By MisterMiniMite

Appetite Cover
For many guitarists and rock fans, Slash’s signature sound in 1987’s “Appetite For Destruction” represents the ultimate rock n’ roll guitar tone. From the melodic, neck-pickup-driven opening riff on “Sweet Child O’ Mine” to the action-packed breakdown solo on “Paradise City,” few would disagree that Slash really “hit the sweet spot” in the studio on that particular rig.

But what exactly *was* this rig?

This is the question that has been debated over and over by countless guitarists since the first time the video for “Welcome to the Jungle” aired on MTV. Seeking to replicate that tone, we’ve eagerly read every Slash interview we could find, scoured the internet for clues, and plugged our Les Pauls into every 1980s Marshall we could get our hands on.

But for most of us, it’s been a discouraging and confusing journey, at best. Reports are conflicted and contradictory. Every interview seems to say something different. Was the ’59 Les Paul replica built by MAX or Derrig (no explanation needed for my fellow Slash fanatics)? Was it a Marshall JCM 800, a Silver Jubilee Model 2555 (not likely, since recording for “Appetite” began in August 1986, and the Jubilees weren’t produced until 1987), or something else? Was the amp modified, and if so, how, and by who?

Personally, I’ve always believed that the amp-related questions were the most crucial – and the most intriguing. This is because I believe that the amp used on Slash’s lead/solo parts was probably the one *constant* ingredient throughout all of the songs on “Appetite.” When you listen carefully to every song on “Appetite,” as I have literally hundreds of times, you just might come to the conclusion that Slash didn’t use the Les Paul replica on *all* of his solo parts.

A perfect example is “Nightrain,” arguably a song with solos that epitomize Slash’s “Appetite” tone. To my ear, Slash makes use of tremolo-bar bending a couple of times (listen carefully, and keep an open mind!) during his “Nightrain” lead work (obviously, impossible to do on an ABR-1-and-tailpiece based Les Paul), and the pickups sound a bit hotter than in other songs. Perhaps this other guitar is the “double-locking superstrat” (said to have been a Jackson) that Slash originally brought to the studio for “Appetite.”

(I don’t want to go off on a tangent here, but if you’re still not quite convinced about the tremolo-bar/Jackson argument, listen for the pinch-harmonics “dive” almost exactly one minute into Nightrain. Also, check the inside of the “Appetite” album insert, and see where the band thanks Jackson Guitars (among a practically endless list of other people and companies). Also, keep in mind that Slash had been a major user of tremolo-bar tricks at that time – the first half of “G N’ R Lies” (the live half) is filled with dramatic examples.)

With respect to amps, after exhaustively putting all of the available clues together, and after being given the opportunity to put the question to Slash himself (albeit through a chain of third parties), I have come to the conclusion that Slash used *at least two* Marshall heads to record “Appetite” – a JCM 800, and another, more mysterious, pre-JCM-800 model Marshall – the *one*, true amp that our ears would recognize as Slash’s “Appetite” Marshall.

And that’s where the really interesting stuff begins.


SIR logoOn multiple occasions, primarily through interviews in guitar magazines, Slash has spoken of a Marshall head that he rented from S.I.R. (Studio Instrument Rentals in Los Angeles) and used heavily during the “Appetite” sessions (“Appetite” was recorded between August and December 1986). According to Slash, he loved the amp so much that, when S.I.R. wouldn’t agree to sell it to him, he invented a scheme to essentially “steal” the amp from them. After wrapping up the “Appetite” recordings, Slash told S.I.R. that the amp had been stolen so that he wouldn’t have to return it. Slash kept the amp for a time until a misstep by his roadie at the time spoiled Slash’s plans. During rehearsals at S.I.R. following the “Appetite” sessions (probably sometime in 1987), the roadie made the mistake of bringing the mystery Marshall to S.I.R.. When the guys at S.I.R. recognized their amp, they took it back.

Slash has said that he had a difficult time finding a suitable replacement for this Marshall (while prepping for the “Use Your Illusions” sessions). It is clear that Slash never again exactly replicated his “Appetite” tone, although this might have at least been partially attributable to an intentional evolution of tone on Slash’s part. Slash’s “Illusions” tone stands in stark sonic contrast to his “Appetite” tone, and seems to have been achieved using a JCM 800 exclusively.


