy to reproduce the music. Dean Peer is an artist that defies easy
classification and opens a window on
unique playing styles and stretching the
boundaries of the bass instrument as we
commonly think of it. I would recommend
that you give it a listen and see if his
unique style of playing harmonics on the
I recently had the oppor- bass speaks to you. This isn’t your stantunity to attend a condard record company recipe but an indecert in Boulder with CAS pendent musician who has tried to capture
member Dave Slattery.
something truly unique in style and apWe went to see Dean
proach.
Peer play selections from
his recently released recording Airborne. The
concert was at Immersive Studio’s and the setting was intimate. Less
than 10 feet from the
stage and less than 100
people made it very upclose and personal. Using a vast array of pedals
4
Tube-Be …... or Not …...Tube-Be
Brian Boehler
Thanks to some members of the Colorado
Audio Society, I have recently embarked on
a journey to explore the sound of tube
electronics compared to solid state. I
don’t intent to use words that are inflammatory or encourage a heated debate, I
just wanted to take an honest look at the
pros and cons of each technology and calibrate my personal reaction to both the
sound quality and the aesthetic/ethos of
the technology at this point in time.
It has been interesting how the topic of
tube versus solid state can really raise the
hackles of most audiophiles. I have a different approach to this topic. My take has
always been that it is the result that matters to me and not the method used to
achieve the end result. Tube versus solid
state, who cares? As long as the final musical experience satisfies and inspires my
imagination, I’m pretty happy. I’ve always
believed that both are capable of great
sound but in different ways. For example,
if you are really into 32 Hz organ notes and
flapping your pant legs then solid state has
the edge. Tube electronics can accomplish
the same thing but in a different way.
There isn’t as much control and brute
force. Some would say that solid state
doesn’t sound like the real thing because it
is too strong and controlled. Conversely,
some would say that tubes are too lose
and flabby and that this isn’t real either.
Who is right? I don’t know or care since I
don’t believe there is an “absolute sound”
for this type of situation. It depends on
how you have been exposed to music,
your hearing, and your ability to suspend
disbelief associated with the recreation of
music in a two channel system.
It really depends on the type of music you
listen to and whether it is amplified music
or un-amplified music. Hard driving rock
music is almost exclusively amplified. Solid
state electronics can mimic this sound and
provide that sense of slam, speed, loudness, and dynamics. On the other hand,
un-amplified music such as a small ensemble in the right size room can provide a
sense of pace, rhythm, and acoustic holography through tubes that is very hard for
solid state to achieve. Different styles of
music lend themselves to different types
of equipment to complement the sonic
landscape. At least this is my opinion and
how I view the situation. Neither technology has proven to be all things to all people.
Aesthetics/looks are an important aspect
5
to many people. The pride of ownership
has much to do with how some people react to a product. I have also come to conclude that some audiophiles appreciate
the engineering and aesthetic aspect as
much as the sound quality. This isn’t right
or wrong, it just is! Truthfully, I don’t
really look at the equipment when I’m listening, only when it is sitting there with
the lights on and my eyes open. Whether
it glows some pretty color or gleams from
the room light shining off the fancy metal
work, it really doesn’t make a difference to
me.
In very simple terms, I have always
thought of tubes as sexy but…………………
they produce heat, they required more
maintenance, more adjustments, and ultimately they change sound due to age and
wear on the tubes. Most of these are
practical considerations and really have
little to do with the sound. In my mind, I
have to admit that I’m lazy and the
thought of a picky piece of tube gear that I
have to constantly adjust and tweak has
never excited me. Obviously, this is somewhat overstated since some tube equipment requires no more maintenance than
solid state gear. I’m overstating the examples to make a point.
