general question about audio amplifiers

Hello,

A family friend swears by using vacuum tube audio amplifiers, saying
that although they are less efficient, they produce a "warmer, less
tiring" sound than the traditional electronic amplifiers do.

Is this really true?

Would, for example, the output waveforms be smoother on a vacuum tube
than they would be on a transistor amplifier?

Thanks in advance for not flaming me too badly.

Mike Darrett
www.darrettenterprises.com

 

[Roger Johansson]

mike-nospam@darrettenterprises.com wrote:

A family friend swears by using vacuum tube audio amplifiers, saying
that although they are less efficient, they produce a "warmer, less
tiring" sound than the traditional electronic amplifiers do.

Is this really true?

Tube amps softens the curve form, a soft clipping action, because they
are not good components. But this is a fault which some people like
better than a perfect reproduction in a modern transistor amp.

There is a whole industry based on making transistor amps sound like tube
amps. And some people build real tube amps after old schematics.
Guitarists are the main target group for this, but other audio
enthusiasts also buy tube amps or effect boxes which reproduce a classic
tube sound.

google:
tube screamer effect box schematic

http://www.geofex.com/Article_Folders/TStech/tsxtech.htm

A good text about creating tube sound in different ways, simple
do-it-yourself circuit schematics.



--
Roger J.

 

[John Larkin]

On 9 Mar 2005 13:49:54 -0800, mike-nospam@darrettenterprises.com
wrote:

Hello,

A family friend swears by using vacuum tube audio amplifiers, saying
that although they are less efficient, they produce a "warmer, less
tiring" sound than the traditional electronic amplifiers do.

So solid-state is now "the traditional electronic amplifier", and
tubes are new? To some people, I guess.

Is this really true?

Would, for example, the output waveforms be smoother on a vacuum tube
than they would be on a transistor amplifier?

This is notoriously subjective, like wine tasting. It would be
interesting to have him do a blind listening comparison and see if he
can tell the difference. Some tube amps *do* have a lot of distortion,
and some people do like the resulting sound. Tube amps have bad
damping factors, so speakers boom more, and some people like that,
too.

John

 

Thanks for the suggestion.

http://www.faqs.org/faqs/AudioFAQ/part4/

Interesting reading.

Mike

 

[Anthony Fremont]

"Roger Johansson" <no-email@no.invalid> wrote in message

There is a whole industry based on making transistor amps sound like
tube
amps. And some people build real tube amps after old schematics.
Guitarists are the main target group for this, but other audio
enthusiasts also buy tube amps or effect boxes which reproduce a
classic
tube sound.

As an amateur guitarist of about 20 years (late starter ;-), I can
attest to the _fact_ that there is a world of difference between solid
state and tube. It's mostly a behavior thing IMO. Feedback in a solid
state amp is a terribly atrocious noise. It tends to seek some magic
frequency known only to the evil force driving it and having nothing to
do with the notes currently being played. The victim has no semblance
of control over the howling and screeching noise that is known as
solid-state feedback.

OTOH, a good tube amp can "sustain" any chosen note for an indefinite
amount of time. The practiced player can have an amazing amount of
control over the effect. Just listen to an early Van Halen album for an
example of what's possible with tubes.

Outside of this, I believe that most audio-phool hype is nothing more
than another form of snake oil for the modern times. For reproduced
audio, I have no qualms with solid state equipment. But a guitar should
only be plugged in to a tube amp, period. ;-)

 

[John Larkin]

On Wed, 9 Mar 2005 14:05:48 -0800, "Larry Brasfield"
<donotspam_larry_brasfield@hotmail.com> wrote:

In fact, most people to whom such gear
would be marketed would still prefer
vacuum tube amps, magnetic bracelets,
and sea salt.

But there is some rationality to sea salt.

John

 

[Roger Johansson]

"Anthony Fremont" <spam@anywhere.com> wrote:

As an amateur guitarist of about 20 years (late starter ;-),

Me too. I have a Casio MG510, a famous guitar you have probably never
heard of. A stratocaster type body with three analog pickups, one of them
is a double humbucker pickup.

