Internal Pics, Audio of Slash Amp Prototype

June 23, 2010 | By | 1 Reply More

Here are Slash's amp settings (click to see way bigger – stoof photo).

Here are Slash's amp settings (click to see way bigger – stoof photo).

Close-up pics of the prototype Slash signature Marshall AFD100 amp were recently posted by user “stoof” at Veeeeeery interesting, especially if you’re a Slash fan and maybe an amp builder – or just want to try his knob settings.

Apparently the prototype is done enough that Slash loves it, so production should start soon with the amp for sale at retail late this year. What’s it sound like? Listen:

I’m no expert, but to me that sounds like an amp with 6550 power tubes. And I believe Slash’s favorite Marshall JCM800 (a 2203, meaning a 100-watter) has 6550s (see pic). Also:

> In this Marshall vid, Slash’s guitar tech (I guess) says Slash “definitely really likes that really aggressive, high-wattage sound” of 6550s – even though the first Slash signature Marshall uses EL34s. Slash also says 6550s are “harder-sounding” and says it’s important to warm them up so “they’re not too abrasive.”

> Marshall also said this about the protoype: “The prototype you have seen in the pictures is built on a standard JCM800 2203 chassis with custom preamp based on both his #34 amp and the AFD tone plus the added effects loop. The power amp has a couple of minor tweaks and has 6550 output valves fitted. Everything is valve circuitry.”

HOWEVER, are you seeing the distinctive big-bottle shape of 6550s in the pics of the prototype? I’m not. To me they look more like 6L6s or 5881s. But I’m not an expert.

Here's the amp. What tubes do you see? (Click to see it bigger – stoof photo.)

Here's the amp. What tubes do you see? (Click to see it bigger – stoof photo.)

Here are the 6550s in Slash's favorite JCM800 (click to see bigger).

Here are the 6550s in Slash's favorite JCM800 (click to see bigger).

And then there’s the fact that the amp the AFD100 (as in Appetite for Destruction, the first GnR album) was based on likely was an EL34-powered amp. As noted on

“The amp was a 100W Marshall Super Tremolo (Model 1959T), built sometime between 1965 and 1973 [and powered by EL34s – Marshall didn’t start replacing EL34s with 6550s (for hardiness reasons) I believe until the ’80s]. The amp was a hand-wired, pre-master volume model, although it is unclear whether the head was of the plexi [faceplate of plexiglass] 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).”

This legendary S.I.R. #39 head was of course modified by a tech who worked for S.I.R. (gear rental outfit in L.A.) in the ’80s – the tech was Tim Caswell, who still mods Marshalls along those lines. From the slashsworld site: “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 S.I.R., he came up with the idea of using the 1959T’s tremolo circuit [powered by an extra preamp tube] for hot-rodding the amp.”

So there it is: An extra gain stage added to a Marshall, a common mod, maybe with a few other tweaks. So why the distinctively great sound? Maybe the tweaks, though Caswell had done similar mods on other S.I.R amps and remember that all Marshalls of vintage age were slightly different from one another. That amp just had “it.”

Will the new AFD100 have it? I’d bet yes. It’s a Slash amp, in the vid he seems genuinely happy with it. I’m not a huge Slash fan, but I look forward to hearing it.


> Marshall noted that the AFD100 amp will have “two inputs, Gain, Master, EQ, Presence and an output power control plus the #34 switch, all in the late 70’s JMP style box.”

> has a very cool story about how Slash really did NOT tour with the S.I.R. #39 amp, as he recollects, but actually with S.I.R. #36. Read it here.

> Here’s a vid of Slash playing the prototype (beware – he says the F word right at the beginning). Slash fans: How does it sound?

Category: Marshall, Slash

Comments (1)

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  1. @Bob453 says:

    You can follow the whole development story at Interesting reading for fans. Wish I had cash lying around when this hits the market!

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