Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Scsoul on July 23, 2018, 02:17:24 pm

Title: pt with no 6.3 filament ct
Post by: Scsoul on July 23, 2018, 02:17:24 pm

If I use the 6.3 taps for a ez81 recto do I put the 100ohm resistors on the socket for the ez81? Or the next tube el84?,,l. The pt.has no ct. It does have 5v,taps I could go with a 5y3 but would like to use ez81 it's a 18watt lite

Title: Re: pt with no 6.3 filament ct
Post by: pompeiisneaks on July 23, 2018, 03:57:38 pm

The EZ81 heaters can be done just like all other 6.3 volt systems where you need either a center tap, OR a pair of 100 ohm resistors from each leg to ground to create a virtual center tap, or a hum dinger pot to allow balance if you really want to go that far.  (100 to 200 ohm with the center being balanced to the least hum).  If you look at the AC15 schematic, it uses that rectifier off of the 6.3V taps.  Just make sure you have enough current capacity on that winding to handle the rectifier and all tubes. 

~Phil

Title: Re: pt with no 6.3 filament ct
Post by: Scsoul on July 23, 2018, 10:51:21 pm

Ok thank!!