The guitars themselves were produced under contract for Casio by Fuji Gen
Gakki, who also built the Roland and Ibanez MIDI guitars.
It has a traditional analog output jack like all electric guitars, and a
midi output like a midi keyboard.

I cut away a lot of wood from its body to make it lighter, and slimmer.
Electric guitars weigh too much in my view, or I am simply not well
trained and strong. It looks better after the slimming. I can use it as a
keyboard and use a sequenser program in the computer to record in midi,
or I use a Zoom 505 effectbox and record analog tracks.

Mechanically it is the best guitar I have ever played, very soft and easy
action. It is probably taken from the same production line as high
quality Ibanez guitars.

OTOH, a good tube amp can "sustain" any chosen note for an indefinite
amount of time. The practiced player can have an amazing amount of
control over the effect. Just listen to an early Van Halen album for
an example of what's possible with tubes.

I think he uses more than just a tube amp. He uses effect boxes, like the
tube screamer I wrote about in another message. You can build your own
effects boxes if you know a little electronics. There are schematics for
most older commercial effects on the web, geofex.com is a good starting
point.

Outside of this, I believe that most audio-phool hype is nothing more
than another form of snake oil for the modern times. For reproduced
audio, I have no qualms with solid state equipment. But a guitar
should only be plugged in to a tube amp, period. ;-)

The latest word in the effects world is "guitar modeller". It is an
effects unit which simulates different guitars, combo cabinets, amps,
loudspeakers, etc.. So you can sound like you are playing a 1972 Fender
with a Marshall amp.

An example:
http://www.imuso.co.uk/ProductDetail.asp?StockCode=EG00071



--
Roger J.

 

[Anthony Fremont]

"Roger Johansson" <no-email@no.invalid> wrote in message
news:Xns9615BB1C841B86336@81.174.12.30...

"Anthony Fremont" <spam@anywhere.com> wrote:

As an amateur guitarist of about 20 years (late starter ;-),

Me too. I have a Casio MG510, a famous guitar you have probably never
heard of. A stratocaster type body with three analog pickups, one of
them
is a double humbucker pickup.

Cool. I have exactly one guitar (the one I started on), an Ibanez Strat
copy with a maple fingerboard. It still looks pretty good even after
more than 20 years. I changed one of the single coils out to a Seymour
Duncan hum bucker that fit in the pick gaurd without cutting (i.e. looks
just like the stock single coil) Ah...way less hum. ;-) I've had
several amps, but I finally found one that I like. It's a Mesa Boogie
DC-3.

The guitars themselves were produced under contract for Casio by Fuji
Gen
Gakki, who also built the Roland and Ibanez MIDI guitars.
It has a traditional analog output jack like all electric guitars, and
a
midi output like a midi keyboard.

I cut away a lot of wood from its body to make it lighter, and
slimmer.
Electric guitars weigh too much in my view, or I am simply not well
trained and strong. It looks better after the slimming. I can use it
as a
keyboard and use a sequenser program in the computer to record in
midi,
or I use a Zoom 505 effectbox and record analog tracks.

Mechanically it is the best guitar I have ever played, very soft and
easy
action. It is probably taken from the same production line as high
quality Ibanez guitars.

I kinda gave up on the stomp boxes when I got a decent amp. Even my
Zoom 505 just didn't sound right. It stole all my head room. I suspect
that more modern stuff may be better now, however I don't play a whole
lot anyway so straight in is fine for me.

OTOH, a good tube amp can "sustain" any chosen note for an
indefinite
amount of time. The practiced player can have an amazing amount of

control over the effect. Just listen to an early Van Halen album
for
an example of what's possible with tubes.

I think he uses more than just a tube amp. He uses effect boxes, like
the
tube screamer I wrote about in another message. You can build your own
effects boxes if you know a little electronics. There are schematics
for
most older commercial effects on the web, geofex.com is a good
starting
point.

