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Got the hum pots, done the tranny mod

I had my local tech install the hum pots, and also do the power tranny wiring mod that George Wrigth had suggested for the series of transformers. The mod, by the way, did not reduce the hum, but did seem to add more life and resolution, to amps that were already very lively and resolving.

The hum is acceptable, but less if better, if the sonics aren't compromised.

Here is what George had written:

"We have found that the vender on the power transformer # 500-7694 and 500-7695 slipped on placing the center tap on the 2.5 volt filament winding, allowing a little AC leakage to pass into the output stage. I have a service note that we are posting on our website about this, but since you have the picture up, I'll explain it here briefly.



To correct the problem, cut the blue/white wire going to the terminal strip where the 100 uf cap, the 750 ohm 10 watt resistor and two 680 ohm .25 watt resistors are tied. Insulate the wire, and attach a new wire to this terminal posistion. Run the new wire over to the output socket area. Next,install two 22 ohm 2 watt resistors to this wire and insulate. The other end of one of the resistor leads goes to the junction of the orange and blue wire on the socket; the other resistor goes to the junction of the orange/white and the green wire also on the socket. These are pins 1 and 4 respectively of the output socket. This will resolve the hum problem and will not affect the sonic quality. . . ."


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  Kimber Kable  

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