Tubes, same ID, different pinout/shape

12/18/2007 7:10:57 AMDave Rust

Hi All,

I bought a 6A7 tube from Ebay for an old DeWald I have. The tube I am replacing is a 7 pin Pentagrid-Converter. The tube I ordered was a "Russian metal case 6A7". I assumed they would be the same. The russian tube has 8 pins (without the contact on top).
Is this the same tube internally?
I assume I would have to change the socket to use this.
I am going back to Ebay to get the correct tube... this time I will "pay attention" to what I am ordering

Dave

12/18/2007 9:36:40 AMNorm Leal

Hi Dave

Someone just supplied you with the wrong tube. All 6A7 tubes have 7 pins with a grid cap on top. Never heard of a Russian metal 6A7 but guess they could make one. It would still have the top cap and 7 pins.

Norm

:Hi All,
:
:I bought a 6A7 tube from Ebay for an old DeWald I have. The tube I am replacing is a 7 pin Pentagrid-Converter. The tube I ordered was a "Russian metal case 6A7". I assumed they would be the same. The russian tube has 8 pins (without the contact on top).
:Is this the same tube internally?
:I assume I would have to change the socket to use this.
:I am going back to Ebay to get the correct tube... this time I will "pay attention" to what I am ordering
:
:Dave

12/18/2007 10:43:42 AMDave Rust

hmmm... thanks... that's the first problem I've had purchasing from ebay. Good thing it was only a few bucks.

Hey I've got a metal 6A7 for sale! (just kidding)
Gotta have a sense of humor to get through life! Don't let the small stuff bug ya...

Dave

:Hi Dave
:
: Someone just supplied you with the wrong tube. All 6A7 tubes have 7 pins with a grid cap on top. Never heard of a Russian metal 6A7 but guess they could make one. It would still have the top cap and 7 pins.
:
:Norm
:
::Hi All,
::
::I bought a 6A7 tube from Ebay for an old DeWald I have. The tube I am replacing is a 7 pin Pentagrid-Converter. The tube I ordered was a "Russian metal case 6A7". I assumed they would be the same. The russian tube has 8 pins (without the contact on top).
::Is this the same tube internally?
::I assume I would have to change the socket to use this.
::I am going back to Ebay to get the correct tube... this time I will "pay attention" to what I am ordering
::
::Dave

12/18/2007 11:16:19 AMCarl T

Apparently the Russian 6A7 is a metal 8 pin tube.
There is a link on Ebay to the data sheet:
http://www.russiantubes.com/prop.php?t=12&p=83
for the tubes for sale:
http://cgi.ebay.com/6A7-Russian-TUBE_W0QQitemZ260170306330QQihZ016QQcategoryZ50598QQrdZ1QQssPageNameZWD1VQQcmdZViewItem?_trksid=p1638.m118

Carl T

:hmmm... thanks... that's the first problem I've had purchasing from ebay. Good thing it was only a few bucks.
:
:Hey I've got a metal 6A7 for sale! (just kidding)
:Gotta have a sense of humor to get through life! Don't let the small stuff bug ya...
:
:Dave
:
::Hi Dave
::
:: Someone just supplied you with the wrong tube. All 6A7 tubes have 7 pins with a grid cap on top. Never heard of a Russian metal 6A7 but guess they could make one. It would still have the top cap and 7 pins.
::
::Norm
::
:::Hi All,
:::
:::I bought a 6A7 tube from Ebay for an old DeWald I have. The tube I am replacing is a 7 pin Pentagrid-Converter. The tube I ordered was a "Russian metal case 6A7". I assumed they would be the same. The russian tube has 8 pins (without the contact on top).
:::Is this the same tube internally?
:::I assume I would have to change the socket to use this.
:::I am going back to Ebay to get the correct tube... this time I will "pay attention" to what I am ordering
:::
:::Dave

12/18/2007 1:15:50 PMDave Rust

Your right Carl, that is the schematic.
I also received a smaller version of the schematic with the tube. The tube is in great shape and is "as advertised". I could use it by modifying the radio (new socket and wiring change). I am going to look for one that has the original form factor (glass 7pin), to keep it a simple remove and replace.