Outside of this, I believe that most audio-phool hype is nothing
more
than another form of snake oil for the modern times. For reproduced
audio, I have no qualms with solid state equipment. But a guitar
should only be plugged in to a tube amp, period. ;-)

The latest word in the effects world is "guitar modeller". It is an
effects unit which simulates different guitars, combo cabinets, amps,
loudspeakers, etc.. So you can sound like you are playing a 1972
Fender
with a Marshall amp.

An example:
http://www.imuso.co.uk/ProductDetail.asp?StockCode=EG00071

Yeah, the amp modeling stuff has been around for a little while, but I
didn't know about guitar modeling. That's pretty impressive looking for
the price, I'd like to hear one. I need to go check out what's
available at Guitar City, I haven't been there in eons. Do you remember
The Rockman?

I think I'll stick with my Boogie though, it really does kick butt.
Worth every penny and then some. It's the freakin' loudest 35W I ever
heard in my life. My cats agree. ;-)

 

[Roger Johansson]

"Anthony Fremont" <spam@anywhere.com> wrote:

Yeah, the amp modeling stuff has been around for a little while, but I
didn't know about guitar modeling. That's pretty impressive looking
for the price, I'd like to hear one. I need to go check out what's
available at Guitar City, I haven't been there in eons. Do you
remember The Rockman?

Yes, if we are talking pocket sized units. I wanted one 10-15 years ago,
when they came out on the market. but never actually got my hands on one.
I built my own effects for several years instead.

The best homebuilt unit made the guitar sound like an organ, with
infinite sustain in its maximum sustain position. I could also set it to
swell, the tone starts quiet and builds up volume.

Years later I got a Zoom 9002 pocket multiprocessor, which I liked very
much. It was trashed by lightning, so I went out and bought the Zoom 505,
because it was the most common unit, I had read a lot about it, and I got
a very good price.


--
Roger J.

 

[tempus fugit]

I think he uses more than just a tube amp. He uses effect boxes, like the
tube screamer I wrote about in another message. You can build your own
effects boxes if you know a little electronics. There are schematics for
most older commercial effects on the web, geofex.com is a good starting
point.

Eddie's thing was to mod the Marshall he was using by using a Variac to up
the tube voltages (or was it down them - can't remember now). Anyway, he
claims he had to retube once a week!!
He used very little in the way of effects, but one of his secrets was to use
a phaser (and MXR I think) turned barely on for a little treble boost. You
can actually hear the phasing if you listen closely though.

 

[Roger Johansson]

"tempus fugit" <toccata@no.spam.ciaccess.com> wrote:

Eddie's thing was to mod the Marshall he was using by using a Variac to
up the tube voltages (or was it down them - can't remember now).
Anyway, he claims he had to retube once a week!!
He used very little in the way of effects, but one of his secrets was
to use a phaser (and MXR I think) turned barely on for a little treble
boost. You can actually hear the phasing if you listen closely though.

I often use a triangle wave from a function generator as input signal to
test and trim circuits to simulate tube distortion.

When I adjust a jfet or mosfet stage, or a tube screamer diode clipping
circuit, I can see on the oscilloscope how the peaks of the triangle wave
are rounded.

It sounds better if the positive peaks and the negative peaks are rounded
differently. That gives a more interesting spectrum of overtones than if
the soft clipping is symmetrical, which sounds more neutral.



--
Roger J.

 

[Kitchen Man]

On Wed, 9 Mar 2005 14:05:48 -0800 in sci.electronics.basics, "Larry
Brasfield" <donotspam_larry_brasfield@hotmail.com> wrote msg
<0rKXd.41$i37.673@news.uswest.net>:

In fact, most people to whom such gear
would be marketed would still prefer
vacuum tube amps, magnetic bracelets,
and sea salt.

There are now available PC sound cards with a vacuum tube final stage.
While I am nostalgic about vacuum tubes, having worked extensively early
in my career with tube power supplies and pentode analog computers, I
don't harbor any great desire to spend the kind of money necessary to
get tube audio equipment. But, I do like sea salt.