Tube-Be …... or Not …… Tube-Be
Brian Boehler
In comparison, solid state gear can look
very good and has even been referred to
as jewel like quality. But…………they just
don’t look as sexy as a glowing tube in a
dark room. They both look good but in
very different ways. It really is personal
preference with no clear winner. If I had to
choose for myself, I would say that tube
gear properly displaying and showcasing a
tube is ultimately better looking. A monster machined solid state amp in a big
metal box with a beautiful well done faceplate can have the “look” but you don’t
showcase an IC or capacitor. In my book
the winner is tubes. But guess what, I care
more about the sound than the look so
this isn’t very important to me.
nent in an amplifier. If I’m really honest, I
can land on either side of the ledger with
either argument. Both have positives,
both have negatives, and neither is truly
superior, just different.
to take this approach to relate the sound
of the electronics. For instance, you might
take a tube amplifier and based on the
checklist say the bass is weak compared to
solid state. If instead you describe the
overall sound you might say the bass was
In the next newsletter I’ll spend some time good and in proper perspective to the rest
on my listening impressions between the of the music. Lacking in one respect but
two technologies. Let me pose a couple of based off of another perspective, just fine.
questions to pique your curiosity! If you
were a reviewer, how would you describe Have you ever heard the expression that
the sound of the equipment in question? you “see the cup as half full or half
Would you break down the various aspects empty”? I think this might apply to how
of the sound such as:
we perceive the sound between solid state
bass, mid-bass, midrange, mid-treble,
and tube. From a solid state perspective
treble, extreme top end, depth, width,
they see tubes as half empty and solid
height, air, soundstage, PRAT, continuity, 3 state electronics as half full. Obviously,
dimensional holography, and on and on,
just the opposite from a tube perspective.
To be fair, solid state has many issues that etc.
The reality is that they both started in the
are also a drawback. A solid state amplisame place but proceed from a different
fier biased into class A can also run very
In other words, do you believe breaking
perspective. Neither is right or wrong but
hot and sometimes hotter than tubes.
down the sound into a checklist will help
both have strong convictions from their
Most solid state amps can’t be adjusted by people understand how the electronics
perspective.
the end user to sound different. You can
sound and how you respond to the music
roll tubes and emphasize different aspects based on this approach? Obviously this is Next time I’ll share some of what I heard
of the sound. With solid state, you get
a valid approach since thousands of reand how I responded to the sound of the
what you get. While we always think of
views have been written this way. The
different electronics in my system. Persontubes wearing out and failing, so do solid other way would be to not describe the
ally, I don’t want either cup half full or half
state electronics. Heat generated by the
sound as individual parts based on a
empty but full to the point of overflowing.
amplifier can degrade solid state compochecklist but to discuss the overall gestalt That would be something special and
nents and eventually change the sound
of the sound and how you respond based probably more expensive than I can afford.
and ultimately fail. You can pop a new
on the whole versus the individual parts.
tube in but it isn’t so easy to fix a compo- I have often found tube versus solid state
6
Extending the Life of You and Your Electronics
Dave Klink
Imagine for a minute that it's the summer of 1959. You have just completed your sophomore year of high school. It's a warm
spring day, and you have decided to hang out in a small mid-western city. While walking by a furniture store you notice a sign in the
window that reads "Please visit our hi-fi parlor upstairs at the front of our store." You have read something about this thing called
"Hi-Fi" so you go in to investigate. What you hear changes your life forever. It's magical! The music is so real, so clear, so right. It
sounds nothing like the Elvis Presley you hear from the AM radio in the car or that pink 5-tube AC/DC radio in the kitchen. You are
listening to a Garrard turntable and a McIntosh amplifier driving Bozak speakers. That image is burned in your mind and heart for
life.
You know immediately you have to pursue hi-fi. But there is a big problem. Even though your family loves music, there is no way
they can afford a hi-fi system of this caliber. Having built your first crystal set a couple years ago you have been learning electronics
at a basement workbench that your dad helped you build. So you dig out your back issues of Popular Electronics and a life long
hobby of DIY audio begins.
Many of us older folks have similar stories to tell. Over the years I've always had an electronics workbench at home, although its
use varied from decade to decade. The love for that vintage golden era electronic equipment has never wavered. Now that I've retired from working for various corporations, I'm back to enjoying that hobby with as much vigor as I can muster. I've picked up quite
a few tips and tricks through the years, both professionally and at those home
benches, so it's time to give back to this hobby I love by taking this opportunity to
pass along a little of what I've learned .
Improving The Safety of Vintage Equipment
Let's start with a safety tip. I now have a H.H. Scott model 345 tube receiver on my
bench (Photo 1). Figure 1 is a partial schematic of its power supply, including the
primary side of the power transformer. Boring right? But it can also be deadly.
