Shortly after the CS4 upgrade, one of the channels stops producing noise. This is the front most channel, black. The other channel works perfectly. I've isolated the problem to the seduction preamp. After upgrading to the CS4 board, I had the unit downstairs. After a while, I took it up to my office. After this move, I noticed the black channel (left in my setup) was not producing any noise. I powered down the unit and after wiggling some wires, the channel started working again. After a few days, it would stop. Now, I happened to be listening to the preamp at the time it stopped working recently. There was static and scratching sound coming from the left channel and then audio stopped. Last thing I did was add some more solder to one of the resistors on CS4 board which weren't soldered very well and I thought that fixed it as unit worked after that. I had no problems until last night and the left channel was again not working. The tube lights up when unit is powered on, just no sound. Is the problem related to the CS4 board? The right channel works perfectly.