--
Al Brennan

 

[John Fields]

On Wed, 9 Mar 2005 14:05:48 -0800, "Larry Brasfield"
<donotspam_larry_brasfield@hotmail.com> wrote:

In fact, most people to whom such gear
would be marketed would still prefer
vacuum tube amps, magnetic bracelets,
and sea salt.

---
That's unfair and isn't a fact at all; it's strictly your caustic
opinion.
---

Would, for example, the output waveforms be smoother on a vacuum tube
than they would be on a transistor amplifier?

Only when the amp is underpowered for
the signal it is being asked to pass.

---
Not 'only'. The transient response of the output transformers has a
lot to do with it as well.
---


--
John Fields

 

[James Beck]

In article <2h1v21p3eba15huhk2ud15tpb910i2n60t@4ax.com>,
jjlarkin@highSNIPlandTHIStechPLEASEnology.com says...

On Wed, 9 Mar 2005 14:05:48 -0800, "Larry Brasfield"
donotspam_larry_brasfield@hotmail.com> wrote:



In fact, most people to whom such gear
would be marketed would still prefer
vacuum tube amps, magnetic bracelets,
and sea salt.


But there is some rationality to sea salt.

John


Yep, there is more than just NaCl in it.

Jim

 

[Larry Brasfield]

"John Fields" <jfields@austininstruments.com> wrote in message
news:van031hpdooljlj4lj2mjevpgglvujrvcl@4ax.com...

On Wed, 9 Mar 2005 14:05:48 -0800, "Larry Brasfield"
donotspam_larry_brasfield@hotmail.com> wrote:

In fact, most people to whom such gear
would be marketed would still prefer
vacuum tube amps, magnetic bracelets,
and sea salt.
---
That's unfair and isn't a fact at all; it's strictly your caustic
opinion.

That might have been overstated a bit. But I think
the point is correct that a large fragment of those
who insist that tube amp distortion is preferable
attribute tubes with magical properties than can
never be replicated otherwise, no matter what
thorough instrumentation might indicate. And
among that fragment, you will find many with
magnetic shoe inserts, copper bracelets, or a
cupboard containing many items with sea salt
in the ingredient list. The superstitious mind is
rarely content with isolated obeisances.

Would, for example, the output waveforms be smoother on a vacuum tube
than they would be on a transistor amplifier?

Only when the amp is underpowered for
the signal it is being asked to pass.
---
Not 'only'. The transient response of the output transformers has a
lot to do with it as well.

Do you believe that, within the nearly linear output
range of a tube amp, the output transformer is
usually going to smooth out the content that a high
fidelity amplifier would have passed? If that is the
basis of your contention, then I must point out that
transistor amplifiers can also act as low pass filters,
either intentionally (treble control) or not. If your
contention is not about frequency response, maybe
your could explain your contradiction.

--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.

 

[John Fields]

On Thu, 10 Mar 2005 07:27:49 -0800, "Larry Brasfield"
<donotspam_larry_brasfield@hotmail.com> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:van031hpdooljlj4lj2mjevpgglvujrvcl@4ax.com...
On Wed, 9 Mar 2005 14:05:48 -0800, "Larry Brasfield"
donotspam_larry_brasfield@hotmail.com> wrote:

In fact, most people to whom such gear
would be marketed would still prefer
vacuum tube amps, magnetic bracelets,
and sea salt.
---
That's unfair and isn't a fact at all; it's strictly your caustic
opinion.

That might have been overstated a bit. But I think
the point is correct that a large fragment of those
who insist that tube amp distortion is preferable
attribute tubes with magical properties than can
never be replicated otherwise, no matter what
thorough instrumentation might indicate. And
among that fragment, you will find many with
magnetic shoe inserts, copper bracelets, or a
cupboard containing many items with sea salt
in the ingredient list. The superstitious mind is
rarely content with isolated obeisances.

