Home brew TRF radio 01A substitute?

[Mike Srock]

Hello group.

I have found an old home brew TRF radio at a garage sale. It is mostly
complete except the tube sockets are missing.
It's pretty ugly too. I would like to patch it up and use it to listen to
my vectronics transmitter while I am out in the carriage house.
Since it is pretty disposable I wouldn't mind leaving it out there. My
question to the group is this:

Is there a octal based tube that performs like an 01A? I have lots of octal
sockets on hand and I would like to use
easily obtainable cheap tubes to replace the 01A's. I actually have a
pretty good stash of 01A tubes here as spares for
my Freed Eisemann NR-6 and AK 10-B but I don't want to use them in a junky
utility radio. Since the sockets all need
replacing anyway I figured it would be a fun experiment. A shoulder type
tube would be preferable. Something common and cheap. Something I could
get from AES.

Your comments are appreciated!

Thanks!

Mike

[John H. Smith]

Subject: Home brew TRF radio 01A substitute?
Date: 9/5/2004 2:04 PM Central Daylight Time
Hello group.
I have found an old home brew TRF radio at a garage sale. It is mostly
complete except the tube sockets are missing.
It's pretty ugly too. I would like to patch it up and use it to listen to
my vectronics transmitter while I am out in the carriage house.
Since it is pretty disposable I wouldn't mind leaving it out there. My
Is there a octal based tube that performs like an 01A? I have lots of octal
sockets on hand and I would like to use
easily obtainable cheap tubes to replace the 01A's. I actually have a
pretty good stash of 01A tubes here as spares for
my Freed Eisemann NR-6 and AK 10-B but I don't want to use them in a junky
utility radio. Since the sockets all need
replacing anyway I figured it would be a fun experiment. A shoulder type
tube would be preferable. Something common and cheap. Something I could
get from AES.
Your comments are appreciated!
Thanks!
Mike

6P5GT is about as close a glass octal as you'll find, don't think you'll find
shoulders on any.. Most of the commoner AC triode replacements have 4 pin bases
as in 37,56,76. the 6A4 (Also known as "LA") is a 5 pin audio power tube that
is said to have characteristics similar to a 201 with the screen tied to the
plate (or the screenb abd grid tied, take your pick & experiment). It look
similar & is a vary common, cheap tube. The triode in a 6F7 would do. As would
the triode in a 55. If you modify the circuit a but, even higher mu tubes would
work.
DC tubes - 30 is a direct replacement with a filament intended for 2V wet
or air cells with a dropping rheostat. A good alkaline "D" cell will run them,
but they are 4 pins and becoming pricier than a run of the mill 201. 1H4 will
do but isn't really common.
There are TONS of miniatures that will do, as well as subminiatures,
usually tetrodes wityh the screen ntird to plate or grid. TV tubes abound with
a triode section suitable. Then you can use your imagination to conceal the
working tube under a nice looking dud.
Or use dud tubes with the FET wafers under them....These can be found
in/at ARC.
Practically any tube you can imagine (even eye tubes) can be wired to act
pretty much like a low gain triode such as a 201 by hooking elements together,
keeping the B+ voltage down and in some cases starving the filament a bit.
Neutrodyne

[Mike Srock]

Thanks John. The 6P5GT is $17 at AES. A litte too pricey for me.

Tell me more about FET wafers. Is this a solid state replacement for the
tubes?
I can make boards. I would love to try making FET replacements!
Is there schematics available somewhere for this?

Thanks again!

Mike

Post by John H. Smith

Subject: Home brew TRF radio 01A substitute?
Date: 9/5/2004 2:04 PM Central Daylight Time
Hello group.
I have found an old home brew TRF radio at a garage sale. It is mostly
complete except the tube sockets are missing.
It's pretty ugly too. I would like to patch it up and use it to listen to
my vectronics transmitter while I am out in the carriage house.
Since it is pretty disposable I wouldn't mind leaving it out there. My
Is there a octal based tube that performs like an 01A? I have lots of octal
sockets on hand and I would like to use
easily obtainable cheap tubes to replace the 01A's. I actually have a
pretty good stash of 01A tubes here as spares for
my Freed Eisemann NR-6 and AK 10-B but I don't want to use them in a junky
utility radio. Since the sockets all need
replacing anyway I figured it would be a fun experiment. A shoulder type
tube would be preferable. Something common and cheap. Something I could
get from AES.
Your comments are appreciated!
Thanks!
Mike

6P5GT is about as close a glass octal as you'll find, don't think you'll find
shoulders on any.. Most of the commoner AC triode replacements have 4 pin bases
as in 37,56,76. the 6A4 (Also known as "LA") is a 5 pin audio power tube that
is said to have characteristics similar to a 201 with the screen tied to the
plate (or the screenb abd grid tied, take your pick & experiment). It look
similar & is a vary common, cheap tube. The triode in a 6F7 would do. As would
the triode in a 55. If you modify the circuit a but, even higher mu tubes would
work.
DC tubes - 30 is a direct replacement with a filament intended for 2V wet
or air cells with a dropping rheostat. A good alkaline "D" cell will run them,
but they are 4 pins and becoming pricier than a run of the mill 201. 1H4 will
do but isn't really common.
There are TONS of miniatures that will do, as well as subminiatures,
usually tetrodes wityh the screen ntird to plate or grid. TV tubes abound with
a triode section suitable. Then you can use your imagination to conceal the
working tube under a nice looking dud.
Or use dud tubes with the FET wafers under them....These can be found
in/at ARC.
Practically any tube you can imagine (even eye tubes) can be wired to act
pretty much like a low gain triode such as a 201 by hooking elements together,
keeping the B+ voltage down and in some cases starving the filament a bit.
Neutrodyne

