Is the aluminium chassis that important in an Express?

[Silvio55]

I´m beggining my Express proyect, I´ve been reading about trainwreck amps for years, and I know what Ken's opinion about chassis material was, but what do you think based on your experience? If I made the amp with a steel chassis would it be that different? Would it have a noticeable difference in response or tone or whatever? I ask because is easier for me to get steel for the chassis, they don't sell aluminium here in my town, I can get it if it´s so important, but have to order it.
Thanks!

[RJ Guitars]

The Magnetic Components kits come with a steel chassis and they seem to sound just fine. Ken Fischer really liked aluminum because it won't couple with the magnetic fields from the transformers but I'm not sure there is much history that points to sonic failure with steel chassis... Fender seemed to do real well with them. YMMV - rj

[Mark]

RJ I wonder if the aluminium chassis was readily available whereas a steel chassis may not have been available. Also bear in mind aluminium is a soft metal and much easier to work with than steel. If Ken was using green lee punches, then aluminium would have been ideal to work with.

I believe the latest and greatest chassis material is (or perhaps was) stainless steel it has the properties that are desirable in both aluminium and steel.

Would Ken have used it? Perhaps if he could have the chassis made cheaply enough and at the quantities he wanted.

[geetarpicker]

I once spoke with Ken on this exact subject. He said he did prefer the tone he got with the aluminum chassis, and also mentioned the original JTM45 as one of his favorite vintage amps that also used an aluminum chassis. That said, it was also easy to work with and affordable which I'm sure helped in his preference but that is just my opinion.

[KellyBass]

I've built two express style amps. One is very tame and predictable. It's a nice sounding amp. Some of the components I chose specifically for stability. I imagine this amp would be just as happy in a steel chassis as it is in an aluminum one.

The other one that I built is the total opposite. It's teeters on that razor edge of stability. But, man is it fun to play! it's a madman...and occasionally a pain in the butt. That amp just might have an issue with chassis material. Sometimes it seems like the whole chassis is "ringing".

[Silvio55]

Hey Glen! I'm big fan of yours, your videos made me know what a Trainwreck Express is, I remeber the first time I watched them a couple of years ago!
If I remember correctly, Ken said that he prefered aluminium chassis cause is better conductor and makes the amp responds faster, and also that it interacts less with the magntic fields from the trannies. He also said this is one of the reasons the early Marshalls sound the way the do, and you can´t replicate their sound with a steel chassis.
But the Express, being such a sensitive beast, made me wonder if the chassis material could make a sensible difference.
KellyBass, that amp you made (the wilder one), has a steel chassis?

[KellyBass]

Sorry bout that. When I posted last, I was kinda in a hurry...and not very clear.

Both of the expresses were built with practically identical aluminum chassis'. I don't remember the exact thickness. The madman amp was so much more sensitive to every thing (lead dress, component type, etc) that I did, I feel that a steel chassis would have definitely made a difference.

[Hogy]

For what It's worth, the very first Trainwreck amp was built on a Super Reverb (steel) chassis. Ken's "nuked" Fenders were all stock steel chassis as well. His answer would have been that you work with whatever you have and just tweak the circuit for it.

I prefer aluminum, and Ken did, too, but that's not the magic ingredient.


Hogy

[KellyBass]

I hadn't heard that! That's very good to know.

Yep,...ya tweak to what ya got.

[Mark]

Hogy, I think you settled the chassis and raised another point of interest regarding Ken's modded Fender amps.

Of all Ken's amps, the nuked Fenders are the one's which little is known about and there doesn't seem to be a lot of interest.

I think I saw one KF modded Marshall and that too didn't get a lot of interest from the Marshall crowd. I suspect the Marshall crowd are well serviced by Ceriatone, Friedman, Caswell and Jose mods but to name a few.

The Dumble stuff seems to account for interest in Fender amps. Fender has come out with Blues Deville, Hodrod Deville which may have reduced interest in modded Fender amps. Hard to say of course when I don't know anything about Ken's versions of these amps.

https://www.youtube.com/watch?v=joqSm37TQaY

http://ampgarage.com/forum/viewtopic.php?t=21753