Ampeg Reverberocket humming

[Tubetec]

Yeah twisted heater wires reduce hum ,the magnetic fields tend to cancel. Its definately worth a try ,you could start with the input valve and work back towards the output stage, just do one valve at a time and see if theres a difference . Its most likely to improve matters on the early stages less so towards the output tubes. If you scroll down on the LAB page and find Anthons 5e3 post ,theres a pic of how he's done the heaters , you loop the wires up and away from the tube sockets .
One other thing , make sure your heater winding has a center tap connected to ground or else a humdinger pot (100 ohm) with the wiper to grounded, on the different Ampeg schematics I have they use either of those two schemes .

 

[CJ]

using a pwr cord with a ground lead?

 

[beatnik]

yep , power cord is three prong

the 6.3 ct is grounded as well

 

[abbey road d enfer]

I can't help noticing how people don't read, because these two points have already been answered before. If it was a long multi-page thread, that would be understandable, but here...come on...

 

[Tubetec]

I was leafing through a few other Ampeg schematics and found that on certain models they tie the heater centre tap to the high end of the output stage cathode resistor ,just wondering if anyone could explain what the reason ,benefits or pitfalls of this arrangement are.

Just to go back to Dc powering the heaters of the input valve , Id say in any case its worth making any improvements you can with Ac wiring first . Mostly you find dc heaters in the early stages of very high gain amps like boogies where you have several gain stages in series .Even with ac heaters most of the time induced hum and noise inherent in the pickups and guitar wiring will probably swamp heater hum in the early stages of the amp .

 

[abbey road d enfer]

I was leafing through a few other Ampeg schematics and found that on certain models they tie the heater centre tap to the high end of the output stage cathode resistor ,just wondering if anyone could explain what the reason ,benefits or pitfalls of this arrangement are.

Elevated heaters; the idea is that, in a cathode-biased tube, the cathode acts like an anode to the heater, because it is more positive. So there is some current between heater and cathode, more than the simple capacitance suggests, because there is some space charge and thus, with AC heaters, some of the AC is injected in the cathode, thus increasing noise.