:Apparently the Russian 6A7 is a metal 8 pin tube.
:There is a link on Ebay to the data sheet:
:http://www.russiantubes.com/prop.php?t=12&p=83
:for the tubes for sale:
:http://cgi.ebay.com/6A7-Russian-TUBE_W0QQitemZ260170306330QQihZ016QQcategoryZ50598QQrdZ1QQssPageNameZWD1VQQcmdZViewItem?_trksid=p1638.m118
:
:Carl T
:
::hmmm... thanks... that's the first problem I've had purchasing from ebay. Good thing it was only a few bucks.
::
::Hey I've got a metal 6A7 for sale! (just kidding)
::Gotta have a sense of humor to get through life! Don't let the small stuff bug ya...
::
::Dave
::
:::Hi Dave
:::
::: Someone just supplied you with the wrong tube. All 6A7 tubes have 7 pins with a grid cap on top. Never heard of a Russian metal 6A7 but guess they could make one. It would still have the top cap and 7 pins.
:::
:::Norm
:::
::::Hi All,
::::
::::I bought a 6A7 tube from Ebay for an old DeWald I have. The tube I am replacing is a 7 pin Pentagrid-Converter. The tube I ordered was a "Russian metal case 6A7". I assumed they would be the same. The russian tube has 8 pins (without the contact on top).
::::Is this the same tube internally?
::::I assume I would have to change the socket to use this.
::::I am going back to Ebay to get the correct tube... this time I will "pay attention" to what I am ordering
::::
::::Dave

12/18/2007 1:31:36 PMNorm Leal

Wonder if the Russians copied a US tube and used the wrong number? A US 6A7 with 8 pins is 6A8. I've heard of others where someone didn't follow the numbering system. How about a 6E5G. They took a 6 pin 6E5 and gave it an octal base.

Norm

:Your right Carl, that is the schematic.
:I also received a smaller version of the schematic with the tube. The tube is in great shape and is "as advertised". I could use it by modifying the radio (new socket and wiring change). I am going to look for one that has the original form factor (glass 7pin), to keep it a simple remove and replace.
:
:
::Apparently the Russian 6A7 is a metal 8 pin tube.
::There is a link on Ebay to the data sheet:
::http://www.russiantubes.com/prop.php?t=12&p=83
::for the tubes for sale:
::http://cgi.ebay.com/6A7-Russian-TUBE_W0QQitemZ260170306330QQihZ016QQcategoryZ50598QQrdZ1QQssPageNameZWD1VQQcmdZViewItem?_trksid=p1638.m118
::
::Carl T
::
:::hmmm... thanks... that's the first problem I've had purchasing from ebay. Good thing it was only a few bucks.
:::
:::Hey I've got a metal 6A7 for sale! (just kidding)
:::Gotta have a sense of humor to get through life! Don't let the small stuff bug ya...
:::
:::Dave
:::
::::Hi Dave
::::
:::: Someone just supplied you with the wrong tube. All 6A7 tubes have 7 pins with a grid cap on top. Never heard of a Russian metal 6A7 but guess they could make one. It would still have the top cap and 7 pins.
::::
::::Norm
::::
:::::Hi All,
:::::
:::::I bought a 6A7 tube from Ebay for an old DeWald I have. The tube I am replacing is a 7 pin Pentagrid-Converter. The tube I ordered was a "Russian metal case 6A7". I assumed they would be the same. The russian tube has 8 pins (without the contact on top).
:::::Is this the same tube internally?
:::::I assume I would have to change the socket to use this.
:::::I am going back to Ebay to get the correct tube... this time I will "pay attention" to what I am ordering
:::::
:::::Dave

12/18/2007 1:35:08 PMNorm Leal

Just looked at the Russian 6A7. Think they actually left out an "S". Their 6A7 looks like a 6SA7.

