Seeking Valves

[Nowhere-Man]

Hi
First of all am I correct in thinking this is the same radio restoration that went on for about 9 pages on UKVRR.

Apart from the valves you mentioned you have just now mentioned the potentiometer wiring and referred to the front and rear.
Here is a photo of a potentiometer, the resistance terminals are the ones on the "front" and the switch terminals which connect to the transformer and the mains are on rear. There may sometimes be 4 resistance terminals, one may be separate further round the body of the resistor, and there are often 4 terminals for the switch.
The term front and rear are normally given as if you were looking at the front of the radio not in the back of the chassis.

It is always helpful to those offering advice if you can study the advice and questions asked of you, and give clear answers backed up with good quality photos.
Was there really a need to use 2 cameras to take that fuzzy shot of the valve base?
I would suggest you study the images of the different types of valve bases posted by Yorkie and familiarise yourself with them. Then you will be able to order the correct valves,  for their specific valve holder, which you are missing.

Dont forget good quality photos so we can see what you are talking about. Use plenty of light on the subject and the photos should come out clear.

Mike

I think for a very short time I'd been slightly muddled due to large periods of time spent on ACDC valve radios. In fact, ACDC sets are really my favourites. However, you tend to get an image of neutral terminating at the chassis and that sort of carried over to my initial Ohms tests on the transformer set. This is no longer a problem for me as I can see the live and neutral are alternating voltage leads connected to the primary and obviously the primary is isolated from the secondary.

Yes, it was necessary to use two camera but the pic I couldn't upload was much clearer but is on my mobile phone. I can only upload here via my digital camera. 

I don't view it as a"restoration". That term may have led to confusion. This was a set that came my way by chance and I was using it as a learning curve. There was no rush or time-limit involved. If it had been a restoration I guess I'd have skipped the silicon rectifier idea but would have tried to get the original tube rectifier which is easier. As it was I figured it would be a good learning experience to try out a silicon rectifier schematic. Now I'll feel better doing all the voltage readings again when the radio is under full load with all the valves replaced.

I can't help but feel there is some different interpretations with regard to silicon vs metal vs valve rectifiers. For the time being I saw the major issue was the fact a silicon rectifier doesn't "kick in" after warming up so is out of synch with the actual tubes. So, there is the surge part of the debate (there is a similar debate with regard to solenoid relays during engine start-up) on yachts. Then as Chas Miller noted, the rectified silicon DC pulse is normally the peak of the AC voltage so tends to be a bit higher than a tube DC.

I did find another thread similar to this dated last year. On it the ECH81 was put forward as substitute for the X79 on grounds of cost saving.