Double Twin Triode Regeneration Radio

I am glad in hosting this design in my website. Please contact the author for any question.

You also will find :


          The original post

          A datasheet of 6SN7 (in English) can be found here. Specifications can be found in a PDF datasheet pointed by this page, in German.


Congratulations to the author.

73 Dimitri F4DYT


The original post

From: Scot Armstrong []
Sent: vendredi 2 janvier 2004 19:53
Subject: Scot's Regen Schematic

Here it is.  Please feel free to put it on a site that everyone can get to. 

This set is the best I have some up with so far.  That is why I have chosen to share it.  It is the product of several years of listening to all of you.  I put into place the lessons from this board and it's members.  If you keep the leads very short, the layout good, and optimize it, it is a very strong performer.  There is nothing revolutionary in it's design.  Just my best construction techniques and keeping it neat and simple. 

Have fun,

Scot Armstrong

Alternative valves for the design



[]On Behalf Of

Prof.Arnaldo Coro Antich

Sent: vendredi 2 janvier 2004 20:20

To: Scot Armstrong


Subject: GB> Re: Scot's Regen Schematic a small mistake


Dear amigos GLOWBUGS

There is a little mistake in the schematic of the Scot Armstrong nice


The input capacitor must go only to the center of the potentiometer, and not to ground too...

Just erase the line that sends the signal from the antenna to ground !!! [Editor's comment: done in this Web page]

BTW, it would be nice to learn about amigo Scot's coil, and how he made it( number of turns, wire diameter and diameter of coil...

May want to test the circuit also with my favorite 6AK5-5654-6ZHE1P tube, using another one triode connected as the grounded grid RF amplifier stage... ( Got plenty of the 6ZHE1P Russian tubes here !!! )


73 and DX


Seasons Greetings to all



More alternative valves and comments on design choices



[]On Behalf Of

Prof.Arnaldo Coro Antich

Sent: vendredi 2 janvier 2004 20:09

To: Scot Armstrong


Subject: GB> Re: Scot's Regen Schematic



Dear amigo:

Regarding Scot's Regen Schematic just received here !!!

You may want to try ( for more audio output to headphones and also quite enough for a loudspeaker ) to use an ECL82 triode-pentode audio amplifier tube, that was very popular among European radio receiver manufacturers of the late fifties and early sixties, before transistors took over the stage.

Also, you may want to test the European ECC85 noval 9 pin miniature dual triode for the RF amplifier and regenerative detector stage instead of the 6SN7.

Your values of 40 pf and 10 megs for the grid of the regenerative detector are ABSOLUTELY RIGHT for best possible results from a regenerative vacuum tube detector !!!

I use here 50 pF and 8,2 megs, as those values are easily found from recycled vacuum tube TV sets that are plentiful locally .

Another fact that people often forget is to build the regenerative detector stage as if you were building a battleship !!! Have you seen the ZL2JJ regenerative receiver ???

I have all the information about it, and can send them to you, including the diagrams and photos of what I believe is the best ever regenerative receiver ever built !


~73 and DX


Your friend in Havana

Arnie Coro



Comments about the 300 pF capacitor

-----Original Message-----
From: []On Behalf Of Prof. Arnaldo Coro Antich
Sent: samedi 3 janvier 2004 03:54
To: Scot Armstrong
Subject: GB> Re: Amended Schematic

OK amigo !

Understand you keep the 300 pf to ground as a fixed capacitance, and that you change the voltage provided to the detector very smoothly...

Have you ever tried a HELIPOT tm , helically wound potentiometer ( 10 turns maybe ) for the regeneration control ???

Will test an exact replica of your circuit tomorrow and then will comment about the results !!!

73 and DX

YOur friend in Havana

Arnie Coro



----- Original Message -----

To: Prof. Arnaldo Coro Antich

Sent: Friday, January 02, 2004 8:19 PM

Subject: Re: Amended Schematic

No mistake, in the version I am running right now the double stack pot takes care of fine regen control.  I did make the suggestion that one cold use a small cap paralled across the first 300pf for the same purpose. 


"Prof. Arnaldo Coro Antich" <> wrote:




If my eyes are good there is a little mistake still there... The 300 pF ""throttle"" regeneration control capacitor should be a variable, not a fixed one !!!

It would only take you a minute to draw the line across the two plates to indicate that this is a variable and not a fixed capacitor !!!

73 and DX

YOur friend in Havana

Arnie Coro



Comments about the 30 Hy choke

-----Original Message-----
From: []On Behalf Of Scot Armstrong
Sent: samedi 3 janvier 2004 21:04
To: Bob Roehrig; glowbugs
Subject: Re: GB> Scot's regen enclosed



Well technically speaking I didn't have one either.  I do have about fifty pounds of vertical output transformers.  So I used the one with the most Henries I could find on the top of the pile. It was higher than my meter could measure, that made it over 20. It seemed to be quite a bit over 20 so, I guessed at 30.  I don't think you would see such difference between a 10, 20 or 30H choke.  The one good thing about a choke is that you could make it resonate for CW reception.  With a 20H choke put about a .002 cap on the side of the choke that is away from the HT and ground the other side of the cap.  A simple audio filter.   Again try several values to se what works best.  If you don't have a choke, I see no reason a guy could not fiddle around with a resistor switch box to find a resistor that worked.  For that matter a transformer could also be used.  Connect one side to the next in the way that gives the highest inductance.  For gosh sakes don't let the lack of a 30H choke stand in the way!


Scot Armstrong

Bob Roehrig <> wrote:

On Fri, 2 Jan 2004 wrote:

> The simplicity of the design is elegance itself.
> The ONLY component I wouldn't have on hand to build this little beauty
> is a 30 Hy. choke.

I'm not knocking anyone's regen design here, but again I am wondering why
there is so much emphasis on choke/transformer coupling in a regen set. I
have had better luck using just plain old resistive plate load.

Bob Roehrig
Aurora University Telecom/IS dept. 73 de K9EUI
630-844-4898 fax 630-844-4222