Geroge LynchTo finish the story, we must first step back a year or two to 1985. According to interviews and other reports, during rehearsals for Dokken’s “Under Lock and Key” tour in late 1985, George Lynch was “blown away” by a modified Marshall owned by S.I.R.. Although George had utilized Lee Jackson-modified Marshalls during the actual recording of “Under Lock and Key,” he was so charmed by the modded Marshall, known to S.I.R. as “Stock #39,” that he tried his best to convince S.I.R. to sell it to him. S.I.R. refused to sell the amp (or even tell him who had done the mod), so George paid a substantial sum of money to S.I.R. just for the privilege of renting the amp during the first leg of the tour. The amp was returned to S.I.R. at some point before the conclusion of the tour in September 1986 (probably at least a few months prior to the tour’s end, since George only rented it for the first leg).

Later, despite S.I.R.’s attempts to keep the modifier’s name in the dark, George was able to track down the person who had modified the S.I.R. Marshall and contacted him personally in order to have four of his own Marshalls similarly modified.


Although, admittedly, the evidence is circumstantial, I believe that the George Lynch S.I.R. amp and the Slash S.I.R. amp are one and the same.

As previously stated, George Lynch discovered #39 in late 1985 during rehearsals for Dokken’s “Under Lock and Key” tour. George rented the amp for *only* the *first leg* of this tour (and the *full* tour concluded in September 1986). Guns N’ Roses began recording “Appetite” in August 1986, and the recording was completed in December 1986. This means that Slash probably began renting *his* Marshall from S.I.R. at some time during the Summer of 1986 (August at the very latest, but probably more like June or July). As you can see, there is a virtually seamless timeline here. Following its return to S.I.R. by George Lynch, #39 probably hadn’t been back at S.I.R. for more than a couple of months, at the most (and possibly a much shorter time period), before Slash scooped up his Marshall for “Appetite.”

Given this chronological evidence, what are the chances that George Lynch (who is famous for being particularly picky about his gear and somewhat technical when it comes to his guitar tone, and who had obviously played through his share of custom and modified Marshalls at the time) and Slash (who has said that he usually must try out 50 or more Marshalls before he finds one that is acceptable to him) went bananas over two *separate* Marshalls – *both* owned by, and located at, S.I.R. – and that S.I.R. would refuse to sell *both* of these amps? Neither player was willing to let their amp slip away, and each took extraordinary steps to hold onto it. Although they were both much younger and less experienced at the time, both players’ reactions were so extraordinary and intense that it is probably very reasonable to conclude that they were both head-over-heels about the same amp: Stock #39.

There is at least one more interesting connection between Slash and George Lynch, although it might just be an ironic coincidence. Prior to serving as Slash’s guitar tech, Adam Day – Slash’s trusty right-hand guitar man since 1988 (post-“Appetite”) – worked for – you guessed it – George Lynch.


So exactly what model Marshall was #39? Although records are not perfect with respect to the year that the amp was manufactured, it is known that the amp was a 100W Marshall Super Tremolo (Model 1959T), built sometime between 1965 and 1973. The amp was a hand-wired, pre-master volume model, although it is unclear whether the head was of the “Plexi” variety (’65 through mid-’69) or the later “Metal Panel” variety (mid-’69 through mid-’73, since Marshall replaced hand-wiring with printed circuit boards in mid-’73). The head was modified by a service/repair tech who worked for S.I.R. throughout the 1980s into 1985 (more to come on him later).

In short, the modification consisted of adding an extra pre-amp gain stage. A master-volume control was also part of the modification to #39, since the amp was a pre-master volume model.

The modification made the Marshall very overdriven, essentially leaving it with extremely limited clean-tone (non-distorted) capabilities. This is where the *other* amp previously mentioned – the JCM 800 that has also been connected to the “Appetite” sessions – might fit into the puzzle. I think that the JCM 800 was probably used on all of Slash’s clean guitar parts in “Appetite” (yes, there *were* some clean parts). It is also possible that the JCM 800 was used by Slash on some of “Appetite’s” rhythm parts. However, I believe that it is highly likely that #39 was used by Slash on the vast majority, if not the entirety, of his lead/solo work on “Appetite.”


Tim CaswellAnd the mystery modifier’s name is . . . Tim Caswell. Tim worked at S.I.R.’s tech/service department for several years until 1985, leaving just prior to George Lynch’s rehearsals for the “Under Lock and Key Tour” (which began in late 1985). Following his time at S.I.R., Tim went on to form his company, Studio Electronics, where he remains today. In effect, Studio Electronics grew out of the internal tech/service department at S.I.R., and has moved on to bigger things since that time.