Take a look at that fuse. The bayonet style fuse holder (Figure 2) is assessable to the
user at the back of the receiver. The original line cord plug is not polarized. If the
user forgets to unplug the unit, or assumes it's safe if the power switch is “OFF”, and
the bottom wire of the line cord (reference the schematic) happens to be plugged
into the hot side of the power line, a bad shock can occur while the user is removing
the fuse.
7
Extending the Life of You and Your Electronics
Dave Klink
You might say "Not so" because the fuse is
removed from the circuit when the cap is
unscrewed from its holder. But the front
fuse contact of the holder is connected to
the power transformer (I checked), and as
you pull the fuse out of the holder the
back of the fuse is dragged across the front
contact. Your finger is holding the cap
with the fuse in it, and that finger can and
often does touch the cap fuse contact as
you drag the cap with the fuse out of the
holder. Bad news; an electrical path exists
from the hot side of the wall power,
through the primary of the power transformer, to the front contact of the fuse
holder, through the fuse (assuming it's not
blown), to your finger, and then through
you to ground!
Be safe. When restoring a piece of older
equipment, the first thing you should do is
replace that non-polarized wall plug with a
polarized one. Make sure the wider blade
is connected to the non-switched (neutral)
side of the unit's
power cord. On the
Scott 345's schematic note the 820K
ohms resistor that
goes from the power
line to ground. Attach the wide blade
of the plug to that
side. As a final
safety check, measure the resistance to
ground and, if it's
lower than 820K, be
suspect of the .01uf
capacitor that is attached from the
power line to
ground.
The same advice
holds if you are
building a new piece
8
Extending the Life of You and Your Electronics
Dave Klink
of equipment. Also consider using a 3wire line cord with the green wire attached
to chassis ground. I always use a DPST
power ON/OFF switch so that both sides of
the power line are disconnected when the
power switch is in the “OFF” position
(some foreign safety agencies require the
use of DPST ON/OFF switches under these
conditions).
As a side benefit, these inexpensive techniques can extend the life of other components in your electronics, particularly
power switches and power-supply electrolytic capacitors.
Inrush Current Limiters
Placing a "NTC Inrush Current Limiter" in
series with the primary side of the power
transformer provides many benefits. I
keep on hand a couple each of the part
numbers GE CL30 through CL90
(www.gesensing.com/downloads/
datasheets/920_325a.pdf ). These cover 2
to 8 amp applications. As usual, the data
sheet provides lots of puzzling equations
and tables for you to try to decipher, but
don't let that scare you away from using
them.
1.32A - not a bad guess). The part number
that comes closest to that current without
going under it is the CL90 at 2 Amps. I
temporarily installed a CL90 in the unit,
and reassuringly watched as the filaments
lit up slowly without that initial flash of
bright red light. I ultimately settled on a
CL70 for this application. I'll go through a
process of measurements and calculations
for us to get a feel for how these devices
work. But after reading the next few paragraphs all you'll need to do is take a look at
Table 1 and select a device for your application.
Returning to the CL90 that we left temporarily installed in the Scott 345, after the
CL90 was allowed to heat up to its final
temperature, I measured the voltage
across the device (2.95V RMS), the current
through it (1.24A RMS) and then calcuIt's difficult to choose a part that will not
lated its resistance to be 2.38 Ohms. The
do some good, as long as you don't exceed drop in measured current draw from 1.32A
its maximum rating. Estimate the current to 1.24A is caused by the resistance and
that your amp (or whatever) draws from
reactance of the CL90 itself in association
the
power
line.
