Greetings Tubulars,
So I have this crazy idea to build a little tube amp just for fun. The
transformers are quite expensive though. I will be looking for old
ones probably because I can't justify spending loads on new ones. So
considering my almost 60 years old ears, 39 of which have been spent
in noisy environments, and my propensity to listen to loud music, what
should I look for that will sound just a little better than I can
hear? Maybe not an audio xmfr will be OK. There are some old tube amps
in a couple local thrift stores. How can I tell if they had good
xmfrs? Or can I?
Eric

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So what do you need. Specs ? lots of them about the shop.

Is it power or is it output ?

What is your design look like ? Got the tubes ?

Martin

On 1/17/2014 3:18 PM, wrote:
Greetings Tubulars,
So I have this crazy idea to build a little tube amp just for fun. The
transformers are quite expensive though. I will be looking for old
ones probably because I can't justify spending loads on new ones. So
considering my almost 60 years old ears, 39 of which have been spent
in noisy environments, and my propensity to listen to loud music, what
should I look for that will sound just a little better than I can
hear? Maybe not an audio xmfr will be OK. There are some old tube amps
in a couple local thrift stores. How can I tell if they had good
xmfrs? Or can I?
Eric

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On Sat, 18 Jan 2014 22:41:05 -0600, Martin Eastburn
wrote:
Greetings Martin,
I don't have any specs yet. Or a design. I just decided I would like
to do this. 20 watts per channel would be the max output, though I
imagine I will end up with something that puts out much less. I will
amplifying the output of some sort of CD player or mp3 player .
Eric
So what do you need. Specs ? lots of them about the shop.

Is it power or is it output ?

What is your design look like ? Got the tubes ?

Martin

On 1/17/2014 3:18 PM, wrote:
Greetings Tubulars,
So I have this crazy idea to build a little tube amp just for fun. The
transformers are quite expensive though. I will be looking for old
ones probably because I can't justify spending loads on new ones. So
considering my almost 60 years old ears, 39 of which have been spent
in noisy environments, and my propensity to listen to loud music, what
should I look for that will sound just a little better than I can
hear? Maybe not an audio xmfr will be OK. There are some old tube amps
in a couple local thrift stores. How can I tell if they had good
xmfrs? Or can I?
Eric

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wrote in message
...
On Sat, 18 Jan 2014 22:41:05 -0600, Martin Eastburn
wrote:
Greetings Martin,
I don't have any specs yet. Or a design. I just decided I would like
to do this. 20 watts per channel would be the max output, though I
imagine I will end up with something that puts out much less. I
will
amplifying the output of some sort of CD player or mp3 player .
Eric

The design will be much easier if you use a Class A output like a
radio rather than Class B (push-pull) like a powerful stereo amp.
http://en.wikipedia.org/wiki/Valve_amplifier
See "Topologies".

On Friday, January 17, 2014 1:18:36 PM UTC-8, wrote:
Greetings Tubulars,

So I have this crazy idea to build a little tube amp just for fun. The

transformers are quite expensive though. I will be looking for old

ones probably because I can't justify spending loads on new ones. So

considering my almost 60 years old ears, 39 of which have been spent

in noisy environments, and my propensity to listen to loud music, what

should I look for that will sound just a little better than I can

hear? Maybe not an audio xmfr will be OK. There are some old tube amps

in a couple local thrift stores. How can I tell if they had good

xmfrs? Or can I?

Eric



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http://www.avast.com

Tube amps color the music often adding "warmth". I think that's the wrong approach. I believe you want an amp that's transparent / invisible. Tube's are great for instruments but I don't believe they are the right approach for music playback.

http://forums.audioholics.com/forums...tube-amps.html

These were awesome amps but I prefer power hungry speakers and very loud listening levels:

http://www.audiocircle.com/index.php?topic=63956.0

Creator has passed on. Easily some of the cleanest amps I've ever heard. Horribly ugly. Badly marketed. Very high quality.

wrote in message
...
Greetings Tubulars,
So I have this crazy idea to build a little tube amp just for fun. The
transformers are quite expensive though. I will be looking for old
ones probably because I can't justify spending loads on new ones. So
considering my almost 60 years old ears, 39 of which have been spent
in noisy environments, and my propensity to listen to loud music, what
should I look for that will sound just a little better than I can
hear? Maybe not an audio xmfr will be OK. There are some old tube amps
in a couple local thrift stores. How can I tell if they had good
xmfrs? Or can I?
Eric


I've built a dozen or so, all point to point wired.