One of the *best* parts of the story of #39 is this: until I contacted Studio Electronics and presented them with all of the information I had gathered, Tim had never connected #39 with Slash and/or “Appetite.” After all, Tim left S.I.R. in 1985, and Slash presumably wouldn’t have rented the “Appetite” Marshall until the Summer of 1986. Although Tim had obviously known about George Lynch’s use of #39 (since George later personally contacted Tim in order to have Tim perform some similar modifications), nobody had ever asked or approached Tim with the Slash-S.I.R. link. After putting all of the clues and bits of information together, and placing them within the context of his personal memories, experience, and knowledge, Tim is now a believer, as I am, that his #39 is likely the primary amp you hear Slash playing on “Appetite.”


Perhaps the most compelling evidence that #39 was, in fact, Slash’s “Appetite” Marshall is this: as of the time that Tim left S.I.R. in 1985 (recall that Slash probably would have initially began renting his Marshall in the Summer of 1986), Tim had been the *one and only* person to ever perform modifications on any of S.I.R.’s amplifiers. It wasn’t until *well after* Tim had left S.I.R. that anyone else performed any modifications on any more of S.I.R.’s amps. Thus, if Slash’s amp had been modified (as is widely believed), Tim would have almost certainly been the one who did it.

Tim recalls that S.I.R. possessed several pre-JCM-800 era Marshalls in its rental inventory. Some of them were 100W Super Leads (non-tremolo Model 1959s); only one was a Super Tremolo. Tim did some relatively standard, mild gain-boost modifications (referred to by Tim as the “stage one” mod) on a few of the Super Leads, but only performed *the* mod – his *signature* mod – on the Super Tremolo (#39). The 1959T and some of the other Marshalls were brought back from the U.K. by Dolph Rhemp, one of the owners of SIR.

Tim got the idea for his unique modification after noticing that S.I.R. had lost the footswitch required to operate the tremolo on the 1959T. One slow day at SIR, he came up with the idea of using the 1959T’s tremolo circuit for hot-rodding the amp.

Tim also recalls that his modded Super Tremolo was, by far and away, S.I.R.’s most exclusive, in-demand, and frequently-requested amplifier, rented primarily to S.I.R.’s higher-profile, celebrity, and discriminating clientele. The amp was used on multiple professional recordings for a number of famous performers. When Tim was at S.I.R., if a high-profile or otherwise important client called S.I.R. to request the company’s best-sounding rock n’ roll amplifier, #39 would have been the automatic, no-doubt-about-it recommendation.

In total, Tim has performed his signature mod on fewer than one dozen amplifiers (all Marshalls). The amps ranged from late ’60s/early ’70s Marshalls through ’80s JCM 800 models. Aside from #39, Tim modified four Marshalls for George Lynch, two for Queensryche, and a few for personal friends of his.


Although it’s been two decades since he modified #39, to my delight, Tim is still available to perform the identical amp mod for customers. The modification can be done on a variety of Marshalls, including, but not limited to, all 1959s, 1959Ts, and JCM 800s (50W or 100W, with or without master volume, hand-wired or PCB) as long as the amp doesn’t have channel switching. In his opinion, the mod works just as well for any of these models. A personal favorite of his is a ’70s Mark II PCB model that he did for his friend Bryan White. SIR #39 was the only 1959T that he ever modified.

Interested parties can contact Tim through his company, Studio Electronics, by visiting the company’s webpage at


I am a firm believer that the abundance of conflicting information and contradictory interviews out there is *not* the result of some sort of conspiracy driven by secrecy or endorsement deals with gear manufacturers. Ultimately, I think that any misstatements have been unintentional, and were made in a good faith effort to answer questions for all of the curious guitarists and fans out there.

First of all, keep in mind that “Appetite” was recorded almost 20 years ago, and that Slash was only 21 years old at the time. Simply stated, memories fade.

Secondly, Slash was, and continues to be, one of those if-it-sounds-good-use-it guitarists when it comes to the amps that he plays through. He’s a guitar collector and a guitar aficionado, but he has admitted that he really is not a “collector” of amps. When Slash was recording “Appetite” with #39, there would have been no need for him to “study” the amp or even take note of the exact model. It is also unlikely that Slash would have even had any particular interest in the technical modifications to #39. He *would* have had an appreciation for the fact that the amp sounded great to him, and that’s probably all that he would have been concerned with at the time. After all, he’s still using his old, reliable ’59 Les Paul replica as his primary recording guitar, simply because it sounds good to him.

