Hello Rsa, I have a PW 116 Ultra, and previously used a first-gen 116 (non-Ultra). IMO, these conditioners are best employed for line-level gear, not high-power amps. The amp outlets (unlike the source/preamp outlets) do not use isolation transformers, just filters and protection devices which are claimed by API to be non-current-limiting. However, in my experience these amp outlets can indeed constrict the sound of higher-power amplifiers (>100W), although they have proved benign with lower-powered ones (<50W). A non-Ultra PW 112/114/116 should always be a commonly available and quite inexpensive piece used, so don't feel you must jump on this one right now for your 4004 when chances are it will probably sound at least as good if not better plugged straight into the wall.