The top quality transformers usually were potted into a square can.

It's important maintain plate-to-plate impedence, so best to use the same
output tubes that the transformers were originally paired with, or at least
look into your tube manual and select a tube a set that is relatively close.

https://www.google.com/search?q=peer...w=1173&bih=564


Or you could wind your own...really no reason to use E laminations you have
a lathe...simply trepann out the coil cavity, leaving a "post" in the center
drop in the coils and screw on a round cover to complete the flux gap

On Sunday, January 19, 2014 1:05:03 AM UTC-5, PrecisionmachinisT wrote:


Or you could wind your own...really no reason to use E laminations you have

a lathe...simply trepann out the coil cavity, leaving a "post" in the center

drop in the coils and screw on a round cover to complete the flux gap

If you do decide to wind your own, I would recommend using laminations from a power transformer before using a solid chunk of material. Audio transformers use thinner laminations than a power transformer, but ones from a power transformer would be better than solid.

If you want I could keep an eye out for kind of suitable transforms at the local scrap yard. The shipping via a flat rate box would not be too bad. The last heavy stuff I shipped using a flat rate box , got separated from the box. But since then I got some stronger tape.

Dan

" wrote:

On Sunday, January 19, 2014 1:05:03 AM UTC-5, PrecisionmachinisT wrote:


Or you could wind your own...really no reason to use E laminations you have

a lathe...simply trepann out the coil cavity, leaving a "post" in the center

drop in the coils and screw on a round cover to complete the flux gap

If you do decide to wind your own, I would recommend using laminations from a power transformer before using a solid chunk of material. Audio transformers use thinner laminations than a power transformer, but ones from a power transformer would be better than solid.

If you want I could keep an eye out for kind of suitable transforms at the local scrap yard. The shipping via a flat rate box would not be too bad. The last heavy stuff I shipped using a flat rate box , got separated from the box. But since then I got some stronger tape.


A large, powdered iron toroid works even better. Like an old 3A
variac. I needed a modulation transformer for a AM mobile radio back in
the '70s. I wound a second winding on a surplus 88 mH telco toroid, and
had excessive audio bandwidth.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

"Michael A. Terrell" wrote in message
m...

A large, powdered iron toroid works even better. Like an old 3A
variac. I needed a modulation transformer for a AM mobile radio
back in
the '70s. I wound a second winding on a surplus 88 mH telco toroid,
and
had excessive audio bandwidth.

However a coiled sheetmetal 3 Amp Variac core may not work at all. The
response of one I measured fell to nothing above 600Hz.

Jim Wilkins wrote:

"Michael A. Terrell" wrote in message
m...

A large, powdered iron toroid works even better. Like an old 3A
variac. I needed a modulation transformer for a AM mobile radio
back in the '70s. I wound a second winding on a surplus 88 mH telco
toroid, and had excessive audio bandwidth.

However a coiled sheetmetal 3 Amp Variac core may not work at all. The
response of one I measured fell to nothing above 600Hz.


Some are wound, some are powdered iron. The one I had may have been
from a 400 Hz unit.



--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

On 2014-01-19, Michael A. Terrell wrote:
" wrote:

On Sunday, January 19, 2014 1:05:03 AM UTC-5, PrecisionmachinisT wrote:

Or you could wind your own...really no reason to use E laminations
you have a lathe...simply trepann out the coil cavity, leaving a "post"
in the center

drop in the coils and screw on a round cover to complete the flux
gap

This is sort of like the permanent magnet assembly in at least
one speaker I destroyed as a kid. (Well, the cone was already a goner.)
The center pole and backing plate were one piece (really the pole was
staked into the plate), and the outer housing was a ring Alnico
permanent magnet). Great construction for a stable permanent magnet
field, but not at all good for a transformer.