For
the
Scott
345,
the
Extending the Life of Your Electronics
with the power transformer. Looking at
schematic says it uses 150-230W. There
Table 1, 1.24A turns out to be about 62%
Vacuum tubes are expensive and are get- are two accessory plugs, so assume the
of the device's maximum allowable curting more so every day. There are a couple receiver itself is drawing 150W. At 117V,
rent draw of 2A, and falls between a 50%
inexpensive ways to extend their lives in
that works out to be about 1.3A (an actual value of 3.04 Ohms and the 75% value of
both vintage equipment and new designs. measurement with a HP3478A DVM was
1.75 Ohms. So our value of 2.38 Ohms ap9
Extending the Life of You and Your Electronics
Dave Klink
pears to be within reason.
only .4 Ohms? Well, its cold resistance is
As with all components, these inrush deonly 2.5 Ohms, and the Scott's power
The spec sheet gives a maximum tempera- vices have their downside, and a little en- transformer DC resistance is 1.5 Ohms, so
ture rating for all the CL family of 347°F
gineering judgment and trade-off comes
the CL30 would not provide much addi(175°C). Using a Raytek IR temperature
into play. While making my measuretional inrush protection. For this reason I
meter, the CL90 is measuring around 305° ments, the CL90 was operating with the
considered only four devices, CL60
F. This is higher than a 62% value should
bottom of the Scott 345's chassis removed. through CL90, with the results shown in
read, and brings into play all those derat- I cannot use my IR temp meter with the
Table 2.
ing formulas in the spec sheet. The device chassis closed up, so chances are the
itself raises the temperature of the air
CL90's temp will climb even higher with
This Scott receiver uses solid-state rectifiaround it, which raises the temperature of less free air around it. Permanently
ers, which brings up the issue of cathode
the limiter, and so on. All of this is demounted inside the chassis, other nearby stripping. I roughly measured the time it
pendent on the environment in which the components will "feel" its heat. Another
takes the high voltage power supply to go
limiter is operating. You want to place the downside is the additional resistance it
from zero to 400V DC on its way to a final
device where it has some air around it, but adds to your power supply. This can theo- value of 445V DC. With no inrush-device it
not in a draft from fans or otherwise.
retically affect the supply’s dynamic perwas ~20 milliseconds, surprisingly just over
formance, alone cycle at 60 Hz. With a CL70 it was 200
though
realistimilliseconds, the CL80 was 1.6 seconds,
GE Inrush Current Limiters
cally in this case
and the CL90 was about 2 seconds. The
Ohms
Amps
Ohms at % Amps
the effect will be negative bias voltage supply was also proP/N
(cold)
(max)
25%
50%
75%
100%
very small.
portionally delayed. So fortunately, and
CL30
2.5
8
0.34
0.14
0.09
0.06
not unexpectedly, slowing down the heatCL40
5
6
0.65
0.27
0.16
0.11
So why not use a ing of the filaments is also accompanied by
CL30 which has an a delay in the other voltages applied to the
CL50
7
5
0.96
0.40
0.24
0.16
8A rating and,
tube.
CL60
10
5
1.09
0.44
0.26
0.18
with a current
CL70
16
4
1.55
0.65
0.39
0.27
draw of only 16%
CL80
47
3
2.94
1.20
0.17
0.49
of its max rating, In the end, I chose to use a CL70 which is
CL90
120
2
7.80
3.04
1.75
1.18
will have a lower rated at 4A maximum. At 1/3 of its rated
current its long term ON resistance is 1.4
operating (hot)
Table 1
Ohms and its turn-on resistance is 16
resistance of
10
Extending the Life of You and Your Electronics
Dave Klink
Ohms. If you want a little more inrush protection, the CL80 has 47 Ohms at turn-on
and settles into a long term resistance of
about 1.8 Ohms, but will run a little
warmer. If you want less long-term operating resistance, the CL60 gives an initial
inrush protection of 10 Ohms with 1.2
Ohms when hot.
when the power line voltages were generally lower than they are today, expecting
117V AC rather than the 120VAC or more
currently provided. That little extra voltage drop across the inrush limiter (1.8V in
If for some reason you really need to fine the case of the CL70) in series with the
tune your design, in addition to the seven power transformer helps by absorbing
CL30 - CL90 devices, GE offers eleven addi- some of that excess voltage.
tional part numbers from CL110 - CL210
Summarizing how to select a CLxx inrush
with fractional current ratings from 1.1A to By the way, most of this information aplimiter; start by choosing one that's rated 4.7A and initial ON resistances from 5
plies to your solid-state designs too. Those
for about twice the current your box draws Ohms to 50 Ohms. Both DigiKey and
huge electrolytic caps in their power sup(in the case of the Scott 345, a CL80).
