UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - Marshall JTM45 Guitar Amplifier- Mains (Primary)Fuse Blows

Radio Wrangler · 15th Aug 2018, 5:39 am

The GZ34 does do something. It's an awful lot faster turning off than a 1N4007/1N4008 diode. So the GZ34 will get all the voltage across it for a number of microseconds when the 1N4007 allows through current in its reverse direction. This won't be enough time for the reverse voltage on the GZ34 to build up to anywhere near its peak value.

The silicon diode takes the worst of the stress off of the thermionic rectifier, and the thermionic rectifier covers for the problems of these very slow silicon diodes. Symbiosis!

I normally try to talk people out of using the higher voltage members of the 1N400x family because of the RF hash they can generate, but in this case they should be OK.

David

15th Aug 2018, 5:39 am	#46
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,858	Re: Marshall JTM45 Guitar Amplifier- Mains (Primary)Fuse Blows The GZ34 does do something. It's an awful lot faster turning off than a 1N4007/1N4008 diode. So the GZ34 will get all the voltage across it for a number of microseconds when the 1N4007 allows through current in its reverse direction. This won't be enough time for the reverse voltage on the GZ34 to build up to anywhere near its peak value. The silicon diode takes the worst of the stress off of the thermionic rectifier, and the thermionic rectifier covers for the problems of these very slow silicon diodes. Symbiosis! I normally try to talk people out of using the higher voltage members of the 1N400x family because of the RF hash they can generate, but in this case they should be OK. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done