Norm

:Wonder if the Russians copied a US tube and used the wrong number? A US 6A7 with 8 pins is 6A8. I've heard of others where someone didn't follow the numbering system. How about a 6E5G. They took a 6 pin 6E5 and gave it an octal base.
:
:Norm
:
:
::Your right Carl, that is the schematic.
::I also received a smaller version of the schematic with the tube. The tube is in great shape and is "as advertised". I could use it by modifying the radio (new socket and wiring change). I am going to look for one that has the original form factor (glass 7pin), to keep it a simple remove and replace.
::
::
:::Apparently the Russian 6A7 is a metal 8 pin tube.
:::There is a link on Ebay to the data sheet:
:::http://www.russiantubes.com/prop.php?t=12&p=83
:::for the tubes for sale:
:::http://cgi.ebay.com/6A7-Russian-TUBE_W0QQitemZ260170306330QQihZ016QQcategoryZ50598QQrdZ1QQssPageNameZWD1VQQcmdZViewItem?_trksid=p1638.m118
:::
:::Carl T
:::
::::hmmm... thanks... that's the first problem I've had purchasing from ebay. Good thing it was only a few bucks.
::::
::::Hey I've got a metal 6A7 for sale! (just kidding)
::::Gotta have a sense of humor to get through life! Don't let the small stuff bug ya...
::::
::::Dave
::::
:::::Hi Dave
:::::
::::: Someone just supplied you with the wrong tube. All 6A7 tubes have 7 pins with a grid cap on top. Never heard of a Russian metal 6A7 but guess they could make one. It would still have the top cap and 7 pins.
:::::
:::::Norm
:::::
::::::Hi All,
::::::
::::::I bought a 6A7 tube from Ebay for an old DeWald I have. The tube I am replacing is a 7 pin Pentagrid-Converter. The tube I ordered was a "Russian metal case 6A7". I assumed they would be the same. The russian tube has 8 pins (without the contact on top).
::::::Is this the same tube internally?
::::::I assume I would have to change the socket to use this.
::::::I am going back to Ebay to get the correct tube... this time I will "pay attention" to what I am ordering
::::::
::::::Dave

12/18/2007 8:32:21 PMRadiodoc

Norm,

I'm with you on this one. The pin out of the elements are the same (unless I overlooked something) for the "Russian 6A7" and a 6SA7 tube.

Radiodoc
**********

:Just looked at the Russian 6A7. Think they actually left out an "S". Their 6A7 looks like a 6SA7.
:
:Norm
:
::Wonder if the Russians copied a US tube and used the wrong number? A US 6A7 with 8 pins is 6A8. I've heard of others where someone didn't follow the numbering system. How about a 6E5G. They took a 6 pin 6E5 and gave it an octal base.
::
::Norm
::
::
:::Your right Carl, that is the schematic.
:::I also received a smaller version of the schematic with the tube. The tube is in great shape and is "as advertised". I could use it by modifying the radio (new socket and wiring change). I am going to look for one that has the original form factor (glass 7pin), to keep it a simple remove and replace.
:::
:::
::::Apparently the Russian 6A7 is a metal 8 pin tube.
::::There is a link on Ebay to the data sheet:
::::http://www.russiantubes.com/prop.php?t=12&p=83
::::for the tubes for sale:
::::http://cgi.ebay.com/6A7-Russian-TUBE_W0QQitemZ260170306330QQihZ016QQcategoryZ50598QQrdZ1QQssPageNameZWD1VQQcmdZViewItem?_trksid=p1638.m118
::::
::::Carl T
::::
:::::hmmm... thanks... that's the first problem I've had purchasing from ebay. Good thing it was only a few bucks.
:::::
:::::Hey I've got a metal 6A7 for sale! (just kidding)
:::::Gotta have a sense of humor to get through life! Don't let the small stuff bug ya...
:::::
:::::Dave
:::::
::::::Hi Dave
::::::
:::::: Someone just supplied you with the wrong tube. All 6A7 tubes have 7 pins with a grid cap on top. Never heard of a Russian metal 6A7 but guess they could make one. It would still have the top cap and 7 pins.
::::::
::::::Norm
::::::
:::::::Hi All,
:::::::
:::::::I bought a 6A7 tube from Ebay for an old DeWald I have. The tube I am replacing is a 7 pin Pentagrid-Converter. The tube I ordered was a "Russian metal case 6A7". I assumed they would be the same. The russian tube has 8 pins (without the contact on top).
:::::::Is this the same tube internally?
:::::::I assume I would have to change the socket to use this.
:::::::I am going back to Ebay to get the correct tube... this time I will "pay attention" to what I am ordering
:::::::
:::::::Dave