Mouser stock the parts.
plies last longer if you limit their turn-on
Then if you want more inrush protection,
currents. An inrush limiter also prevents
select the next higher numbered device
Vintage equipment was designed at a time contact arcing in power-ON/OFF switches.
In general, most electronic equipment
Inrush Limiters Measured & Calculated Results (hot, static)
benefits from a gentler turn-on.
No NTC
I rms
1.32A
(CL90). Be sure its current or thermo ratings will not be exceeded. If you want less
heat or lower final resistance move down
one numbered device (CL70).
For HH Scott 345
CL60
CL70
CL80
CL90
1.31A
1.30A
1.27A
1.24A
26%
32%
42%
62%
V rms
1.58v
1.80v
2.35v
2.95v
R (calc)
1.20Ω
1.38Ω
1.85Ω
2.38Ω
P (calc)
2.01w
2.34w
2.98w
3.66w
200º
225º
265º
305º
80ms
200ms
1.6s
2.0s
% Max Amps
Temp Fº
HV rise time
20ms
Table 2
11
Three More Random Tips
First. Refrain from hot-swapping tubes.
There is no way to tell which order the
tube's pins are going to get inserted or disconnected from its socket, or vibrated in
and out of the circuit. Turn the power OFF
and let the power supplies bleed down for
a minute before plugging in or removing a
tube. Plugging in a tube with the power
already applied defeats the purpose of any
Extending the Life of You and Your Electronics
Dave Klink
inrush protection or cathode stripping prevention circuits you may have installed. I
had a tube arc on me once while I was
plugging it in with the power ON; be assured it will convince you to adopt this tip
when it happens to you! And don't take a
chance on burning your fingers.
Second. I do not add surge protectors either to vintage equipment or new designs.
I had one explode and catch fire, so I'm a
little shell shocked by them. I don't want a
bomb like that inside one of my boxes!
My advice on surge protection is to buy a
surge protected power strip, or go first
class and buy one of Paul McGowan's PS
There are times when I'm trouble-shooting Audio power boxes which has surge proa piece of electronics when I will remove a tection built in.
tube (with the power OFF) and then turn
power ON to make some measurements. I And third. If you have tubes with DC on
study the circuit first to understand what their filaments, it's considered a good idea
consequences to expect, and am careful to to switch the direction of the current
avoid any secondary problems that could through those tubes periodically. A DPDT
cause permanent damage to other compo- switch on the front panel (or a 4PDT cennents. But I never plug the tube back in
ter-OFF switch, which can incorporate the
without first turning the power OFF.
power-ON function) serves the purpose.
12
But, how do you know which way to throw
the switch; or stated another way, how
long has the switch been in one direction
or the other? Short of designing some
fancy hour counting circuit, here is a clever
idea. Label the switch ODD MO and EVEN
MO. If it's an odd month of the year,
throw the switch to ODD. Throw it to
EVEN for an even month of the year. Hey,
I didn't claim it was high tech.
None of this is very exotic nor will it directly improve the sound of your equipment. My hope is that this information
may help both you and your equipment
last longer.
Class D: The MP-3 of Amplifiers?
Art Tedeschi
Excerpted from an auto magazine of a
Mazda RX-7 road test, ca. 1980:
eration as I ran through the gears sounded
unlike any other in my experience.” Negative comments continued to cast a shadow
“… The Wankel-powered RX-7 is, overall, a over this new technology, even when the
fine machine and fun to drive, but the un- great majority of owners were befuddled
tested rotary engine could make this auto- in their inability to replicate the testers’
mobile a risky buy, considering the fact
curious results. Readers’ comments to
that we have no history of its reliability
these reviews also began to take a
over time. An anomaly noted by our test guarded tone regarding the performance
driver was the strange nature of the car’s of the engine, mostly from those with limacceleration pattern as he shifted through ited or no direct experience with the car,
the gears. Its acceleration characteristics and rarely from actual owners.
seemed unusual compared to all piston
engine cars tested in the past – the RX-7’s A few small manufacturers emerged to
acceleration pattern was more linear and take advantage of the new engine but utilsmooth compared to the others. This
ized conventional or poorly-conceived anunique behavior left our driver with some cillary parts to support the technology.
