Pignose G40V Heater Voltage is 7.2V?

[reddinis]

It looks like most amps use a heater voltage of 6.3V. The Pignose G40V schematic says the heater voltage will be 7.2V, I've never actually measured it.

Isn't the max rating for heater voltage on guitar tubes 7.0V?

I'm wondering why he would design the amp this way?

I see the DC heater mod online, which also lowers the voltage, and I'm thinking about doing it.

[MWJB]

Data sheets say 6.3 to 6.9 VAC, nearly every amp you will see runs ovre 6.3VAC, vintage Fenders often nearer 7VAC, as you've never measured it you might even find it a little over 7.2VAC, 4-5% over rating wouldn't bother me as long as other secondary voltages were good.

[Jazz P Bass]

I had two Bugeras come through last month.
Both of them had 7.2 volts on the heaters.

[Chuck H]

I'll wager that the PT on many new amps has a "limited" multi tap primary. As in a 110V tap and a 230V tap and whatever is closest for the country of destination is the tap that is used. This instead of having multiple taps or even different PT's for export models. I can think of no good electronic reason to spec filaments so high so I'm guessing there is an economic reason.

6.3 X 10% (the typical +/- figure) is .63. 6.3 + .63 is 6.93. So 7.2V too many volts for filaments "." (period) I call shinnanagins!!!

[reddinis]

Okay, so I want to lower the voltage a little. I measured it at 7.26V.

I just bought a 4-pack of fat, 6 amp rectifier diodes at Radio Shack.

I was going to try to do as in the drawing in this link - http://music-electronics-forum.com/t1833/

or would that be too much voltage drop for me?

Thanks for your help!

[reddinis]

I put those diodes in. The heater voltage is now 6V. I'd rather it be .3V low instead of .3V high.