[tubegarden]

Hi RATs!

I got an A7-D off Ebay for $60., about four times its price as a new
kit in '56. It has new coupling caps. Hooked to the Neo-phone 5-1/4" on
a flat baffle, direct. It sounds heavenly. The ehorn woofer does no
harm

I have an A7-E waiting for repairs. It has an 12SL7 for the phono
stage, opposed to the "D", which has two line stage inputs.

Happy Ears!
Al

[tubegarden]

tubegarden wrote:
Hi RATs!

I got an A7-D off Ebay for $60., about four times its price as a new
kit in '56. It has new coupling caps. Hooked to the Neo-phone 5-1/4" on
a flat baffle, direct. It sounds heavenly. The ehorn woofer does no
harm

I have an A7-E waiting for repairs. It has an 12SL7 for the phono
stage, opposed to the "D", which has two line stage inputs.

Happy Ears!
Al

Hi RATs!

Just got the A7-E working. Replaced the output coupling caps and
bypassed the selector switch and tone cpntrols. Also replaced the
broken B+ wire to the 12SN7 ...

Joy! Stereo! Monoblocks!

Happy Ears!
Al

PS new caps are Illinois Capacitor 0.1uF 630V, my reigning favorite
under a buck

[tubegarden]

Hi RATs!

OK, I bypassed the tone controls on the "D", so now both amps are
reasonably simple.

Also sound OK

Next, add chokes and oil caps

Happy Ears!
Al

[tubegarden]

Hi RATs!

My A7-E population is up to three. Also, an A7-D and an A7-C. Being in
the dim future twilight years is fun, if you accept the madness as just
the flavor of the decade.

I imagine I could set up elaborate controls and learn to identify each
of my old amps by their sound alone. I haven't got the energy nor
interest, but, I have a fine imagination.

I was always happy to know Goofy, the comic book character, was around
in my early childhood, but, when I discovered Gyro Gearloose, my soul
found a Fountainhead. Walt Disney was cool, but, he had a moustache,
and modern Disney business practices do not allow moustaches ... it
ain't evil we should fear, it is nice-nice.

So, I am drenched in fine sound, with more flavors waiting patiently
while many of you are busy using the online thesaurus to insult others.
It's OK, my first wife's Mother collected books of insults. It is just
the way some folks are wired.

Radically changing an amplifiers topology is easy-peasy. Teaching you
morons the meaning of the words self respect may take a bit longer. It
is my life's work. Good thing I am old, it is pretty much given it is a
waste of time

We are meerly human. If your insults lack humor, what is left?

If some of the tubes in my amps are only there to load the filament
supply, it doesn't hurt anything. Sanity is not Holy, just another way
to tell yourself you have a grip on the important thngs in life, as if
there ever were any

Happy Ears!
Al

[thomas]

tubegarden wrote:
Hi RATs!

My A7-E population is up to three. Also, an A7-D and an A7-C. Being in
the dim future twilight years is fun, if you accept the madness as just
the flavor of the decade.

I imagine I could set up elaborate controls and learn to identify each
of my old amps by their sound alone. I haven't got the energy nor
interest, but, I have a fine imagination.

I was always happy to know Goofy, the comic book character, was around
in my early childhood, but, when I discovered Gyro Gearloose, my soul
found a Fountainhead. Walt Disney was cool, but, he had a moustache,
and modern Disney business practices do not allow moustaches ... it
ain't evil we should fear, it is nice-nice.

So, I am drenched in fine sound, with more flavors waiting patiently
while many of you are busy using the online thesaurus to insult others.
It's OK, my first wife's Mother collected books of insults. It is just
the way some folks are wired.

Radically changing an amplifiers topology is easy-peasy. Teaching you
morons the meaning of the words self respect may take a bit longer. It
is my life's work. Good thing I am old, it is pretty much given it is a
waste of time

We are meerly human. If your insults lack humor, what is left?

If some of the tubes in my amps are only there to load the filament
supply, it doesn't hurt anything. Sanity is not Holy, just another way
to tell yourself you have a grip on the important thngs in life, as if
there ever were any

Happy Ears!
Al

I am following your adventure, even though I don't have anything to
say. Keep on posting.

[tubegarden]

thomas wrote:

I am following your adventure, even though I don't have anything to
say. Keep on posting.

Hi RATs!

The A7s are all homemade, from kits. The C and E's have a phono stage.
It seems there was a tendency to hum ... each shows a different
approach. None follow the schematic I have seen

One has star ground. Each component that needs to be grounded has a
wire to a common grounding point.

