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

buggies · 14th Aug 2018, 10:35 pm

When I rebuilt my Linear Conchord amplifier I followed a hint and added a 1N4008 in series with each GZ34 anode. The idea is that in the event of flash-over in the GZ34, AC does not reach the reservoir cap so no fuse/cap/transformer problem.
This technique is also used in a Fender amp. You still get the desired "sag" but of course the HT is reduced by 0.7 volt!

14th Aug 2018, 10:35 pm	#42
buggies Heptode Join Date: Jan 2009 Location: West Lothian, UK. Posts: 761	Re: Marshall JTM45 Guitar Amplifier- Mains (Primary)Fuse Blows When I rebuilt my Linear Conchord amplifier I followed a hint and added a 1N4008 in series with each GZ34 anode. The idea is that in the event of flash-over in the GZ34, AC does not reach the reservoir cap so no fuse/cap/transformer problem. This technique is also used in a Fender amp. You still get the desired "sag" but of course the HT is reduced by 0.7 volt! __________________ George