by EWBrown » Thu Mar 06, 2008 12:55 pm
I'd suspect that the i-pod cable is the most likely cause of the hum problem, the shielding can't be very good, if indeed the cables are, in fact, even shielded at all... interfecing the "pods" to tube amps can be challenging.
The "fatman" brand i-pod tubed amps use a docking adapter / connector so that no external cabling is needed. Most other ipod amplified speaker sets also use the docking adapter approach.
One "trick" I learned (if there is no volume control) is to connect the input tube's grid resistor across the input RCA jack, then run shielded or twisted pair wire to the VA tube, and use a 1K CC grid stopper resistor connected reasonably close to the grid pin on the socket. This is another neat "humbuster" method which works for me.
The 'pods were never intended to play well with tubes, so YMMV at best...
It's best to run the 'pod or any other "portable" source off its batteries, and not using the charger, the latter is a recipe for ground loops and hum insanity Yellow_Light_Colorz_PDT_09 :o Yellow_Light_Colorz_PDT_09 :o
/ed B in NH
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