Tube Amp Archive

resistance of pins to ground.

be best at this point to disconnect the transformer wires and do a good check of all pin 2 pin 7 at each socket.

remember your also reading the low resistance of the transformer winding.

I would double check the 1 ohm and 100 ohms as they are there together per the layout , may have confused which one connected where?
because a 1 ohm where a 100 suppose to be would do exactly what your describing.

dave

that would cause hum for sure, one side of the heaters is grounded or shorted,.

ouch,. now there is an argument for a fuse on that secondary HT? better check them diodes!

norburybrook wrote: ↑Thu Apr 20, 2017 9:41 pm is that instead of the 220k on the plate of V4b?


M

no, I would just change the 68k for a 100k and start there.

dave

didn't see your last post, going to far like a 220k will introduce some distortion , which may not be what you want.
100k was just a quick guess I made looking at schematics.

dave

yes a resistor to ground , closer you go to zero ohms the more signal is taken from the path, that is a simplification of what's happening there of course.

also 1 megohm trim pot at that location would allow you to adjust it to your taste.

Hello again, take a look at v1b plate cap there is a 1m/68k to ground thats like a master on 2? mabe increase that 68k to 100k and see if that gives you more output.

hope that helps,
dave

Hey first post here, just like to point out your schematic and layout on pg.4 do not match at the 220uf caps and 220k r. your problem may be in that area, if you could post a pic of the caps and wiring there may be helpful, according to schematic those caps should be totem poled and resisters in par...