Now -- for really high frequencies (Ultrasonic, not RF) a
ferrite pot core is really nice. Formed in pretty much the shape
defined above for lathe construction, except that there were two of
them, mounted cup to cup. The cups were available in a large number of
sizes and a number of different ferrite compositions for different
frequency ranges and maximum flux densities.

If you do decide to wind your own, I would recommend using
laminations from a power transformer before using a solid chunk of
material. Audio transformers use thinner laminations than a power
transformer, but ones from a power transformer would be better than
solid.

Agreed! Thinner laminations are better at higher frequencies.

I do remember some special transformers for really old
telephones which were wound on a core of a number of lengths of straight
iron wire bundled together.

A large, powdered iron toroid works even better. Like an old 3A
variac.

Woah! A Variac did *not* use a powedered iron toroid -- nor
did the Superior Electric "Powerstats", nor any other variable
autotransformer by anyone else that I ever saw. :-)

Take a strip of the proper alloy (permalloy? Some other alloy?),
and wind it into a hollow cylinder (with insulating coatings between
layers) and *that* is the toroid that a variable autotransformer is
wound upon. Ideally -- pot that in an insulating material, and use that
to wind the coil on.

Powdered iron (ferrites) are much better at high frequencies,
while most variable autotransformers were optimized for 60 Hz or 50 Hz.
(I have held in my hand some optimized for 400 Hz -- and for those, the
length of the cylinder is about 1/3 that of one for the same current at
60 Hz.

I needed a modulation transformer for a AM mobile radio back in
the '70s. I wound a second winding on a surplus 88 mH telco toroid, and
had excessive audio bandwidth.

:-)

Filtration time. :-)

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"DoN. Nichols" wrote in message
...
On 2014-01-19, Michael A. Terrell wrote:
" wrote:

On Sunday, January 19, 2014 1:05:03 AM UTC-5, PrecisionmachinisT wrote:

Or you could wind your own...really no reason to use E laminations
you have a lathe...simply trepann out the coil cavity, leaving a
"post"
in the center

drop in the coils and screw on a round cover to complete the flux
gap

This is sort of like the permanent magnet assembly in at least
one speaker I destroyed as a kid. (Well, the cone was already a goner.)
The center pole and backing plate were one piece (really the pole was
staked into the plate), and the outer housing was a ring Alnico
permanent magnet). Great construction for a stable permanent magnet
field, but not at all good for a transformer.

Now -- for really high frequencies (Ultrasonic, not RF) a
ferrite pot core is really nice. Formed in pretty much the shape
defined above for lathe construction, except that there were two of

That's what I was referring to, had not realized they were ferrite.

them, mounted cup to cup. The cups were available in a large number of
sizes and a number of different ferrite compositions for different
frequency ranges and maximum flux densities.

If you do decide to wind your own, I would recommend using
laminations from a power transformer before using a solid chunk of
material. Audio transformers use thinner laminations than a power
transformer, but ones from a power transformer would be better than
solid.

Agreed! Thinner laminations are better at higher frequencies.

I do remember some special transformers for really old
telephones which were wound on a core of a number of lengths of straight
iron wire bundled together.

A large, powdered iron toroid works even better. Like an old 3A
variac.

Woah! A Variac did *not* use a powedered iron toroid -- nor
did the Superior Electric "Powerstats", nor any other variable
autotransformer by anyone else that I ever saw. :-)

Take a strip of the proper alloy (permalloy? Some other alloy?),
and wind it into a hollow cylinder (with insulating coatings between
layers) and *that* is the toroid that a variable autotransformer is
wound upon. Ideally -- pot that in an insulating material, and use that
to wind the coil on.

Powdered iron (ferrites) are much better at high frequencies,
while most variable autotransformers were optimized for 60 Hz or 50 Hz.
(I have held in my hand some optimized for 400 Hz -- and for those, the
length of the cylinder is about 1/3 that of one for the same current at
60 Hz.

