Every schematic of the ST-70 power supply that I've seen to date shows the selenium rectifier as a diode symbol with the red/black power transformer tap being run directly to the cathode/negative side of that diode...
http://diyaudioprojects.com/Schematics/Dynaco-ST70-Tube-Amp-Schematic.htm
...However, the wiring up section step # 1 of the ST-70 assembly manual states that this wire should be run to the positive/ anode side of the rectifier...
"(1) Connect the red-black transformer lead to the lower (+) lug of the selenium rectifier (S)"
...So the two appear to be in disagreement. Which one is correct? Is the lower lug of the selenium rectifier really the anode? What little bit I know about rectification leads me to think that the lead should go to the anode to act as a proper half-wave rectifier. If you install the diode the other way as the schematic shows then I would think the diode would only conduct when voltage swung past the diode's breakdown voltage. I want to turn this diode around but before trying this and potentially blowing something up I really wanted to get some other opinions.
I actually bought a selenium rectifier replacement "kit" off ebay years ago that included a drawing of the ST-70's underside with supposedly the correct installation. This diagram (I still have this) shows it the way the schematic does with the red/black lead running to the cathode. I still see this kit being sold as a NOS item from time to time.
Any thoughts?
http://diyaudioprojects.com/Schematics/Dynaco-ST70-Tube-Amp-Schematic.htm
...However, the wiring up section step # 1 of the ST-70 assembly manual states that this wire should be run to the positive/ anode side of the rectifier...
"(1) Connect the red-black transformer lead to the lower (+) lug of the selenium rectifier (S)"
...So the two appear to be in disagreement. Which one is correct? Is the lower lug of the selenium rectifier really the anode? What little bit I know about rectification leads me to think that the lead should go to the anode to act as a proper half-wave rectifier. If you install the diode the other way as the schematic shows then I would think the diode would only conduct when voltage swung past the diode's breakdown voltage. I want to turn this diode around but before trying this and potentially blowing something up I really wanted to get some other opinions.
I actually bought a selenium rectifier replacement "kit" off ebay years ago that included a drawing of the ST-70's underside with supposedly the correct installation. This diagram (I still have this) shows it the way the schematic does with the red/black lead running to the cathode. I still see this kit being sold as a NOS item from time to time.
Any thoughts?