{"product_id":"tube-amplifier-bias-adjustment","title":"Tube Amplifier Bias Adjustment","description":"\u003cp class=\"p1\"\u003eOutput tubes drift as they age. The bias current wanders off the manufacturer's specification, and the amp starts to sound soft or hazy, or runs hot enough to eat through tubes faster than it should. Setting it back to spec is a meter-and-screwdriver job on the bench, and it is worth doing before you start replacing tubes that were never the problem.\u003c\/p\u003e\n\u003cp class=\"p1\"\u003eThis is an in-store service at our Chestertown shop. Bring the amp to us and Mike will set the bias on each output tube. Buy it here and we will contact you to arrange a time.\u003c\/p\u003e\n\u003ch5\u003e\u003cb\u003eFree When You Bought Your Tube Amp From Us\u003c\/b\u003e\u003c\/h5\u003e\n\u003cp class=\"p1\"\u003eIf you bought your tube amp from The Listening Room and it has adjustable bias, your first bias adjustment is free. You do not need to order it here. \u003ca href=\"\/pages\/contact\"\u003eContact Mike\u003c\/a\u003e after your purchase and he will set a time for you to bring it in.\u003c\/p\u003e\n\u003ch5\u003e\u003cb\u003eWhat's Included:\u003c\/b\u003e\u003c\/h5\u003e\n\u003cul\u003e\n\u003cli class=\"p1\"\u003eWarm-up to operating temperature before anything is measured, so the reading is the one the amp runs at\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eBias measured on every output tube, with no music playing and the volume down\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eEach tube adjusted to the specification for your amp and the tubes in it\u003c\/li\u003e\n\u003cli class=\"p1\"\u003eA check that your tubes are seated in the positions they are labeled for\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch5\u003e\u003cb\u003eWhen Your Amp Needs It\u003c\/b\u003e\u003c\/h5\u003e\n\u003cp class=\"p1\"\u003eMike's guidance, from his own bias walkthrough: check it about every six months, any time you hear a channel imbalance, and always after you replace a tube. Every tube has slightly different efficiency, so a new tube needs its bias set.\u003c\/p\u003e\n\u003ch5\u003e\u003cb\u003eBefore You Come In\u003c\/b\u003e\u003c\/h5\u003e\n\u003cp class=\"p1\"\u003eBring the amp itself. You do not need to pull the tubes or bring anything else. If you have recently swapped in a new set of output tubes, say so when we schedule. If you are not sure whether your amp has adjustable bias at all, call or text Mike at 410-239-2020 before you order and he will tell you.\u003c\/p\u003e\n\u003cp\u003e\u003cspan class=\"s2\"\u003e\u003cb\u003eNo product will be shipped to you as part of this listing.\u003c\/b\u003e\u003c\/span\u003e This covers the bias adjustment only. After purchase we will reach out to set a time.\u003c\/p\u003e","brand":"The Listening Room","offers":[{"title":"Default Title","offer_id":43151465283680,"sku":"LRSVCTUBEBIAS","price":100.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0555\/5073\/8528\/files\/tube-amplifier-bias-adjustment-meter.jpg?v=1791391617","url":"https:\/\/listenroom.com\/products\/tube-amplifier-bias-adjustment","provider":"The Listening Room","version":"1.0","type":"link"}