I needed a modulation transformer for a AM mobile radio back in
the '70s. I wound a second winding on a surplus 88 mH telco toroid, and
had excessive audio bandwidth.

:-)

Filtration time. :-)

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703)
938-4564
(too) near Washington D.C. |
http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"DoN. Nichols" wrote:

On 2014-01-19, Michael A. Terrell wrote:
" wrote:

On Sunday, January 19, 2014 1:05:03 AM UTC-5, PrecisionmachinisT wrote:

Or you could wind your own...really no reason to use E laminations
you have a lathe...simply trepann out the coil cavity, leaving a "post"
in the center

drop in the coils and screw on a round cover to complete the flux
gap

This is sort of like the permanent magnet assembly in at least
one speaker I destroyed as a kid. (Well, the cone was already a goner.)
The center pole and backing plate were one piece (really the pole was
staked into the plate), and the outer housing was a ring Alnico
permanent magnet). Great construction for a stable permanent magnet
field, but not at all good for a transformer.


That is because the magnetic bias had the same effect as DC flowing
in the windings. That caused the core to saturate at much lower power
levels.


Now -- for really high frequencies (Ultrasonic, not RF) a
ferrite pot core is really nice. Formed in pretty much the shape
defined above for lathe construction, except that there were two of
them, mounted cup to cup. The cups were available in a large number of
sizes and a number of different ferrite compositions for different
frequency ranges and maximum flux densities.


Pot cores are generally used where the absolute minimum leakage is
allowed.


If you do decide to wind your own, I would recommend using
laminations from a power transformer before using a solid chunk of
material. Audio transformers use thinner laminations than a power
transformer, but ones from a power transformer would be better than
solid.

Agreed! Thinner laminations are better at higher frequencies.

I do remember some special transformers for really old
telephones which were wound on a core of a number of lengths of straight
iron wire bundled together.


These were called 'Loading Coils' and were all over the surplus
market in the '70s for pocket change.


A large, powdered iron toroid works even better. Like an old 3A
variac.

Woah! A Variac did *not* use a powedered iron toroid -- nor
did the Superior Electric "Powerstats", nor any other variable
autotransformer by anyone else that I ever saw. :-)


The one I had was salvaged from a damaged, imported 3A unit.


Take a strip of the proper alloy (permalloy? Some other alloy?),
and wind it into a hollow cylinder (with insulating coatings between
layers) and *that* is the toroid that a variable autotransformer is
wound upon. Ideally -- pot that in an insulating material, and use that
to wind the coil on.

Powdered iron (ferrites) are much better at high frequencies,
while most variable autotransformers were optimized for 60 Hz or 50 Hz.
(I have held in my hand some optimized for 400 Hz -- and for those, the
length of the cylinder is about 1/3 that of one for the same current at
60 Hz.

I needed a modulation transformer for a AM mobile radio back in
the '70s. I wound a second winding on a surplus 88 mH telco toroid, and
had excessive audio bandwidth.

:-)

Filtration time. :-)


No, I liked the shocked responses I got from other users. Everyone
else sounded muddy, with their 2K roll off. That radio sounded crisp
and clear after on going through one frequency limiting core than the
usual pair.


--
Anyone wanting to run for any political office in the US should have to
have a DD214, and a honorable discharge.

On Sun, 19 Jan 2014 06:05:37 -0800 (PST), "
wrote:

On Sunday, January 19, 2014 1:05:03 AM UTC-5, PrecisionmachinisT wrote:


Or you could wind your own...really no reason to use E laminations you have

a lathe...simply trepann out the coil cavity, leaving a "post" in the center

drop in the coils and screw on a round cover to complete the flux gap

If you do decide to wind your own, I would recommend using laminations from a power transformer before using a solid chunk of material. Audio transformers use thinner laminations than a power transformer, but ones from a power transformer would be better than solid.

If you want I could keep an eye out for kind of suitable transforms at the local scrap yard. The shipping via a flat rate box would not be too bad. The last heavy stuff I shipped using a flat rate box , got separated from the box. But since then I got some stronger tape.

