I have heard of installing a FET in the base of tubes. Where can I find out information about this?

Back in the late '60s, this was a popular idea. Commercial "Fetrons" were supplied by Teledyne Semiconductor. Check out this web site for a beginning.

http://www.sigtel.com/tel_tech_fetrons.html

Good luck ! Rich

:I have heard of installing a FET in the base of tubes. Where can I find out information about this?

Hi Rich

I have some Fetrons but this is the first time I heard anyone talk about them. They are is small metal cans a little larger than Nuvistors.

Norm

:Back in the late '60s, this was a popular idea. Commercial "Fetrons" were supplied by Teledyne Semiconductor. Check out this web site for a beginning.
:
:http://www.sigtel.com/tel_tech_fetrons.html
:
:
:Good luck ! Rich
:
::I have heard of installing a FET in the base of tubes. Where can I find out information about this?

Hi Steve

In Antique Radio Classified a person was selling FET wafers which can be used below 01A and other similar triode tubes.

I have an article where a FET can be used with photo cell input. A small lamp operated by filament voltage of a radio controlling brightness and volume, similar to old TRF radios.

Norm

:I have heard of installing a FET in the base of tubes. Where can I find out information about this?

I tested some of these wafers prior to their sale. They work well for amplifiers, but are poor detectors. They will easily install upside down over the pins of the tube, so extreme caution is advised.

Several years before the wafers, I got the bright idea that an FET should work inside the base of an 01A tube and tried some from Radio Shack. I didn’t know squat about what I was doing, but even in my ignorance, they worked reasonably well. Soon afterward, I discovered that 01A tubes were fairly easy to come by at reasonable cost, so I soon forgot everything about an FET that I ever wanted to know. Seems like I remember that the greatest advantage for using them was that they use a lot less current from the “A” battery.

Hi Billy

I sent you an email using a 958A in the base of a 201A. They work well but not worth the effort as 201A's are still available.

Norm

:I tested some of these wafers prior to their sale. They work well for amplifiers, but are poor detectors. They will easily install upside down over the pins of the tube, so extreme caution is advised.
:
:Several years before the wafers, I got the bright idea that an FET should work inside the base of an 01A tube and tried some from Radio Shack. I didn’t know squat about what I was doing, but even in my ignorance, they worked reasonably well. Soon afterward, I discovered that 01A tubes were fairly easy to come by at reasonable cost, so I soon forgot everything about an FET that I ever wanted to know. Seems like I remember that the greatest advantage for using them was that they use a lot less current from the “A” battery.
:

Thanks for sending the attachment Norm. I never thought to use an acorn tube this way, but can easily see where it would work. I did sort of the same thing years ago with a 12SA7, which believe it or not, can be made to fit inside a 201A by grinding everything off the bottom of the globe. Of course, I was not using it to replace the 201A, but to disguise the 12SA7. I'll send you some details about it later on today.

How were these acorn tubes secured? That sounds very interesting.

:Hi Billy
:
: I sent you an email using a 958A in the base of a 201A. They work well but not worth the effort as 201A's are still available.
:
:Norm
:
::I tested some of these wafers prior to their sale. They work well for amplifiers, but are poor detectors. They will easily install upside down over the pins of the tube, so extreme caution is advised.
::
::Several years before the wafers, I got the bright idea that an FET should work inside the base of an 01A tube and tried some from Radio Shack. I didn’t know squat about what I was doing, but even in my ignorance, they worked reasonably well. Soon afterward, I discovered that 01A tubes were fairly easy to come by at reasonable cost, so I soon forgot everything about an FET that I ever wanted to know. Seems like I remember that the greatest advantage for using them was that they use a lot less current from the “A” battery.
::

Would you mind sharing with me the procedure for using the FET in a 201A base. I would be most thankful.

Mike Landon

:Hi Billy
:
: I sent you an email using a 958A in the base of a 201A. They work well but not worth the effort as 201A's are still available.
:
:Norm
:
::I tested some of these wafers prior to their sale. They work well for amplifiers, but are poor detectors. They will easily install upside down over the pins of the tube, so extreme caution is advised.
::
::Several years before the wafers, I got the bright idea that an FET should work inside the base of an 01A tube and tried some from Radio Shack. I didn’t know squat about what I was doing, but even in my ignorance, they worked reasonably well. Soon afterward, I discovered that 01A tubes were fairly easy to come by at reasonable cost, so I soon forgot everything about an FET that I ever wanted to know. Seems like I remember that the greatest advantage for using them was that they use a lot less current from the “A” battery.
::

Rich
Norm
Billy
Thanks for the infor, I think I have found out all I need to know about FET conversion. NOT worth the effort.
Thanks
Steve

I worked for Siliconix for 7 yrs. We were one of the largest mfrs. of JFETs. We never took the FETRON idea seriously as it wasn't a big enough market and most users decided "not worth the effort." I do like to build regen radios using JFETs instead of tubes. No "A: supply needed, lower B+ voltages, and no microphonics.

Rich

:Rich
:Norm
:Billy
:Thanks for the infor, I think I have found out all I need to know about FET conversion. NOT worth the effort.
:Thanks
:Steve