Conversion using UF5407 800V 3Amp 2-Pin DO-2 Soft Recovery Ultrafast Plastic Rectifier Diodes in a standard octal plug with the cap off of a fabric conditioner bottle a perfect press fit to finish it off 😀
Nice job !
I remember when those metal cap like rectifiers came out and with two WW resistors were used to replace rectifiers in valve radios , radio valves needed surge limiting due to "cathode stripping " .
Might not be so bad nowadays and apply more to RF but read this thread from antique radios-
A bit controversial but read a the posts .
Antique Radio Forums • View topic - Cathode stripping
I remember when those metal cap like rectifiers came out and with two WW resistors were used to replace rectifiers in valve radios , radio valves needed surge limiting due to "cathode stripping " .
Might not be so bad nowadays and apply more to RF but read this thread from antique radios-
A bit controversial but read a the posts .
Antique Radio Forums • View topic - Cathode stripping
I fit NTC 5D-15 Inrush Current Limiters or similar into the B+ to give the valves a few seconds to warm up.
If you parallel them up the time to full voltage increases.
If you parallel them up the time to full voltage increases.
Well it certainly looks different 😀
32V into 8 Ohm 16 Watts per channel. I think I'll leave well alone. 🙂
32V into 8 Ohm 16 Watts per channel. I think I'll leave well alone. 🙂
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According to a friend who has been in business repairing and modifying SS and valve equipment for years, cathode stripping isn't a huge problem, as he has found that valves frequently fail for other reasons before cathode stripping becomes a problem. There are a lot of valve equipment designs out there that have ss rectifiers with no standby switch or B+ delay, and they seem to function perfectly well.
At the time -50,s the surge from SS converted valve radio rectifiers blew a lot of radio valves , the resistors were there to try and stop this happening of course more sophisticated methods and components were later used but by that time solid state active components started to sell to the public increasingly .
But that wasn't the end of the matter ,CRT TV,s had Thermistors in the heater chain as well as the above WW resistors .
This was common practice as I have a set of =Radio & Television Servicing books by E.Molloy & W.F,Poole from the late ,40,s into the 70,s .
The industry "isn't daft " they found they needed those components otherwise they could reduce costs by leaving them out.
But then be faced with public uproar as xxx brand is called "unreliable"/"breaks down quickly" /etc and the products boycotted .
Not only were thermistors included but some designs had WW resistors paralled up with them as additional safety.
But that wasn't the end of the matter ,CRT TV,s had Thermistors in the heater chain as well as the above WW resistors .
This was common practice as I have a set of =Radio & Television Servicing books by E.Molloy & W.F,Poole from the late ,40,s into the 70,s .
The industry "isn't daft " they found they needed those components otherwise they could reduce costs by leaving them out.
But then be faced with public uproar as xxx brand is called "unreliable"/"breaks down quickly" /etc and the products boycotted .
Not only were thermistors included but some designs had WW resistors paralled up with them as additional safety.