12/18/2007 9:11:59 PMThomas Dermody

Hmmmm....keep it for when you need a 6SA7. I was thinking the same thing regarding how the grids are wired, though I didn't realize that the pinout was the same. Mark it with a silver marker.

I have some Russian 6E5 tubes. The number is actually 6E5C, and yes, it has an octal base. They work fairly well. The auction I bought them from was a fairly good deal--10 for $75...and actually I think I got them for $65. Can't beat that. For new projects I'll use an octal socket, and for existing ones I'll probably use an adaptor.

12/18/2007 9:41:03 PMLewis Linson

Excuse me, but wouldn't putting a grid cap (or a plate cap for that matter) on a metal tube be just a little difficult??
Lewis

:Hmmmm....keep it for when you need a 6SA7. I was thinking the same thing regarding how the grids are wired, though I didn't realize that the pinout was the same. Mark it with a silver marker.
:
:I have some Russian 6E5 tubes. The number is actually 6E5C, and yes, it has an octal base. They work fairly well. The auction I bought them from was a fairly good deal--10 for $75...and actually I think I got them for $65. Can't beat that. For new projects I'll use an octal socket, and for existing ones I'll probably use an adaptor.

12/18/2007 10:40:45 PMThomas Dermody

No. They're fairly common. The wire is sealed inside with a glass bead that is bonded to the metal, much like how the wires are sealed on the bottom. Then a phenolic or porcelain insulator is placed in a special part of the metal shell that's designed to retain the insulator. The grid cap is mounted to the phenolic or porcelain insulator. Sometime, if you happen to run across a metal tube with a grid cap on top, disect it. A pipe cutter will open a metal tube well, or you can just rip it apart if you prefer.

12/18/2007 10:55:59 PMThomas Dermody

I couldn't find that familiar cut-open drawing that I've seen so many times of a metal tube with a grid cap, but here's an example of the real thing, a 6A8 converter:

http://www.shinjo.info/frank/photos/021/6/6A8.jpg

12/19/2007 1:01:19 PMLewis Linson

:I couldn't find that familiar cut-open drawing that I've seen so many times of a metal tube with a grid cap, but here's an example of the real thing, a 6A8 converter:
:
:http://www.shinjo.info/frank/photos/021/6/6A8.jpg

Oh, yeah, I remember those...been a loooong time since I've seen one, tho.
Lewis

12/19/2007 4:45:23 PMJon

Dave,
I have a 6A7 all boxed up-just need a mailing address.It tested fine on both amp. and osc.Email me your address and it will be on its way.
Regards and Happy Holidays,
Jon.

12/19/2007 5:17:42 PMDave Rust

Thanks Jon!

You should have my address now.

Dave

::Hi All,
::
::I bought a 6A7 tube from Ebay for an old DeWald I have. The tube I am replacing is a 7 pin Pentagrid-Converter. The tube I ordered was a "Russian metal case 6A7". I assumed they would be the same. The russian tube has 8 pins (without the contact on top).
::Is this the same tube internally?
::I assume I would have to change the socket to use this.
::I am going back to Ebay to get the correct tube... this time I will "pay attention" to what I am ordering
::
::Dave
:
:Dave,
:I have a 6A7 all boxed up-just need a mailing address.It tested fine on both amp. and osc.Email me your address and it will be on its way.
:Regards and Happy Holidays,
:Jon.