Dan
Greetings Dan,
If I decide to wind my own laminations I'll let you know. Thanks for
the offer. My local scrap yard is good but I cannot recall seeing and
xmfrs there.
Eric

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This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com

"PrecisionmachinisT" wrote in
message news:PNydnddXCtyB9kbPnZ2dnUVZ_rKdnZ2d@scnresearch. com...

Or you could wind your own...really no reason to use E laminations
you have a lathe...simply trepann out the coil cavity, leaving a
"post" in the center drop in the coils and screw on a round cover to
complete the flux gap

This is why transformer cores aren't solid iron:
http://en.wikipedia.org/wiki/Transfo...ed_steel_cores
"Early transformer developers soon realized that cores constructed
from solid iron resulted in prohibitive eddy current losses, and their
designs mitigated this effect with cores consisting of bundles of
insulated iron wires."

http://en.wikibooks.org/wiki/Electro...sformer_Design

jsw

"Jim Wilkins" wrote in message
...
"PrecisionmachinisT" wrote in message
news:PNydnddXCtyB9kbPnZ2dnUVZ_rKdnZ2d@scnresearch. com...

Or you could wind your own...really no reason to use E laminations you
have a lathe...simply trepann out the coil cavity, leaving a "post" in
the center drop in the coils and screw on a round cover to complete the
flux gap

This is why transformer cores aren't solid iron:
http://en.wikipedia.org/wiki/Transfo...ed_steel_cores
"Early transformer developers soon realized that cores constructed from
solid iron resulted in prohibitive eddy current losses, and their designs
mitigated this effect with cores consisting of bundles of insulated iron
wires."

http://en.wikibooks.org/wiki/Electro...sformer_Design


Aww okay thanks.

On Sun, 19 Jan 2014 10:39:37 -0500, "Jim Wilkins"
wrote:

"PrecisionmachinisT" wrote in
message news:PNydnddXCtyB9kbPnZ2dnUVZ_rKdnZ2d@scnresearch. com...

Or you could wind your own...really no reason to use E laminations
you have a lathe...simply trepann out the coil cavity, leaving a
"post" in the center drop in the coils and screw on a round cover to
complete the flux gap

This is why transformer cores aren't solid iron:
http://en.wikipedia.org/wiki/Transfo...ed_steel_cores
"Early transformer developers soon realized that cores constructed
from solid iron resulted in prohibitive eddy current losses, and their
designs mitigated this effect with cores consisting of bundles of
insulated iron wires."

http://en.wikibooks.org/wiki/Electro...sformer_Design


There's that damned Crazy Eddy again...

--
Education is that which remains when one has
forgotten everything he learned in school.
--Albert Einstein

"Larry Jaques" wrote in message
news
On Sun, 19 Jan 2014 10:39:37 -0500, "Jim Wilkins"
wrote:

"PrecisionmachinisT" wrote in
message news:PNydnddXCtyB9kbPnZ2dnUVZ_rKdnZ2d@scnresearch. com...

Or you could wind your own...really no reason to use E laminations
you have a lathe...simply trepann out the coil cavity, leaving a
"post" in the center drop in the coils and screw on a round cover
to
complete the flux gap

This is why transformer cores aren't solid iron:
http://en.wikipedia.org/wiki/Transfo...ed_steel_cores
"Early transformer developers soon realized that cores constructed
from solid iron resulted in prohibitive eddy current losses, and
their
designs mitigated this effect with cores consisting of bundles of
insulated iron wires."

http://en.wikibooks.org/wiki/Electro...sformer_Design


There's that damned Crazy Eddy again...

Not meatloaf again!!

On Sun, 19 Jan 2014 13:29:10 -0500, "Jim Wilkins"
wrote:

"Larry Jaques" wrote in message
news
On Sun, 19 Jan 2014 10:39:37 -0500, "Jim Wilkins"
wrote:

"PrecisionmachinisT" wrote in
message news:PNydnddXCtyB9kbPnZ2dnUVZ_rKdnZ2d@scnresearch. com...

