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-   -   Single valve receiver circuit required (https://www.vintage-radio.net/forum/showthread.php?t=62337)

Trannytuner 28th Nov 2010 2:27 pm

Single valve receiver circuit required
 
Hi All

Does anyone know where I can get a circuit for a single valve receiver? similar to the old HAC radios, also what type of valve would I need etc.

I have also been constructing crystal sets, but would ideally like to add a one or two transistors to the circuit, anyone got any ideas to get me going with these projects?

Many Thanks in advance...Les

oldticktock 28th Nov 2010 2:47 pm

Re: Single valve receiver circuit required
 
http://vintageradio.me.uk/kits/hac_dx.htm

Guest 28th Nov 2010 3:08 pm

Re: Single valve receiver circuit required
 
1 Attachment(s)
Google 'One Tube Radio' (we tend to forget the Americans) lots out there.

Every now and again I knock one up just to see how good one valve is. Any battery valve wired as a triode (if needed) as per attached sketch will let you listen to the world. Anything approximatly like it will (probably) work.

Tractorfan 28th Nov 2010 3:31 pm

Re: Single valve receiver circuit required
 
Hi,
The June 1961 edition of Practical Wireless published a mains one valve TRF set that used an ECC83, if that's any help. I'm sure you can still find a copy somewhere.
Not sure of the copyright situation re: scanning circuits for folks on this forum.
Cheers, Pete:thumbsup:

Just thought: Does an ECC83 count as one valve or two?

paulsherwin 28th Nov 2010 3:43 pm

Re: Single valve receiver circuit required
 
There are lots of valve and transistor radio projects here.

Aerodyne 28th Nov 2010 3:47 pm

Re: Single valve receiver circuit required
 
ECC83 must count as two! - there's also the ECL80 reflex (count as 3!!) from c.1954, but I got the impression (I might be wrong) that a simple battery circuit was wanted.
Les, don't forget the modern 1-valver, from PW c. 1954 and it is also in later editions of Practical Wireless Circuits.

Headphones can be a problem. High resistance types are needed for such circuits, but a step-down output transformer can be used to match modern low impedance types.

Another problem is the RF choke. There are miniature types that look like resistors, available from RS and Farnell but how efficient they are when used in these types of circuit is an unknown to me. You can wind one, but best bet is to search radiojumble at meetings.
If you are stuck for the circuitry of the two sets mentioned, PM me your email address and I'll scan and email them to you.
-Tony

Ed_Dinning 28th Nov 2010 4:37 pm

Re: Single valve receiver circuit required
 
Hi Les, a copy of the book Radio for Boys (Bradley), or A Beginners Guide to Radio (Camm) will yeild the details you need, together wth a simple explanation of how they work. If you are in the Newcastle area I can show you copies of both.
The Camm book goes as far as showing how to make your own coils while the Bradley book is a progressive set that will allow you to extend it to a 4 valve LS set. My son built this when he was 8. Commercial coils are required for this one, but should be available on e-bay.


Ed

OErjan_S 28th Nov 2010 5:47 pm

Re: Single valve receiver circuit required
 
here you have a bunch of one and two tube radios.
http://makearadio.com/tube/index.php

one of my favourites is the 1T4 (DF91) shortwave set,
http://makearadio.com/tube/sw1.php

6K7 one tuber is another
http://makearadio.com/tube/6k7-dx-radio.php

he also has a one tube superhet (ok he uses a germanium diode detector but...)
http://makearadio.com/tube/6ba7-superhet.php

David G4EBT 28th Nov 2010 6:34 pm

Re: Single valve receiver circuit required
 
Just a small point as to the choice of valve, the original HL23DD valve used in the HAC kits wasn't a good choice as it had a 2V heater. I do wonder whether HAC chose that valve because at the time, it was plentiful and cheap on the surplus market. In the same way, at the end of the war, there were (still are for that matter) millions of surplus acrorn valves - a trimuph of miniturisation in their day. I count myself among those who bought and made a two-valve acorn portable 'camping radio' back in the late 1950s, but as it had 6.3V heaters it made short work of 4 U2 batteries!

If you are trying to make a HAC style radio which looks a bit 'retro' and hence, prefer a larger valve, the 1Q5GT would be a good choice. It has an octal base, but a 1.4V filament, and will happliy work down to low HT voltages, allegedly as low as 18V. Several builders of the 'Hiker's One' and Two have used that valve to good advantage.

The datasheet at the link below will show the data and pin connections of the 1Q5GT:

http://tubedata.tubes.se/sheets/049/1/1Q5GT.pdf

The 'Hikers' radios' have a considerable following 'down under' and might be of interest:

http://www.oldradios.co.nz/hikers/

I'm presently getting the bits together to build a 'Hikers' Two, like this one:

http://www.oldradios.co.nz/hikers/kb7nrn/index.htm

Hope that's of interest.

If you do want to replicate the HAC, you will of course need a Denco green range coil, which command ridiculous sums these days, so may have to wind your own. You may get some ideas from the coils used in the Hiker's series of radios.

Have fun!

David

Trannytuner 28th Nov 2010 7:39 pm

Re: Single valve receiver circuit required
 
Hi Everyone

My sincere thanks to you all for your help with circuits and info on these sets, I have no excuse now, I'll get the soldering iron on.

Best wishes from a VERY snowy Scottish Borders

terrykc 29th Nov 2010 11:58 am

Re: Single valve receiver circuit required
 
Quote:

Originally Posted by OErjan_S (Post 383746)
... one of my favourites is the 1T4 (DF91) shortwave set,
http://makearadio.com/tube/sw1.php

That looks very much like the radio I built over 50 years ago!

Mine was MW/LW using a Repanco DRR2 coil. Anybody got one of those kicking around?

I used a 1N5GT in mine. Why? Because someone gave me a bare chassis punched for Octal valveholders and it was the cheapest 1.5V Octal Pentode I could find advertised in Practical Wireless!

Most designs at the time used two 500pF solid dielectric variable capacitors, one for tuning and one for reaction. I used a twin gang air spaced one for tuning (one section only), rescued from somewhere, which fitted the pre-drilled holes on my chassis.

Many solid dielectric ones didn't have the smoothest rotation characteristics, so the use of a (much cheaper) pot to vary the screen voltage ensured a nice smooth reaction control.

The headphone was a low resistance one - Government surplus from Duke's in Manor Park -with a salvaged output transformer to drive it. (Low resistance headphones were always much cheaper than high resistance types because of lower demand but my solution suited my limited pocket money supply and worked well.)

Aerodyne 29th Nov 2010 6:00 pm

Re: Single valve receiver circuit required
 
Quote:

I used a 1N5GT in mine
An excellent choice, as is the DF33 Mullard equivalent. Ideal valve for a one-valve receiver.
-Tony


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