---
Superstitious minds also exist among those who prefer "semiconductor
sound" and I'm sure that, among that fragment, you'll also find many
with magnetic shoe inserts, copper bracelets, or a cupboard containing
many items with sea salt in the ingredient list, so I can't see why
you're singling out those who prefer "the tube sound" as a population
more likely to be superstitious than another unless it's for the
purpose of denigrating them because they have preferenes different
from yours.
---

Would, for example, the output waveforms be smoother on a vacuum tube
than they would be on a transistor amplifier?

Only when the amp is underpowered for
the signal it is being asked to pass.
---
Not 'only'. The transient response of the output transformers has a
lot to do with it as well.

Do you believe that, within the nearly linear output
range of a tube amp, the output transformer is
usually going to smooth out the content that a high
fidelity amplifier would have passed? If that is the
basis of your contention, then I must point out that
transistor amplifiers can also act as low pass filters,
either intentionally (treble control) or not. If your
contention is not about frequency response, maybe
your could explain your contradiction.

---
There is no contradiction.

The frequency response of a transformer is determined by using a
constant voltage, constant impedance source with a sinusioidal output
to sweep the input of the transformer (the "primary") through a band
of frequencies while measuring the output voltage from the resistively
loaded secondary and taking note of the output amplitude variations.

The transient response, on the other hand, deals with the behavior of
the transformer when subjected to complex input signals and is
affected by, among other things, the leakage reactance and
interwinding capacitance in ways which wouldn't be readily apparent
when exciting the transformer with a single spectral line. For
example, do you think that if you had a transformer with a flat
frequency response from 10Hz to 20kHz at 10 watts and you fed it with,
say, 100Hz and 8372Hz simultaneously that its output would exactly
mimic its input? I don't, and I don't believe that if you fed the
output of that transformer into a loudspeaker side-by-side with an
identical loudspeaker being fed with the output of a solid-state amp
with a treble control that the inputs to both loudspeakers could be
made indentical no matter how the treble control was adjusted.

--
John Fields

 

[Larry Brasfield]

"John Fields" <jfields@austininstruments.com> wrote in message
news:msr031ha8s6cc8jebd9k055nbed88rpco0@4ax.com...

On Thu, 10 Mar 2005 07:27:49 -0800, "Larry Brasfield"
donotspam_larry_brasfield@hotmail.com> wrote:
....
That might have been overstated a bit. But I think
the point is correct that a large fragment of those
who insist that tube amp distortion is preferable
attribute tubes with magical properties than can
never be replicated otherwise, no matter what
thorough instrumentation might indicate. And
among that fragment, you will find many with
magnetic shoe inserts, copper bracelets, or a
cupboard containing many items with sea salt
in the ingredient list. The superstitious mind is
rarely content with isolated obeisances.
---
Superstitious minds also exist among those who prefer "semiconductor
sound" and I'm sure that, among that fragment, you'll also find many
with magnetic shoe inserts, copper bracelets, or a cupboard containing
many items with sea salt in the ingredient list, so I can't see why
you're singling out those who prefer "the tube sound" as a population
more likely to be superstitious than another unless it's for the
purpose of denigrating them because they have preferenes different
from yours.

You are mistaken about my preferences. I cringe
when I hear hard-limited sound and would prefer
the softer limiting that tube amps can provide.

My "singling out" is directed not to those who may
prefer a given type of distortion or limiting, but to
those who believe only tube amps can deliver that
performance. I have seen no studies of how tube
amp preference correlates to superstition, so my
above statement is based on a small sample and
may well be unrepresentative.

Would, for example, the output waveforms be smoother on a vacuum tube
than they would be on a transistor amplifier?

Only when the amp is underpowered for
the signal it is being asked to pass.
---
Not 'only'. The transient response of the output transformers has a
lot to do with it as well.

Do you believe that, within the nearly linear output
range of a tube amp, the output transformer is
usually going to smooth out the content that a high
fidelity amplifier would have passed? If that is the
basis of your contention, then I must point out that
transistor amplifiers can also act as low pass filters,
either intentionally (treble control) or not. If your
contention is not about frequency response, maybe
your could explain your contradiction.