Or you could wind your own...really no reason to use E laminations
you have a lathe...simply trepann out the coil cavity, leaving a
"post" in the center drop in the coils and screw on a round cover
to
complete the flux gap

This is why transformer cores aren't solid iron:
http://en.wikipedia.org/wiki/Transfo...ed_steel_cores
"Early transformer developers soon realized that cores constructed
from solid iron resulted in prohibitive eddy current losses, and
their
designs mitigated this effect with cores consisting of bundles of
insulated iron wires."

http://en.wikibooks.org/wiki/Electro...sformer_Design


There's that damned Crazy Eddy again...

Not meatloaf again!!

I must have gotten a mote in my eye. What did you say?
I don't understand.

--
Education is that which remains when one has
forgotten everything he learned in school.
--Albert Einstein

On Sat, 18 Jan 2014 22:05:03 -0800, "PrecisionmachinisT"
wrote:


wrote in message
.. .
Greetings Tubulars,
So I have this crazy idea to build a little tube amp just for fun. The
transformers are quite expensive though. I will be looking for old
ones probably because I can't justify spending loads on new ones. So
considering my almost 60 years old ears, 39 of which have been spent
in noisy environments, and my propensity to listen to loud music, what
should I look for that will sound just a little better than I can
hear? Maybe not an audio xmfr will be OK. There are some old tube amps
in a couple local thrift stores. How can I tell if they had good
xmfrs? Or can I?
Eric


I've built a dozen or so, all point to point wired.

The top quality transformers usually were potted into a square can.

It's important maintain plate-to-plate impedence, so best to use the same
output tubes that the transformers were originally paired with, or at least
look into your tube manual and select a tube a set that is relatively close.

https://www.google.com/search?q=peer...w=1173&bih=564


Or you could wind your own...really no reason to use E laminations you have
a lathe...simply trepann out the coil cavity, leaving a "post" in the center
drop in the coils and screw on a round cover to complete the flux gap

Winding a transformer like you describe above sounds like fun. There
must be somebody selling the right kind of steel sheet for folks who
want to make their own transformers.
Eric

---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com

wrote in message
...

Winding a transformer like you describe above sounds like fun. There
must be somebody selling the right kind of steel sheet for folks who
want to make their own transformers.
Eric

It's vastly easier to recycle an old transformer of adequate core
cross-section for your planned output power. You get the right size of
bobbin to wind your own wire on.
jsw

On Mon, 20 Jan 2014 08:51:34 -0800, wrote:

On Sat, 18 Jan 2014 22:05:03 -0800, "PrecisionmachinisT"
wrote:


wrote in message
. ..
Greetings Tubulars,
So I have this crazy idea to build a little tube amp just for fun. The
transformers are quite expensive though. I will be looking for old
ones probably because I can't justify spending loads on new ones. So
considering my almost 60 years old ears, 39 of which have been spent
in noisy environments, and my propensity to listen to loud music, what
should I look for that will sound just a little better than I can
hear? Maybe not an audio xmfr will be OK. There are some old tube amps
in a couple local thrift stores. How can I tell if they had good
xmfrs? Or can I?
Eric


I've built a dozen or so, all point to point wired.

The top quality transformers usually were potted into a square can.

It's important maintain plate-to-plate impedence, so best to use the same
output tubes that the transformers were originally paired with, or at least
look into your tube manual and select a tube a set that is relatively close.

https://www.google.com/search?q=peer...w=1173&bih=564


Or you could wind your own...really no reason to use E laminations you have
a lathe...simply trepann out the coil cavity, leaving a "post" in the center
drop in the coils and screw on a round cover to complete the flux gap

Winding a transformer like you describe above sounds like fun. There
must be somebody selling the right kind of steel sheet for folks who
want to make their own transformers.

Gawd, reaching back to Coleman College in 1987, IIRC, the stuff is
called lamination steel. Low hysteresis + high permeability.
Googlit.