Another has a dedicated filament transformer for the 12SL7 phono stage.
My kind of insanity This one also uses all cotton braid covered
wires. Not in the original kit

It is refreshing to realize many have trod these pathways before me
I am intent on changing the PS filter to C-L-C-L-C. But, all in good
time.

Meanwhile, this is the best match for the Neo-phones I have heard. And,
I am hearing more than I thought likely, ever ...

Perhaps a choke load on the plate of the 12SN7 VA ...

Happy Ears!
Al

[tubegarden]

Hi RATs!

A recording of organ got the voice coils rattling, so I put a 22uF oil
cap in series with the little drivers. Rattle gone.

The ehorn never has rattled

Happy Ears!
Al

[John Byrns]

In article . com,
"tubegarden" wrote:

Hi RATs!

A recording of organ got the voice coils rattling, so I put a 22uF oil
cap in series with the little drivers. Rattle gone.

What is a "Neo-phone"? The name sounds like it is a "New Telephone",
but from the context you are using it in it sounds like you are talking
about a speaker?


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[Peter Wieck]

John Byrns wrote:

but from the context you are using it in it sounds like you are talking
about a speaker?

Look up Neofone.

Some have a hard time with neologisms...

Peter Wieck
Wyncote, PA

[tubegarden]

John Byrns wrote:
In article . com,
"tubegarden" wrote:

Hi RATs!

A recording of organ got the voice coils rattling, so I put a 22uF oil
cap in series with the little drivers. Rattle gone.

What is a "Neo-phone"? The name sounds like it is a "New Telephone",
but from the context you are using it in it sounds like you are talking
about a speaker?


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/


Hi RATs!

http://diyhifisupply.com/diyhs_speaker.htm

Neo-Fone. Neo-Fone. Neo-Fone.

Sound good. Not too expensive. Forgettable name ...

Happy Ears!
Al

[John Byrns]

In article ,
Here in Ohio wrote:

On 7 Nov 2006 07:49:26 -0800, "tubegarden" wrote:

Hi RATs!

http://diyhifisupply.com/diyhs_speaker.htm

Neo-Fone. Neo-Fone. Neo-Fone.

Sound good. Not too expensive. Forgettable name ...

Happy Ears!
Al

From the looks of the drivers and their impedance curve, I'm betting
that any output above 1KHz is cone breakup. :-)

If you're going the "full range" route, at least buy drivers from
someone who knows what they're doing like Ted Jordan. He's worked out
the best compromises for this type of speaker.

http://www.ejjordan.co.uk/index.html

For those of us less knowledgeable about the operation of speakers could
you explain your reasoning here, specifically why you are "betting" that
cone breakup begins at 1KHz?

It isn't clear to me that Ted Jordan's speakers are a better compromise
than the Neo-Phone, the best compromise depends on how you weight a
speaker's characteristics. For example the Jordan speakers have an
unacceptably low efficiency, while the Neo-Fones do better in this
regard. The Neo-Fones also appear to have better low frequency
extension, while the Jordan's seem to put a priority on extending the
high frequency response to blue light.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[John Byrns]

In article ,
Here in Ohio wrote:

On Wed, 08 Nov 2006 19:02:36 GMT, John Byrns
wrote:


For those of us less knowledgeable about the operation of speakers could
you explain your reasoning here, specifically why you are "betting" that
cone breakup begins at 1KHz?


Look at the impedance curve. It starts going way up above 1K and, from
what I've seen of cone drivers, that usually indicates they're
resonating.

Wouldn't resonances produce peaks in the impedance curve similar to the
one just below 60 Hz? The rise is very smooth and follows a curve
similar to that typically caused by voice coil inductance alone.

In other words, exhibiting cone breakup.

You have utterly failed to prove your point so far. I'm not disputing
that there may be cone breakup, I am simply saying that I don't
understand how you can tell from the published impedance curve that
there is cone breakup?

(The inductance
of the voice coil also raises the impedance at high frequencies, so
it's harder to drive a cone driver at precisely the point where it's
having the most trouble.)

It's also a 5.25" cone driver and those just don't work well for high
frequencies. (They don't really work well for bass either.) :-)

And the Jordan driver is much worse for bass, it's all a matter of the
compromise you are willing to accept.

It's physically impossible to make a full-range driver that works
well. It's going to suck at either one extreme or the other (or maybe
both). Jordan has pretty much given up on trying to move a lot of air
in order to do a better job at the rest of the spectrum. (This is
actually a good thing since it removes a major source of IM
distortion.)