[Mark Oppat]

Mike,
I had an RCA Radiola III that someone had converted to 7 pin minatures. I
think they were 1U4 or 1T4,.1S4, dont recall. It worked...
Mark Oppat

Post by Mike Srock
Thanks John. The 6P5GT is $17 at AES. A litte too pricey for me.
Tell me more about FET wafers. Is this a solid state replacement for the
tubes?
I can make boards. I would love to try making FET replacements!
Is there schematics available somewhere for this?
Thanks again!
Mike

Post by John H. Smith

Subject: Home brew TRF radio 01A substitute?
Date: 9/5/2004 2:04 PM Central Daylight Time
Hello group.
I have found an old home brew TRF radio at a garage sale. It is mostly
complete except the tube sockets are missing.
It's pretty ugly too. I would like to patch it up and use it to listen

to

Post by John H. Smith

my vectronics transmitter while I am out in the carriage house.
Since it is pretty disposable I wouldn't mind leaving it out there. My
Is there a octal based tube that performs like an 01A? I have lots of

octal

Post by John H. Smith

sockets on hand and I would like to use
easily obtainable cheap tubes to replace the 01A's. I actually have a
pretty good stash of 01A tubes here as spares for
my Freed Eisemann NR-6 and AK 10-B but I don't want to use them in a

junky

Post by John H. Smith

utility radio. Since the sockets all need
replacing anyway I figured it would be a fun experiment. A shoulder type
tube would be preferable. Something common and cheap. Something I could
get from AES.
Your comments are appreciated!
Thanks!
Mike

6P5GT is about as close a glass octal as you'll find, don't think you'll

find

Post by John H. Smith
shoulders on any.. Most of the commoner AC triode replacements have 4

pin

Post by Mike Srock
bases

Post by John H. Smith
as in 37,56,76. the 6A4 (Also known as "LA") is a 5 pin audio power tube

that

Post by John H. Smith
is said to have characteristics similar to a 201 with the screen tied to

the

Post by John H. Smith
plate (or the screenb abd grid tied, take your pick & experiment). It look
similar & is a vary common, cheap tube. The triode in a 6F7 would do. As

would

Post by John H. Smith
the triode in a 55. If you modify the circuit a but, even higher mu

tubes

Post by Mike Srock
would

Post by John H. Smith
work.
DC tubes - 30 is a direct replacement with a filament intended for

2V

Post by Mike Srock
wet

Post by John H. Smith
or air cells with a dropping rheostat. A good alkaline "D" cell will run

them,

Post by John H. Smith
but they are 4 pins and becoming pricier than a run of the mill 201.

1H4

Post by Mike Srock
will

Post by John H. Smith
do but isn't really common.
There are TONS of miniatures that will do, as well as

subminiatures,

Post by Mike Srock

Post by John H. Smith
usually tetrodes wityh the screen ntird to plate or grid. TV tubes

abound

Post by Mike Srock
with

Post by John H. Smith
a triode section suitable. Then you can use your imagination to conceal

the

Post by John H. Smith
working tube under a nice looking dud.
Or use dud tubes with the FET wafers under them....These can be found
in/at ARC.
Practically any tube you can imagine (even eye tubes) can be wired

to

Post by Mike Srock
act

Post by John H. Smith
pretty much like a low gain triode such as a 201 by hooking elements

together,

Post by John H. Smith
keeping the B+ voltage down and in some cases starving the filament a bit.
Neutrodyne

[Travis Ogden]

I emailed you the FET replacements I have made in the past.
Travis

Post by Mike Srock
Thanks John. The 6P5GT is $17 at AES. A litte too pricey for me.
Tell me more about FET wafers. Is this a solid state replacement for the
tubes?
I can make boards. I would love to try making FET replacements!
Is there schematics available somewhere for this?
Thanks again!
Mike

[Mike Srock]

Thanks Travis.

I will give it a go and let the group know how I make out.
It will probably have to wait a while because I am busy restoring my
grandparents old house for sale. (been at it 3 months now...)

Mike

Post by Travis Ogden
I emailed you the FET replacements I have made in the past.
Travis

Post by Mike Srock
Thanks John. The 6P5GT is $17 at AES. A litte too pricey for me.
Tell me more about FET wafers. Is this a solid state replacement for the
tubes?
I can make boards. I would love to try making FET replacements!
Is there schematics available somewhere for this?
Thanks again!
Mike

[Robert Casey]

Post by Mike Srock
Is there a octal based tube that performs like an 01A? I have lots of octal
sockets on hand and I would like to use
easily obtainable cheap tubes to replace the 01A's. I actually have a
pretty good stash of 01A tubes here as spares for
my Freed Eisemann NR-6 and AK 10-B but I don't want to use them in a junky
utility radio. Since the sockets all need
replacing anyway I figured it would be a fun experiment. A shoulder type
tube would be preferable. Something common and cheap. Something I could
get from AES.

IIRC Bill T makes a direct plug in sub that is made to look like
the real thing. He uses a submini indicator tube 6977 which
happens to have characteristics like the 01A except for less filament
current demand. Parallel a resistor to make it draw more current
if you don't want to change the reostat. A bit pricey at about $13
at aes though.