If you get tired of trying to find stuff, here's a 12x12W kit:
http://www.diyaudio.com/forums/silic...ifier-kit.html

-
To change one's self is sufficient. It's the idiots who want
to change the world who are causing all the trouble.
--Anonymous

On Mon, 20 Jan 2014 11:11:57 -0800, Larry Jaques
wrote:

On Mon, 20 Jan 2014 08:51:34 -0800, wrote:

On Sat, 18 Jan 2014 22:05:03 -0800, "PrecisionmachinisT"
wrote:


wrote in message
...
Greetings Tubulars,
So I have this crazy idea to build a little tube amp just for fun. The
transformers are quite expensive though. I will be looking for old
ones probably because I can't justify spending loads on new ones. So
considering my almost 60 years old ears, 39 of which have been spent
in noisy environments, and my propensity to listen to loud music, what
should I look for that will sound just a little better than I can
hear? Maybe not an audio xmfr will be OK. There are some old tube amps
in a couple local thrift stores. How can I tell if they had good
xmfrs? Or can I?
Eric


I've built a dozen or so, all point to point wired.

The top quality transformers usually were potted into a square can.

It's important maintain plate-to-plate impedence, so best to use the same
output tubes that the transformers were originally paired with, or at least
look into your tube manual and select a tube a set that is relatively close.

https://www.google.com/search?q=peer...w=1173&bih=564


Or you could wind your own...really no reason to use E laminations you have
a lathe...simply trepann out the coil cavity, leaving a "post" in the center
drop in the coils and screw on a round cover to complete the flux gap

Winding a transformer like you describe above sounds like fun. There
must be somebody selling the right kind of steel sheet for folks who
want to make their own transformers.

Gawd, reaching back to Coleman College in 1987, IIRC, the stuff is
called lamination steel. Low hysteresis + high permeability.
Googlit.


If you get tired of trying to find stuff, here's a 12x12W kit:
http://www.diyaudio.com/forums/silic...ifier-kit.html

-
To change one's self is sufficient. It's the idiots who want
to change the world who are causing all the trouble.
--Anonymous
High silicon steel.

wrote in message
...
On Sat, 18 Jan 2014 22:05:03 -0800, "PrecisionmachinisT"
wrote:


wrote in message
. ..
Greetings Tubulars,
So I have this crazy idea to build a little tube amp just for fun. The
transformers are quite expensive though. I will be looking for old
ones probably because I can't justify spending loads on new ones. So
considering my almost 60 years old ears, 39 of which have been spent
in noisy environments, and my propensity to listen to loud music, what
should I look for that will sound just a little better than I can
hear? Maybe not an audio xmfr will be OK. There are some old tube amps
in a couple local thrift stores. How can I tell if they had good
xmfrs? Or can I?
Eric


I've built a dozen or so, all point to point wired.

The top quality transformers usually were potted into a square can.

It's important maintain plate-to-plate impedence, so best to use the same
output tubes that the transformers were originally paired with, or at
least
look into your tube manual and select a tube a set that is relatively
close.

https://www.google.com/search?q=peer...w=1173&bih=564


Or you could wind your own...really no reason to use E laminations you
have
a lathe...simply trepann out the coil cavity, leaving a "post" in the
center
drop in the coils and screw on a round cover to complete the flux gap

Winding a transformer like you describe above sounds like fun. There
must be somebody selling the right kind of steel sheet for folks who
want to make their own transformers.
Eric


http://www.ebay.com/itm/FISHER-VINTA...em46 196eb8ab

http://www.ebay.com/itm/Magnavox-Ste...em58 aac2c5d5

wrote in message
...
Greetings Tubulars,
So I have this crazy idea to build a little tube amp just for fun.
The
transformers are quite expensive though. I will be looking for old
ones probably because I can't justify spending loads on new ones. So
considering my almost 60 years old ears, 39 of which have been spent
in noisy environments, and my propensity to listen to loud music,
what
should I look for that will sound just a little better than I can
hear?

Better speakers, properly placed.

