Hello Gang. Re: rolling regulators and rectifiers. Jazzdude's observations regarding soundstage stability and re: equipment employing vaccum tubed power supplies is rather astute and really very relevent here. Most of us with the supratek preamps know the pre is quite sensitive to the tubes employed in it.Ones choice of 6sn7's is usually chosen for it's voicing and its synergy with the partnered amps and speakers in a given room.Ones choice of rectifier and its marriage with the regulation tubes used will also add another spice to the recipe. A rather sublime artifact; that is not so easy to put your finger on right away because they do not directly affect tone or frequency. Soundstage stability is the primary reason why Mullard rectifiers have long been considered the rectifier of choice among tube amp enthusiast,guitar players,hobbyist and collectors alike.When employed in amplifiers using power tubes in the output,this soundstage stability artifact becomes a much larger issue and paramount with ones choice of rectifier. Ask yourself:Why do Mullard rectifiers command 5 to 10 times the price of the modern equivalents or other 5ar4's from the same vintage?[new or used] Collectors and speculators ya say? Think again! The soundstage stabilty thing that Jazzdude is talking about here is "THE" reason.Any competent guitar player with half an ear and a vintage tube amp will tell you the same and the mullard rectifier will last as long as the amp. ASA has really nailed down the sonic signature of the supratek and apptly penned it as being on the "clear side". NOW gang,just for fun....You want to hear "clearly" what Jazzdude is on about??? For those that are presently using a strong testing NOS mullard or bendex rectifier[90% minimum] Choose an appropriate live recording that you are very familiar with and would consider to having large dynamic swings and accompanied by a vocal.Pay particular attention to the precise placement or location and size of the vocalist on the stage. NOW pull your nos rectifier and replace it with the stock 5ar4/gz34,let it warm up a least 1/2 hour and replay it again. In my rig... the precise location of the vocalist will wander or slightly drift from his/or her precise place on the stage both laterally and vertically.The size does not change,but his/her location will drift. With the mullard in place,the vocalist is precicely focused in his/her own place on the stage.There is no drift,wander or shift. This artifact really becomes obvious in size and scale when the accompaning band gets cooking at the same time....drummers kicking,horns are honking,pianos a hammering in time with the vocal.Does everthing remain in scale and in the same place?does the drum kit get a little smaller or the cymbals wander slighty left or right of the drum kit? Or maybe the piano sounds wider on the bottom registers in relation to the upper keys when the band gets going. The piano size and scale [distortion thing] is one that is easily heard and can be very difficult to get right to begin with, let alone listening to rectifiers for chrissakes!However..Of all instrument,the piano is the easiest instrument to hear this drifting thing happen especially if accompanied by a human voice. Geez gang.....I think Im getting a little carried away here.Just try it people,let your ears be the judge!