doubts, even when learning that test
The poor performance of these models
measurements of the car indicated no
continued to cloud the reputation of the
problems, and even when thousands of
engine even when the engine itself was
satisfied and enthusiastic RX7 owners
blameless in these implementations.
judged the acceleration response to be a Mazda continued to improve the Wankel,
positive attribute of the Wankel.”
increasing horsepower and torque, but did
not dare to venture beyond the RX-7, itself
Not long after the above fictional article
relegated to the ranks of a curiosity of the
hit the streets, the glow of initial exciteproduction car industry. And so the RX-7
ment created by the new, revolutionary
became the RX-8, and continues to be the
engine had begun to fade. Subsequent
lone product of the auto industry sporting
road test reports of the car echoed the
the fabled Wankel engine.
concerns of the above reviewer and elicited comments such as, “… the car’s accel- The above story can be applied to various
13
audio products developed over the years
that had eventually earned the “exotic”
label. The example that comes to mind is
the strain gauge phono cartridge. Weathers was the first manufacturer to develop
the strain gauge technology, followed by
Panasonic/Technics who designed a strain
gauge to support its emerging quadraphonic CD-4 technology of the early 70’s.
Well, we all remember the history of the
“quad” revolution – it failed miserably.
And so this cartridge system was itself
relegated to tiny specialty manufacturers
and experimenters who continued to explore and refine the technology. Sao Win
ventured out and developed another
strain gauge cartridge in the 80’s, itself a
flawed design with a nasty spike in the 10
kHz range that was difficult to ameliorate.
Still, the Win as well as other systems
based on the old Technics cartridge held
great promise. The technology benefited
by the elimination of most problems associated with magnetic cartridges (tiny voltages, magnetic anomalies, etc) that today
still continues to afflict the mainstream of
vinyl reproduction. Indeed, a few members of the Colorado Audio Society continue to utilize strain gauge cartridges in
our analog rigs. While not a perfect device, we “throwbacks” have adored our
Class D: The MP-3 of Amplifiers?
Art Tedeschi
phono playback systems featuring several
modified versions of the Technics cartridge, typically driven by 25-year old Jeff
Rowland strain gauge electronics. In recent years, Soundsmith has ventured forth
with its own strain gauge system, though
at multi-kilobuck prices. Sadly, this technology failed to gain traction among
manufacturers and was eventually relegated, like the Wankel engine, to the
“exotic” or “specialty” category, gaining
little to no respect from the mainstream
high-end press or its reviewers. Ultimately, the promise of this technology
may have revolutionized vinyl playback
and provided vinyl lovers with an efficient,
inexpensive and, in my opinion, sonically
superior transducer.
had to be continuously replenished).
provide for powerful, inexpensive, efficient, and physically compact solutions for
Along with these examples are products
applications where these virtues are highly
that simply failed to ascend to the mainbeneficial. The same can be said of MP-3
stream, decidedly due to the lack of an
music files: efficient, inexpensive, and acenthusiastic press and its inability, for
ceptable to all but the tiny cadre of highwhatever reason, to foresee their ultimate performance audio enthusiasts. I can
potential and contribution to our pursuit state with certainty that every single
of audio excellence. Class D amplifiers
owner of Class D amplifiers in my acnow appear to be traveling down this long quaintance has summarily disagreed with
and disappointing road of undeserved,
this criticism.
damning-with-faint-praise criticism. Here
we have a technology that sports cheap
So, is Class D the sonic equivalent of mid-fi
watts per dollar, diminutive size and
MP-3? I think not.
weight, cool operating temperatures, and
they are GREEN (hmm, I wonder if these
Greg Graff comments:
amps qualify for energy-saving tax credits.)
