Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tylerrussell on January 21, 2015, 08:36:11 am

Title: Another quick question (seriously)
Post by: tylerrussell on January 21, 2015, 08:36:11 am

The Hammond 290AX PT data sheet shows 5V 2A at the yellow wires. Those hook up to pins 2 and 8 of the 5y3 in a 5e3 build. I get 346VDC at those yellow connections. Where do the 5V 2A figures come from on the data sheet?

Title: Re: Another quick question (seriously)
Post by: sluckey on January 21, 2015, 08:48:08 am

Quote

Where do the 5V 2A figures come from on the data sheet?

That's the voltage required to heat the filaments inside the 5Y3. This voltage is floating, ie, it is not referenced to chassis ground. To measure that voltage set your meter to measure AC volts. Then connect one probe to one pin 2 and the other probe to pin 8.

Title: Re: Another quick question (seriously)
Post by: tylerrussell on January 21, 2015, 09:24:13 am

Got it. Thank you Sluckey.