Bush VHF64

[pwdrive]

Interesting, not shown on this one, it has the hum cancelling transformer instead:

http://85.144.220.212/nvhr/Bush_VHF64.pdf

Lawrence.

[Murphyv310]

It certainly has, I wonder if this was added later on?

[boater sam]

That could be a good mod to replace a non available transformer which had a hum bucking winding, must remember it.

[pwdrive]

Ref. Post#32: Yes, so far as I can make out from page 12 of that manual.

Lawrence.

[Crackle]

Thats something new on me, I never realised why some OP transformers had that small tap.

Mike

[Murphyv310]

These transformers were common on Pye sets from the mid 50's onward. I've a few I have scavenged over the years.

[pwdrive]

Hum cancelling output transformers were not uncommon, there's always a resistor associated with them, R36 (1k) in the case of the later VHF64 fitted with that type of transformer.

Lawrence.

[pwdrive]

Explanation of hum cancelling sound output transformer, Radio and Television Engineers Reference Book, Hawker & Pannett, 4th Edition:

   

Lawrence.

[Crackle]

Thanks for explanation Lawrence.

Mike

[pwdrive]

No problem.

Lawrence.