---
There is no contradiction.

Well, prepending 'not' to what I posted can certainly
be reasonably interpreted as a contradiction.

The frequency response of a transformer is determined by using a
constant voltage, constant impedance source with a sinusioidal output
to sweep the input of the transformer (the "primary") through a band
of frequencies while measuring the output voltage from the resistively
loaded secondary and taking note of the output amplitude variations.

The transient response, on the other hand, deals with the behavior of
the transformer when subjected to complex input signals and is
affected by, among other things, the leakage reactance and
interwinding capacitance in ways which wouldn't be readily apparent
when exciting the transformer with a single spectral line.

For a linear time-invariant system, the transient response
is perfectly predictable from the frequency response. So
your distinction is somewhat puzzling in this context.

As for the properties you attribute to the transient response
that are not visible in a magnitude versus frequency plot, my
understanding is that humans are insensitive to the phase
relationships among components of an audio signal.

For
example, do you think that if you had a transformer with a flat
frequency response from 10Hz to 20kHz at 10 watts and you fed it with,
say, 100Hz and 8372Hz simultaneously that its output would exactly
mimic its input?

Such fidelity would surpise me.

I don't, and I don't believe that if you fed the
output of that transformer into a loudspeaker side-by-side with an
identical loudspeaker being fed with the output of a solid-state amp
with a treble control that the inputs to both loudspeakers could be
made indentical no matter how the treble control was adjusted.

I agree with that. But I doubt anybody could
hear the difference provided that there was no
wild difference in the phase response of the
two systems, such as delay in excess of a mS.

What triggers my skepticism is the suggestion
that transformer transient response uniformly
tends to smooth output waveforms. I expect
that in the case of soft limiting, but I see little
reason to predict that the uneven phase response
of a transformer, together with the phase response
of whatever is done to preceeding stages to get
the magnitude response straightened out, will act
to produce smoother outputs.

--
--Larry Brasfield
email: donotspam_larry_brasfield@hotmail.com
Above views may belong only to me.

 

[John Larkin]

On Thu, 10 Mar 2005 15:25:18 GMT, James Beck
<jim@reallykillersystems.com> wrote:

In article <2h1v21p3eba15huhk2ud15tpb910i2n60t@4ax.com>,
jjlarkin@highSNIPlandTHIStechPLEASEnology.com says...
On Wed, 9 Mar 2005 14:05:48 -0800, "Larry Brasfield"
donotspam_larry_brasfield@hotmail.com> wrote:



In fact, most people to whom such gear
would be marketed would still prefer
vacuum tube amps, magnetic bracelets,
and sea salt.


But there is some rationality to sea salt.

John


Yep, there is more than just NaCl in it.

Jim

A relative-by-marriage used to be head chemist for a big salt mine in
Louisiana. Every day he'd go to work, analyze some samples, and file a
report: yep, it's still salt. He got bored, took up selling drugs, and
now he's a successful and respected mobster, sort of the cajun Tony
Soprano.

John

 

[John Larkin]

On Thu, 10 Mar 2005 08:52:50 -0600, John Fields
<jfields@austininstruments.com> wrote:

In fact, most people to whom such gear
would be marketed would still prefer
vacuum tube amps, magnetic bracelets,
and sea salt.


That's unfair and isn't a fact at all; it's strictly your caustic
opinion.

Oh, don't be bitter.

John

 

[John Larkin]

On Thu, 10 Mar 2005 11:00:14 -0600, John Fields
<jfields@austininstruments.com> wrote:

Superstitious minds also exist among those who prefer "semiconductor
sound" and I'm sure that, among that fragment, you'll also find many
with magnetic shoe inserts, copper bracelets, or a cupboard containing
many items with sea salt in the ingredient list,

Get a bunch of skinny asparagus. Spray with Pam, sprinkle with coarse
sea salt, grind a little pepper on top, and broil until the tips turn
black. Yummy.

John