Thirdly, I imagine that there might have been a bit of a “falling-out” between Slash and S.I.R. following Slash’s failed attempt at swiping #39 from them. In light of this debacle, Slash probably wouldn’t have been in any realistic position to approach S.I.R. in order to get the specs on the amp, and then go to Tim to have the necessary modifications done.

Fourth, there’s the fact that Tim had already left by the time Slash actually rented #39 to record “Appetite.” Tim’s physical absence from S.I.R. at that time just makes it more unlikely that Slash would have ever come to know who actually modified #39. Besides, as a company in the business of renting out gear, S.I.R. might have been understandably
reluctant to give out Tim’s name, so that anyone who wanted an amp that sounded like #39 would have no choice but to get it from S.I.R. (recall that George Lynch had difficulty convincing S.I.R. to tell him who had modified #39).

Finally, Slash might simply have wanted to move in a new sonic direction, and find a different recording tone, following his “Appetite” days. The fact that he never really tried to *exactly* replicate his “Appetite” guitar tone (by tracking down the specific Marshall model, and locating Tim) might simply be indicative of his intentionally evolving sound. While it is true that Slash has said that he found it difficult to locate a suitable replacement for his “Appetite” Marshall, this does not mean that he wouldn’t have been looking to change his sound anyway for the “Illusions” sessions.


The short answer to this question is: nobody seems to know. Currently, S.I.R. doesn’t carry or rent out any ’65-’73 Marshall Super Tremolo Model 1959T heads, or even own a “Stock #39” amplifier for that matter. The closest amp that they have now is a non-tremolo 100W Super Lead of the same era. It’s been modified, but the mod was done by another person (*not* Tim) who also modified several other amps in the years following Tim’s departure from S.I.R. in 1985. S.I.R. also carries a couple of old 50W Marshall heads from the ’70s; everything else that they have is JCM 800 and newer.

So what happened to #39? Most likely, the amp was either sold, or rented and never returned, at some point following the “Appetite” sessions.

The amp might still exist out there somewhere. Whether or not it has been further modified or altered is a different story. Maybe the owner knows *exactly* what it is and is keeping the amp locked in a safe. Obviously, there is also a good chance that the amp might never be identified.

So . . . the next time you come across a (presumably beat-up and heavily-gigged by now) modified ’65-’73 Super Tremolo, open up the back of the amp. If it’s signed and dated (in 1985 or earlier) by Tim Caswell, it’s not only the first amp that Tim performed his signature modification on – it very well might be one of the most influential, and mysterious, amps in rock n’ roll history.

Something else I figured I’d include. Here are a couple of related excerpts from some old guitar magazines – interviews with George Lynch and Slash. There are others out there, but here are a couple of really good ones:

(1) Guitar For the Practicing Musician, April 1987 (George Lynch inverview):

“For the first album I used old Marshalls, which I’d used for years. Then I tried the Randalls and was happy with them for a while. Then I went to Laney and back to Marshall. I was using Lee Jackson Metaltronics, which is what Vai is using. I also used the Jose modified Marshalls for a while. Now I’m using Tim Caswell modified Marshalls. What happened was that I went into S.I.R. and rented an amp. It sounded amazing. It was the perfect amp. You just plug in and it was all there. I went to the guy and said I’ve got to have this amp. It got to the point where they were calling the owner of S.I.R., who was on vacation, and I was offering him three Marshall heads in trade or $2,000, whatever they wanted. They wouldn’t sell it. They said it was their number one amp. Everybody who came in requested it. I ended up renting it for the whole Twisted Sister tour, which cost me about $2,000. Eventually I had to give it back. I had all kinds of schemes in mind. I thought I’d take all the guts out of the brain and put in different guts. I couldn’t do that. Eventually one of the repairmen told me the guy’s name who did the modification. I called the guy and he did one for me. Now he’s done six for me. He is amazing.”

(2) Guitar Magazine, April 1992 (Slash interview):

“I had one when I did Appetite, which was great. I stole it from S.I.R., and when we were rehearsing at S.I.R. after the record came out, my idiot roadie at the time brought that amp down by mistake, and they took it back. When we went back into the studio a couple years later, I had to find the ultimate amp again…”