With Class D, the anomalous RX-7 accelArt has given me the opportunity to add
eration pattern relates to Class D’s rean addendum to his thought piece about
The history of high-end audio is littered
ported lack of (or strangeness, of late) high Class D amps. By way of background, I
with one-hit wonder products in virtually frequency response plaguing all products was a (mediocre) musician for a number of
all component categories: The Hill Plasma- spawned from this technology. This reyears, playing both the double and electric
tronics tweeter, the Beveridge acoustic
porting certainly provides comfort for
bass in a number of groups which played
lens-based electrostatic loudspeaker, wa- those owning pricey tube-based or cona variety of music. During that time I beter-cooled class A amplifiers, the Dayton- ventional solid state amplifier owners, but gan to understand what musicianship was
Wright gas-filled electrostatic speaker, the does little to advance acceptance of a
(even if I wasn’t very good). It is subtle,
Stax capacitor phono cartridge, etc. Most product that could eventually revolution- but when you hear a true musician versus
of these technologies were eventually dis- ize the high-end amplifier market. Not
someone just playing an instrument, you
carded by the industry due to design or
insignificant is the trend for manufacturers know the difference. It’s the personalizaproduction difficulties (for example, the
embracing Class D to power their non-high tion of the music by the musician to exDayton-Wright leaked insulating gas that end products such as car amps, etc; they
press his/her feelings or their interpreta14
Class D: The MP-3 of Amplifiers?
Art Tedeschi
tion of what the composer was after.
Some people try to define musicianship as
pacing, rhythm, inflection, bending, etc.
While those may be some of the tools, it’s
how the artist uses those tools to convey
the desired feeling. All of us can put paint
to canvas; not many of us can be Renoir.
window into what the musician is trying to speakers for another Lee M design using a
express, but the “better” the system the
completely different tweeter. On a lark, I
easier it is to feel the emotion(s).
borrowed the Class D amps again and all
of a sudden my new system went to an
I have been in the hobby for more years
entirely new level of musicality and resoluthan I care to think about (have I really
tion. The Class D amp was a fabulous
gotten that old?). I have had a number of match for the speakers- extremely revealamps in my various systems- everything
ing while also being very musical. At no
I digressed from the subject, but I wanted from single ended triodes to Class D amps. time did I feel the Class D amps did somethe readers to know my personal listening Each had their own “sound”; some worked thing “funny” in the top end. They may
bias - can I get the feeling that the musiwell with my system at the time, other’s
have been too revealing with my old
cian is trying to convey? If I can, I am
didn’t. When I first listened to Class D in
speakers, but that was not the fault of the
happy; if I can’t, its time to change some- my system of the time, I wasn’t really
amp; it was caused by my voicing of the
thing in the system. It does not take big
taken with the sound. I had voiced my
speakers. Over the past two months I
megabuck systems to provide at least a
speakers with a very good Class A/B amp have had three “tube heads” over to hear
that had a tube-like sound.
the system (we are working on assaulting
The Class D amp did not mate the state of the art in computer music).
well with the tweeters in the Each one of them said they couldn’t besystem- it was a little too relieve they were listening to
vealing and lacked some
Class D amps after all they had read about
warmth I was used to. To put their “faults”. To a person, no one hearing
it bluntly, the Class D was too my system has thought there was someaggressive in the top end and I thing “strange” about the top end of the
lost a lot of the musicality I
system.
had in the system. Several
years later, I traded out those
15
CDs Not to Take to An Audio Show
Art Tedeschi
With RMAF 2010 just around the corner, I have begun to contemplate which of my CDs I would take to the show. Over the years,
I’ve observed that most visitors to exhibitor rooms offered up either the typical audiophile favorites or mainstream jazz or pop music, none of which could possibly embarrass the visitor by displaying their taste for obscure, strange, unconventional, or “cheesey”
music. So since the following disks will NOT be accompanying me to Audio Fest, I’m offering them up as some favorites, with
mostly excellent sonics, musically satisfying, and for me, guilty pleasures.
Vienna Teng
Waking Hour
Warm Strangers
Dreaming Through the Noise
Inland Territory
Vienna Teng (John Francis tells me this is pronounced “Tong” in Chinese) is an Asian-American singer-songwriter and classicallytrained pianist. Vienna’s first album, “Waking Hour” is easily the best of the lot. This is one of those rare CDs where each and
every cut contains a bit of musical genius. Vienna’s songs speak of tried and true stories typical of singer-songwriters: lovers,
friends, and the angst of heartbreak, but her intelligent lyricism and creative melodies transcend the typical. Here we have a talent
of the highest order, and to this day I fail to understand why she hasn’t evolved to the mainstream (maybe because the mainstream promotes the mediocre?). Highly recommended. Out of 5 stars: Performance: 5, Sonics: 4.
