I bought a Avalon u5 preamp from the seller and there was an issue with the preamp. contacted the seller and told him of the issue I was having and he suggested that I take it to be check out, which I did and the technician informed me that the active through switch was damaged/doesn't work. Got back with the seller and informed him what the issue the Tec. had found. The seller stated he wouldn't issue a refund, I had to file a complaint through paypal to get a refund. Beware of this seller and that Avalon u5 preamp, that he stated he bought for a backup to his other Avalon u5 preamp, Hummmmmmmmmmm!