I shared the following with a few members through a PM and I was encouraged to post this in the forum. Let me preface this by saying that I am not posting to contridict but rather to simply share my own experience.
I love the tone on the Whitesnake record as well as the Blue Murder records and John is amazing player (great tone and vibrato!) I favor the tone on the Whitesnake record (Still of The Night, etc) but the Blue Murder tones were great as well! I always though the amp was a Mesa Coliseum as well as that is what I had heard for years. I believe John also said that is what he used on that record. I even went to far as to track down and purchase a Coliseum. I am presuming he said he used this in the studio to misdirect people?
I say this as; Years ago when I was recording a record at Phase One Studios in Toronto Canada I became friends with one of the engineers that was assigned to work with our band. He was one of the on staff engineers and worked for the studio. Before we arrived he was given the task of reorganizing the tape library. There were some amazing safety copies of iconic records that were in that library and there was a safety copy of that record. Along with the session track sheets were notes regarding a Marshall & Les Paul for the guitar tracks. A Strat was also listed on the songs that contained clean parts.
I had never heard a regular Marshall sound like that and I have always loved that tone so I was very curious. Lord knows I would have loved to have that tone! (lol) Approximately one week later I was able to meet the gentleman who owned the studio at that time when we were there. He also had owned the studio at the time that record was being recorded. He had a lot of great stories but the one that is relevant to this thread is that he recalled John's Modded Marshall going down during the tracking of the rhythm guitar tracks. The studio had a repair tech on staff (IE: they had old vintage Neve consoles, tape machines, outboard gear, etc that required constant maintenance) and he offered to have a look at the amp to see if he could fix it for them. John insisted that the amp be sent to the gentleman in CA who had modified it. This was a big to-do at the time as there was 3 weeks of down time at the studio that the label was paying for though nothing was being recorded. Back in those days the big studios had lock-out rates that were pricey even by today’s standards. In the end it was obviously water under the bridge as the record did in fact sell very well and the guitar tone is still amazing to this day. Naturally I was dying to know who the tech was as I really wanted that tone but when I asked him if he recalled the name of the tech that John sent his amp to he said Jose was his first name but could not be certain of his last name.
I have always wanted to work with John as I have always loved his playing. Fast forward to a few years ago; I was able to talk with a gentleman that was John’s guitar tech at the time. He said John has been using Marshalls that Jose Modded for a long time and was not interested in using anything else. Apparently John spent some time purchasing several Jose Modded Marshalls around Los Angeles CA area and eBay in order to find one that sounded like his main amp so that he had a back up. We have worked on a lot of Jose A Modded amps and Jose did a lot of Mods that were different from one another, all cool in their own way. There is one that will get you that tone and while it does not do cleans very well the gain tones are certainly in line with John’s tone. It was what Jose referred to as his “Studio Mod” as the volume is padded down. Earlier on he would install a transformer isolated line out (which sounded best to me ears) and later on it was resistor based. This was done to capture the amps tone and send it to either a power amp or to effects and then to the power amp.
Much the same as a lot of great guitar players who have amazing tone (EVH, etc) there can be conflicting reports with regards to which amps/gear were used on various records. Again, I am only sharing my own experience in the hopes that it helps. I have been a long time fan of John's and regardless of what amps he uses - he is an incredibly talented player as well as an outstanding singer.
All the best to everyone here;
Trace