The Strawbs
Live at the BBC Vol 1 and 2
Sandy Denny and the Strawbs—All Our Own Work
The Strawbs emerged onto the music scene in the early 70’s with their folk-rock album, “Grave New World.” Since that time, this
British group released several albums (most of which I own on vinyl) with a decidedly large fan base in Great Britain . Longtime
mainstay of the group, singer-guitarist-composer, David Cousins, dominates their repertoire with his singing voice which is decidedly untypical of English crooners: he doesn’t lose his British accent. Strawbs did enjoy a popular hit over the years: “Part of the
Union”, which is somewhat unlike their predominant musical style. The albums noted above were recorded live on the BBC, so
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CDs Not to Take to An Audio Show
Art Tedeschi
some of the tunes may be of questionable audio quality, even mono at times, but overall with much presence and a you-are-there
quality. The recordings were made in the early 70’s and released on CD in 2010.
Sandy Denny is considered by many to be the founder of British folk-rock, and performed with the British band, Fairport Convention in the late 60s. Some may know her as the female vocalist on the Led Zeppelin track , The Battle of Evermore, from their fourth
album. Sandy is reportedly the only guest performer to ever appear on a Led Zeppelin album. In “Sandy Denny & the Strawbs”,
Sandy performed with the group in several British clubs, again in the late 60’s. Sadly, she passed away in 1978 at the age of 31.
British folk-rock is a decidedly acquired taste, but if this music appeals to you, I couldn’t recommend these disks more highly. Performance: 4, Sonics: 3.
Songs for Drella
Lou Reed and John Cale
“Drella” was the nickname given to the late Andy Warhol, avant-garde painter and creator of the musical group, “The Velvet Underground.” Both rocker Lou Reed and violist John Cale were members of the fabled 80’s rock group and good friends of Warhol
(though Andy’s friends seemed more as “entourage” than friends). This album serves as Reed and Cale’s memorial to Andy, who
passed away in 1987, and reveals their deep-seated regrets for breaking their friendship with Andy in the years leading up to his
death. The songs, modestly recorded at Lou Reed’s home, are devoted to Andy and are filled with emotion, both sweetness and
anger, and stories of their time with Warhol. This is a fascinating album, and features some of the best songwriting to emerge from
these two artists. Performance: 5, Sonics 3+.
Riverdance
Bill Whelan
17
CDs Not to Take to An Audio Show
Art Tedeschi
If you’ve lived in a cave for the past 20 years, you may not know of the Irish step-dancing Riverdance troupe, originally starring Michael Flatley. (Think of the numerous TV situation comedies of the 90’s imitating the head-banded Flatley, and it should trigger a
memory.) I must admit that Jennifer and I are big fans of Riverdance and have attended the Denver performances on more than
one occasion. The dancing is wonderful, but the real attraction for me is the music of Bill Whelan. From the opening cut to the
last, these Celtic-infused pieces complement the dancing perfectly, and are powerful even without the visual presentation. Performance: 4+, Sonics: 3+.
Dead Can Dance
Toward the Within (CD or SACD)
Into the Labyrinth (CD or SACD)
Dead Can Dance is an Aussie-based goth-rock group that drew my interest well after the group had broken up. Most fans of this
music consider them the premiere performers of this musical genre. The term “goth rock” may not seem appealing to many of us,
but ignoring DCD for this reason would be a mistake. The group is headed by Lisa Gerrard, of “Gladiator” soundtrack fame and
Brendan Perry, an accomplished vocalist, musician and composer. The musicianship is of the highest order and includes instruments gleaned from diverse cultures, most of them absent in Western music. Toward the Within, their live concert album, is the
one to have, and if you can come up with the bucks, the box set that includes a DVD of the concert is another one to have. Some
have been put off by their goth-like appearance, but I recommend that you simply overlook this characteristic and focus on the
dense, instrumentally-complex music. Performance: 5, Sonics 4.
Addendum: As I thought about writing this article, it became clear, upon looking through my CD shelves, that most of the music I
own SHOULD NOT be taken to an audio show. Conversely, if most of my music was of the kind that SHOULD be taken to an audio
show, I would have to seriously reconsider my audiophile priorities.
More to come in the next issue.
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