UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Bazz4CQJ · 27th Mar 2021, 9:26 pm

As regards height limits, this all depends on what each of us wants to do.

My preference is to ditch both old boards and try build one new board with the osc, amp and 9-0-9V psu on it (dimension of the original boards are 100x125mm).

The Wien oscillator I have played with has a PCB of 40x35mm and the AF millivoltmeter is on a piece of veroboard about 40x35 mm (coincidence).

If that were done, we wouldn't have any limit on height for transformers.

Using a dual op-amp IC for the amplifier, we could dial in whatever gain we needed; we don't have match exactly the existing amp transformer on the secondary. I'd say that the $64M issue with that transformer is that it needs to cope well with 400V on the primary (relative to the chassis).

However, I do appreciate that the "one new board" strategy may not be good for everyone.

B

27th Mar 2021, 9:26 pm	#92
Bazz4CQJ Dekatron Join Date: Apr 2009 Location: Oxfordshire, UK. Posts: 4,935	Re: AVO 163 amp board ~ transformers As regards height limits, this all depends on what each of us wants to do. My preference is to ditch both old boards and try build one new board with the osc, amp and 9-0-9V psu on it (dimension of the original boards are 100x125mm). The Wien oscillator I have played with has a PCB of 40x35mm and the AF millivoltmeter is on a piece of veroboard about 40x35 mm (coincidence). If that were done, we wouldn't have any limit on height for transformers. Using a dual op-amp IC for the amplifier, we could dial in whatever gain we needed; we don't have match exactly the existing amp transformer on the secondary. I'd say that the $64M issue with that transformer is that it needs to cope well with 400V on the primary (relative to the chassis). However, I do appreciate that the "one new board" strategy may not be good for everyone. B __________________ Saturn V had 6 million pounds of fuel. It would take thirty thousand strong men to lift it an inch. Last edited by Bazz4CQJ; 27th Mar 2021 at 9:42 pm.