Patchett Receiver

[kellys_eye]

As an introductory exercise to superhets I intend to build the receiver from the Patchett book Radio Servicing - Volume 4 - Fault Finding.

The circuit diagram is shown....

Can anyone recommend a valve set suitable for this circuit? I saw a 'full set' of valves for a receiver on eBay a while ago (but missed the opportunity to purchase it) which originated from a set I recognised but can't for the life of me recall now!

All input appreciated - thanks

[Ed_Dinning]

Hi, try the "classic" set or equivalents:

ECH35, EF39, EBC33, 6V6 and use a 5Z4 for the rectifier.

Ed

[Radio Wrangler]

It looks like the rectifier shares the heater winding, so that rules out the 5Z4 unless the circuit is modified to use a different transformer with a floating 5v rectifier heater winding as well as the 6.3v winding for the rest.

David

[n_r_muir]

A 6X5 will run of the same heater winding as the other valves.

[Restoration73]

Valves contemporary with the date of the book would have been (B8A types)
ECH42, EF41, EBC41, EL41, EZ41 which is the types in the Pye P75 I am just doing !
B9A types exist although ECH81 is a triode-heptode.

[kellys_eye]

Originally Posted by Restoration73

..... which is the types in the Pye P75 I am just doing !

Yes, the P75 sounds like the set that were on eBay.

You mention B9A versions..... I would prefer these so what would the equivalents be?

[Restoration73]

You should be able to use the following :
ECH81, EF89, EBC81 or EABC80 (extra diode), EL84, EZ80. Replace the EZ80 with
silicon diodes if you would like less heat. Other types exist in B7G bases, but before
you start ensure you can obtain suitable r.f and i.f inductors. Examine commercial
circuits, there is nothing untoward in copying a known design.

[kellys_eye]

Thanks for that list - I tried developing the valve designations myself and got pretty close to your selection (courtesy of a Pro Electron/Mullard device code list).

Sacrilege I suppose but I am looking for a 'non-popular' valve set to strip for the major parts for this project to ensure the coils are correct - to begin with. eBay seem to have a plethora of such sets at prices that make purchasing individual IF's, sockets etc simply non-realistic.

In the fullness of time I intend to replace the coils/IFs with home made devices as the end aim of the project is to use the completed receiver as a test bed for such.

I thank everyone for the input - some useful information that I can save for later

[HamishBoxer]

If you go for octals bear in mind the cost of rectifier and 6V6 unless they are Russian ones.

[Ed_Dinning]

Hi, if you are going to build your own coils keep a lookout for a "Q" meter, it will tell you all you need to know about the coils you are winding, much better than an inductance bridge.

Advance type T2 is a good starting instrument and often quite cheap on auction sites.

Ed

[kellys_eye]

Ed - Thanks for the tip