You haven't explained how the Jordan driver minimizes IM? I was under
the impression that at given acoustic output a larger cone will
generally have lower IM, other things being equal. The smaller cone
must move a longer distance, thus generating more IM.

That Neo-Fone thing is a neither here nor there product that tries to
compromise too much.

Same thing with the Jordan, it just has a different set of compromises.

Who cares if it's more efficient? The Jordan drivers are fine and it's
not like we don't have good power amps with plenty of power in this
day and age.

This is "rec.audio.tubes", tube amps generally have a somewhat lower
power output capability than semiconductor amps.

Maybe you should ask them to supply you with some info on how much
distortion these Neo-Fone things put out. I bet it's pretty
horrendous.

Unfortunately speakers and "horrendous" distortion go together.

In short, this fad for "full-range" speakers is rather silly in the
first place, but if you're going to buy into it you might as well
choose drivers from someone like Jordan who actually knows
loudspeakers and has been working on full-range for decades.

Fine, but why doesn't he offer a model with the response range skewed
towards the low end rather than to frequencies well above the range of
human hearing, for those that would like a better compromise?

(Indeed, I've heard speakers with 4 vertically stacked Jordan 50mm
modules per side crossed over to a sub at about 150 Hz and they did a
rather nice job.)

What if a "sub" is not part of the game? I would rather give up the
octave between 15 kHz and 30 kHz, in exchange for the octave between 75
Hz and 150 Hz.


Regards,

John Byrns

--
Surf my web pages at, http://fmamradios.com/

[Arny Krueger]

"John Byrns" wrote in message
...
In article ,
Here in Ohio wrote:

On Wed, 08 Nov 2006 19:02:36 GMT, John Byrns
wrote:


For those of us less knowledgeable about the operation of speakers could
you explain your reasoning here, specifically why you are "betting" that
cone breakup begins at 1KHz?

Look at the impedance curve. It starts going way up above 1K and, from
what I've seen of cone drivers, that usually indicates they're
resonating.

Not necessarily. You have to back out the rises due to voice coil inductance
and cone mass.

Wouldn't resonances produce peaks in the impedance curve similar to the
one just below 60 Hz?

Not necessarily. Cone break up involves the cone being decoupled from the
voice coil. Below 100 Hz, the voice coil and the cone are tightly coupled so
anything the cone does, shows up in the impedance curve. Above some high
frequency, the voice coil decouples from the cone due to the compliance of
the mechanical coupling, and the cone's motion is not transmitted back to
the voice coil.

The rise is very smooth and follows a curve
similar to that typically caused by voice coil inductance alone.

Agreed.

In other words, exhibiting cone breakup.

Cone breakup usually shows up in acoustical response curves.

I see cone breakup quite clearly in this curve:

http://www.ejjordan.co.uk/drivers/jx92.html

I'd say that there is significant breakup above 4 KHz. Some decoupling of
the cone related to the small peak at 2K.


but not so clearly in this curve:

http://www.ejjordan.co.uk/drivers/jxr6.html

Looking again, I'd say that there is mild breakup above 6 KHz. Maybe some
decoupling of the cone related to the small peak at 3K.

[tubegarden]

Hi RATs!

I put a fresh quad of RCA 12A6 tubes into the A7s. Sounds wonderfuller.

The Neo-Fone speakers are in the system.

The V-Caps are in the system.

The ehorn is in the system. (I like subwoofers)

I am gonna be sixty in a few months. I'll pass on the super-tweeters.
Or, rather, I'd fail ...

Please, people, let us remember, audio is idiotic. I do it for fun, not
revenge

Happy Ears!
Al

[Sander deWaal]

"tubegarden" said:

Hi RATs!

I put a fresh quad of RCA 12A6 tubes into the A7s. Sounds wonderfuller.

The Neo-Fone speakers are in the system.

The V-Caps are in the system.

The ehorn is in the system. (I like subwoofers)

I am gonna be sixty in a few months. I'll pass on the super-tweeters.
Or, rather, I'd fail ...

Please, people, let us remember, audio is idiotic. I do it for fun, not
revenge

Happy Ears!
Al


DIY forever, Al!

A bit too flea-powered for my hungry Maggies, you will note.

Environmental activists overhere already signed a petition to shut
down all my class A amplifiers, but didn't succeed yet ;-)

--
"Due knot trussed yore spell chequer two fined awl miss steaks."