Maybe not an audio xmfr will be OK. There are some old tube amps
in a couple local thrift stores. How can I tell if they had good
xmfrs? Or can I?
Eric

http://lenardaudio.com/education/14_valve_amps_5.html


jsw

On Friday, January 17, 2014 3:18:36 PM UTC-6, wrote:
Greetings Tubulars,

So I have this crazy idea to build a little tube amp just for fun. The


TedWeber.com

On Mon, 20 Jan 2014 11:51:08 -0800 (PST), "Thanks for all the free
stuff -TeaBillies !" wrote:

On Friday, January 17, 2014 3:18:36 PM UTC-6, wrote:
Greetings Tubulars,

So I have this crazy idea to build a little tube amp just for fun. The


TedWeber.com
look at http://diyaudioprojects.com/Tubes/57...-Tube-Amp-Kit/.
lots of others out there too.

On Mon, 20 Jan 2014 11:51:08 -0800 (PST), "Thanks for all the free
stuff -TeaBillies !" wrote:

On Friday, January 17, 2014 3:18:36 PM UTC-6, wrote:
Greetings Tubulars,

So I have this crazy idea to build a little tube amp just for fun. The


TedWeber.com
try ax84.com - I think it is still active.

On Fri, 17 Jan 2014 13:18:36 -0800, the renowned
wrote:

Greetings Tubulars,
So I have this crazy idea to build a little tube amp just for fun. The
transformers are quite expensive though. I will be looking for old
ones probably because I can't justify spending loads on new ones. So
considering my almost 60 years old ears, 39 of which have been spent
in noisy environments, and my propensity to listen to loud music, what
should I look for that will sound just a little better than I can
hear? Maybe not an audio xmfr will be OK. There are some old tube amps
in a couple local thrift stores. How can I tell if they had good
xmfrs? Or can I?
Eric

If you ever run across something from McIntosh, in almost any
condition, that would be a good bet.


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

On Mon, 27 Jan 2014 08:32:25 -0500, Spehro Pefhany
wrote:

On Fri, 17 Jan 2014 13:18:36 -0800, the renowned
wrote:

Greetings Tubulars,
So I have this crazy idea to build a little tube amp just for fun. The
transformers are quite expensive though. I will be looking for old
ones probably because I can't justify spending loads on new ones. So
considering my almost 60 years old ears, 39 of which have been spent
in noisy environments, and my propensity to listen to loud music, what
should I look for that will sound just a little better than I can
hear? Maybe not an audio xmfr will be OK. There are some old tube amps
in a couple local thrift stores. How can I tell if they had good
xmfrs? Or can I?
Eric

If you ever run across something from McIntosh, in almost any
condition, that would be a good bet.


Best regards,
Spehro Pefhany
So I could either re-build the old McIntosh or just use the
transformers and any good tubes to build my own? Probably rebuilding
would be best, and I bet there are schematics available online.
Thanks,
Eric

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Mostly it is the electrolytic caps that dry out. Some are power
and some are Bias or bypass / blockers - filters of all types.

Foil and mica don't go bad unless really high voltage is generated.

Good idea. Most tubes last and last.

Martin

On 1/29/2014 6:37 PM, wrote:
On Mon, 27 Jan 2014 08:32:25 -0500, Spehro Pefhany
wrote:

On Fri, 17 Jan 2014 13:18:36 -0800, the renowned
wrote:

Greetings Tubulars,
So I have this crazy idea to build a little tube amp just for fun. The
transformers are quite expensive though. I will be looking for old
ones probably because I can't justify spending loads on new ones. So
considering my almost 60 years old ears, 39 of which have been spent
in noisy environments, and my propensity to listen to loud music, what
should I look for that will sound just a little better than I can
hear? Maybe not an audio xmfr will be OK. There are some old tube amps
in a couple local thrift stores. How can I tell if they had good
xmfrs? Or can I?
Eric

If you ever run across something from McIntosh, in almost any
condition, that would be a good bet.


Best regards,
Spehro Pefhany
So I could either re-build the old McIntosh or just use the
transformers and any good tubes to build my own? Probably rebuilding
would be best, and I bet there are schematics available online.
Thanks,
Eric

---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com